diff --git a/IMX6ULL/doc_pic/12_USB/06_libusb的使用.md b/IMX6ULL/doc_pic/12_USB/06_libusb的使用.md
index 47af285..9397458 100644
--- a/IMX6ULL/doc_pic/12_USB/06_libusb的使用.md
+++ b/IMX6ULL/doc_pic/12_USB/06_libusb的使用.md
@@ -39,7 +39,7 @@ libusb封装了更好用的函数，这些函数的使用可以分为5个步骤
 * 传输
 * 关闭设备
 
-![image-20220919162539849](pic/54_libusb_flow.png)
+![image-20220920101859185](pic/54_libusb_flow.png)
 
 
 
@@ -75,11 +75,11 @@ if (r == 0 && actual_length == sizeof(data)) {
 
 
 
-### 2.2 初始化
+### 2.2 初始化/反初始化
 
 ```c
-/** 
- * 初始化libusb，这个函数必须先与其他libusb的函数执行
+/** \ingroup libusb_lib
+ * 初始化libusb，这个函数必须先于其他libusb的函数执行
  *
  * 如果传入NULL，那么函数内部会穿件一个默认的context
  * 如果已经创建过默认的context，这个context会被重新使用(不会重新初始化它)
@@ -97,6 +97,23 @@ int API_EXPORTED libusb_init(libusb_context **ctx);
 
 
 
+程序退出前，调用如下函数：
+
+```c
+/** \ingroup libusb_lib
+ * 发初始化libusb
+ * 在关闭usb设备(libusb_close)后、退出程序前调用此函数
+ *
+ * 参数:
+ * ctx : context, 传入NULL表示default context
+ */
+void API_EXPORTED libusb_exit(libusb_context *ctx);
+```
+
+
+
+
+
 ### 2.3 获取设备
 
 可以使用`libusb_get_device_list`取出所有设备，函数接口如下：
@@ -210,10 +227,58 @@ libusb_device_handle * LIBUSB_CALL libusb_open_device_with_vid_pid(
 ```
 
 
+### 2.6 描述符相关函数
 
-### 2.6 detach/attach驱动
+#### 2.6.1 获得设备描述符
 
-#### 2.6.1 两种方法
+```c
+/** \ingroup libusb_desc
+ * 获得设备描述符
+ *
+ * 参数:
+ * dev - 哪个设备
+ * desc - 输出参数, 用来保存设备描述符
+ *
+ * 返回值:
+ * 0 - 成功, 或其他LIBUSB_ERROR错误码
+ */
+int API_EXPORTED libusb_get_device_descriptor(libusb_device *dev,
+	struct libusb_device_descriptor *desc);
+```
+
+#### 2.6.2 获得/释放配置描述符
+
+```c
+/** \ingroup libusb_desc
+ * 获得指定的配置描述符
+ *
+ * 参数:
+ * dev - 哪个设备
+ * config_index - 哪个配置
+ * config - 输出参数, 用来保存配置描述符, 使用完毕要调用libusb_free_config_descriptor()释放掉
+ * 
+ * 返回值:
+ * 0 - 成功
+ * LIBUSB_ERROR_NOT_FOUND - 没有这个配置
+ * 其他LIBUSB_ERROR错误码
+ */
+int API_EXPORTED libusb_get_config_descriptor(libusb_device *dev,
+	uint8_t config_index, struct libusb_config_descriptor **config);
+
+/** \ingroup libusb_desc
+ * Free a configuration descriptor obtained from
+ * 前面使用libusb_get_active_config_descriptor()或libusb_get_config_descriptor()获得配置描述符，
+ * 用完后调用libusb_free_config_descriptor()释放掉
+ */
+void API_EXPORTED libusb_free_config_descriptor(
+	struct libusb_config_descriptor *config);
+```
+
+
+
+### 2.7 detach/attach驱动
+
+#### 2.7.1 两种方法
 
 使用libusb访问USB设备时，需要先移除(detach)设备原来的驱动程序，然后认领接口(claim interface)。有两种办法：
 
@@ -224,7 +289,7 @@ libusb_device_handle * LIBUSB_CALL libusb_open_device_with_vid_pid(
   // 使用libusb_claim_interface时会detach原来的驱动
   libusb_set_auto_detach_kernel_driver(hdev, 1);  
   
-  // 给interface安装驱动程序，标记这个interface已经被使用认领了
+  // 标记这个interface已经被使用认领了
   libusb_claim_interface(hdev, interface_number);
   ```
 
@@ -234,13 +299,13 @@ libusb_device_handle * LIBUSB_CALL libusb_open_device_with_vid_pid(
   // detach原来的驱动
   libusb_detach_kernel_driver(hdev, interface_number);
   
-  // 给interface安装驱动程序，标记这个interface已经被使用认领了
+  // 标记这个interface已经被使用认领了
   libusb_claim_interface(hdev, interface_number);
   ```
 
   
 
-#### 2.6.2 函数原型
+#### 2.7.2 函数原型
 
 函数`libusb_detach_kernel_driver`原型如下：
 
@@ -331,54 +396,6 @@ int API_EXPORTED libusb_release_interface(libusb_device_handle *dev_handle,
 
 
 
-### 2.7 描述符相关函数
-
-#### 2.7.1 获得设备描述符
-
-```c
-/** \ingroup libusb_desc
- * 获得设备描述符
- *
- * 参数:
- * dev - 哪个设备
- * desc - 输出参数, 用来保存设备描述符
- *
- * 返回值:
- * 0 - 成功, 或其他LIBUSB_ERROR错误码
- */
-int API_EXPORTED libusb_get_device_descriptor(libusb_device *dev,
-	struct libusb_device_descriptor *desc);
-```
-
-#### 2.7.2 获得/释放配置描述符
-
-```c
-/** \ingroup libusb_desc
- * 获得指定的配置描述符
- *
- * 参数:
- * dev - 哪个设备
- * config_index - 哪个配置
- * config - 输出参数, 用来保存配置描述符, 使用完毕要调用libusb_free_config_descriptor()释放掉
- * 
- * 返回值:
- * 0 - 成功
- * LIBUSB_ERROR_NOT_FOUND - 没有这个配置
- * 其他LIBUSB_ERROR错误码
- */
-int API_EXPORTED libusb_get_config_descriptor(libusb_device *dev,
-	uint8_t config_index, struct libusb_config_descriptor **config);
-
-/** \ingroup libusb_desc
- * Free a configuration descriptor obtained from
- * 前面使用libusb_get_active_config_descriptor()或libusb_get_config_descriptor()获得配置描述符，
- * 用完后调用libusb_free_config_descriptor()释放掉
- */
-void API_EXPORTED libusb_free_config_descriptor(
-	struct libusb_config_descriptor *config);
-```
-
-
 
 ### 2.8 同步传输函数
 
@@ -504,11 +521,11 @@ int API_EXPORTED libusb_interrupt_transfer(libusb_device_handle *dev_handle,
 
 使用libusb的异步函数时，有如下步骤：
 
-* 分配：分配一个`libus_transfer`结构体
-* 填充：填充`libus_transfer`结构体，比如想访问哪个endpoint、数据buffer、长度等等
-* 提交：提交`libus_transfer`结构体启动传输
-* 处理事件：检查传输的结果，调用`libus_transfer`结构体的回调函数
-* 释放：释放资源，比如释放`libus_transfer`结构体
+* 分配：分配一个`libusb_transfer`结构体
+* 填充：填充`libusb_transfer`结构体，比如想访问哪个endpoint、数据buffer、长度等等
+* 提交：提交`libusb_transfer`结构体启动传输
+* 处理事件：检查传输的结果，调用`libusb_transfer`结构体的回调函数
+* 释放：释放资源，比如释放`libusb_transfer`结构体
 
 
 
@@ -832,17 +849,11 @@ dnw是s3c2440时代的工具，使用它可以从PC给开发板传输文件。
 
 
 
-### 3.2 adb
-
-
-
-
-
-### 3.3 openocd
+### 3.2 openocd
 
 openocd是一个开源的USB JTAG调试软件，它也是使用libusb，涉及USB的操作代码如下。
 
-#### 3.3.1 找到设备
+#### 3.2.1 找到设备
 
 ```c
 static int cmsis_dap_usb_open(struct cmsis_dap *dap, uint16_t vids[], uint16_t pids[], const char *serial)
@@ -1184,7 +1195,7 @@ static int cmsis_dap_usb_open(struct cmsis_dap *dap, uint16_t vids[], uint16_t p
 
 
 
-#### 3.3.2 读写数据
+#### 3.2.2 读写数据
 
 ```c
 static int cmsis_dap_usb_read(struct cmsis_dap *dap, int timeout_ms)
diff --git a/IMX6ULL/doc_pic/12_USB/06_libusb的使用流程.tif b/IMX6ULL/doc_pic/12_USB/06_libusb的使用流程.tif
new file mode 100644
index 0000000..6b99e0b
Binary files /dev/null and b/IMX6ULL/doc_pic/12_USB/06_libusb的使用流程.tif differ
diff --git a/IMX6ULL/doc_pic/12_USB/07_使用libusb读取鼠标数据.md b/IMX6ULL/doc_pic/12_USB/07_使用libusb读取鼠标数据.md
new file mode 100644
index 0000000..49c38d7
--- /dev/null
+++ b/IMX6ULL/doc_pic/12_USB/07_使用libusb读取鼠标数据.md
@@ -0,0 +1,16 @@
+# 使用libusb读取鼠标数据 #
+
+参考资料：
+
+* libusb API接口：https://libusb.sourceforge.io/api-1.0/
+
+* libusb 示例：https://github.com/libusb/libusb/tree/master/examples
+
+* HID规范：https://www.usb.org/sites/default/files/hid1_11.pdf (文件已经下载放在GIT仓库)
+
+* 文档：USB Human Interface Devices,  https://wiki.osdev.org/USB_Human_Interface_Devices
+
+  
+
+## 1. HID协议
+
diff --git a/IMX6ULL/doc_pic/12_USB/pic/54_libusb_flow.png b/IMX6ULL/doc_pic/12_USB/pic/54_libusb_flow.png
index 988fc28..fb5ee42 100644
Binary files a/IMX6ULL/doc_pic/12_USB/pic/54_libusb_flow.png and b/IMX6ULL/doc_pic/12_USB/pic/54_libusb_flow.png differ
diff --git a/IMX6ULL/doc_pic/12_USB/usb_20_20211008/hid1_11.pdf b/IMX6ULL/doc_pic/12_USB/usb_20_20211008/hid1_11.pdf
new file mode 100644
index 0000000..88c3edc
Binary files /dev/null and b/IMX6ULL/doc_pic/12_USB/usb_20_20211008/hid1_11.pdf differ
diff --git a/IMX6ULL/source/12_USB/01_libusb示例程序/dnw_for_libusb1.0/Makefile b/IMX6ULL/source/12_USB/01_libusb示例程序/dnw_for_libusb1.0/Makefile
new file mode 100644
index 0000000..1f8c030
--- /dev/null
+++ b/IMX6ULL/source/12_USB/01_libusb示例程序/dnw_for_libusb1.0/Makefile
@@ -0,0 +1,10 @@
+CROSS=
+
+all: exe
+
+exe:dnw.c
+	$(CROSS)gcc -Wall -o dnw dnw.c libusb-1.0.a -lpthread -static
+cpy:
+	cp dnw /usr/local/bin -f
+clean:
+	@rm -f dnw *.o *~
diff --git a/IMX6ULL/source/12_USB/01_libusb示例程序/dnw_for_libusb1.0/dnw b/IMX6ULL/source/12_USB/01_libusb示例程序/dnw_for_libusb1.0/dnw
new file mode 100644
index 0000000..c83c90e
Binary files /dev/null and b/IMX6ULL/source/12_USB/01_libusb示例程序/dnw_for_libusb1.0/dnw differ
diff --git a/IMX6ULL/source/12_USB/01_libusb示例程序/dnw_for_libusb1.0/dnw.c b/IMX6ULL/source/12_USB/01_libusb示例程序/dnw_for_libusb1.0/dnw.c
new file mode 100644
index 0000000..d6eb08d
--- /dev/null
+++ b/IMX6ULL/source/12_USB/01_libusb示例程序/dnw_for_libusb1.0/dnw.c
@@ -0,0 +1,250 @@
+/*
+ *      To send file through USB for s3c2410/s3c2440's bootloader, vivi/u-boot
+ *
+ *      Copyright (C) 2006 thisway.diy@163.com
+ */
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <sys/ioctl.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <sys/select.h>
+#include <sys/time.h>
+#include <errno.h>
+#include <string.h>
+#include "libusb.h"
+
+#define DMA_BUF_SIZE	0x8000
+#define	DNW_DEVICE_IDVENDOR		0x5345
+#define	DNW_DEVICE_IDPRODUCT	0x1234
+
+
+const char version[] = "DNW on linux for www.100ask.net, v2.0 with libusb1.0";
+const char author[]  = "thisway.diy@163.com";
+	
+void printusage(char *name)
+{
+	printf("Usage: %s <file> [address], send file to USB device\n", name);
+	printf("       %s -v, show the version\n", name);
+	printf("examples:\n");
+	printf("1. %s vmlinus\n", name);
+	printf("2. %s yaffs_image 0x30000000\n", name);
+}
+
+
+int main(int argc, char *argv[])
+{
+	int i;
+
+	int first = 1;
+	
+	int fd_file;
+
+	struct stat stat_buf;
+
+	libusb_device_handle *hdev = NULL;
+
+
+	unsigned int ret;
+	int status;
+	
+	unsigned int num_remain = 2;
+	unsigned int num_read = 0;
+	unsigned int num_write = 0;
+	unsigned int num_read_total = 0;
+	unsigned int num_write_total = 0;
+	unsigned int num_has_write_total = 0;
+
+	int transferred;
+
+	unsigned int download_addr = 0x30000000;
+	unsigned short check_sum = 0;
+
+	unsigned char *buf = 0;
+
+	struct timeval time_start;
+	struct timeval time_end;
+	unsigned int time_us;
+
+	if (argc == 2 && strcmp(argv[1], "-v") == 0)
+	{
+		printf("Version: %s\n", version);
+		printf("Complie Time: %s, %s\n", __DATE__, __TIME__);
+		printf("Author: %s\n", author);
+		return 0;
+	}
+
+	if (argc < 2 || argc > 3)
+	{
+		printusage(argv[0]);
+		return -1;
+	}
+
+	/* open the device using libusb */
+	status = libusb_init(NULL);
+	if (status < 0) {
+		printf("libusb_init() failed: %s\n", libusb_error_name(status));
+		return -1;
+	}
+
+	hdev = libusb_open_device_with_vid_pid(NULL, (uint16_t)DNW_DEVICE_IDVENDOR, (uint16_t)DNW_DEVICE_IDPRODUCT);
+	if (hdev == NULL) {
+		printf("libusb_open() failed\n");
+		goto err3;
+	}
+
+	/* We need to claim the first interface */
+	libusb_set_auto_detach_kernel_driver(hdev, 1);
+	status = libusb_claim_interface(hdev, 0);
+	if (status != LIBUSB_SUCCESS) {
+		libusb_close(hdev);
+		printf("libusb_claim_interface failed: %s\n", libusb_error_name(status));
+		goto err2;
+	}
+	
+	
+	fd_file = open(argv[1], O_RDONLY);
+	if (fd_file < 0) 
+	{
+		printf("open %s failed!\n", argv[2]);
+		goto err1;
+	}
+
+	if (fstat(fd_file, &stat_buf))
+	{
+		printf("Can't get status of file %s\n", argv[2]);
+		goto err;
+	}
+
+	printf("Size of file: %d byte(s)\n", (unsigned int)stat_buf.st_size);
+
+	/* FORMAT: <ADDR(DATA):4>+<SIZE(n+10):4>+<DATA:n>+<CS:2> */
+	num_write_total = stat_buf.st_size + 10;
+
+	if (argc == 3)
+	{
+		download_addr = (unsigned int)strtoul((const char *)argv[2], NULL, 0);
+	}
+
+	printf("Address of bootloader to receive data: 0x%x\n", download_addr);
+
+	buf = malloc(DMA_BUF_SIZE);
+	if (!buf)
+	{
+		printf("Can't alloc memory\n");
+		goto err;
+	}
+
+	memcpy(buf, &download_addr, 4);
+	memcpy(buf + 4, &num_write_total, 4);
+
+	gettimeofday(&time_start, 0);
+
+	while (num_read_total < stat_buf.st_size)
+	{
+		num_read = read(fd_file, buf + (first ? 8 : 0), DMA_BUF_SIZE - (first ? 8 : 0));
+
+		if (num_read)
+		{
+			num_read_total += num_read;
+			for (i = 0; i < num_read; i++)
+			{
+				check_sum += (unsigned short)buf[i];
+			}
+		}
+		else
+		{
+			printf("Can't read file, num_read = %d, num_read_total = %d\n", num_read, num_read_total);
+			goto err;
+		}
+
+		num_write = num_read + (first ? 8 : 0);
+		
+		if (num_read_total == stat_buf.st_size)
+		{
+			for (i = 0; i < 2; i++)
+			{
+				if (num_write < DMA_BUF_SIZE)
+				{
+					buf[num_write++] = (unsigned char)(check_sum >> (i*8));
+					num_remain--;
+				}
+			}
+		}
+
+/*
+int libusb_bulk_transfer 	( 	struct libusb_device_handle *  	dev_handle,
+		unsigned char  	endpoint,
+		unsigned char *  	data,
+		int  	length,
+		int *  	transferred,
+		unsigned int  	timeout 
+	) 	
+
+*/
+		ret =  libusb_bulk_transfer(hdev, 0x03, buf, num_write, &transferred, 3000);
+
+		if ((ret != 0) || (transferred != num_write))
+		{
+			printf("Error, can't send to the board: num_write = %d, transferred = %d, ret = %d\n", num_write, transferred, ret);
+			goto err;			
+		}
+		
+		num_has_write_total += num_write;
+
+		gettimeofday(&time_end, 0);
+
+		time_us = (time_end.tv_sec - time_start.tv_sec) * 1000000 +(time_end.tv_usec - time_start.tv_usec);
+
+		printf("\rTx: %d/%d, Percentage: %.1f%%, Speed: %.1fKB/s, Time: %.1fS", num_has_write_total, num_write_total, ((float)num_has_write_total)/((float)num_write_total)*100., ((float)num_has_write_total/1024)/((float)time_us/1000000), time_us/1000000.);
+
+		if (first)
+		{
+			first = 0;
+		}
+		
+	}		
+
+	if (num_remain == 2)
+	{
+		buf[0] = (unsigned char)check_sum;
+		buf[1] = (unsigned char)(check_sum >> 8);
+	}
+	else if (num_remain == 1)
+	{
+		buf[0] = (unsigned char)(check_sum >> 8);
+	}
+
+	if (num_remain)
+	{
+		num_write = num_remain;
+		ret =  libusb_bulk_transfer(hdev, 0x03, buf, num_write, &transferred, 3000);
+
+		if ((ret != 0) || (transferred != num_write))
+		{
+			printf("Error, can't send to the board: num_write = %d, ret = %d\n", num_write, ret);
+			goto err;
+		}
+		
+		num_has_write_total += num_write;
+	}
+
+	gettimeofday(&time_end, 0);
+
+	time_us = (time_end.tv_sec - time_start.tv_sec) * 1000000 +(time_end.tv_usec - time_start.tv_usec);
+
+	printf("\rTx: %d/%d, Percentage: %.1f%%, Speed: %.1fKB/s, Time: %.1fS\n", num_has_write_total, num_write_total, ((float)num_has_write_total)/((float)num_write_total)*100., ((float)num_has_write_total/1024)/((float)time_us/1000000), time_us/1000000.);
+
+err:
+	close(fd_file);
+err1:
+	libusb_release_interface(hdev, 0);
+err2:
+	libusb_close(hdev);
+err3:
+	libusb_exit(NULL);
+	return 0;
+}
+
diff --git a/IMX6ULL/source/12_USB/01_libusb示例程序/dnw_for_libusb1.0/dnw使用说明.txt b/IMX6ULL/source/12_USB/01_libusb示例程序/dnw_for_libusb1.0/dnw使用说明.txt
new file mode 100644
index 0000000..af448d4
--- /dev/null
+++ b/IMX6ULL/source/12_USB/01_libusb示例程序/dnw_for_libusb1.0/dnw使用说明.txt
@@ -0,0 +1,87 @@
+linux�汾��
+
+1. dnw��һ��USB���ߣ�ͨ��USB�����ļ�������USB���ع��ܵ�bootloader��
+�������ʹ�÷���Ϊ(Ҫ���ͳɹ�������������о���USB���ع��ܵ�bootloader)��
+sudo dnw <file> [address]
+��˼Ϊ�������ļ�<file>ͨ��USB�ڷ��͵������ϣ�
+        [address]������ʾdnw����߿����壬����ļ��뱣���ڵ�SDRAM��ַ��
+        ���Բ�д[address]��Ĭ��Ϊ0x30000000��
+        bootloader���Լ��������ļ�������SDRAM����Ƿ�ʹ��[address]ȡ����bootloader��
+
+
+2. �������u-boot����ʱ���ڴ��ڹ���������ո����u-boot��������²˵���
+##### 100ask Bootloader for OpenJTAG #####
+[n] Download u-boot to Nand Flash
+[o] Download u-boot to Nor Flash               // �����Nand Flash�����Ļ�������˵���û��
+[k] Download Linux kernel uImage
+[j] Download root_jffs2 image
+[y] Download root_yaffs image
+[d] Download to SDRAM & Run
+[z] Download zImage into RAM
+[g] Boot linux from RAM
+[f] Format the Nand Flash
+[s] Set the boot parameters
+[b] Boot the system
+[r] Reboot u-boot
+[q] Quit from menu
+
+����ǰ���Сд��ĸ�����������أ�Ȼ��ʹ��dnw���߷����ļ���
+���磺
+a. ��u-boot��������k��u-boot���ȴ����������ں�ӳ����ʱ�����������С�sudo dnw uImage�����ɷ����ں˸�u-boot��
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+   u-boot���յ��ļ�����ַ0x31000000�����uart.bin�����ݴ����0x31000000����Ȼ����תȥִ����
+   
+   
+3. Ҳ���Բ�ʹ��u-boot�IJ˵�������q�˳��˵���Ȼ��ʹ��u-boot��������в�����
+   usb�����ʹ�÷����������롰help usbslave���������
+usbslave [wait] [loadAddress]
+"wait" is 0 or 1, 0 means for return immediately, not waits for the finish of transferring
+
+   ���ʾ������usbslave��������USB���أ�[wait]��[loadAddress]��������ַ�ǿ�ѡ�ģ�
+           ���[wait]��ֵ��0��u-boot�����ȴ�USB������ɣ���ʱ���������������һ��u-boot���
+           ���[wait]��ֵ��1��u-boto���ȴ�USB������ɣ����֮�������������һ��u-boot���
+           ���ָ��[loadAddress]����ô���ص��ļ���������SDRAM��ַ[loadAddress]���������ŵ�ַ��������dnw����ָ��
+   
+
+
+windows�汾��
+1. dnw.exe��һ��USB���ߣ�ͨ��USB�����ļ�������USB���ع��ܵ�bootloader��
+���߱�����ʹ�÷���Ϊ(Ҫ���ͳɹ�������������о���USB���ع��ܵ�bootloader)��
+�� �ڡ�Configuration -> Options�� �˵����������ص�ַ��Download Address��
+�� ͨ����USB Port -> Transmit���˵���ѡ�񡢷����ļ�
+
+2. �������u-boot����ʱ���ڴ��ڹ���������ո����u-boot��������²˵���
+##### 100ask Bootloader for OpenJTAG #####
+[n] Download u-boot to Nand Flash
+[o] Download u-boot to Nor Flash               // �����Nand Flash�����Ļ�������˵���û��
+[k] Download Linux kernel uImage
+[j] Download root_jffs2 image
+[y] Download root_yaffs image
+[d] Download to SDRAM & Run
+[z] Download zImage into RAM
+[g] Boot linux from RAM
+[f] Format the Nand Flash
+[s] Set the boot parameters
+[b] Boot the system
+[r] Reboot u-boot
+[q] Quit from menu
+
+����ǰ���Сд��ĸ�����������أ�Ȼ��ʹ��dnw���߷����ļ���
+���磺
+a. ��u-boot��������k��u-boot���ȴ����������ں�ӳ����ʱ��������ʹ��dnw.exeѡ��uImage���ɷ����ں˸�u-boot��
+b. ��u-boot��������y��u-boot���ȴ���������yaffs�ļ�ϵͳӳ����ʱ��������ʹ��dnw.exeѡ��yaffs�ļ�ϵͳӳ�󼴿ɷ����ں˸�u-boot��
+c. ��u-boot��������d��u-boot���ȴ����������ļ�����ʱ������������dnw.exe�����������ص�ַ��Ϊ0x31000000��Ȼ�����ļ���
+   u-boot���յ��ļ�����ַ0x31000000����Ѵ��ļ����ݴ����0x31000000����Ȼ����תȥִ����
+   
+   
+3. Ҳ���Բ�ʹ��u-boot�IJ˵�������q�˳��˵���Ȼ��ʹ��u-boot��������в�����
+   usb�����ʹ�÷����������롰help usbslave���������
+usbslave [wait] [loadAddress]
+"wait" is 0 or 1, 0 means for return immediately, not waits for the finish of transferring
+
+   ���ʾ������usbslave��������USB���أ�[wait]��[loadAddress]��������ַ�ǿ�ѡ�ģ�
+           ���[wait]��ֵ��0��u-boot�����ȴ�USB������ɣ���ʱ���������������һ��u-boot���
+           ���[wait]��ֵ��1��u-boto���ȴ�USB������ɣ����֮�������������һ��u-boot���
+           ���ָ��[loadAddress]����ô���ص��ļ���������SDRAM��ַ[loadAddress]���������ŵ�ַ��������dnw����ָ��
+   
diff --git a/IMX6ULL/source/12_USB/01_libusb示例程序/dnw_for_libusb1.0/libusb-1.0.21.tar.bz2 b/IMX6ULL/source/12_USB/01_libusb示例程序/dnw_for_libusb1.0/libusb-1.0.21.tar.bz2
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diff --git a/IMX6ULL/source/12_USB/01_libusb示例程序/dnw_for_libusb1.0/libusb-1.0.a b/IMX6ULL/source/12_USB/01_libusb示例程序/dnw_for_libusb1.0/libusb-1.0.a
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diff --git a/IMX6ULL/source/12_USB/01_libusb示例程序/dnw_for_libusb1.0/libusb.h b/IMX6ULL/source/12_USB/01_libusb示例程序/dnw_for_libusb1.0/libusb.h
new file mode 100644
index 0000000..f73e31c
--- /dev/null
+++ b/IMX6ULL/source/12_USB/01_libusb示例程序/dnw_for_libusb1.0/libusb.h
@@ -0,0 +1,2008 @@
+/*
+ * Public libusb header file
+ * Copyright © 2001 Johannes Erdfelt <johannes@erdfelt.com>
+ * Copyright © 2007-2008 Daniel Drake <dsd@gentoo.org>
+ * Copyright © 2012 Pete Batard <pete@akeo.ie>
+ * Copyright © 2012 Nathan Hjelm <hjelmn@cs.unm.edu>
+ * For more information, please visit: http://libusb.info
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#ifndef LIBUSB_H
+#define LIBUSB_H
+
+#ifdef _MSC_VER
+/* on MS environments, the inline keyword is available in C++ only */
+#if !defined(__cplusplus)
+#define inline __inline
+#endif
+/* ssize_t is also not available (copy/paste from MinGW) */
+#ifndef _SSIZE_T_DEFINED
+#define _SSIZE_T_DEFINED
+#undef ssize_t
+#ifdef _WIN64
+  typedef __int64 ssize_t;
+#else
+  typedef int ssize_t;
+#endif /* _WIN64 */
+#endif /* _SSIZE_T_DEFINED */
+#endif /* _MSC_VER */
+
+/* stdint.h is not available on older MSVC */
+#if defined(_MSC_VER) && (_MSC_VER < 1600) && (!defined(_STDINT)) && (!defined(_STDINT_H))
+typedef unsigned __int8   uint8_t;
+typedef unsigned __int16  uint16_t;
+typedef unsigned __int32  uint32_t;
+#else
+#include <stdint.h>
+#endif
+
+#if !defined(_WIN32_WCE)
+#include <sys/types.h>
+#endif
+
+#if defined(__linux) || defined(__APPLE__) || defined(__CYGWIN__) || defined(__HAIKU__)
+#include <sys/time.h>
+#endif
+
+#include <time.h>
+#include <limits.h>
+
+/* 'interface' might be defined as a macro on Windows, so we need to
+ * undefine it so as not to break the current libusb API, because
+ * libusb_config_descriptor has an 'interface' member
+ * As this can be problematic if you include windows.h after libusb.h
+ * in your sources, we force windows.h to be included first. */
+#if defined(_WIN32) || defined(__CYGWIN__) || defined(_WIN32_WCE)
+#include <windows.h>
+#if defined(interface)
+#undef interface
+#endif
+#if !defined(__CYGWIN__)
+#include <winsock.h>
+#endif
+#endif
+
+#if __GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 5)
+#define LIBUSB_DEPRECATED_FOR(f) \
+  __attribute__((deprecated("Use " #f " instead")))
+#else
+#define LIBUSB_DEPRECATED_FOR(f)
+#endif /* __GNUC__ */
+
+/** \def LIBUSB_CALL
+ * \ingroup libusb_misc
+ * libusb's Windows calling convention.
+ *
+ * Under Windows, the selection of available compilers and configurations
+ * means that, unlike other platforms, there is not <em>one true calling
+ * convention</em> (calling convention: the manner in which parameters are
+ * passed to functions in the generated assembly code).
+ *
+ * Matching the Windows API itself, libusb uses the WINAPI convention (which
+ * translates to the <tt>stdcall</tt> convention) and guarantees that the
+ * library is compiled in this way. The public header file also includes
+ * appropriate annotations so that your own software will use the right
+ * convention, even if another convention is being used by default within
+ * your codebase.
+ *
+ * The one consideration that you must apply in your software is to mark
+ * all functions which you use as libusb callbacks with this LIBUSB_CALL
+ * annotation, so that they too get compiled for the correct calling
+ * convention.
+ *
+ * On non-Windows operating systems, this macro is defined as nothing. This
+ * means that you can apply it to your code without worrying about
+ * cross-platform compatibility.
+ */
+/* LIBUSB_CALL must be defined on both definition and declaration of libusb
+ * functions. You'd think that declaration would be enough, but cygwin will
+ * complain about conflicting types unless both are marked this way.
+ * The placement of this macro is important too; it must appear after the
+ * return type, before the function name. See internal documentation for
+ * API_EXPORTED.
+ */
+#if defined(_WIN32) || defined(__CYGWIN__) || defined(_WIN32_WCE)
+#define LIBUSB_CALL WINAPI
+#else
+#define LIBUSB_CALL
+#endif
+
+/** \def LIBUSB_API_VERSION
+ * \ingroup libusb_misc
+ * libusb's API version.
+ *
+ * Since version 1.0.13, to help with feature detection, libusb defines
+ * a LIBUSB_API_VERSION macro that gets increased every time there is a
+ * significant change to the API, such as the introduction of a new call,
+ * the definition of a new macro/enum member, or any other element that
+ * libusb applications may want to detect at compilation time.
+ *
+ * The macro is typically used in an application as follows:
+ * \code
+ * #if defined(LIBUSB_API_VERSION) && (LIBUSB_API_VERSION >= 0x01001234)
+ * // Use one of the newer features from the libusb API
+ * #endif
+ * \endcode
+ *
+ * Internally, LIBUSB_API_VERSION is defined as follows:
+ * (libusb major << 24) | (libusb minor << 16) | (16 bit incremental)
+ */
+#define LIBUSB_API_VERSION 0x01000105
+
+/* The following is kept for compatibility, but will be deprecated in the future */
+#define LIBUSBX_API_VERSION LIBUSB_API_VERSION
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * \ingroup libusb_misc
+ * Convert a 16-bit value from host-endian to little-endian format. On
+ * little endian systems, this function does nothing. On big endian systems,
+ * the bytes are swapped.
+ * \param x the host-endian value to convert
+ * \returns the value in little-endian byte order
+ */
+static inline uint16_t libusb_cpu_to_le16(const uint16_t x)
+{
+	union {
+		uint8_t  b8[2];
+		uint16_t b16;
+	} _tmp;
+	_tmp.b8[1] = (uint8_t) (x >> 8);
+	_tmp.b8[0] = (uint8_t) (x & 0xff);
+	return _tmp.b16;
+}
+
+/** \def libusb_le16_to_cpu
+ * \ingroup libusb_misc
+ * Convert a 16-bit value from little-endian to host-endian format. On
+ * little endian systems, this function does nothing. On big endian systems,
+ * the bytes are swapped.
+ * \param x the little-endian value to convert
+ * \returns the value in host-endian byte order
+ */
+#define libusb_le16_to_cpu libusb_cpu_to_le16
+
+/* standard USB stuff */
+
+/** \ingroup libusb_desc
+ * Device and/or Interface Class codes */
+enum libusb_class_code {
+	/** In the context of a \ref libusb_device_descriptor "device descriptor",
+	 * this bDeviceClass value indicates that each interface specifies its
+	 * own class information and all interfaces operate independently.
+	 */
+	LIBUSB_CLASS_PER_INTERFACE = 0,
+
+	/** Audio class */
+	LIBUSB_CLASS_AUDIO = 1,
+
+	/** Communications class */
+	LIBUSB_CLASS_COMM = 2,
+
+	/** Human Interface Device class */
+	LIBUSB_CLASS_HID = 3,
+
+	/** Physical */
+	LIBUSB_CLASS_PHYSICAL = 5,
+
+	/** Printer class */
+	LIBUSB_CLASS_PRINTER = 7,
+
+	/** Image class */
+	LIBUSB_CLASS_PTP = 6, /* legacy name from libusb-0.1 usb.h */
+	LIBUSB_CLASS_IMAGE = 6,
+
+	/** Mass storage class */
+	LIBUSB_CLASS_MASS_STORAGE = 8,
+
+	/** Hub class */
+	LIBUSB_CLASS_HUB = 9,
+
+	/** Data class */
+	LIBUSB_CLASS_DATA = 10,
+
+	/** Smart Card */
+	LIBUSB_CLASS_SMART_CARD = 0x0b,
+
+	/** Content Security */
+	LIBUSB_CLASS_CONTENT_SECURITY = 0x0d,
+
+	/** Video */
+	LIBUSB_CLASS_VIDEO = 0x0e,
+
+	/** Personal Healthcare */
+	LIBUSB_CLASS_PERSONAL_HEALTHCARE = 0x0f,
+
+	/** Diagnostic Device */
+	LIBUSB_CLASS_DIAGNOSTIC_DEVICE = 0xdc,
+
+	/** Wireless class */
+	LIBUSB_CLASS_WIRELESS = 0xe0,
+
+	/** Application class */
+	LIBUSB_CLASS_APPLICATION = 0xfe,
+
+	/** Class is vendor-specific */
+	LIBUSB_CLASS_VENDOR_SPEC = 0xff
+};
+
+/** \ingroup libusb_desc
+ * Descriptor types as defined by the USB specification. */
+enum libusb_descriptor_type {
+	/** Device descriptor. See libusb_device_descriptor. */
+	LIBUSB_DT_DEVICE = 0x01,
+
+	/** Configuration descriptor. See libusb_config_descriptor. */
+	LIBUSB_DT_CONFIG = 0x02,
+
+	/** String descriptor */
+	LIBUSB_DT_STRING = 0x03,
+
+	/** Interface descriptor. See libusb_interface_descriptor. */
+	LIBUSB_DT_INTERFACE = 0x04,
+
+	/** Endpoint descriptor. See libusb_endpoint_descriptor. */
+	LIBUSB_DT_ENDPOINT = 0x05,
+
+	/** BOS descriptor */
+	LIBUSB_DT_BOS = 0x0f,
+
+	/** Device Capability descriptor */
+	LIBUSB_DT_DEVICE_CAPABILITY = 0x10,
+
+	/** HID descriptor */
+	LIBUSB_DT_HID = 0x21,
+
+	/** HID report descriptor */
+	LIBUSB_DT_REPORT = 0x22,
+
+	/** Physical descriptor */
+	LIBUSB_DT_PHYSICAL = 0x23,
+
+	/** Hub descriptor */
+	LIBUSB_DT_HUB = 0x29,
+
+	/** SuperSpeed Hub descriptor */
+	LIBUSB_DT_SUPERSPEED_HUB = 0x2a,
+
+	/** SuperSpeed Endpoint Companion descriptor */
+	LIBUSB_DT_SS_ENDPOINT_COMPANION = 0x30
+};
+
+/* Descriptor sizes per descriptor type */
+#define LIBUSB_DT_DEVICE_SIZE			18
+#define LIBUSB_DT_CONFIG_SIZE			9
+#define LIBUSB_DT_INTERFACE_SIZE		9
+#define LIBUSB_DT_ENDPOINT_SIZE			7
+#define LIBUSB_DT_ENDPOINT_AUDIO_SIZE		9	/* Audio extension */
+#define LIBUSB_DT_HUB_NONVAR_SIZE		7
+#define LIBUSB_DT_SS_ENDPOINT_COMPANION_SIZE	6
+#define LIBUSB_DT_BOS_SIZE			5
+#define LIBUSB_DT_DEVICE_CAPABILITY_SIZE	3
+
+/* BOS descriptor sizes */
+#define LIBUSB_BT_USB_2_0_EXTENSION_SIZE	7
+#define LIBUSB_BT_SS_USB_DEVICE_CAPABILITY_SIZE	10
+#define LIBUSB_BT_CONTAINER_ID_SIZE		20
+
+/* We unwrap the BOS => define its max size */
+#define LIBUSB_DT_BOS_MAX_SIZE		((LIBUSB_DT_BOS_SIZE)     +\
+					(LIBUSB_BT_USB_2_0_EXTENSION_SIZE)       +\
+					(LIBUSB_BT_SS_USB_DEVICE_CAPABILITY_SIZE) +\
+					(LIBUSB_BT_CONTAINER_ID_SIZE))
+
+#define LIBUSB_ENDPOINT_ADDRESS_MASK	0x0f    /* in bEndpointAddress */
+#define LIBUSB_ENDPOINT_DIR_MASK		0x80
+
+/** \ingroup libusb_desc
+ * Endpoint direction. Values for bit 7 of the
+ * \ref libusb_endpoint_descriptor::bEndpointAddress "endpoint address" scheme.
+ */
+enum libusb_endpoint_direction {
+	/** In: device-to-host */
+	LIBUSB_ENDPOINT_IN = 0x80,
+
+	/** Out: host-to-device */
+	LIBUSB_ENDPOINT_OUT = 0x00
+};
+
+#define LIBUSB_TRANSFER_TYPE_MASK			0x03    /* in bmAttributes */
+
+/** \ingroup libusb_desc
+ * Endpoint transfer type. Values for bits 0:1 of the
+ * \ref libusb_endpoint_descriptor::bmAttributes "endpoint attributes" field.
+ */
+enum libusb_transfer_type {
+	/** Control endpoint */
+	LIBUSB_TRANSFER_TYPE_CONTROL = 0,
+
+	/** Isochronous endpoint */
+	LIBUSB_TRANSFER_TYPE_ISOCHRONOUS = 1,
+
+	/** Bulk endpoint */
+	LIBUSB_TRANSFER_TYPE_BULK = 2,
+
+	/** Interrupt endpoint */
+	LIBUSB_TRANSFER_TYPE_INTERRUPT = 3,
+
+	/** Stream endpoint */
+	LIBUSB_TRANSFER_TYPE_BULK_STREAM = 4,
+};
+
+/** \ingroup libusb_misc
+ * Standard requests, as defined in table 9-5 of the USB 3.0 specifications */
+enum libusb_standard_request {
+	/** Request status of the specific recipient */
+	LIBUSB_REQUEST_GET_STATUS = 0x00,
+
+	/** Clear or disable a specific feature */
+	LIBUSB_REQUEST_CLEAR_FEATURE = 0x01,
+
+	/* 0x02 is reserved */
+
+	/** Set or enable a specific feature */
+	LIBUSB_REQUEST_SET_FEATURE = 0x03,
+
+	/* 0x04 is reserved */
+
+	/** Set device address for all future accesses */
+	LIBUSB_REQUEST_SET_ADDRESS = 0x05,
+
+	/** Get the specified descriptor */
+	LIBUSB_REQUEST_GET_DESCRIPTOR = 0x06,
+
+	/** Used to update existing descriptors or add new descriptors */
+	LIBUSB_REQUEST_SET_DESCRIPTOR = 0x07,
+
+	/** Get the current device configuration value */
+	LIBUSB_REQUEST_GET_CONFIGURATION = 0x08,
+
+	/** Set device configuration */
+	LIBUSB_REQUEST_SET_CONFIGURATION = 0x09,
+
+	/** Return the selected alternate setting for the specified interface */
+	LIBUSB_REQUEST_GET_INTERFACE = 0x0A,
+
+	/** Select an alternate interface for the specified interface */
+	LIBUSB_REQUEST_SET_INTERFACE = 0x0B,
+
+	/** Set then report an endpoint's synchronization frame */
+	LIBUSB_REQUEST_SYNCH_FRAME = 0x0C,
+
+	/** Sets both the U1 and U2 Exit Latency */
+	LIBUSB_REQUEST_SET_SEL = 0x30,
+
+	/** Delay from the time a host transmits a packet to the time it is
+	  * received by the device. */
+	LIBUSB_SET_ISOCH_DELAY = 0x31,
+};
+
+/** \ingroup libusb_misc
+ * Request type bits of the
+ * \ref libusb_control_setup::bmRequestType "bmRequestType" field in control
+ * transfers. */
+enum libusb_request_type {
+	/** Standard */
+	LIBUSB_REQUEST_TYPE_STANDARD = (0x00 << 5),
+
+	/** Class */
+	LIBUSB_REQUEST_TYPE_CLASS = (0x01 << 5),
+
+	/** Vendor */
+	LIBUSB_REQUEST_TYPE_VENDOR = (0x02 << 5),
+
+	/** Reserved */
+	LIBUSB_REQUEST_TYPE_RESERVED = (0x03 << 5)
+};
+
+/** \ingroup libusb_misc
+ * Recipient bits of the
+ * \ref libusb_control_setup::bmRequestType "bmRequestType" field in control
+ * transfers. Values 4 through 31 are reserved. */
+enum libusb_request_recipient {
+	/** Device */
+	LIBUSB_RECIPIENT_DEVICE = 0x00,
+
+	/** Interface */
+	LIBUSB_RECIPIENT_INTERFACE = 0x01,
+
+	/** Endpoint */
+	LIBUSB_RECIPIENT_ENDPOINT = 0x02,
+
+	/** Other */
+	LIBUSB_RECIPIENT_OTHER = 0x03,
+};
+
+#define LIBUSB_ISO_SYNC_TYPE_MASK		0x0C
+
+/** \ingroup libusb_desc
+ * Synchronization type for isochronous endpoints. Values for bits 2:3 of the
+ * \ref libusb_endpoint_descriptor::bmAttributes "bmAttributes" field in
+ * libusb_endpoint_descriptor.
+ */
+enum libusb_iso_sync_type {
+	/** No synchronization */
+	LIBUSB_ISO_SYNC_TYPE_NONE = 0,
+
+	/** Asynchronous */
+	LIBUSB_ISO_SYNC_TYPE_ASYNC = 1,
+
+	/** Adaptive */
+	LIBUSB_ISO_SYNC_TYPE_ADAPTIVE = 2,
+
+	/** Synchronous */
+	LIBUSB_ISO_SYNC_TYPE_SYNC = 3
+};
+
+#define LIBUSB_ISO_USAGE_TYPE_MASK 0x30
+
+/** \ingroup libusb_desc
+ * Usage type for isochronous endpoints. Values for bits 4:5 of the
+ * \ref libusb_endpoint_descriptor::bmAttributes "bmAttributes" field in
+ * libusb_endpoint_descriptor.
+ */
+enum libusb_iso_usage_type {
+	/** Data endpoint */
+	LIBUSB_ISO_USAGE_TYPE_DATA = 0,
+
+	/** Feedback endpoint */
+	LIBUSB_ISO_USAGE_TYPE_FEEDBACK = 1,
+
+	/** Implicit feedback Data endpoint */
+	LIBUSB_ISO_USAGE_TYPE_IMPLICIT = 2,
+};
+
+/** \ingroup libusb_desc
+ * A structure representing the standard USB device descriptor. This
+ * descriptor is documented in section 9.6.1 of the USB 3.0 specification.
+ * All multiple-byte fields are represented in host-endian format.
+ */
+struct libusb_device_descriptor {
+	/** Size of this descriptor (in bytes) */
+	uint8_t  bLength;
+
+	/** Descriptor type. Will have value
+	 * \ref libusb_descriptor_type::LIBUSB_DT_DEVICE LIBUSB_DT_DEVICE in this
+	 * context. */
+	uint8_t  bDescriptorType;
+
+	/** USB specification release number in binary-coded decimal. A value of
+	 * 0x0200 indicates USB 2.0, 0x0110 indicates USB 1.1, etc. */
+	uint16_t bcdUSB;
+
+	/** USB-IF class code for the device. See \ref libusb_class_code. */
+	uint8_t  bDeviceClass;
+
+	/** USB-IF subclass code for the device, qualified by the bDeviceClass
+	 * value */
+	uint8_t  bDeviceSubClass;
+
+	/** USB-IF protocol code for the device, qualified by the bDeviceClass and
+	 * bDeviceSubClass values */
+	uint8_t  bDeviceProtocol;
+
+	/** Maximum packet size for endpoint 0 */
+	uint8_t  bMaxPacketSize0;
+
+	/** USB-IF vendor ID */
+	uint16_t idVendor;
+
+	/** USB-IF product ID */
+	uint16_t idProduct;
+
+	/** Device release number in binary-coded decimal */
+	uint16_t bcdDevice;
+
+	/** Index of string descriptor describing manufacturer */
+	uint8_t  iManufacturer;
+
+	/** Index of string descriptor describing product */
+	uint8_t  iProduct;
+
+	/** Index of string descriptor containing device serial number */
+	uint8_t  iSerialNumber;
+
+	/** Number of possible configurations */
+	uint8_t  bNumConfigurations;
+};
+
+/** \ingroup libusb_desc
+ * A structure representing the standard USB endpoint descriptor. This
+ * descriptor is documented in section 9.6.6 of the USB 3.0 specification.
+ * All multiple-byte fields are represented in host-endian format.
+ */
+struct libusb_endpoint_descriptor {
+	/** Size of this descriptor (in bytes) */
+	uint8_t  bLength;
+
+	/** Descriptor type. Will have value
+	 * \ref libusb_descriptor_type::LIBUSB_DT_ENDPOINT LIBUSB_DT_ENDPOINT in
+	 * this context. */
+	uint8_t  bDescriptorType;
+
+	/** The address of the endpoint described by this descriptor. Bits 0:3 are
+	 * the endpoint number. Bits 4:6 are reserved. Bit 7 indicates direction,
+	 * see \ref libusb_endpoint_direction.
+	 */
+	uint8_t  bEndpointAddress;
+
+	/** Attributes which apply to the endpoint when it is configured using
+	 * the bConfigurationValue. Bits 0:1 determine the transfer type and
+	 * correspond to \ref libusb_transfer_type. Bits 2:3 are only used for
+	 * isochronous endpoints and correspond to \ref libusb_iso_sync_type.
+	 * Bits 4:5 are also only used for isochronous endpoints and correspond to
+	 * \ref libusb_iso_usage_type. Bits 6:7 are reserved.
+	 */
+	uint8_t  bmAttributes;
+
+	/** Maximum packet size this endpoint is capable of sending/receiving. */
+	uint16_t wMaxPacketSize;
+
+	/** Interval for polling endpoint for data transfers. */
+	uint8_t  bInterval;
+
+	/** For audio devices only: the rate at which synchronization feedback
+	 * is provided. */
+	uint8_t  bRefresh;
+
+	/** For audio devices only: the address if the synch endpoint */
+	uint8_t  bSynchAddress;
+
+	/** Extra descriptors. If libusb encounters unknown endpoint descriptors,
+	 * it will store them here, should you wish to parse them. */
+	const unsigned char *extra;
+
+	/** Length of the extra descriptors, in bytes. */
+	int extra_length;
+};
+
+/** \ingroup libusb_desc
+ * A structure representing the standard USB interface descriptor. This
+ * descriptor is documented in section 9.6.5 of the USB 3.0 specification.
+ * All multiple-byte fields are represented in host-endian format.
+ */
+struct libusb_interface_descriptor {
+	/** Size of this descriptor (in bytes) */
+	uint8_t  bLength;
+
+	/** Descriptor type. Will have value
+	 * \ref libusb_descriptor_type::LIBUSB_DT_INTERFACE LIBUSB_DT_INTERFACE
+	 * in this context. */
+	uint8_t  bDescriptorType;
+
+	/** Number of this interface */
+	uint8_t  bInterfaceNumber;
+
+	/** Value used to select this alternate setting for this interface */
+	uint8_t  bAlternateSetting;
+
+	/** Number of endpoints used by this interface (excluding the control
+	 * endpoint). */
+	uint8_t  bNumEndpoints;
+
+	/** USB-IF class code for this interface. See \ref libusb_class_code. */
+	uint8_t  bInterfaceClass;
+
+	/** USB-IF subclass code for this interface, qualified by the
+	 * bInterfaceClass value */
+	uint8_t  bInterfaceSubClass;
+
+	/** USB-IF protocol code for this interface, qualified by the
+	 * bInterfaceClass and bInterfaceSubClass values */
+	uint8_t  bInterfaceProtocol;
+
+	/** Index of string descriptor describing this interface */
+	uint8_t  iInterface;
+
+	/** Array of endpoint descriptors. This length of this array is determined
+	 * by the bNumEndpoints field. */
+	const struct libusb_endpoint_descriptor *endpoint;
+
+	/** Extra descriptors. If libusb encounters unknown interface descriptors,
+	 * it will store them here, should you wish to parse them. */
+	const unsigned char *extra;
+
+	/** Length of the extra descriptors, in bytes. */
+	int extra_length;
+};
+
+/** \ingroup libusb_desc
+ * A collection of alternate settings for a particular USB interface.
+ */
+struct libusb_interface {
+	/** Array of interface descriptors. The length of this array is determined
+	 * by the num_altsetting field. */
+	const struct libusb_interface_descriptor *altsetting;
+
+	/** The number of alternate settings that belong to this interface */
+	int num_altsetting;
+};
+
+/** \ingroup libusb_desc
+ * A structure representing the standard USB configuration descriptor. This
+ * descriptor is documented in section 9.6.3 of the USB 3.0 specification.
+ * All multiple-byte fields are represented in host-endian format.
+ */
+struct libusb_config_descriptor {
+	/** Size of this descriptor (in bytes) */
+	uint8_t  bLength;
+
+	/** Descriptor type. Will have value
+	 * \ref libusb_descriptor_type::LIBUSB_DT_CONFIG LIBUSB_DT_CONFIG
+	 * in this context. */
+	uint8_t  bDescriptorType;
+
+	/** Total length of data returned for this configuration */
+	uint16_t wTotalLength;
+
+	/** Number of interfaces supported by this configuration */
+	uint8_t  bNumInterfaces;
+
+	/** Identifier value for this configuration */
+	uint8_t  bConfigurationValue;
+
+	/** Index of string descriptor describing this configuration */
+	uint8_t  iConfiguration;
+
+	/** Configuration characteristics */
+	uint8_t  bmAttributes;
+
+	/** Maximum power consumption of the USB device from this bus in this
+	 * configuration when the device is fully operation. Expressed in units
+	 * of 2 mA when the device is operating in high-speed mode and in units
+	 * of 8 mA when the device is operating in super-speed mode. */
+	uint8_t  MaxPower;
+
+	/** Array of interfaces supported by this configuration. The length of
+	 * this array is determined by the bNumInterfaces field. */
+	const struct libusb_interface *interface;
+
+	/** Extra descriptors. If libusb encounters unknown configuration
+	 * descriptors, it will store them here, should you wish to parse them. */
+	const unsigned char *extra;
+
+	/** Length of the extra descriptors, in bytes. */
+	int extra_length;
+};
+
+/** \ingroup libusb_desc
+ * A structure representing the superspeed endpoint companion
+ * descriptor. This descriptor is documented in section 9.6.7 of
+ * the USB 3.0 specification. All multiple-byte fields are represented in
+ * host-endian format.
+ */
+struct libusb_ss_endpoint_companion_descriptor {
+
+	/** Size of this descriptor (in bytes) */
+	uint8_t  bLength;
+
+	/** Descriptor type. Will have value
+	 * \ref libusb_descriptor_type::LIBUSB_DT_SS_ENDPOINT_COMPANION in
+	 * this context. */
+	uint8_t  bDescriptorType;
+
+
+	/** The maximum number of packets the endpoint can send or
+	 *  receive as part of a burst. */
+	uint8_t  bMaxBurst;
+
+	/** In bulk EP:	bits 4:0 represents the	maximum	number of
+	 *  streams the	EP supports. In	isochronous EP:	bits 1:0
+	 *  represents the Mult	- a zero based value that determines
+	 *  the	maximum	number of packets within a service interval  */
+	uint8_t  bmAttributes;
+
+	/** The	total number of bytes this EP will transfer every
+	 *  service interval. valid only for periodic EPs. */
+	uint16_t wBytesPerInterval;
+};
+
+/** \ingroup libusb_desc
+ * A generic representation of a BOS Device Capability descriptor. It is
+ * advised to check bDevCapabilityType and call the matching
+ * libusb_get_*_descriptor function to get a structure fully matching the type.
+ */
+struct libusb_bos_dev_capability_descriptor {
+	/** Size of this descriptor (in bytes) */
+	uint8_t bLength;
+	/** Descriptor type. Will have value
+	 * \ref libusb_descriptor_type::LIBUSB_DT_DEVICE_CAPABILITY
+	 * LIBUSB_DT_DEVICE_CAPABILITY in this context. */
+	uint8_t bDescriptorType;
+	/** Device Capability type */
+	uint8_t bDevCapabilityType;
+	/** Device Capability data (bLength - 3 bytes) */
+	uint8_t dev_capability_data
+#if defined(__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L)
+	[] /* valid C99 code */
+#else
+	[0] /* non-standard, but usually working code */
+#endif
+	;
+};
+
+/** \ingroup libusb_desc
+ * A structure representing the Binary Device Object Store (BOS) descriptor.
+ * This descriptor is documented in section 9.6.2 of the USB 3.0 specification.
+ * All multiple-byte fields are represented in host-endian format.
+ */
+struct libusb_bos_descriptor {
+	/** Size of this descriptor (in bytes) */
+	uint8_t  bLength;
+
+	/** Descriptor type. Will have value
+	 * \ref libusb_descriptor_type::LIBUSB_DT_BOS LIBUSB_DT_BOS
+	 * in this context. */
+	uint8_t  bDescriptorType;
+
+	/** Length of this descriptor and all of its sub descriptors */
+	uint16_t wTotalLength;
+
+	/** The number of separate device capability descriptors in
+	 * the BOS */
+	uint8_t  bNumDeviceCaps;
+
+	/** bNumDeviceCap Device Capability Descriptors */
+	struct libusb_bos_dev_capability_descriptor *dev_capability
+#if defined(__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L)
+	[] /* valid C99 code */
+#else
+	[0] /* non-standard, but usually working code */
+#endif
+	;
+};
+
+/** \ingroup libusb_desc
+ * A structure representing the USB 2.0 Extension descriptor
+ * This descriptor is documented in section 9.6.2.1 of the USB 3.0 specification.
+ * All multiple-byte fields are represented in host-endian format.
+ */
+struct libusb_usb_2_0_extension_descriptor {
+	/** Size of this descriptor (in bytes) */
+	uint8_t  bLength;
+
+	/** Descriptor type. Will have value
+	 * \ref libusb_descriptor_type::LIBUSB_DT_DEVICE_CAPABILITY
+	 * LIBUSB_DT_DEVICE_CAPABILITY in this context. */
+	uint8_t  bDescriptorType;
+
+	/** Capability type. Will have value
+	 * \ref libusb_capability_type::LIBUSB_BT_USB_2_0_EXTENSION
+	 * LIBUSB_BT_USB_2_0_EXTENSION in this context. */
+	uint8_t  bDevCapabilityType;
+
+	/** Bitmap encoding of supported device level features.
+	 * A value of one in a bit location indicates a feature is
+	 * supported; a value of zero indicates it is not supported.
+	 * See \ref libusb_usb_2_0_extension_attributes. */
+	uint32_t  bmAttributes;
+};
+
+/** \ingroup libusb_desc
+ * A structure representing the SuperSpeed USB Device Capability descriptor
+ * This descriptor is documented in section 9.6.2.2 of the USB 3.0 specification.
+ * All multiple-byte fields are represented in host-endian format.
+ */
+struct libusb_ss_usb_device_capability_descriptor {
+	/** Size of this descriptor (in bytes) */
+	uint8_t  bLength;
+
+	/** Descriptor type. Will have value
+	 * \ref libusb_descriptor_type::LIBUSB_DT_DEVICE_CAPABILITY
+	 * LIBUSB_DT_DEVICE_CAPABILITY in this context. */
+	uint8_t  bDescriptorType;
+
+	/** Capability type. Will have value
+	 * \ref libusb_capability_type::LIBUSB_BT_SS_USB_DEVICE_CAPABILITY
+	 * LIBUSB_BT_SS_USB_DEVICE_CAPABILITY in this context. */
+	uint8_t  bDevCapabilityType;
+
+	/** Bitmap encoding of supported device level features.
+	 * A value of one in a bit location indicates a feature is
+	 * supported; a value of zero indicates it is not supported.
+	 * See \ref libusb_ss_usb_device_capability_attributes. */
+	uint8_t  bmAttributes;
+
+	/** Bitmap encoding of the speed supported by this device when
+	 * operating in SuperSpeed mode. See \ref libusb_supported_speed. */
+	uint16_t wSpeedSupported;
+
+	/** The lowest speed at which all the functionality supported
+	 * by the device is available to the user. For example if the
+	 * device supports all its functionality when connected at
+	 * full speed and above then it sets this value to 1. */
+	uint8_t  bFunctionalitySupport;
+
+	/** U1 Device Exit Latency. */
+	uint8_t  bU1DevExitLat;
+
+	/** U2 Device Exit Latency. */
+	uint16_t bU2DevExitLat;
+};
+
+/** \ingroup libusb_desc
+ * A structure representing the Container ID descriptor.
+ * This descriptor is documented in section 9.6.2.3 of the USB 3.0 specification.
+ * All multiple-byte fields, except UUIDs, are represented in host-endian format.
+ */
+struct libusb_container_id_descriptor {
+	/** Size of this descriptor (in bytes) */
+	uint8_t  bLength;
+
+	/** Descriptor type. Will have value
+	 * \ref libusb_descriptor_type::LIBUSB_DT_DEVICE_CAPABILITY
+	 * LIBUSB_DT_DEVICE_CAPABILITY in this context. */
+	uint8_t  bDescriptorType;
+
+	/** Capability type. Will have value
+	 * \ref libusb_capability_type::LIBUSB_BT_CONTAINER_ID
+	 * LIBUSB_BT_CONTAINER_ID in this context. */
+	uint8_t  bDevCapabilityType;
+
+	/** Reserved field */
+	uint8_t bReserved;
+
+	/** 128 bit UUID */
+	uint8_t  ContainerID[16];
+};
+
+/** \ingroup libusb_asyncio
+ * Setup packet for control transfers. */
+struct libusb_control_setup {
+	/** Request type. Bits 0:4 determine recipient, see
+	 * \ref libusb_request_recipient. Bits 5:6 determine type, see
+	 * \ref libusb_request_type. Bit 7 determines data transfer direction, see
+	 * \ref libusb_endpoint_direction.
+	 */
+	uint8_t  bmRequestType;
+
+	/** Request. If the type bits of bmRequestType are equal to
+	 * \ref libusb_request_type::LIBUSB_REQUEST_TYPE_STANDARD
+	 * "LIBUSB_REQUEST_TYPE_STANDARD" then this field refers to
+	 * \ref libusb_standard_request. For other cases, use of this field is
+	 * application-specific. */
+	uint8_t  bRequest;
+
+	/** Value. Varies according to request */
+	uint16_t wValue;
+
+	/** Index. Varies according to request, typically used to pass an index
+	 * or offset */
+	uint16_t wIndex;
+
+	/** Number of bytes to transfer */
+	uint16_t wLength;
+};
+
+#define LIBUSB_CONTROL_SETUP_SIZE (sizeof(struct libusb_control_setup))
+
+/* libusb */
+
+struct libusb_context;
+struct libusb_device;
+struct libusb_device_handle;
+
+/** \ingroup libusb_lib
+ * Structure providing the version of the libusb runtime
+ */
+struct libusb_version {
+	/** Library major version. */
+	const uint16_t major;
+
+	/** Library minor version. */
+	const uint16_t minor;
+
+	/** Library micro version. */
+	const uint16_t micro;
+
+	/** Library nano version. */
+	const uint16_t nano;
+
+	/** Library release candidate suffix string, e.g. "-rc4". */
+	const char *rc;
+
+	/** For ABI compatibility only. */
+	const char* describe;
+};
+
+/** \ingroup libusb_lib
+ * Structure representing a libusb session. The concept of individual libusb
+ * sessions allows for your program to use two libraries (or dynamically
+ * load two modules) which both independently use libusb. This will prevent
+ * interference between the individual libusb users - for example
+ * libusb_set_debug() will not affect the other user of the library, and
+ * libusb_exit() will not destroy resources that the other user is still
+ * using.
+ *
+ * Sessions are created by libusb_init() and destroyed through libusb_exit().
+ * If your application is guaranteed to only ever include a single libusb
+ * user (i.e. you), you do not have to worry about contexts: pass NULL in
+ * every function call where a context is required. The default context
+ * will be used.
+ *
+ * For more information, see \ref libusb_contexts.
+ */
+typedef struct libusb_context libusb_context;
+
+/** \ingroup libusb_dev
+ * Structure representing a USB device detected on the system. This is an
+ * opaque type for which you are only ever provided with a pointer, usually
+ * originating from libusb_get_device_list().
+ *
+ * Certain operations can be performed on a device, but in order to do any
+ * I/O you will have to first obtain a device handle using libusb_open().
+ *
+ * Devices are reference counted with libusb_ref_device() and
+ * libusb_unref_device(), and are freed when the reference count reaches 0.
+ * New devices presented by libusb_get_device_list() have a reference count of
+ * 1, and libusb_free_device_list() can optionally decrease the reference count
+ * on all devices in the list. libusb_open() adds another reference which is
+ * later destroyed by libusb_close().
+ */
+typedef struct libusb_device libusb_device;
+
+
+/** \ingroup libusb_dev
+ * Structure representing a handle on a USB device. This is an opaque type for
+ * which you are only ever provided with a pointer, usually originating from
+ * libusb_open().
+ *
+ * A device handle is used to perform I/O and other operations. When finished
+ * with a device handle, you should call libusb_close().
+ */
+typedef struct libusb_device_handle libusb_device_handle;
+
+/** \ingroup libusb_dev
+ * Speed codes. Indicates the speed at which the device is operating.
+ */
+enum libusb_speed {
+	/** The OS doesn't report or know the device speed. */
+	LIBUSB_SPEED_UNKNOWN = 0,
+
+	/** The device is operating at low speed (1.5MBit/s). */
+	LIBUSB_SPEED_LOW = 1,
+
+	/** The device is operating at full speed (12MBit/s). */
+	LIBUSB_SPEED_FULL = 2,
+
+	/** The device is operating at high speed (480MBit/s). */
+	LIBUSB_SPEED_HIGH = 3,
+
+	/** The device is operating at super speed (5000MBit/s). */
+	LIBUSB_SPEED_SUPER = 4,
+};
+
+/** \ingroup libusb_dev
+ * Supported speeds (wSpeedSupported) bitfield. Indicates what
+ * speeds the device supports.
+ */
+enum libusb_supported_speed {
+	/** Low speed operation supported (1.5MBit/s). */
+	LIBUSB_LOW_SPEED_OPERATION   = 1,
+
+	/** Full speed operation supported (12MBit/s). */
+	LIBUSB_FULL_SPEED_OPERATION  = 2,
+
+	/** High speed operation supported (480MBit/s). */
+	LIBUSB_HIGH_SPEED_OPERATION  = 4,
+
+	/** Superspeed operation supported (5000MBit/s). */
+	LIBUSB_SUPER_SPEED_OPERATION = 8,
+};
+
+/** \ingroup libusb_dev
+ * Masks for the bits of the
+ * \ref libusb_usb_2_0_extension_descriptor::bmAttributes "bmAttributes" field
+ * of the USB 2.0 Extension descriptor.
+ */
+enum libusb_usb_2_0_extension_attributes {
+	/** Supports Link Power Management (LPM) */
+	LIBUSB_BM_LPM_SUPPORT = 2,
+};
+
+/** \ingroup libusb_dev
+ * Masks for the bits of the
+ * \ref libusb_ss_usb_device_capability_descriptor::bmAttributes "bmAttributes" field
+ * field of the SuperSpeed USB Device Capability descriptor.
+ */
+enum libusb_ss_usb_device_capability_attributes {
+	/** Supports Latency Tolerance Messages (LTM) */
+	LIBUSB_BM_LTM_SUPPORT = 2,
+};
+
+/** \ingroup libusb_dev
+ * USB capability types
+ */
+enum libusb_bos_type {
+	/** Wireless USB device capability */
+	LIBUSB_BT_WIRELESS_USB_DEVICE_CAPABILITY	= 1,
+
+	/** USB 2.0 extensions */
+	LIBUSB_BT_USB_2_0_EXTENSION			= 2,
+
+	/** SuperSpeed USB device capability */
+	LIBUSB_BT_SS_USB_DEVICE_CAPABILITY		= 3,
+
+	/** Container ID type */
+	LIBUSB_BT_CONTAINER_ID				= 4,
+};
+
+/** \ingroup libusb_misc
+ * Error codes. Most libusb functions return 0 on success or one of these
+ * codes on failure.
+ * You can call libusb_error_name() to retrieve a string representation of an
+ * error code or libusb_strerror() to get an end-user suitable description of
+ * an error code.
+ */
+enum libusb_error {
+	/** Success (no error) */
+	LIBUSB_SUCCESS = 0,
+
+	/** Input/output error */
+	LIBUSB_ERROR_IO = -1,
+
+	/** Invalid parameter */
+	LIBUSB_ERROR_INVALID_PARAM = -2,
+
+	/** Access denied (insufficient permissions) */
+	LIBUSB_ERROR_ACCESS = -3,
+
+	/** No such device (it may have been disconnected) */
+	LIBUSB_ERROR_NO_DEVICE = -4,
+
+	/** Entity not found */
+	LIBUSB_ERROR_NOT_FOUND = -5,
+
+	/** Resource busy */
+	LIBUSB_ERROR_BUSY = -6,
+
+	/** Operation timed out */
+	LIBUSB_ERROR_TIMEOUT = -7,
+
+	/** Overflow */
+	LIBUSB_ERROR_OVERFLOW = -8,
+
+	/** Pipe error */
+	LIBUSB_ERROR_PIPE = -9,
+
+	/** System call interrupted (perhaps due to signal) */
+	LIBUSB_ERROR_INTERRUPTED = -10,
+
+	/** Insufficient memory */
+	LIBUSB_ERROR_NO_MEM = -11,
+
+	/** Operation not supported or unimplemented on this platform */
+	LIBUSB_ERROR_NOT_SUPPORTED = -12,
+
+	/* NB: Remember to update LIBUSB_ERROR_COUNT below as well as the
+	   message strings in strerror.c when adding new error codes here. */
+
+	/** Other error */
+	LIBUSB_ERROR_OTHER = -99,
+};
+
+/* Total number of error codes in enum libusb_error */
+#define LIBUSB_ERROR_COUNT 14
+
+/** \ingroup libusb_asyncio
+ * Transfer status codes */
+enum libusb_transfer_status {
+	/** Transfer completed without error. Note that this does not indicate
+	 * that the entire amount of requested data was transferred. */
+	LIBUSB_TRANSFER_COMPLETED,
+
+	/** Transfer failed */
+	LIBUSB_TRANSFER_ERROR,
+
+	/** Transfer timed out */
+	LIBUSB_TRANSFER_TIMED_OUT,
+
+	/** Transfer was cancelled */
+	LIBUSB_TRANSFER_CANCELLED,
+
+	/** For bulk/interrupt endpoints: halt condition detected (endpoint
+	 * stalled). For control endpoints: control request not supported. */
+	LIBUSB_TRANSFER_STALL,
+
+	/** Device was disconnected */
+	LIBUSB_TRANSFER_NO_DEVICE,
+
+	/** Device sent more data than requested */
+	LIBUSB_TRANSFER_OVERFLOW,
+
+	/* NB! Remember to update libusb_error_name()
+	   when adding new status codes here. */
+};
+
+/** \ingroup libusb_asyncio
+ * libusb_transfer.flags values */
+enum libusb_transfer_flags {
+	/** Report short frames as errors */
+	LIBUSB_TRANSFER_SHORT_NOT_OK = 1<<0,
+
+	/** Automatically free() transfer buffer during libusb_free_transfer().
+	 * Note that buffers allocated with libusb_dev_mem_alloc() should not
+	 * be attempted freed in this way, since free() is not an appropriate
+	 * way to release such memory. */
+	LIBUSB_TRANSFER_FREE_BUFFER = 1<<1,
+
+	/** Automatically call libusb_free_transfer() after callback returns.
+	 * If this flag is set, it is illegal to call libusb_free_transfer()
+	 * from your transfer callback, as this will result in a double-free
+	 * when this flag is acted upon. */
+	LIBUSB_TRANSFER_FREE_TRANSFER = 1<<2,
+
+	/** Terminate transfers that are a multiple of the endpoint's
+	 * wMaxPacketSize with an extra zero length packet. This is useful
+	 * when a device protocol mandates that each logical request is
+	 * terminated by an incomplete packet (i.e. the logical requests are
+	 * not separated by other means).
+	 *
+	 * This flag only affects host-to-device transfers to bulk and interrupt
+	 * endpoints. In other situations, it is ignored.
+	 *
+	 * This flag only affects transfers with a length that is a multiple of
+	 * the endpoint's wMaxPacketSize. On transfers of other lengths, this
+	 * flag has no effect. Therefore, if you are working with a device that
+	 * needs a ZLP whenever the end of the logical request falls on a packet
+	 * boundary, then it is sensible to set this flag on <em>every</em>
+	 * transfer (you do not have to worry about only setting it on transfers
+	 * that end on the boundary).
+	 *
+	 * This flag is currently only supported on Linux.
+	 * On other systems, libusb_submit_transfer() will return
+	 * LIBUSB_ERROR_NOT_SUPPORTED for every transfer where this flag is set.
+	 *
+	 * Available since libusb-1.0.9.
+	 */
+	LIBUSB_TRANSFER_ADD_ZERO_PACKET = 1 << 3,
+};
+
+/** \ingroup libusb_asyncio
+ * Isochronous packet descriptor. */
+struct libusb_iso_packet_descriptor {
+	/** Length of data to request in this packet */
+	unsigned int length;
+
+	/** Amount of data that was actually transferred */
+	unsigned int actual_length;
+
+	/** Status code for this packet */
+	enum libusb_transfer_status status;
+};
+
+struct libusb_transfer;
+
+/** \ingroup libusb_asyncio
+ * Asynchronous transfer callback function type. When submitting asynchronous
+ * transfers, you pass a pointer to a callback function of this type via the
+ * \ref libusb_transfer::callback "callback" member of the libusb_transfer
+ * structure. libusb will call this function later, when the transfer has
+ * completed or failed. See \ref libusb_asyncio for more information.
+ * \param transfer The libusb_transfer struct the callback function is being
+ * notified about.
+ */
+typedef void (LIBUSB_CALL *libusb_transfer_cb_fn)(struct libusb_transfer *transfer);
+
+/** \ingroup libusb_asyncio
+ * The generic USB transfer structure. The user populates this structure and
+ * then submits it in order to request a transfer. After the transfer has
+ * completed, the library populates the transfer with the results and passes
+ * it back to the user.
+ */
+struct libusb_transfer {
+	/** Handle of the device that this transfer will be submitted to */
+	libusb_device_handle *dev_handle;
+
+	/** A bitwise OR combination of \ref libusb_transfer_flags. */
+	uint8_t flags;
+
+	/** Address of the endpoint where this transfer will be sent. */
+	unsigned char endpoint;
+
+	/** Type of the endpoint from \ref libusb_transfer_type */
+	unsigned char type;
+
+	/** Timeout for this transfer in millseconds. A value of 0 indicates no
+	 * timeout. */
+	unsigned int timeout;
+
+	/** The status of the transfer. Read-only, and only for use within
+	 * transfer callback function.
+	 *
+	 * If this is an isochronous transfer, this field may read COMPLETED even
+	 * if there were errors in the frames. Use the
+	 * \ref libusb_iso_packet_descriptor::status "status" field in each packet
+	 * to determine if errors occurred. */
+	enum libusb_transfer_status status;
+
+	/** Length of the data buffer */
+	int length;
+
+	/** Actual length of data that was transferred. Read-only, and only for
+	 * use within transfer callback function. Not valid for isochronous
+	 * endpoint transfers. */
+	int actual_length;
+
+	/** Callback function. This will be invoked when the transfer completes,
+	 * fails, or is cancelled. */
+	libusb_transfer_cb_fn callback;
+
+	/** User context data to pass to the callback function. */
+	void *user_data;
+
+	/** Data buffer */
+	unsigned char *buffer;
+
+	/** Number of isochronous packets. Only used for I/O with isochronous
+	 * endpoints. */
+	int num_iso_packets;
+
+	/** Isochronous packet descriptors, for isochronous transfers only. */
+	struct libusb_iso_packet_descriptor iso_packet_desc
+#if defined(__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L)
+	[] /* valid C99 code */
+#else
+	[0] /* non-standard, but usually working code */
+#endif
+	;
+};
+
+/** \ingroup libusb_misc
+ * Capabilities supported by an instance of libusb on the current running
+ * platform. Test if the loaded library supports a given capability by calling
+ * \ref libusb_has_capability().
+ */
+enum libusb_capability {
+	/** The libusb_has_capability() API is available. */
+	LIBUSB_CAP_HAS_CAPABILITY = 0x0000,
+	/** Hotplug support is available on this platform. */
+	LIBUSB_CAP_HAS_HOTPLUG = 0x0001,
+	/** The library can access HID devices without requiring user intervention.
+	 * Note that before being able to actually access an HID device, you may
+	 * still have to call additional libusb functions such as
+	 * \ref libusb_detach_kernel_driver(). */
+	LIBUSB_CAP_HAS_HID_ACCESS = 0x0100,
+	/** The library supports detaching of the default USB driver, using 
+	 * \ref libusb_detach_kernel_driver(), if one is set by the OS kernel */
+	LIBUSB_CAP_SUPPORTS_DETACH_KERNEL_DRIVER = 0x0101
+};
+
+/** \ingroup libusb_lib
+ *  Log message levels.
+ *  - LIBUSB_LOG_LEVEL_NONE (0)    : no messages ever printed by the library (default)
+ *  - LIBUSB_LOG_LEVEL_ERROR (1)   : error messages are printed to stderr
+ *  - LIBUSB_LOG_LEVEL_WARNING (2) : warning and error messages are printed to stderr
+ *  - LIBUSB_LOG_LEVEL_INFO (3)    : informational messages are printed to stdout, warning
+ *    and error messages are printed to stderr
+ *  - LIBUSB_LOG_LEVEL_DEBUG (4)   : debug and informational messages are printed to stdout,
+ *    warnings and errors to stderr
+ */
+enum libusb_log_level {
+	LIBUSB_LOG_LEVEL_NONE = 0,
+	LIBUSB_LOG_LEVEL_ERROR,
+	LIBUSB_LOG_LEVEL_WARNING,
+	LIBUSB_LOG_LEVEL_INFO,
+	LIBUSB_LOG_LEVEL_DEBUG,
+};
+
+int LIBUSB_CALL libusb_init(libusb_context **ctx);
+void LIBUSB_CALL libusb_exit(libusb_context *ctx);
+void LIBUSB_CALL libusb_set_debug(libusb_context *ctx, int level);
+const struct libusb_version * LIBUSB_CALL libusb_get_version(void);
+int LIBUSB_CALL libusb_has_capability(uint32_t capability);
+const char * LIBUSB_CALL libusb_error_name(int errcode);
+int LIBUSB_CALL libusb_setlocale(const char *locale);
+const char * LIBUSB_CALL libusb_strerror(enum libusb_error errcode);
+
+ssize_t LIBUSB_CALL libusb_get_device_list(libusb_context *ctx,
+	libusb_device ***list);
+void LIBUSB_CALL libusb_free_device_list(libusb_device **list,
+	int unref_devices);
+libusb_device * LIBUSB_CALL libusb_ref_device(libusb_device *dev);
+void LIBUSB_CALL libusb_unref_device(libusb_device *dev);
+
+int LIBUSB_CALL libusb_get_configuration(libusb_device_handle *dev,
+	int *config);
+int LIBUSB_CALL libusb_get_device_descriptor(libusb_device *dev,
+	struct libusb_device_descriptor *desc);
+int LIBUSB_CALL libusb_get_active_config_descriptor(libusb_device *dev,
+	struct libusb_config_descriptor **config);
+int LIBUSB_CALL libusb_get_config_descriptor(libusb_device *dev,
+	uint8_t config_index, struct libusb_config_descriptor **config);
+int LIBUSB_CALL libusb_get_config_descriptor_by_value(libusb_device *dev,
+	uint8_t bConfigurationValue, struct libusb_config_descriptor **config);
+void LIBUSB_CALL libusb_free_config_descriptor(
+	struct libusb_config_descriptor *config);
+int LIBUSB_CALL libusb_get_ss_endpoint_companion_descriptor(
+	struct libusb_context *ctx,
+	const struct libusb_endpoint_descriptor *endpoint,
+	struct libusb_ss_endpoint_companion_descriptor **ep_comp);
+void LIBUSB_CALL libusb_free_ss_endpoint_companion_descriptor(
+	struct libusb_ss_endpoint_companion_descriptor *ep_comp);
+int LIBUSB_CALL libusb_get_bos_descriptor(libusb_device_handle *dev_handle,
+	struct libusb_bos_descriptor **bos);
+void LIBUSB_CALL libusb_free_bos_descriptor(struct libusb_bos_descriptor *bos);
+int LIBUSB_CALL libusb_get_usb_2_0_extension_descriptor(
+	struct libusb_context *ctx,
+	struct libusb_bos_dev_capability_descriptor *dev_cap,
+	struct libusb_usb_2_0_extension_descriptor **usb_2_0_extension);
+void LIBUSB_CALL libusb_free_usb_2_0_extension_descriptor(
+	struct libusb_usb_2_0_extension_descriptor *usb_2_0_extension);
+int LIBUSB_CALL libusb_get_ss_usb_device_capability_descriptor(
+	struct libusb_context *ctx,
+	struct libusb_bos_dev_capability_descriptor *dev_cap,
+	struct libusb_ss_usb_device_capability_descriptor **ss_usb_device_cap);
+void LIBUSB_CALL libusb_free_ss_usb_device_capability_descriptor(
+	struct libusb_ss_usb_device_capability_descriptor *ss_usb_device_cap);
+int LIBUSB_CALL libusb_get_container_id_descriptor(struct libusb_context *ctx,
+	struct libusb_bos_dev_capability_descriptor *dev_cap,
+	struct libusb_container_id_descriptor **container_id);
+void LIBUSB_CALL libusb_free_container_id_descriptor(
+	struct libusb_container_id_descriptor *container_id);
+uint8_t LIBUSB_CALL libusb_get_bus_number(libusb_device *dev);
+uint8_t LIBUSB_CALL libusb_get_port_number(libusb_device *dev);
+int LIBUSB_CALL libusb_get_port_numbers(libusb_device *dev, uint8_t* port_numbers, int port_numbers_len);
+LIBUSB_DEPRECATED_FOR(libusb_get_port_numbers)
+int LIBUSB_CALL libusb_get_port_path(libusb_context *ctx, libusb_device *dev, uint8_t* path, uint8_t path_length);
+libusb_device * LIBUSB_CALL libusb_get_parent(libusb_device *dev);
+uint8_t LIBUSB_CALL libusb_get_device_address(libusb_device *dev);
+int LIBUSB_CALL libusb_get_device_speed(libusb_device *dev);
+int LIBUSB_CALL libusb_get_max_packet_size(libusb_device *dev,
+	unsigned char endpoint);
+int LIBUSB_CALL libusb_get_max_iso_packet_size(libusb_device *dev,
+	unsigned char endpoint);
+
+int LIBUSB_CALL libusb_open(libusb_device *dev, libusb_device_handle **dev_handle);
+void LIBUSB_CALL libusb_close(libusb_device_handle *dev_handle);
+libusb_device * LIBUSB_CALL libusb_get_device(libusb_device_handle *dev_handle);
+
+int LIBUSB_CALL libusb_set_configuration(libusb_device_handle *dev_handle,
+	int configuration);
+int LIBUSB_CALL libusb_claim_interface(libusb_device_handle *dev_handle,
+	int interface_number);
+int LIBUSB_CALL libusb_release_interface(libusb_device_handle *dev_handle,
+	int interface_number);
+
+libusb_device_handle * LIBUSB_CALL libusb_open_device_with_vid_pid(
+	libusb_context *ctx, uint16_t vendor_id, uint16_t product_id);
+
+int LIBUSB_CALL libusb_set_interface_alt_setting(libusb_device_handle *dev_handle,
+	int interface_number, int alternate_setting);
+int LIBUSB_CALL libusb_clear_halt(libusb_device_handle *dev_handle,
+	unsigned char endpoint);
+int LIBUSB_CALL libusb_reset_device(libusb_device_handle *dev_handle);
+
+int LIBUSB_CALL libusb_alloc_streams(libusb_device_handle *dev_handle,
+	uint32_t num_streams, unsigned char *endpoints, int num_endpoints);
+int LIBUSB_CALL libusb_free_streams(libusb_device_handle *dev_handle,
+	unsigned char *endpoints, int num_endpoints);
+
+unsigned char * LIBUSB_CALL libusb_dev_mem_alloc(libusb_device_handle *dev_handle,
+	size_t length);
+int LIBUSB_CALL libusb_dev_mem_free(libusb_device_handle *dev_handle,
+	unsigned char *buffer, size_t length);
+
+int LIBUSB_CALL libusb_kernel_driver_active(libusb_device_handle *dev_handle,
+	int interface_number);
+int LIBUSB_CALL libusb_detach_kernel_driver(libusb_device_handle *dev_handle,
+	int interface_number);
+int LIBUSB_CALL libusb_attach_kernel_driver(libusb_device_handle *dev_handle,
+	int interface_number);
+int LIBUSB_CALL libusb_set_auto_detach_kernel_driver(
+	libusb_device_handle *dev_handle, int enable);
+
+/* async I/O */
+
+/** \ingroup libusb_asyncio
+ * Get the data section of a control transfer. This convenience function is here
+ * to remind you that the data does not start until 8 bytes into the actual
+ * buffer, as the setup packet comes first.
+ *
+ * Calling this function only makes sense from a transfer callback function,
+ * or situations where you have already allocated a suitably sized buffer at
+ * transfer->buffer.
+ *
+ * \param transfer a transfer
+ * \returns pointer to the first byte of the data section
+ */
+static inline unsigned char *libusb_control_transfer_get_data(
+	struct libusb_transfer *transfer)
+{
+	return transfer->buffer + LIBUSB_CONTROL_SETUP_SIZE;
+}
+
+/** \ingroup libusb_asyncio
+ * Get the control setup packet of a control transfer. This convenience
+ * function is here to remind you that the control setup occupies the first
+ * 8 bytes of the transfer data buffer.
+ *
+ * Calling this function only makes sense from a transfer callback function,
+ * or situations where you have already allocated a suitably sized buffer at
+ * transfer->buffer.
+ *
+ * \param transfer a transfer
+ * \returns a casted pointer to the start of the transfer data buffer
+ */
+static inline struct libusb_control_setup *libusb_control_transfer_get_setup(
+	struct libusb_transfer *transfer)
+{
+	return (struct libusb_control_setup *)(void *) transfer->buffer;
+}
+
+/** \ingroup libusb_asyncio
+ * Helper function to populate the setup packet (first 8 bytes of the data
+ * buffer) for a control transfer. The wIndex, wValue and wLength values should
+ * be given in host-endian byte order.
+ *
+ * \param buffer buffer to output the setup packet into
+ * This pointer must be aligned to at least 2 bytes boundary.
+ * \param bmRequestType see the
+ * \ref libusb_control_setup::bmRequestType "bmRequestType" field of
+ * \ref libusb_control_setup
+ * \param bRequest see the
+ * \ref libusb_control_setup::bRequest "bRequest" field of
+ * \ref libusb_control_setup
+ * \param wValue see the
+ * \ref libusb_control_setup::wValue "wValue" field of
+ * \ref libusb_control_setup
+ * \param wIndex see the
+ * \ref libusb_control_setup::wIndex "wIndex" field of
+ * \ref libusb_control_setup
+ * \param wLength see the
+ * \ref libusb_control_setup::wLength "wLength" field of
+ * \ref libusb_control_setup
+ */
+static inline void libusb_fill_control_setup(unsigned char *buffer,
+	uint8_t bmRequestType, uint8_t bRequest, uint16_t wValue, uint16_t wIndex,
+	uint16_t wLength)
+{
+	struct libusb_control_setup *setup = (struct libusb_control_setup *)(void *) buffer;
+	setup->bmRequestType = bmRequestType;
+	setup->bRequest = bRequest;
+	setup->wValue = libusb_cpu_to_le16(wValue);
+	setup->wIndex = libusb_cpu_to_le16(wIndex);
+	setup->wLength = libusb_cpu_to_le16(wLength);
+}
+
+struct libusb_transfer * LIBUSB_CALL libusb_alloc_transfer(int iso_packets);
+int LIBUSB_CALL libusb_submit_transfer(struct libusb_transfer *transfer);
+int LIBUSB_CALL libusb_cancel_transfer(struct libusb_transfer *transfer);
+void LIBUSB_CALL libusb_free_transfer(struct libusb_transfer *transfer);
+void LIBUSB_CALL libusb_transfer_set_stream_id(
+	struct libusb_transfer *transfer, uint32_t stream_id);
+uint32_t LIBUSB_CALL libusb_transfer_get_stream_id(
+	struct libusb_transfer *transfer);
+
+/** \ingroup libusb_asyncio
+ * Helper function to populate the required \ref libusb_transfer fields
+ * for a control transfer.
+ *
+ * If you pass a transfer buffer to this function, the first 8 bytes will
+ * be interpreted as a control setup packet, and the wLength field will be
+ * used to automatically populate the \ref libusb_transfer::length "length"
+ * field of the transfer. Therefore the recommended approach is:
+ * -# Allocate a suitably sized data buffer (including space for control setup)
+ * -# Call libusb_fill_control_setup()
+ * -# If this is a host-to-device transfer with a data stage, put the data
+ *    in place after the setup packet
+ * -# Call this function
+ * -# Call libusb_submit_transfer()
+ *
+ * It is also legal to pass a NULL buffer to this function, in which case this
+ * function will not attempt to populate the length field. Remember that you
+ * must then populate the buffer and length fields later.
+ *
+ * \param transfer the transfer to populate
+ * \param dev_handle handle of the device that will handle the transfer
+ * \param buffer data buffer. If provided, this function will interpret the
+ * first 8 bytes as a setup packet and infer the transfer length from that.
+ * This pointer must be aligned to at least 2 bytes boundary.
+ * \param callback callback function to be invoked on transfer completion
+ * \param user_data user data to pass to callback function
+ * \param timeout timeout for the transfer in milliseconds
+ */
+static inline void libusb_fill_control_transfer(
+	struct libusb_transfer *transfer, libusb_device_handle *dev_handle,
+	unsigned char *buffer, libusb_transfer_cb_fn callback, void *user_data,
+	unsigned int timeout)
+{
+	struct libusb_control_setup *setup = (struct libusb_control_setup *)(void *) buffer;
+	transfer->dev_handle = dev_handle;
+	transfer->endpoint = 0;
+	transfer->type = LIBUSB_TRANSFER_TYPE_CONTROL;
+	transfer->timeout = timeout;
+	transfer->buffer = buffer;
+	if (setup)
+		transfer->length = (int) (LIBUSB_CONTROL_SETUP_SIZE
+			+ libusb_le16_to_cpu(setup->wLength));
+	transfer->user_data = user_data;
+	transfer->callback = callback;
+}
+
+/** \ingroup libusb_asyncio
+ * Helper function to populate the required \ref libusb_transfer fields
+ * for a bulk transfer.
+ *
+ * \param transfer the transfer to populate
+ * \param dev_handle handle of the device that will handle the transfer
+ * \param endpoint address of the endpoint where this transfer will be sent
+ * \param buffer data buffer
+ * \param length length of data buffer
+ * \param callback callback function to be invoked on transfer completion
+ * \param user_data user data to pass to callback function
+ * \param timeout timeout for the transfer in milliseconds
+ */
+static inline void libusb_fill_bulk_transfer(struct libusb_transfer *transfer,
+	libusb_device_handle *dev_handle, unsigned char endpoint,
+	unsigned char *buffer, int length, libusb_transfer_cb_fn callback,
+	void *user_data, unsigned int timeout)
+{
+	transfer->dev_handle = dev_handle;
+	transfer->endpoint = endpoint;
+	transfer->type = LIBUSB_TRANSFER_TYPE_BULK;
+	transfer->timeout = timeout;
+	transfer->buffer = buffer;
+	transfer->length = length;
+	transfer->user_data = user_data;
+	transfer->callback = callback;
+}
+
+/** \ingroup libusb_asyncio
+ * Helper function to populate the required \ref libusb_transfer fields
+ * for a bulk transfer using bulk streams.
+ *
+ * Since version 1.0.19, \ref LIBUSB_API_VERSION >= 0x01000103
+ *
+ * \param transfer the transfer to populate
+ * \param dev_handle handle of the device that will handle the transfer
+ * \param endpoint address of the endpoint where this transfer will be sent
+ * \param stream_id bulk stream id for this transfer
+ * \param buffer data buffer
+ * \param length length of data buffer
+ * \param callback callback function to be invoked on transfer completion
+ * \param user_data user data to pass to callback function
+ * \param timeout timeout for the transfer in milliseconds
+ */
+static inline void libusb_fill_bulk_stream_transfer(
+	struct libusb_transfer *transfer, libusb_device_handle *dev_handle,
+	unsigned char endpoint, uint32_t stream_id,
+	unsigned char *buffer, int length, libusb_transfer_cb_fn callback,
+	void *user_data, unsigned int timeout)
+{
+	libusb_fill_bulk_transfer(transfer, dev_handle, endpoint, buffer,
+				  length, callback, user_data, timeout);
+	transfer->type = LIBUSB_TRANSFER_TYPE_BULK_STREAM;
+	libusb_transfer_set_stream_id(transfer, stream_id);
+}
+
+/** \ingroup libusb_asyncio
+ * Helper function to populate the required \ref libusb_transfer fields
+ * for an interrupt transfer.
+ *
+ * \param transfer the transfer to populate
+ * \param dev_handle handle of the device that will handle the transfer
+ * \param endpoint address of the endpoint where this transfer will be sent
+ * \param buffer data buffer
+ * \param length length of data buffer
+ * \param callback callback function to be invoked on transfer completion
+ * \param user_data user data to pass to callback function
+ * \param timeout timeout for the transfer in milliseconds
+ */
+static inline void libusb_fill_interrupt_transfer(
+	struct libusb_transfer *transfer, libusb_device_handle *dev_handle,
+	unsigned char endpoint, unsigned char *buffer, int length,
+	libusb_transfer_cb_fn callback, void *user_data, unsigned int timeout)
+{
+	transfer->dev_handle = dev_handle;
+	transfer->endpoint = endpoint;
+	transfer->type = LIBUSB_TRANSFER_TYPE_INTERRUPT;
+	transfer->timeout = timeout;
+	transfer->buffer = buffer;
+	transfer->length = length;
+	transfer->user_data = user_data;
+	transfer->callback = callback;
+}
+
+/** \ingroup libusb_asyncio
+ * Helper function to populate the required \ref libusb_transfer fields
+ * for an isochronous transfer.
+ *
+ * \param transfer the transfer to populate
+ * \param dev_handle handle of the device that will handle the transfer
+ * \param endpoint address of the endpoint where this transfer will be sent
+ * \param buffer data buffer
+ * \param length length of data buffer
+ * \param num_iso_packets the number of isochronous packets
+ * \param callback callback function to be invoked on transfer completion
+ * \param user_data user data to pass to callback function
+ * \param timeout timeout for the transfer in milliseconds
+ */
+static inline void libusb_fill_iso_transfer(struct libusb_transfer *transfer,
+	libusb_device_handle *dev_handle, unsigned char endpoint,
+	unsigned char *buffer, int length, int num_iso_packets,
+	libusb_transfer_cb_fn callback, void *user_data, unsigned int timeout)
+{
+	transfer->dev_handle = dev_handle;
+	transfer->endpoint = endpoint;
+	transfer->type = LIBUSB_TRANSFER_TYPE_ISOCHRONOUS;
+	transfer->timeout = timeout;
+	transfer->buffer = buffer;
+	transfer->length = length;
+	transfer->num_iso_packets = num_iso_packets;
+	transfer->user_data = user_data;
+	transfer->callback = callback;
+}
+
+/** \ingroup libusb_asyncio
+ * Convenience function to set the length of all packets in an isochronous
+ * transfer, based on the num_iso_packets field in the transfer structure.
+ *
+ * \param transfer a transfer
+ * \param length the length to set in each isochronous packet descriptor
+ * \see libusb_get_max_packet_size()
+ */
+static inline void libusb_set_iso_packet_lengths(
+	struct libusb_transfer *transfer, unsigned int length)
+{
+	int i;
+	for (i = 0; i < transfer->num_iso_packets; i++)
+		transfer->iso_packet_desc[i].length = length;
+}
+
+/** \ingroup libusb_asyncio
+ * Convenience function to locate the position of an isochronous packet
+ * within the buffer of an isochronous transfer.
+ *
+ * This is a thorough function which loops through all preceding packets,
+ * accumulating their lengths to find the position of the specified packet.
+ * Typically you will assign equal lengths to each packet in the transfer,
+ * and hence the above method is sub-optimal. You may wish to use
+ * libusb_get_iso_packet_buffer_simple() instead.
+ *
+ * \param transfer a transfer
+ * \param packet the packet to return the address of
+ * \returns the base address of the packet buffer inside the transfer buffer,
+ * or NULL if the packet does not exist.
+ * \see libusb_get_iso_packet_buffer_simple()
+ */
+static inline unsigned char *libusb_get_iso_packet_buffer(
+	struct libusb_transfer *transfer, unsigned int packet)
+{
+	int i;
+	size_t offset = 0;
+	int _packet;
+
+	/* oops..slight bug in the API. packet is an unsigned int, but we use
+	 * signed integers almost everywhere else. range-check and convert to
+	 * signed to avoid compiler warnings. FIXME for libusb-2. */
+	if (packet > INT_MAX)
+		return NULL;
+	_packet = (int) packet;
+
+	if (_packet >= transfer->num_iso_packets)
+		return NULL;
+
+	for (i = 0; i < _packet; i++)
+		offset += transfer->iso_packet_desc[i].length;
+
+	return transfer->buffer + offset;
+}
+
+/** \ingroup libusb_asyncio
+ * Convenience function to locate the position of an isochronous packet
+ * within the buffer of an isochronous transfer, for transfers where each
+ * packet is of identical size.
+ *
+ * This function relies on the assumption that every packet within the transfer
+ * is of identical size to the first packet. Calculating the location of
+ * the packet buffer is then just a simple calculation:
+ * <tt>buffer + (packet_size * packet)</tt>
+ *
+ * Do not use this function on transfers other than those that have identical
+ * packet lengths for each packet.
+ *
+ * \param transfer a transfer
+ * \param packet the packet to return the address of
+ * \returns the base address of the packet buffer inside the transfer buffer,
+ * or NULL if the packet does not exist.
+ * \see libusb_get_iso_packet_buffer()
+ */
+static inline unsigned char *libusb_get_iso_packet_buffer_simple(
+	struct libusb_transfer *transfer, unsigned int packet)
+{
+	int _packet;
+
+	/* oops..slight bug in the API. packet is an unsigned int, but we use
+	 * signed integers almost everywhere else. range-check and convert to
+	 * signed to avoid compiler warnings. FIXME for libusb-2. */
+	if (packet > INT_MAX)
+		return NULL;
+	_packet = (int) packet;
+
+	if (_packet >= transfer->num_iso_packets)
+		return NULL;
+
+	return transfer->buffer + ((int) transfer->iso_packet_desc[0].length * _packet);
+}
+
+/* sync I/O */
+
+int LIBUSB_CALL libusb_control_transfer(libusb_device_handle *dev_handle,
+	uint8_t request_type, uint8_t bRequest, uint16_t wValue, uint16_t wIndex,
+	unsigned char *data, uint16_t wLength, unsigned int timeout);
+
+int LIBUSB_CALL libusb_bulk_transfer(libusb_device_handle *dev_handle,
+	unsigned char endpoint, unsigned char *data, int length,
+	int *actual_length, unsigned int timeout);
+
+int LIBUSB_CALL libusb_interrupt_transfer(libusb_device_handle *dev_handle,
+	unsigned char endpoint, unsigned char *data, int length,
+	int *actual_length, unsigned int timeout);
+
+/** \ingroup libusb_desc
+ * Retrieve a descriptor from the default control pipe.
+ * This is a convenience function which formulates the appropriate control
+ * message to retrieve the descriptor.
+ *
+ * \param dev_handle a device handle
+ * \param desc_type the descriptor type, see \ref libusb_descriptor_type
+ * \param desc_index the index of the descriptor to retrieve
+ * \param data output buffer for descriptor
+ * \param length size of data buffer
+ * \returns number of bytes returned in data, or LIBUSB_ERROR code on failure
+ */
+static inline int libusb_get_descriptor(libusb_device_handle *dev_handle,
+	uint8_t desc_type, uint8_t desc_index, unsigned char *data, int length)
+{
+	return libusb_control_transfer(dev_handle, LIBUSB_ENDPOINT_IN,
+		LIBUSB_REQUEST_GET_DESCRIPTOR, (uint16_t) ((desc_type << 8) | desc_index),
+		0, data, (uint16_t) length, 1000);
+}
+
+/** \ingroup libusb_desc
+ * Retrieve a descriptor from a device.
+ * This is a convenience function which formulates the appropriate control
+ * message to retrieve the descriptor. The string returned is Unicode, as
+ * detailed in the USB specifications.
+ *
+ * \param dev_handle a device handle
+ * \param desc_index the index of the descriptor to retrieve
+ * \param langid the language ID for the string descriptor
+ * \param data output buffer for descriptor
+ * \param length size of data buffer
+ * \returns number of bytes returned in data, or LIBUSB_ERROR code on failure
+ * \see libusb_get_string_descriptor_ascii()
+ */
+static inline int libusb_get_string_descriptor(libusb_device_handle *dev_handle,
+	uint8_t desc_index, uint16_t langid, unsigned char *data, int length)
+{
+	return libusb_control_transfer(dev_handle, LIBUSB_ENDPOINT_IN,
+		LIBUSB_REQUEST_GET_DESCRIPTOR, (uint16_t)((LIBUSB_DT_STRING << 8) | desc_index),
+		langid, data, (uint16_t) length, 1000);
+}
+
+int LIBUSB_CALL libusb_get_string_descriptor_ascii(libusb_device_handle *dev_handle,
+	uint8_t desc_index, unsigned char *data, int length);
+
+/* polling and timeouts */
+
+int LIBUSB_CALL libusb_try_lock_events(libusb_context *ctx);
+void LIBUSB_CALL libusb_lock_events(libusb_context *ctx);
+void LIBUSB_CALL libusb_unlock_events(libusb_context *ctx);
+int LIBUSB_CALL libusb_event_handling_ok(libusb_context *ctx);
+int LIBUSB_CALL libusb_event_handler_active(libusb_context *ctx);
+void LIBUSB_CALL libusb_interrupt_event_handler(libusb_context *ctx);
+void LIBUSB_CALL libusb_lock_event_waiters(libusb_context *ctx);
+void LIBUSB_CALL libusb_unlock_event_waiters(libusb_context *ctx);
+int LIBUSB_CALL libusb_wait_for_event(libusb_context *ctx, struct timeval *tv);
+
+int LIBUSB_CALL libusb_handle_events_timeout(libusb_context *ctx,
+	struct timeval *tv);
+int LIBUSB_CALL libusb_handle_events_timeout_completed(libusb_context *ctx,
+	struct timeval *tv, int *completed);
+int LIBUSB_CALL libusb_handle_events(libusb_context *ctx);
+int LIBUSB_CALL libusb_handle_events_completed(libusb_context *ctx, int *completed);
+int LIBUSB_CALL libusb_handle_events_locked(libusb_context *ctx,
+	struct timeval *tv);
+int LIBUSB_CALL libusb_pollfds_handle_timeouts(libusb_context *ctx);
+int LIBUSB_CALL libusb_get_next_timeout(libusb_context *ctx,
+	struct timeval *tv);
+
+/** \ingroup libusb_poll
+ * File descriptor for polling
+ */
+struct libusb_pollfd {
+	/** Numeric file descriptor */
+	int fd;
+
+	/** Event flags to poll for from <poll.h>. POLLIN indicates that you
+	 * should monitor this file descriptor for becoming ready to read from,
+	 * and POLLOUT indicates that you should monitor this file descriptor for
+	 * nonblocking write readiness. */
+	short events;
+};
+
+/** \ingroup libusb_poll
+ * Callback function, invoked when a new file descriptor should be added
+ * to the set of file descriptors monitored for events.
+ * \param fd the new file descriptor
+ * \param events events to monitor for, see \ref libusb_pollfd for a
+ * description
+ * \param user_data User data pointer specified in
+ * libusb_set_pollfd_notifiers() call
+ * \see libusb_set_pollfd_notifiers()
+ */
+typedef void (LIBUSB_CALL *libusb_pollfd_added_cb)(int fd, short events,
+	void *user_data);
+
+/** \ingroup libusb_poll
+ * Callback function, invoked when a file descriptor should be removed from
+ * the set of file descriptors being monitored for events. After returning
+ * from this callback, do not use that file descriptor again.
+ * \param fd the file descriptor to stop monitoring
+ * \param user_data User data pointer specified in
+ * libusb_set_pollfd_notifiers() call
+ * \see libusb_set_pollfd_notifiers()
+ */
+typedef void (LIBUSB_CALL *libusb_pollfd_removed_cb)(int fd, void *user_data);
+
+const struct libusb_pollfd ** LIBUSB_CALL libusb_get_pollfds(
+	libusb_context *ctx);
+void LIBUSB_CALL libusb_free_pollfds(const struct libusb_pollfd **pollfds);
+void LIBUSB_CALL libusb_set_pollfd_notifiers(libusb_context *ctx,
+	libusb_pollfd_added_cb added_cb, libusb_pollfd_removed_cb removed_cb,
+	void *user_data);
+
+/** \ingroup libusb_hotplug
+ * Callback handle.
+ *
+ * Callbacks handles are generated by libusb_hotplug_register_callback()
+ * and can be used to deregister callbacks. Callback handles are unique
+ * per libusb_context and it is safe to call libusb_hotplug_deregister_callback()
+ * on an already deregisted callback.
+ *
+ * Since version 1.0.16, \ref LIBUSB_API_VERSION >= 0x01000102
+ *
+ * For more information, see \ref libusb_hotplug.
+ */
+typedef int libusb_hotplug_callback_handle;
+
+/** \ingroup libusb_hotplug
+ *
+ * Since version 1.0.16, \ref LIBUSB_API_VERSION >= 0x01000102
+ *
+ * Flags for hotplug events */
+typedef enum {
+	/** Default value when not using any flags. */
+	LIBUSB_HOTPLUG_NO_FLAGS = 0,
+
+	/** Arm the callback and fire it for all matching currently attached devices. */
+	LIBUSB_HOTPLUG_ENUMERATE = 1<<0,
+} libusb_hotplug_flag;
+
+/** \ingroup libusb_hotplug
+ *
+ * Since version 1.0.16, \ref LIBUSB_API_VERSION >= 0x01000102
+ *
+ * Hotplug events */
+typedef enum {
+	/** A device has been plugged in and is ready to use */
+	LIBUSB_HOTPLUG_EVENT_DEVICE_ARRIVED = 0x01,
+
+	/** A device has left and is no longer available.
+	 * It is the user's responsibility to call libusb_close on any handle associated with a disconnected device.
+	 * It is safe to call libusb_get_device_descriptor on a device that has left */
+	LIBUSB_HOTPLUG_EVENT_DEVICE_LEFT    = 0x02,
+} libusb_hotplug_event;
+
+/** \ingroup libusb_hotplug
+ * Wildcard matching for hotplug events */
+#define LIBUSB_HOTPLUG_MATCH_ANY -1
+
+/** \ingroup libusb_hotplug
+ * Hotplug callback function type. When requesting hotplug event notifications,
+ * you pass a pointer to a callback function of this type.
+ *
+ * This callback may be called by an internal event thread and as such it is
+ * recommended the callback do minimal processing before returning.
+ *
+ * libusb will call this function later, when a matching event had happened on
+ * a matching device. See \ref libusb_hotplug for more information.
+ *
+ * It is safe to call either libusb_hotplug_register_callback() or
+ * libusb_hotplug_deregister_callback() from within a callback function.
+ *
+ * Since version 1.0.16, \ref LIBUSB_API_VERSION >= 0x01000102
+ *
+ * \param ctx            context of this notification
+ * \param device         libusb_device this event occurred on
+ * \param event          event that occurred
+ * \param user_data      user data provided when this callback was registered
+ * \returns bool whether this callback is finished processing events.
+ *                       returning 1 will cause this callback to be deregistered
+ */
+typedef int (LIBUSB_CALL *libusb_hotplug_callback_fn)(libusb_context *ctx,
+						libusb_device *device,
+						libusb_hotplug_event event,
+						void *user_data);
+
+/** \ingroup libusb_hotplug
+ * Register a hotplug callback function
+ *
+ * Register a callback with the libusb_context. The callback will fire
+ * when a matching event occurs on a matching device. The callback is
+ * armed until either it is deregistered with libusb_hotplug_deregister_callback()
+ * or the supplied callback returns 1 to indicate it is finished processing events.
+ *
+ * If the \ref LIBUSB_HOTPLUG_ENUMERATE is passed the callback will be
+ * called with a \ref LIBUSB_HOTPLUG_EVENT_DEVICE_ARRIVED for all devices
+ * already plugged into the machine. Note that libusb modifies its internal
+ * device list from a separate thread, while calling hotplug callbacks from
+ * libusb_handle_events(), so it is possible for a device to already be present
+ * on, or removed from, its internal device list, while the hotplug callbacks
+ * still need to be dispatched. This means that when using \ref
+ * LIBUSB_HOTPLUG_ENUMERATE, your callback may be called twice for the arrival
+ * of the same device, once from libusb_hotplug_register_callback() and once
+ * from libusb_handle_events(); and/or your callback may be called for the
+ * removal of a device for which an arrived call was never made.
+ *
+ * Since version 1.0.16, \ref LIBUSB_API_VERSION >= 0x01000102
+ *
+ * \param[in] ctx context to register this callback with
+ * \param[in] events bitwise or of events that will trigger this callback. See \ref
+ *            libusb_hotplug_event
+ * \param[in] flags hotplug callback flags. See \ref libusb_hotplug_flag
+ * \param[in] vendor_id the vendor id to match or \ref LIBUSB_HOTPLUG_MATCH_ANY
+ * \param[in] product_id the product id to match or \ref LIBUSB_HOTPLUG_MATCH_ANY
+ * \param[in] dev_class the device class to match or \ref LIBUSB_HOTPLUG_MATCH_ANY
+ * \param[in] cb_fn the function to be invoked on a matching event/device
+ * \param[in] user_data user data to pass to the callback function
+ * \param[out] callback_handle pointer to store the handle of the allocated callback (can be NULL)
+ * \returns LIBUSB_SUCCESS on success LIBUSB_ERROR code on failure
+ */
+int LIBUSB_CALL libusb_hotplug_register_callback(libusb_context *ctx,
+						libusb_hotplug_event events,
+						libusb_hotplug_flag flags,
+						int vendor_id, int product_id,
+						int dev_class,
+						libusb_hotplug_callback_fn cb_fn,
+						void *user_data,
+						libusb_hotplug_callback_handle *callback_handle);
+
+/** \ingroup libusb_hotplug
+ * Deregisters a hotplug callback.
+ *
+ * Deregister a callback from a libusb_context. This function is safe to call from within
+ * a hotplug callback.
+ *
+ * Since version 1.0.16, \ref LIBUSB_API_VERSION >= 0x01000102
+ *
+ * \param[in] ctx context this callback is registered with
+ * \param[in] callback_handle the handle of the callback to deregister
+ */
+void LIBUSB_CALL libusb_hotplug_deregister_callback(libusb_context *ctx,
+						libusb_hotplug_callback_handle callback_handle);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif
diff --git a/IMX6ULL/source/12_USB/01_libusb示例程序/dnw_for_libusb1.0/说明.txt b/IMX6ULL/source/12_USB/01_libusb示例程序/dnw_for_libusb1.0/说明.txt
new file mode 100644
index 0000000..bfe1d37
--- /dev/null
+++ b/IMX6ULL/source/12_USB/01_libusb示例程序/dnw_for_libusb1.0/说明.txt
@@ -0,0 +1,22 @@
+1．可以直接使用我们编译好的dnw可执行程序:
+   先把dnw放入ubuntu的/usr/bin目录
+   然后修改属性:
+   sudo chmod +x /usr/bin/dnw
+   最后参考"dnw使用说明.txt"
+   
+2. 我们也提供了源码, 你可以尝试自己编译:
+2.1 先编译libusb1.0库:
+    tar xjf libusb-1.0.21.tar.bz2
+	cd libusb-1.0.21
+	./configure --enable-udev=no
+	make
+
+2.2 把库文件、头文件取出来:	
+	cp  libusb-1.0.21/libusb/.libs/libusb-1.0.a    <dnw.c的目录>
+	cp  libusb-1.0.21/libusb/libusb.h              <dnw.c的目录>
+
+2.3 编译dnw:
+    cd 	<dnw.c的目录>
+	make
+	
+	
\ No newline at end of file
diff --git a/IMX6ULL/source/12_USB/01_libusb示例程序/openocd-master.zip b/IMX6ULL/source/12_USB/01_libusb示例程序/openocd-master.zip
new file mode 100644
index 0000000..2c3c278
Binary files /dev/null and b/IMX6ULL/source/12_USB/01_libusb示例程序/openocd-master.zip differ
diff --git a/README.md b/README.md
index 761111c..140cd50 100644
--- a/README.md
+++ b/README.md
@@ -651,6 +651,14 @@ git clone https://e.coding.net/weidongshan/linux/doc_and_source_for_drivers.git
   05.2_设备枚举过程
   ```
 
+* 2021.09.20 发布"USB子系统"
+
+  ```shell
+  06.1_libusb的使用流程
+  06.2_libusb的API接口简单介绍
+  06.3_libusb的示例代码
+  ```
+
   
 
 
diff --git a/STM32MP157/doc_pic/12_USB/06_libusb的使用.md b/STM32MP157/doc_pic/12_USB/06_libusb的使用.md
new file mode 100644
index 0000000..9397458
--- /dev/null
+++ b/STM32MP157/doc_pic/12_USB/06_libusb的使用.md
@@ -0,0 +1,1245 @@
+# libusb的使用 #
+
+参考资料：
+
+* 《圈圈教你玩USB》
+* 简书jianshu_kevin@126.com的文章
+  * [USB协议（一）](https://www.jianshu.com/p/3afc1eb5bd32)
+  * [USB协议(二)](https://www.jianshu.com/p/cf8e7df5ff09)
+  * [USB协议(三)](https://www.jianshu.com/p/2a6e22194cd3)
+* 官网：https://www.usb.org/documents
+  ![image-20220721151007143](pic/02_usb_doc.png)
+* libusb GIT仓库：https://github.com/libusb/libusb.git
+* libusb 官网：https://libusb.info/
+* libusb API接口：https://libusb.sourceforge.io/api-1.0/
+* libusb 示例：https://github.com/libusb/libusb/tree/master/examples
+
+## 1. 概述
+
+### 1.1 介绍
+
+libusb是一个使用C编写的库，它提供USB设备的通用的访问方法。APP通过它，可以方便地访问USB设备，无需编写USB设备驱动程序。
+
+* 可移植性：支持Linux、macOS、Windows、Android、OpenBSD等
+* 用户模式：APP不需要特权模式、也不需要提升自己的权限即可访问USB设备
+* 支持所有USB协议：从1.0到3.1都支持
+
+libusb支持所有的传输类型(控制/批量/中断/实时)，有两类API接口：同步(Synchronous，简单)，异步(Asynchronous，复杂但是更强大)。它是轻量级的、线程安全的。还支持热拔插。
+
+
+
+### 1.2 用法
+
+可以通过libusb访问USB设备，不需要USB设备端的驱动程序，需要移除原来的驱动程序。然后就可以直接访问USB控制器的驱动程序，使用open/read/write/ioctl/close这些接口来打开设备、收发数据、关闭设备。
+libusb封装了更好用的函数，这些函数的使用可以分为5个步骤：
+
+* 初始化
+* 打开设备
+* 移除原驱动/认领接口
+* 传输
+* 关闭设备
+
+![image-20220920101859185](pic/54_libusb_flow.png)
+
+
+
+## 2. API接口
+
+### 2.1 分类
+
+libusb的接口函数分为两类：同步(Synchronous device I/O)、异步(Asynchronous device I/O)。
+
+USB数据传输分为两个步骤，对于读数据，先给设备发出数据的请求，一段时间后数据返回；对于写数据，先发送数据给设备，一段时间后得到回应。
+
+同步接口的核心在于把上述两个步骤放在一个函数里面。比如想去读取一个USB键盘的数据，给键盘发出读请求后，如果用户一直没有按下键盘，那么读函数会一直等待。
+
+异步接口的核心在于把上述两个步骤分开：使用一个非阻塞的函数启动传输，它会立刻返回；提供一个回调函数用来处理返回结果。
+
+同步接口的示例代码如下，在`libusb_bulk_transfer`函数内部，如果没有数据则会休眠：
+
+```c
+unsigned char data[4];
+int actual_length;
+int r = libusb_bulk_transfer(dev_handle, LIBUSB_ENDPOINT_IN, data, sizeof(data), &actual_length, 0);
+if (r == 0 && actual_length == sizeof(data)) {
+    // 接收到的数据保存在data数组里
+    // 解析这些数据就可以知道按键状态
+} else {
+    error();
+}
+```
+
+使用同步接口时，代码比较简单。但是无法实现"多endpoint"的操作：上一个endpoint的传输在休眠，除非使用另一个线程，否则在同一个线程内部在等待期间是无法操作另一个endpoint的。还有另一个缺点：无法取消传输。
+
+异步接口是在libusb-1.0引入的新性能，接口更复杂，但是功能更强大。在异步接口函数里，它启动传输、设置回调函数后就立刻返回。等"读到数据"或是"得到回应"后，回调函数被调用。发起数据传输的线程无需休眠等待结果，它支持"多endpoint"的操作，也支持取消传输。
+
+
+
+### 2.2 初始化/反初始化
+
+```c
+/** \ingroup libusb_lib
+ * 初始化libusb，这个函数必须先于其他libusb的函数执行
+ *
+ * 如果传入NULL，那么函数内部会穿件一个默认的context
+ * 如果已经创建过默认的context，这个context会被重新使用(不会重新初始化它)
+ *
+ * 参数：
+ * ctx : context pointer的位置，也可以传入NULL
+ * 返回值
+ * 0 - 成功
+ * 负数 - 失败
+ */
+int API_EXPORTED libusb_init(libusb_context **ctx);
+```
+
+初始化libusb，参数是一个"a context pointer"的指针，如果这个参数为NULL，则函数内部会创建一个"default context"。所谓"libusb context"就是libusb上下文，就是一个结构体，里面保存有各类信息，比如：libusb的调试信息是否需要打印、各种互斥锁、各类链表(用来记录USB传输等等)。
+
+
+
+程序退出前，调用如下函数：
+
+```c
+/** \ingroup libusb_lib
+ * 发初始化libusb
+ * 在关闭usb设备(libusb_close)后、退出程序前调用此函数
+ *
+ * 参数:
+ * ctx : context, 传入NULL表示default context
+ */
+void API_EXPORTED libusb_exit(libusb_context *ctx);
+```
+
+
+
+
+
+### 2.3 获取设备
+
+可以使用`libusb_get_device_list`取出所有设备，函数接口如下：
+
+```c
+/** @ingroup libusb_dev
+ * 返回一个list，list里含有当前系统中所有的USB设备
+ *
+ * 我们一般会在list里寻找需要访问的设备，找到之后使用libusb_open函数打开它
+ * 然后调用libusb_free_device_list释放list
+ *
+ * 这个函数的返回值表示list中有多少个设备
+ * list的最后一项是NULL
+ *
+ * 参数:
+ * ctx  : context
+ * list : output location for a list of devices, 最后必须调用libusb_free_device_list()来释放它
+ * 返回值: list中设备的个数, 或错误值
+ */
+ssize_t API_EXPORTED libusb_get_device_list(libusb_context *ctx,
+	libusb_device ***list);
+```
+
+调用此函数后，所有设备的信息存入list，然后遍历list，找到想操作的设备。这个函数内部会分配list的空间，所以用完后要释放掉，使用以下函数释放：
+
+```c
+/** \ingroup libusb_dev
+ * 前面使用libusb_get_device_list()获得了设备list, 
+ * 使用完后要调用libusb_free_device_list()释放这个list
+ * 如果参数unref_devices为1, 则list中每个设备的引用计数值减小1
+ * 参数: 
+ * list : 要释放的设备list
+ * unref_devices : 是否要将设备的引用计数减1
+ */
+void API_EXPORTED libusb_free_device_list(libusb_device **list,
+	int unref_devices);
+```
+
+### 2.4 打开/关闭设备
+
+使用libusb_get_device_list得到设备列表后，可以选择里面的某个设备，然后调用libusb_open：
+
+```c
+/** \ingroup libusb_dev
+ * 打开一个设备并得到它的句柄, 以后进行IO操作时都是使用句柄
+ *
+ * 使用libusb_get_device()函数可以得到设备的list, 
+ * 从list里确定你要访问的设备后, 使用libusb_open()去打开它。
+ * libusb_open()函数内部会增加此设备的引用计数, 使用完毕后要调用libusb_close()减小引用计数。
+ *
+ * 参数:
+ * dev : 要打开的设备
+ * dev_handle : 输出参数, 用来保存句柄
+ * 返回值: 
+ * 0 - 成功
+ * LIBUSB_ERROR_NO_MEM : 缺少内存
+ * LIBUSB_ERROR_ACCESS : 权限不足
+ * LIBUSB_ERROR_NO_DEVICE : 这个设备未连接
+ * 其他错误 : 其他LIBUSB_ERROR错误码
+ */
+int API_EXPORTED libusb_open(libusb_device *dev,
+	libusb_device_handle **dev_handle);
+```
+
+使用libusb_open函数打开USB设备后，可以得到一个句柄：libusb_device_handle。以后调用各种数据传输函数时，就是使用libusb_device_handle。
+
+使用完毕后，调用libusb_close关闭设备，函数原型如下：
+
+```c
+/** \ingroup libusb_dev
+ * 关闭设备句柄, 在程序退出之前应该使用它去关闭已经打开的句柄
+ *
+ * 设备的引用计数在前面被libusb_open()函数增加了。
+ * 在libusb_close()函数的内部，它会减小设备的引用计数。
+ *
+ * 参数: dev_handle - 句柄
+ */
+void API_EXPORTED libusb_close(libusb_device_handle *dev_handle);
+```
+
+
+
+### 2.5 根据ID打开设备
+
+如果知道设备的VID、PID，那么可以使用libusb_open_device_with_vid_pid来找到它、打开它。这个函数的内部，先使用`libusb_get_device_list`列出所有设备，然后遍历它们根据ID选出设备，接着调用libusb_open打开它，最后调用libusb_free_device_list释放设备。
+
+libusb_open_device_with_vid_pid函数原型如下：
+
+```c
+/** \ingroup libusb_dev
+ * 打开设备的常规做法是使用libusb_get_device_list()得到设备list，
+ * 然后遍历list，找到设备
+ * 接着使用libusb_open()函数得到句柄
+ * 
+ * 如果知道USB设备的VID、PID，那么可以使用libusb_open_device_with_vid_pid()函数快速打开它，得到句柄。
+ * 
+ * 这个函数有一个缺点: 如果系统中有多个ID相同的设备，你只能打开第1个设备
+ *
+ * 参数:
+ * ctx : context, 或者传入NULL以使用默认的context
+ * vendor_id : 厂家ID
+ * product_id : 产品ID
+ * 
+ * 返回值: 
+ * 句柄 - 找到的第1个设备的句柄
+ * NULL - 没有找到设备
+ */
+DEFAULT_VISIBILITY
+libusb_device_handle * LIBUSB_CALL libusb_open_device_with_vid_pid(
+	libusb_context *ctx, uint16_t vendor_id, uint16_t product_id);
+```
+
+
+### 2.6 描述符相关函数
+
+#### 2.6.1 获得设备描述符
+
+```c
+/** \ingroup libusb_desc
+ * 获得设备描述符
+ *
+ * 参数:
+ * dev - 哪个设备
+ * desc - 输出参数, 用来保存设备描述符
+ *
+ * 返回值:
+ * 0 - 成功, 或其他LIBUSB_ERROR错误码
+ */
+int API_EXPORTED libusb_get_device_descriptor(libusb_device *dev,
+	struct libusb_device_descriptor *desc);
+```
+
+#### 2.6.2 获得/释放配置描述符
+
+```c
+/** \ingroup libusb_desc
+ * 获得指定的配置描述符
+ *
+ * 参数:
+ * dev - 哪个设备
+ * config_index - 哪个配置
+ * config - 输出参数, 用来保存配置描述符, 使用完毕要调用libusb_free_config_descriptor()释放掉
+ * 
+ * 返回值:
+ * 0 - 成功
+ * LIBUSB_ERROR_NOT_FOUND - 没有这个配置
+ * 其他LIBUSB_ERROR错误码
+ */
+int API_EXPORTED libusb_get_config_descriptor(libusb_device *dev,
+	uint8_t config_index, struct libusb_config_descriptor **config);
+
+/** \ingroup libusb_desc
+ * Free a configuration descriptor obtained from
+ * 前面使用libusb_get_active_config_descriptor()或libusb_get_config_descriptor()获得配置描述符，
+ * 用完后调用libusb_free_config_descriptor()释放掉
+ */
+void API_EXPORTED libusb_free_config_descriptor(
+	struct libusb_config_descriptor *config);
+```
+
+
+
+### 2.7 detach/attach驱动
+
+#### 2.7.1 两种方法
+
+使用libusb访问USB设备时，需要先移除(detach)设备原来的驱动程序，然后认领接口(claim interface)。有两种办法：
+
+* 方法1：
+
+  ```c
+  // 只是设置一个标记位表示libusb_claim_interface
+  // 使用libusb_claim_interface时会detach原来的驱动
+  libusb_set_auto_detach_kernel_driver(hdev, 1);  
+  
+  // 标记这个interface已经被使用认领了
+  libusb_claim_interface(hdev, interface_number);
+  ```
+
+* 方法2：
+
+  ```c
+  // detach原来的驱动
+  libusb_detach_kernel_driver(hdev, interface_number);
+  
+  // 标记这个interface已经被使用认领了
+  libusb_claim_interface(hdev, interface_number);
+  ```
+
+  
+
+#### 2.7.2 函数原型
+
+函数`libusb_detach_kernel_driver`原型如下：
+
+```c
+/** \ingroup libusb_dev
+ * 给USB设备的接口(interface)移除驱动程序. If successful, you will then be
+ * 移除原来的驱动后才能"claim the interface"、执行IO操作
+ *
+ * 实际上libusb会给这个接口安装一个特殊的内核驱动,
+ * 所以本函数"移除驱动"是移除其他驱动，不是移除这个特殊的驱动。
+ * 若干这个接口已经安装了这个特殊的驱动，本函数会返回LIBUSB_ERROR_NOT_FOUND.
+ *
+ * 参数:
+ * dev_handle - 设备句柄
+ * interface_number - 哪一个接口
+ * 
+ * 返回值:
+ * 0 - 成功
+ * LIBUSB_ERROR_NOT_FOUND - 这个接口没有安装其他驱动
+ * LIBUSB_ERROR_INVALID_PARAM - 没有这个接口
+ * LIBUSB_ERROR_NO_DEVICE - 这个设备未连接
+ * LIBUSB_ERROR_NOT_SUPPORTED - 系统不支持此操作, 比如Windows
+ * 其他LIBUSB_ERROR错误码
+ */
+int API_EXPORTED libusb_detach_kernel_driver(libusb_device_handle *dev_handle,
+	int interface_number);
+```
+
+
+
+函数`libusb_claim_interface`原型如下：
+
+```c
+/** \ingroup libusb_dev
+ * libusb使用内核里一个特殊的驱动程序，
+ * libusb_claim_interface()函数就是给某个usb接口安装这个特殊的驱动程序，
+ * 在使用libusb的函数执行IO操作之前必须调用本函数。
+ *
+ * 你可以给"已经claim过的接口"再次调用本函数，它直接返回0。
+ *
+ * 如果这个接口的auto_detach_kernel_driver被设置为1，
+ * libusb_claim_interface()函数会先移除其他驱动。
+ *
+ * 本函数时纯粹的逻辑操作：只是替换接口的驱动程序而已，不会导致USB硬件传输。
+ *
+ * 参数:
+ * dev_handle - 句柄, 表示USB设备
+ * interface_number - 接口
+ *
+ * 返回值:
+ * 0 - 成功
+ * LIBUSB_ERROR_NOT_FOUND - 没有这个接口
+ * LIBUSB_ERROR_BUSY - 其他APP或者驱动正在使用这个接口
+ * LIBUSB_ERROR_NO_DEVICE - 设备未连接
+ * 其他LIBUSB_ERROR错误码
+ */
+int API_EXPORTED libusb_claim_interface(libusb_device_handle *dev_handle,
+	int interface_number);
+```
+
+
+
+使用完USB设备后，在调用libusb_close之前，应该`libusb_release_interface`释放接口：
+
+```c
+/** \ingroup libusb_dev
+ * 前面使用libusb_claim_interface()给接口安装了给libusb使用的特殊驱动程序,
+ * 使用完毕后，在调用libusb_close()关闭句柄之前，
+ * 可以调用libusb_release_interface()卸载特殊驱动程序
+ * 如果设备的auto_detach_kernel_driver为1，还会重新安装普通驱动程序
+ * 
+ * 这是一个阻塞函数, 它会给USB设备发送一个请求: SET_INTERFACE control,
+ * 用来把接口的状态复位到第1个setting(the first alternate setting)
+ *
+ * 参数:
+ * dev_handle - 设备句柄
+ * interface_number - 哪个接口
+ * 
+ * 返回值:
+ * 0 - 成功
+ * LIBUSB_ERROR_NOT_FOUND - 这个接口没有被claim(没有安装特殊的驱动程序)
+ * LIBUSB_ERROR_NO_DEVICE - 设备未连接
+ * 其他LIBUSB_ERROR错误码
+ */
+int API_EXPORTED libusb_release_interface(libusb_device_handle *dev_handle,
+	int interface_number);
+```
+
+
+
+
+### 2.8 同步传输函数
+
+#### 2.8.1 控制传输
+
+```c
+/** \ingroup libusb_syncio
+ * 启动控制传输
+ *
+ * 传输方向在bmRequestType里
+ * wValue,wIndex和wLength是host-endian字节序
+ *
+ * 参数:
+ * dev_handle - 设备句柄
+ * bmRequestType - setup数据包的bmRequestType域
+ * bRequest      - setup数据包的bRequest域
+ * wValue        - setup数据包的wValue域
+ * wIndex        - setup数据包的wIndex域
+ * data          - 保存数据的buffer, 可以是in、out数据
+ * wLength       - setup数据包的wLength域
+ * timeout       - 超时时间(单位ms)，就是这个函数能等待的最大时间; 0表示一直等待直到成功
+ * 
+ * 返回值:
+ * 正整数 - 成功传输的数据的长度
+ * LIBUSB_ERROR_TIMEOUT - 超时
+ * LIBUSB_ERROR_PIPE  - 设备不支持该请求
+ * LIBUSB_ERROR_NO_DEVICE - 设备未连接
+ * LIBUSB_ERROR_BUSY - 如果这个函数时在事件处理上下文(event handling context)里则返回这个错误
+ * LIBUSB_ERROR_INVALID_PARAM - 传输的字节超过OS或硬件的支持
+ * the operating system and/or hardware can support (see \ref asynclimits)
+ * 其他LIBUSB_ERROR错误码
+ */
+int API_EXPORTED libusb_control_transfer(libusb_device_handle *dev_handle,
+	uint8_t bmRequestType, uint8_t bRequest, uint16_t wValue, uint16_t wIndex,
+	unsigned char *data, uint16_t wLength, unsigned int timeout);
+```
+
+
+
+#### 2.8.2 批量传输
+
+```c
+/** \ingroup libusb_syncio
+ * 启动批量传输
+ * 传输方向在endpoint的"方向位"里表示
+ *
+ * 对于批量读，参数length表示"期望读到的数据最大长度", 实际读到的长度保存在transferred参数里
+ *
+ * 对于批量写, transferred参数表示实际发送出去的数据长度
+ *
+ * 发生超时错误时，也应该检查transferred参数。
+ * libusb会根据硬件的特点把数据拆分为一小段一小段地发送出去，
+ * 这意味着发送满某段数据后可能就发生超时错误，需要根据transferred参数判断传输了多少数据。
+ *
+ * 参数:
+ * dev_handle - 设备句柄
+ * endpoint - 端点
+ * data          - 保存数据的buffer, 可以是in、out数据
+ * length  - 对于批量写，它表示要发送的数据长度; 对于批量读，它表示"要读的数据的最大长度"
+ * transferred - 输出参数，表示实际传输的数据长度
+ * timeout       - 超时时间(单位ms)，就是这个函数能等待的最大时间; 0表示一直等待直到成功
+ *
+ * 返回值:
+ * 0 - 成功，根据transferred参数判断传输了多少长度的数据
+ * LIBUSB_ERROR_TIMEOUT - 超时, 根据transferred参数判断传输了多少长度的数据
+ * LIBUSB_ERROR_PIPE - 端点错误，端点被挂起了
+ * LIBUSB_ERROR_OVERFLOW - 溢出，设备提供的数据太多了
+ * LIBUSB_ERROR_NO_DEVICE - 设备未连接
+ * LIBUSB_ERROR_BUSY - 如果这个函数时在事件处理上下文(event handling context)里则返回这个错误
+ * LIBUSB_ERROR_INVALID_PARAM - 传输的字节超过OS或硬件的支持
+ * 其他LIBUSB_ERROR错误码
+ */
+int API_EXPORTED libusb_bulk_transfer(libusb_device_handle *dev_handle,
+	unsigned char endpoint, unsigned char *data, int length,
+	int *transferred, unsigned int timeout);
+```
+
+
+
+#### 2.8.3 中断传输
+
+```c
+/** \ingroup libusb_syncio
+ * 启动中断传输
+ * 传输方向在endpoint的"方向位"里表示
+ *
+ * 对于中断读，参数length表示"期望读到的数据最大长度", 实际读到的长度保存在transferred参数里
+ *
+ * 对于中断写, transferred参数表示实际发送出去的数据长度，不一定能发送完全部数据。
+ *
+ * 发生超时错误时，也应该检查transferred参数。
+ * libusb会根据硬件的特点把数据拆分为一小段一小段地发送出去，
+ * 这意味着发送满某段数据后可能就发生超时错误，需要根据transferred参数判断传输了多少数据。
+ *
+ * 参数:
+ * dev_handle - 设备句柄
+ * endpoint - 端点
+ * data          - 保存数据的buffer, 可以是in、out数据
+ * length  - 对于批量写，它表示要发送的数据长度; 对于批量读，它表示"要读的数据的最大长度"
+ * transferred - 输出参数，表示实际传输的数据长度
+ * timeout       - 超时时间(单位ms)，就是这个函数能等待的最大时间; 0表示一直等待直到成功
+ *
+ * 返回值:
+ * 0 - 成功，根据transferred参数判断传输了多少长度的数据
+ * LIBUSB_ERROR_TIMEOUT - 超时, 根据transferred参数判断传输了多少长度的数据
+ * LIBUSB_ERROR_PIPE - 端点错误，端点被挂起了
+ * LIBUSB_ERROR_OVERFLOW - 溢出，设备提供的数据太多了
+ * LIBUSB_ERROR_NO_DEVICE - 设备未连接
+ * LIBUSB_ERROR_BUSY - 如果这个函数时在事件处理上下文(event handling context)里则返回这个错误
+ * LIBUSB_ERROR_INVALID_PARAM - 传输的字节超过OS或硬件的支持
+ * 其他LIBUSB_ERROR错误码
+ */
+int API_EXPORTED libusb_interrupt_transfer(libusb_device_handle *dev_handle,
+	unsigned char endpoint, unsigned char *data, int length,
+	int *transferred, unsigned int timeout);
+```
+
+
+
+### 2.9 异步传输函数
+
+#### 2.9.1 使用步骤
+
+使用libusb的异步函数时，有如下步骤：
+
+* 分配：分配一个`libusb_transfer`结构体
+* 填充：填充`libusb_transfer`结构体，比如想访问哪个endpoint、数据buffer、长度等等
+* 提交：提交`libusb_transfer`结构体启动传输
+* 处理事件：检查传输的结果，调用`libusb_transfer`结构体的回调函数
+* 释放：释放资源，比如释放`libusb_transfer`结构体
+
+
+
+#### 2.9.2 分配transfer结构体
+
+```c
+/** \ingroup libusb_asyncio
+ * 分配一个libusb_transfer结构体，
+ * 如果iso_packets不为0，还会分配iso_packets个libusb_iso_packet_descriptor结构体
+ * 使用完毕后需要调用libusb_free_transfer()函数释放掉
+ *
+ * 对于控制传输、批量传输、中断传输，iso_packets参数需要设置为0
+ *
+ * 对于实时传输，需要指定iso_packets参数，
+ * 这个函数会一起分配iso_packets个libusb_iso_packet_descriptor结构体。
+ * 这个函数返回的libusb_transfer结构体并未初始化，
+ * 你还需要初始化它的这些成员:
+ *   libusb_transfer::num_iso_packets
+ *   libusb_transfer::type
+ *
+ * 你可以指定iso_packets参数，意图给实时传输分配结构体，
+ * 但是你可以把这个结构题用于其他类型的传输，
+ * 在这种情况下，只要确保num_iso_packets为0就可以。
+ *
+ * 参数:
+ * iso_packets - 分配多少个isochronous packet descriptors to allocate
+ *
+ * 返回值:
+ * 返回一个libusb_transfer结构体或NULL
+ */
+DEFAULT_VISIBILITY
+struct libusb_transfer * LIBUSB_CALL libusb_alloc_transfer(
+	int iso_packets);
+```
+
+
+
+#### 2.9.3 填充控制传输
+
+```c
+/** \ingroup libusb_asyncio
+ * 构造控制传输结构体
+ *
+ * 如果你传入buffer参数，那么buffer的前面8字节会被当做"control setup packet"来解析，
+ * buffer的最后2字节表示wLength，它也会被用来设置libusb_transfer::length
+ * 所以，建议使用流程如下:
+ * 1. 分配buffer，这个buffer的前面8字节对应"control setup packet"，后面的空间可以用来保存其他数据
+ * 2. 设置"control setup packet"，通过调用libusb_fill_control_setup()函数来设置
+ * 3. 如果是要把数据发送个设备，把要发送的数据放在buffer的后面(从buffer[8]开始放)
+ * 4. 调用libusb_fill_bulk_transfer
+ * 5. 提交传输: 调用libusb_submit_transfer()
+ *
+ * 也可以让buffer参数为NULL，
+ * 这种情况下libusb_transfer::length就不会被设置,
+ * 需要手工去设置ibusb_transfer::buffer、ibusb_transfer::length
+ *
+ * 参数:
+ * transfer - 要设置的libusb_transfer结构体
+ * dev_handle - 设备句柄
+ * buffer - 数据buffer，如果不是NULL的话，它前面8直接会被当做"control setup packet"来处理，
+ *          也会从buffer[6], buffer[7]把length提取出来，用来设置libusb_transfer::length
+ *           这个buffer必须是2字节对齐
+ * callback - 传输完成时的回调函数
+ * user_data - 传给回调函数的参数
+ * timeout - 超时时间(单位: ms)
+ */
+static inline void libusb_fill_control_transfer(
+	struct libusb_transfer *transfer, libusb_device_handle *dev_handle,
+	unsigned char *buffer, libusb_transfer_cb_fn callback, void *user_data,
+	unsigned int timeout);
+```
+
+
+
+#### 2.9.4 填充批量传输
+
+```c
+/** \ingroup libusb_asyncio
+ * 构造批量传输结构体
+ *
+ * 参数:
+ * transfer - 要设置的libusb_transfer结构体
+ * dev_handle - 设备句柄
+ * endpoint - 端点
+ * buffer - 数据buffer
+ * length - buffer的数据长度
+ * callback - 传输完成时的回调函数
+ * user_data - 传给回调函数的参数
+ * timeout - 超时时间(单位: ms)
+ */
+static inline void libusb_fill_bulk_transfer(struct libusb_transfer *transfer,
+	libusb_device_handle *dev_handle, unsigned char endpoint,
+	unsigned char *buffer, int length, libusb_transfer_cb_fn callback,
+	void *user_data, unsigned int timeout);
+```
+
+
+
+#### 2.9.5 填充中断传输
+
+```c
+/** \ingroup libusb_asyncio
+ * 构造中断传输结构体
+ *
+ * 参数:
+ * transfer - 要设置的libusb_transfer结构体
+ * dev_handle - 设备句柄
+ * endpoint - 端点
+ * buffer - 数据buffer
+ * length - buffer的数据长度
+ * callback - 传输完成时的回调函数
+ * user_data - 传给回调函数的参数
+ * timeout - 超时时间(单位: ms)
+ */
+static inline void libusb_fill_interrupt_transfer(
+	struct libusb_transfer *transfer, libusb_device_handle *dev_handle,
+	unsigned char endpoint, unsigned char *buffer, int length,
+	libusb_transfer_cb_fn callback, void *user_data, unsigned int timeout);
+```
+
+
+
+#### 2.9.6 填充实时传输
+
+```c
+/** \ingroup libusb_asyncio
+ * 构造实时传输结构体
+ *
+ * 参数:
+ * transfer - 要设置的libusb_transfer结构体
+ * dev_handle - 设备句柄
+ * endpoint - 端点
+ * buffer - 数据buffer
+ * length - buffer的数据长度
+ * num_iso_packets - 实时传输包的个数
+ * callback - 传输完成时的回调函数
+ * user_data - 传给回调函数的参数
+ * timeout - 超时时间(单位: ms)
+ */
+static inline void libusb_fill_iso_transfer(struct libusb_transfer *transfer,
+	libusb_device_handle *dev_handle, unsigned char endpoint,
+	unsigned char *buffer, int length, int num_iso_packets,
+	libusb_transfer_cb_fn callback, void *user_data, unsigned int timeout);
+```
+
+
+
+#### 2.9.7 提交传输
+
+```c
+/** \ingroup libusb_asyncio
+ * 提交传输Submit，这个函数会启动传输，然后立刻返回
+ *
+ * 参数:
+ * transfer - 要传输的libusb_transfer结构体
+ *
+ * 返回值:
+ * 0 - 成功
+ * LIBUSB_ERROR_NO_DEVICE - 设备未连接
+ * LIBUSB_ERROR_BUSY - 这个传输已经提交过了
+ * LIBUSB_ERROR_NOT_SUPPORTED - 不支持这个传输
+ * LIBUSB_ERROR_INVALID_PARAM - 传输的字节超过OS或硬件的支持
+ * 其他LIBUSB_ERROR错误码
+ */
+int API_EXPORTED libusb_submit_transfer(struct libusb_transfer *transfer);
+```
+
+
+
+#### 2.9.8 处理事件
+
+有4个函数，其中2个没有`completed`后缀的函数过时了：
+
+```c
+/** \ingroup libusb_poll
+ * 处理任何"pengding的事件"
+ *
+ * 使用异步传输函数时，提交的tranfer结构体后就返回了。
+ * 可以使用本函数处理这些传输的返回结果。
+ *
+ * 如果timeval参数为0，本函数会处理"当前、已经pending的事件"，然后马上返回。
+ *
+ * 如果timeval参数不为0，并且当前没有待处理的事件，本函数会阻塞以等待事件，直到超时。
+ * 在等待过程中，如果事件发生了、或者得到了信号(signal)，那么这个函数会提前返回。
+ *
+ * completed参数用来避免竞争，如果它不为NULL:
+ * 本函数获得"event handling lock"后，会判断completed指向的数值，
+ * 如果这个数值非0(表示别的线程已经处理了、已经completed了)，
+ * 则本函数会立刻返回(既然都completed了，当然无需再处理)
+ *
+ * 参数:
+ * ctx - context(如果传入NULL则使用默认context)
+ * tv - 等待事件的最大时间，0表示不等待
+ * completed - 指针，可以传入NULL
+ *
+ * 返回值:
+ * 0 - 成功
+ * LIBUSB_ERROR_INVALID_PARAM - timeval参数无效
+ * 其他LIBUSB_ERROR错误码
+ */
+int API_EXPORTED libusb_handle_events_timeout_completed(libusb_context *ctx,
+	struct timeval *tv, int *completed);
+
+/** \ingroup libusb_poll
+ * 处理任何"pengding的事件"
+ *
+ * 跟libusb_handle_events_timeout_completed()类似,
+ * 就是调用"libusb_handle_events_timeout_completed(ctx, tv, NULL);"
+ * 最后的completed参数为NULL。
+ *
+ * 这个函数只是为了保持向后兼容，新的代码建议使用libusb_handle_events_completed()或
+ * libusb_handle_events_timeout_completed()，
+ * 这2个新函数可以处理竞争。
+ *
+ * 参数:
+ * ctx - context(如果传入NULL则使用默认context)
+ * tv - 等待事件的最大时间，0表示不等待
+ *
+ * 返回值:
+ * 0 - 成功
+ * LIBUSB_ERROR_INVALID_PARAM - timeval参数无效
+ * 其他LIBUSB_ERROR错误码
+ */
+int API_EXPORTED libusb_handle_events_timeout(libusb_context *ctx,
+	struct timeval *tv);
+
+/** \ingroup libusb_poll
+ * 处理任何"pengding的事件"，以阻塞方式处理(blocking mode)
+ *
+ * 本函数的内部实现就是调用: libusb_handle_events_timeout_completed(ctx, &tv, completed);
+ * 超时时间设置为60秒
+ *
+ * 参数:
+ * ctx - context(如果传入NULL则使用默认context)
+ * completed - 指针，可以传入NULL
+ *
+ * 返回值:
+ * 0 - 成功
+ * LIBUSB_ERROR_INVALID_PARAM - timeval参数无效
+ * 其他LIBUSB_ERROR错误码
+ */
+int API_EXPORTED libusb_handle_events_completed(libusb_context *ctx,
+	int *completed);
+
+/** \ingroup libusb_poll
+ * 处理任何"pengding的事件"，以阻塞方式处理(blocking mode)
+ *
+ * 本函数的内部实现就是调用: libusb_handle_events_timeout_completed(ctx, &tv, NULL);
+ * 超时时间设置为60秒
+ *
+ * 这个函数只是为了保持向后兼容，新的代码建议使用libusb_handle_events_completed()或
+ * libusb_handle_events_timeout_completed()，
+ * 这2个新函数可以处理竞争。
+ * 
+ * 参数:
+ * ctx - context(如果传入NULL则使用默认context)
+ *
+ * 返回值:
+ * 0 - 成功
+ * LIBUSB_ERROR_INVALID_PARAM - timeval参数无效
+ * 其他LIBUSB_ERROR错误码
+ */
+int API_EXPORTED libusb_handle_events(libusb_context *ctx);
+```
+
+
+
+#### 2.9.9 释放transfer结构体
+
+传输完毕，需要释放libusb_transfer结构体，如果要重复利用这个结构体则无需释放。
+
+```c
+/** \ingroup libusb_asyncio
+ * 释放libusb_transfer结构体
+ * 前面使用libusb_alloc_transfer()分配的结构体，要使用本函数来释放。
+ *
+ * 如果libusb_transfer::flags的LIBUSB_TRANSFER_FREE_BUFFER位非0，
+ * 那么会使用free()函数释放ibusb_transfer::buffer
+ * 
+ * 不能使用本函数释放一个活动的传输结构体(active, 已经提交尚未结束)
+ * 
+ */
+void API_EXPORTED libusb_free_transfer(struct libusb_transfer *transfer);
+```
+
+
+
+## 3. 使用示例
+
+在libusb源码的examples目录下有示例程序，我们也有一些真实的案列。
+
+### 3.1 dnw工具
+
+dnw是s3c2440时代的工具，使用它可以从PC给开发板传输文件。它的核心源码如下，使用同步接口进行数据传输：
+
+```c
+	/* open the device using libusb */
+	status = libusb_init(NULL);
+	if (status < 0) {
+		printf("libusb_init() failed: %s\n", libusb_error_name(status));
+		return -1;
+	}
+
+	hdev = libusb_open_device_with_vid_pid(NULL, (uint16_t)DNW_DEVICE_IDVENDOR, (uint16_t)DNW_DEVICE_IDPRODUCT);
+	if (hdev == NULL) {
+		printf("libusb_open() failed\n");
+		goto err3;
+	}
+
+	/* We need to claim the first interface */
+	libusb_set_auto_detach_kernel_driver(hdev, 1);
+	status = libusb_claim_interface(hdev, 0);
+	if (status != LIBUSB_SUCCESS) {
+		libusb_close(hdev);
+		printf("libusb_claim_interface failed: %s\n", libusb_error_name(status));
+		goto err2;
+	}
+
+	ret =  libusb_bulk_transfer(hdev, 0x03, buf, num_write, &transferred, 3000);
+```
+
+
+
+### 3.2 openocd
+
+openocd是一个开源的USB JTAG调试软件，它也是使用libusb，涉及USB的操作代码如下。
+
+#### 3.2.1 找到设备
+
+```c
+static int cmsis_dap_usb_open(struct cmsis_dap *dap, uint16_t vids[], uint16_t pids[], const char *serial)
+{
+	int err;
+	struct libusb_context *ctx;
+	struct libusb_device **device_list;
+
+	err = libusb_init(&ctx);
+	if (err) {
+		LOG_ERROR("libusb initialization failed: %s", libusb_strerror(err));
+		return ERROR_FAIL;
+	}
+
+	int num_devices = libusb_get_device_list(ctx, &device_list);
+	if (num_devices < 0) {
+		LOG_ERROR("could not enumerate USB devices: %s", libusb_strerror(num_devices));
+		libusb_exit(ctx);
+		return ERROR_FAIL;
+	}
+
+	for (int i = 0; i < num_devices; i++) {
+		struct libusb_device *dev = device_list[i];
+		struct libusb_device_descriptor dev_desc;
+
+		err = libusb_get_device_descriptor(dev, &dev_desc);
+		if (err) {
+			LOG_ERROR("could not get device descriptor for device %d: %s", i, libusb_strerror(err));
+			continue;
+		}
+
+		/* Match VID/PID */
+
+		bool id_match = false;
+		bool id_filter = vids[0] || pids[0];
+		for (int id = 0; vids[id] || pids[id]; id++) {
+			id_match = !vids[id] || dev_desc.idVendor == vids[id];
+			id_match &= !pids[id] || dev_desc.idProduct == pids[id];
+
+			if (id_match)
+				break;
+		}
+
+		if (id_filter && !id_match)
+			continue;
+
+		/* Don't continue if we asked for a serial number and the device doesn't have one */
+		if (dev_desc.iSerialNumber == 0 && serial && serial[0])
+			continue;
+
+		struct libusb_device_handle *dev_handle = NULL;
+		err = libusb_open(dev, &dev_handle);
+		if (err) {
+			/* It's to be expected that most USB devices can't be opened
+			 * so only report an error if it was explicitly selected
+			 */
+			if (id_filter) {
+				LOG_ERROR("could not open device 0x%04x:0x%04x: %s",
+						dev_desc.idVendor, dev_desc.idProduct, libusb_strerror(err));
+			} else {
+				LOG_DEBUG("could not open device 0x%04x:0x%04x: %s",
+						dev_desc.idVendor, dev_desc.idProduct, libusb_strerror(err));
+			}
+			continue;
+		}
+
+		/* Match serial number */
+
+		bool serial_match = false;
+		char dev_serial[256] = {0};
+		if (dev_desc.iSerialNumber > 0) {
+			err = libusb_get_string_descriptor_ascii(
+					dev_handle, dev_desc.iSerialNumber,
+					(uint8_t *)dev_serial, sizeof(dev_serial));
+
+			if (err < 0) {
+				const char *msg = "could not read serial number for device 0x%04x:0x%04x: %s";
+				if (serial)
+					LOG_WARNING(msg, dev_desc.idVendor, dev_desc.idProduct,
+								libusb_strerror(err));
+				else
+					LOG_DEBUG(msg, dev_desc.idVendor, dev_desc.idProduct,
+								libusb_strerror(err));
+			} else if (serial && strncmp(dev_serial, serial, sizeof(dev_serial)) == 0) {
+				serial_match = true;
+			}
+		}
+
+		if (serial && !serial_match) {
+			libusb_close(dev_handle);
+			continue;
+		}
+
+		/* Find the CMSIS-DAP string in product string */
+
+		bool cmsis_dap_in_product_str = false;
+		char product_string[256] = {0};
+		if (dev_desc.iProduct > 0) {
+			err = libusb_get_string_descriptor_ascii(
+					dev_handle, dev_desc.iProduct,
+					(uint8_t *)product_string, sizeof(product_string));
+			if (err < 0) {
+				LOG_WARNING("could not read product string for device 0x%04x:0x%04x: %s",
+						dev_desc.idVendor, dev_desc.idProduct, libusb_strerror(err));
+			} else if (strstr(product_string, "CMSIS-DAP")) {
+				LOG_DEBUG("found product string of 0x%04x:0x%04x '%s'",
+						  dev_desc.idVendor, dev_desc.idProduct, product_string);
+				cmsis_dap_in_product_str = true;
+			}
+		}
+
+		bool device_identified_reliably = cmsis_dap_in_product_str
+											|| serial_match || id_match;
+
+		/* Find the CMSIS-DAP interface */
+
+		for (int config = 0; config < dev_desc.bNumConfigurations; config++) {
+			struct libusb_config_descriptor *config_desc;
+			err = libusb_get_config_descriptor(dev, config, &config_desc);
+			if (err) {
+				LOG_ERROR("could not get configuration descriptor %d for device 0x%04x:0x%04x: %s",
+						config, dev_desc.idVendor, dev_desc.idProduct, libusb_strerror(err));
+				continue;
+			}
+
+			LOG_DEBUG("enumerating interfaces of 0x%04x:0x%04x",
+					  dev_desc.idVendor, dev_desc.idProduct);
+			int config_num = config_desc->bConfigurationValue;
+			const struct libusb_interface_descriptor *intf_desc_candidate = NULL;
+			const struct libusb_interface_descriptor *intf_desc_found = NULL;
+
+			for (int interface = 0; interface < config_desc->bNumInterfaces; interface++) {
+				const struct libusb_interface_descriptor *intf_desc = &config_desc->interface[interface].altsetting[0];
+				int interface_num = intf_desc->bInterfaceNumber;
+
+				/* Skip this interface if another one was requested explicitly */
+				if (cmsis_dap_usb_interface != -1 && cmsis_dap_usb_interface != interface_num)
+					continue;
+
+				/* CMSIS-DAP v2 spec says:
+				 *
+				 * CMSIS-DAP with default V2 configuration uses WinUSB and is therefore faster.
+				 * Optionally support for streaming SWO trace is provided via an additional USB endpoint.
+				 *
+				 * The WinUSB configuration requires custom class support with the interface setting
+				 *     Class Code: 0xFF (Vendor specific)
+				 *     Subclass: 0x00
+				 *     Protocol code: 0x00
+				 *
+				 * Depending on the configuration it uses the following USB endpoints which should be configured
+				 * in the interface descriptor in this order:
+				 *  - Endpoint 1: Bulk Out – used for commands received from host PC.
+				 *  - Endpoint 2: Bulk In – used for responses send to host PC.
+				 *  - Endpoint 3: Bulk In (optional) – used for streaming SWO trace (if enabled with SWO_STREAM).
+				 */
+
+				/* Search for "CMSIS-DAP" in the interface string */
+				bool cmsis_dap_in_interface_str = false;
+				if (intf_desc->iInterface != 0) {
+
+					char interface_str[256] = {0};
+
+					err = libusb_get_string_descriptor_ascii(
+							dev_handle, intf_desc->iInterface,
+							(uint8_t *)interface_str, sizeof(interface_str));
+					if (err < 0) {
+						LOG_DEBUG("could not read interface string %d for device 0x%04x:0x%04x: %s",
+								  intf_desc->iInterface,
+								  dev_desc.idVendor, dev_desc.idProduct,
+								  libusb_strerror(err));
+					} else if (strstr(interface_str, "CMSIS-DAP")) {
+						cmsis_dap_in_interface_str = true;
+						LOG_DEBUG("found interface %d string '%s'",
+								  interface_num, interface_str);
+					}
+				}
+
+				/* Bypass the following check if this interface was explicitly requested. */
+				if (cmsis_dap_usb_interface == -1) {
+					if (!cmsis_dap_in_product_str && !cmsis_dap_in_interface_str)
+						continue;
+				}
+
+				/* check endpoints */
+				if (intf_desc->bNumEndpoints < 2) {
+					LOG_DEBUG("skipping interface %d, has only %d endpoints",
+							  interface_num, intf_desc->bNumEndpoints);
+					continue;
+				}
+
+				if ((intf_desc->endpoint[0].bmAttributes & 3) != LIBUSB_TRANSFER_TYPE_BULK ||
+						(intf_desc->endpoint[0].bEndpointAddress & 0x80) != LIBUSB_ENDPOINT_OUT) {
+					LOG_DEBUG("skipping interface %d, endpoint[0] is not bulk out",
+							  interface_num);
+					continue;
+				}
+
+				if ((intf_desc->endpoint[1].bmAttributes & 3) != LIBUSB_TRANSFER_TYPE_BULK ||
+						(intf_desc->endpoint[1].bEndpointAddress & 0x80) != LIBUSB_ENDPOINT_IN) {
+					LOG_DEBUG("skipping interface %d, endpoint[1] is not bulk in",
+							  interface_num);
+					continue;
+				}
+
+				/* We can rely on the interface is really CMSIS-DAP if
+				 * - we've seen CMSIS-DAP in the interface string
+				 * - config asked explicitly for an interface number
+				 * - the device has only one interface
+				 * The later two cases should be honored only if we know
+				 * we are on the right device */
+				bool intf_identified_reliably = cmsis_dap_in_interface_str
+							|| (device_identified_reliably &&
+									(cmsis_dap_usb_interface != -1
+									 || config_desc->bNumInterfaces == 1));
+
+				if (intf_desc->bInterfaceClass != LIBUSB_CLASS_VENDOR_SPEC ||
+						intf_desc->bInterfaceSubClass != 0 || intf_desc->bInterfaceProtocol != 0) {
+					/* If the interface is reliably identified
+					 * then we need not insist on setting USB class, subclass and protocol
+					 * exactly as the specification requires.
+					 * At least KitProg3 uses class 0 contrary to the specification */
+					if (intf_identified_reliably) {
+						LOG_WARNING("Using CMSIS-DAPv2 interface %d with wrong class %" PRId8
+								  " subclass %" PRId8 " or protocol %" PRId8,
+								  interface_num,
+								  intf_desc->bInterfaceClass,
+								  intf_desc->bInterfaceSubClass,
+								  intf_desc->bInterfaceProtocol);
+					} else {
+						LOG_DEBUG("skipping interface %d, class %" PRId8
+								  " subclass %" PRId8 " protocol %" PRId8,
+								  interface_num,
+								  intf_desc->bInterfaceClass,
+								  intf_desc->bInterfaceSubClass,
+								  intf_desc->bInterfaceProtocol);
+						continue;
+
+					}
+				}
+
+				if (intf_identified_reliably) {
+					/* That's the one! */
+					intf_desc_found = intf_desc;
+					break;
+				}
+
+				if (!intf_desc_candidate && device_identified_reliably) {
+					/* This interface looks suitable for CMSIS-DAP. Store the pointer to it
+					 * and keep searching for another one with CMSIS-DAP in interface string */
+					intf_desc_candidate = intf_desc;
+				}
+			}
+
+			if (!intf_desc_found) {
+				/* We were not able to identify reliably which interface is CMSIS-DAP.
+				 * Let's use the first suitable if we found one */
+				intf_desc_found = intf_desc_candidate;
+			}
+
+			if (!intf_desc_found) {
+				libusb_free_config_descriptor(config_desc);
+				continue;
+			}
+
+			/* We've chosen an interface, connect to it */
+			int interface_num = intf_desc_found->bInterfaceNumber;
+			int packet_size = intf_desc_found->endpoint[0].wMaxPacketSize;
+			int ep_out = intf_desc_found->endpoint[0].bEndpointAddress;
+			int ep_in = intf_desc_found->endpoint[1].bEndpointAddress;
+
+			libusb_free_config_descriptor(config_desc);
+			libusb_free_device_list(device_list, true);
+
+			LOG_INFO("Using CMSIS-DAPv2 interface with VID:PID=0x%04x:0x%04x, serial=%s",
+					dev_desc.idVendor, dev_desc.idProduct, dev_serial);
+
+			int current_config;
+			err = libusb_get_configuration(dev_handle, &current_config);
+			if (err) {
+				LOG_ERROR("could not find current configuration: %s", libusb_strerror(err));
+				libusb_close(dev_handle);
+				libusb_exit(ctx);
+				return ERROR_FAIL;
+			}
+
+			if (config_num != current_config) {
+				err = libusb_set_configuration(dev_handle, config_num);
+				if (err) {
+					LOG_ERROR("could not set configuration: %s", libusb_strerror(err));
+					libusb_close(dev_handle);
+					libusb_exit(ctx);
+					return ERROR_FAIL;
+				}
+			}
+
+			err = libusb_claim_interface(dev_handle, interface_num);
+			if (err)
+				LOG_WARNING("could not claim interface: %s", libusb_strerror(err));
+
+			dap->bdata = malloc(sizeof(struct cmsis_dap_backend_data));
+			if (!dap->bdata) {
+				LOG_ERROR("unable to allocate memory");
+				libusb_release_interface(dev_handle, interface_num);
+				libusb_close(dev_handle);
+				libusb_exit(ctx);
+				return ERROR_FAIL;
+			}
+
+			dap->packet_size = packet_size;
+			dap->packet_buffer_size = packet_size;
+			dap->bdata->usb_ctx = ctx;
+			dap->bdata->dev_handle = dev_handle;
+			dap->bdata->ep_out = ep_out;
+			dap->bdata->ep_in = ep_in;
+			dap->bdata->interface = interface_num;
+
+			dap->packet_buffer = malloc(dap->packet_buffer_size);
+			if (!dap->packet_buffer) {
+				LOG_ERROR("unable to allocate memory");
+				cmsis_dap_usb_close(dap);
+				return ERROR_FAIL;
+			}
+
+			dap->command = dap->packet_buffer;
+			dap->response = dap->packet_buffer;
+
+			return ERROR_OK;
+		}
+
+		libusb_close(dev_handle);
+	}
+
+	libusb_free_device_list(device_list, true);
+
+	libusb_exit(ctx);
+	return ERROR_FAIL;
+}
+```
+
+
+
+#### 3.2.2 读写数据
+
+```c
+static int cmsis_dap_usb_read(struct cmsis_dap *dap, int timeout_ms)
+{
+	int transferred = 0;
+	int err;
+
+	err = libusb_bulk_transfer(dap->bdata->dev_handle, dap->bdata->ep_in,
+							dap->packet_buffer, dap->packet_size, &transferred, timeout_ms);
+	if (err) {
+		if (err == LIBUSB_ERROR_TIMEOUT) {
+			return ERROR_TIMEOUT_REACHED;
+		} else {
+			LOG_ERROR("error reading data: %s", libusb_strerror(err));
+			return ERROR_FAIL;
+		}
+	}
+
+	memset(&dap->packet_buffer[transferred], 0, dap->packet_buffer_size - transferred);
+
+	return transferred;
+}
+
+static int cmsis_dap_usb_write(struct cmsis_dap *dap, int txlen, int timeout_ms)
+{
+	int transferred = 0;
+	int err;
+
+	/* skip the first byte that is only used by the HID backend */
+	err = libusb_bulk_transfer(dap->bdata->dev_handle, dap->bdata->ep_out,
+							dap->packet_buffer, txlen, &transferred, timeout_ms);
+	if (err) {
+		if (err == LIBUSB_ERROR_TIMEOUT) {
+			return ERROR_TIMEOUT_REACHED;
+		} else {
+			LOG_ERROR("error writing data: %s", libusb_strerror(err));
+			return ERROR_FAIL;
+		}
+	}
+
+	return transferred;
+}
+
+```
+
+
+
diff --git a/STM32MP157/doc_pic/12_USB/06_libusb的使用流程.tif b/STM32MP157/doc_pic/12_USB/06_libusb的使用流程.tif
new file mode 100644
index 0000000..6b99e0b
Binary files /dev/null and b/STM32MP157/doc_pic/12_USB/06_libusb的使用流程.tif differ
diff --git a/STM32MP157/doc_pic/12_USB/07_使用libusb读取鼠标数据.md b/STM32MP157/doc_pic/12_USB/07_使用libusb读取鼠标数据.md
new file mode 100644
index 0000000..49c38d7
--- /dev/null
+++ b/STM32MP157/doc_pic/12_USB/07_使用libusb读取鼠标数据.md
@@ -0,0 +1,16 @@
+# 使用libusb读取鼠标数据 #
+
+参考资料：
+
+* libusb API接口：https://libusb.sourceforge.io/api-1.0/
+
+* libusb 示例：https://github.com/libusb/libusb/tree/master/examples
+
+* HID规范：https://www.usb.org/sites/default/files/hid1_11.pdf (文件已经下载放在GIT仓库)
+
+* 文档：USB Human Interface Devices,  https://wiki.osdev.org/USB_Human_Interface_Devices
+
+  
+
+## 1. HID协议
+
diff --git a/STM32MP157/doc_pic/12_USB/pic/54_libusb_flow.png b/STM32MP157/doc_pic/12_USB/pic/54_libusb_flow.png
new file mode 100644
index 0000000..fb5ee42
Binary files /dev/null and b/STM32MP157/doc_pic/12_USB/pic/54_libusb_flow.png differ
diff --git a/STM32MP157/doc_pic/12_USB/usb_20_20211008/hid1_11.pdf b/STM32MP157/doc_pic/12_USB/usb_20_20211008/hid1_11.pdf
new file mode 100644
index 0000000..88c3edc
Binary files /dev/null and b/STM32MP157/doc_pic/12_USB/usb_20_20211008/hid1_11.pdf differ
diff --git a/STM32MP157/doc_pic/12_USB/其他参考资料.md b/STM32MP157/doc_pic/12_USB/其他参考资料.md
index efbad0c..5c9a52f 100644
--- a/STM32MP157/doc_pic/12_USB/其他参考资料.md
+++ b/STM32MP157/doc_pic/12_USB/其他参考资料.md
@@ -11,4 +11,10 @@ https://programmerall.com/article/42562063276/
 
 
 就是usb 的vcp 模式和msd 挂载
-我先加入笔记里，到时看看是否实用、实用的话再讲
\ No newline at end of file
+我先加入笔记里，到时看看是否实用、实用的话再讲
+
+
+
+
+
+韦老师，USB里面休眠唤醒suspend/resueme/autosuspend/remote-wakeup这些也挺常用的，希望老师后面也可以讲一下
\ No newline at end of file
diff --git a/STM32MP157/source/A7/12_USB/01_libusb示例程序/dnw_for_libusb1.0/Makefile b/STM32MP157/source/A7/12_USB/01_libusb示例程序/dnw_for_libusb1.0/Makefile
new file mode 100644
index 0000000..1f8c030
--- /dev/null
+++ b/STM32MP157/source/A7/12_USB/01_libusb示例程序/dnw_for_libusb1.0/Makefile
@@ -0,0 +1,10 @@
+CROSS=
+
+all: exe
+
+exe:dnw.c
+	$(CROSS)gcc -Wall -o dnw dnw.c libusb-1.0.a -lpthread -static
+cpy:
+	cp dnw /usr/local/bin -f
+clean:
+	@rm -f dnw *.o *~
diff --git a/STM32MP157/source/A7/12_USB/01_libusb示例程序/dnw_for_libusb1.0/dnw b/STM32MP157/source/A7/12_USB/01_libusb示例程序/dnw_for_libusb1.0/dnw
new file mode 100644
index 0000000..c83c90e
Binary files /dev/null and b/STM32MP157/source/A7/12_USB/01_libusb示例程序/dnw_for_libusb1.0/dnw differ
diff --git a/STM32MP157/source/A7/12_USB/01_libusb示例程序/dnw_for_libusb1.0/dnw.c b/STM32MP157/source/A7/12_USB/01_libusb示例程序/dnw_for_libusb1.0/dnw.c
new file mode 100644
index 0000000..d6eb08d
--- /dev/null
+++ b/STM32MP157/source/A7/12_USB/01_libusb示例程序/dnw_for_libusb1.0/dnw.c
@@ -0,0 +1,250 @@
+/*
+ *      To send file through USB for s3c2410/s3c2440's bootloader, vivi/u-boot
+ *
+ *      Copyright (C) 2006 thisway.diy@163.com
+ */
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <sys/ioctl.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <sys/select.h>
+#include <sys/time.h>
+#include <errno.h>
+#include <string.h>
+#include "libusb.h"
+
+#define DMA_BUF_SIZE	0x8000
+#define	DNW_DEVICE_IDVENDOR		0x5345
+#define	DNW_DEVICE_IDPRODUCT	0x1234
+
+
+const char version[] = "DNW on linux for www.100ask.net, v2.0 with libusb1.0";
+const char author[]  = "thisway.diy@163.com";
+	
+void printusage(char *name)
+{
+	printf("Usage: %s <file> [address], send file to USB device\n", name);
+	printf("       %s -v, show the version\n", name);
+	printf("examples:\n");
+	printf("1. %s vmlinus\n", name);
+	printf("2. %s yaffs_image 0x30000000\n", name);
+}
+
+
+int main(int argc, char *argv[])
+{
+	int i;
+
+	int first = 1;
+	
+	int fd_file;
+
+	struct stat stat_buf;
+
+	libusb_device_handle *hdev = NULL;
+
+
+	unsigned int ret;
+	int status;
+	
+	unsigned int num_remain = 2;
+	unsigned int num_read = 0;
+	unsigned int num_write = 0;
+	unsigned int num_read_total = 0;
+	unsigned int num_write_total = 0;
+	unsigned int num_has_write_total = 0;
+
+	int transferred;
+
+	unsigned int download_addr = 0x30000000;
+	unsigned short check_sum = 0;
+
+	unsigned char *buf = 0;
+
+	struct timeval time_start;
+	struct timeval time_end;
+	unsigned int time_us;
+
+	if (argc == 2 && strcmp(argv[1], "-v") == 0)
+	{
+		printf("Version: %s\n", version);
+		printf("Complie Time: %s, %s\n", __DATE__, __TIME__);
+		printf("Author: %s\n", author);
+		return 0;
+	}
+
+	if (argc < 2 || argc > 3)
+	{
+		printusage(argv[0]);
+		return -1;
+	}
+
+	/* open the device using libusb */
+	status = libusb_init(NULL);
+	if (status < 0) {
+		printf("libusb_init() failed: %s\n", libusb_error_name(status));
+		return -1;
+	}
+
+	hdev = libusb_open_device_with_vid_pid(NULL, (uint16_t)DNW_DEVICE_IDVENDOR, (uint16_t)DNW_DEVICE_IDPRODUCT);
+	if (hdev == NULL) {
+		printf("libusb_open() failed\n");
+		goto err3;
+	}
+
+	/* We need to claim the first interface */
+	libusb_set_auto_detach_kernel_driver(hdev, 1);
+	status = libusb_claim_interface(hdev, 0);
+	if (status != LIBUSB_SUCCESS) {
+		libusb_close(hdev);
+		printf("libusb_claim_interface failed: %s\n", libusb_error_name(status));
+		goto err2;
+	}
+	
+	
+	fd_file = open(argv[1], O_RDONLY);
+	if (fd_file < 0) 
+	{
+		printf("open %s failed!\n", argv[2]);
+		goto err1;
+	}
+
+	if (fstat(fd_file, &stat_buf))
+	{
+		printf("Can't get status of file %s\n", argv[2]);
+		goto err;
+	}
+
+	printf("Size of file: %d byte(s)\n", (unsigned int)stat_buf.st_size);
+
+	/* FORMAT: <ADDR(DATA):4>+<SIZE(n+10):4>+<DATA:n>+<CS:2> */
+	num_write_total = stat_buf.st_size + 10;
+
+	if (argc == 3)
+	{
+		download_addr = (unsigned int)strtoul((const char *)argv[2], NULL, 0);
+	}
+
+	printf("Address of bootloader to receive data: 0x%x\n", download_addr);
+
+	buf = malloc(DMA_BUF_SIZE);
+	if (!buf)
+	{
+		printf("Can't alloc memory\n");
+		goto err;
+	}
+
+	memcpy(buf, &download_addr, 4);
+	memcpy(buf + 4, &num_write_total, 4);
+
+	gettimeofday(&time_start, 0);
+
+	while (num_read_total < stat_buf.st_size)
+	{
+		num_read = read(fd_file, buf + (first ? 8 : 0), DMA_BUF_SIZE - (first ? 8 : 0));
+
+		if (num_read)
+		{
+			num_read_total += num_read;
+			for (i = 0; i < num_read; i++)
+			{
+				check_sum += (unsigned short)buf[i];
+			}
+		}
+		else
+		{
+			printf("Can't read file, num_read = %d, num_read_total = %d\n", num_read, num_read_total);
+			goto err;
+		}
+
+		num_write = num_read + (first ? 8 : 0);
+		
+		if (num_read_total == stat_buf.st_size)
+		{
+			for (i = 0; i < 2; i++)
+			{
+				if (num_write < DMA_BUF_SIZE)
+				{
+					buf[num_write++] = (unsigned char)(check_sum >> (i*8));
+					num_remain--;
+				}
+			}
+		}
+
+/*
+int libusb_bulk_transfer 	( 	struct libusb_device_handle *  	dev_handle,
+		unsigned char  	endpoint,
+		unsigned char *  	data,
+		int  	length,
+		int *  	transferred,
+		unsigned int  	timeout 
+	) 	
+
+*/
+		ret =  libusb_bulk_transfer(hdev, 0x03, buf, num_write, &transferred, 3000);
+
+		if ((ret != 0) || (transferred != num_write))
+		{
+			printf("Error, can't send to the board: num_write = %d, transferred = %d, ret = %d\n", num_write, transferred, ret);
+			goto err;			
+		}
+		
+		num_has_write_total += num_write;
+
+		gettimeofday(&time_end, 0);
+
+		time_us = (time_end.tv_sec - time_start.tv_sec) * 1000000 +(time_end.tv_usec - time_start.tv_usec);
+
+		printf("\rTx: %d/%d, Percentage: %.1f%%, Speed: %.1fKB/s, Time: %.1fS", num_has_write_total, num_write_total, ((float)num_has_write_total)/((float)num_write_total)*100., ((float)num_has_write_total/1024)/((float)time_us/1000000), time_us/1000000.);
+
+		if (first)
+		{
+			first = 0;
+		}
+		
+	}		
+
+	if (num_remain == 2)
+	{
+		buf[0] = (unsigned char)check_sum;
+		buf[1] = (unsigned char)(check_sum >> 8);
+	}
+	else if (num_remain == 1)
+	{
+		buf[0] = (unsigned char)(check_sum >> 8);
+	}
+
+	if (num_remain)
+	{
+		num_write = num_remain;
+		ret =  libusb_bulk_transfer(hdev, 0x03, buf, num_write, &transferred, 3000);
+
+		if ((ret != 0) || (transferred != num_write))
+		{
+			printf("Error, can't send to the board: num_write = %d, ret = %d\n", num_write, ret);
+			goto err;
+		}
+		
+		num_has_write_total += num_write;
+	}
+
+	gettimeofday(&time_end, 0);
+
+	time_us = (time_end.tv_sec - time_start.tv_sec) * 1000000 +(time_end.tv_usec - time_start.tv_usec);
+
+	printf("\rTx: %d/%d, Percentage: %.1f%%, Speed: %.1fKB/s, Time: %.1fS\n", num_has_write_total, num_write_total, ((float)num_has_write_total)/((float)num_write_total)*100., ((float)num_has_write_total/1024)/((float)time_us/1000000), time_us/1000000.);
+
+err:
+	close(fd_file);
+err1:
+	libusb_release_interface(hdev, 0);
+err2:
+	libusb_close(hdev);
+err3:
+	libusb_exit(NULL);
+	return 0;
+}
+
diff --git a/STM32MP157/source/A7/12_USB/01_libusb示例程序/dnw_for_libusb1.0/dnw使用说明.txt b/STM32MP157/source/A7/12_USB/01_libusb示例程序/dnw_for_libusb1.0/dnw使用说明.txt
new file mode 100644
index 0000000..af448d4
--- /dev/null
+++ b/STM32MP157/source/A7/12_USB/01_libusb示例程序/dnw_for_libusb1.0/dnw使用说明.txt
@@ -0,0 +1,87 @@
+linux�汾��
+
+1. dnw��һ��USB���ߣ�ͨ��USB�����ļ�������USB���ع��ܵ�bootloader��
+�������ʹ�÷���Ϊ(Ҫ���ͳɹ�������������о���USB���ع��ܵ�bootloader)��
+sudo dnw <file> [address]
+��˼Ϊ�������ļ�<file>ͨ��USB�ڷ��͵������ϣ�
+        [address]������ʾdnw����߿����壬����ļ��뱣���ڵ�SDRAM��ַ��
+        ���Բ�д[address]��Ĭ��Ϊ0x30000000��
+        bootloader���Լ��������ļ�������SDRAM����Ƿ�ʹ��[address]ȡ����bootloader��
+
+
+2. �������u-boot����ʱ���ڴ��ڹ���������ո����u-boot��������²˵���
+##### 100ask Bootloader for OpenJTAG #####
+[n] Download u-boot to Nand Flash
+[o] Download u-boot to Nor Flash               // �����Nand Flash�����Ļ�������˵���û��
+[k] Download Linux kernel uImage
+[j] Download root_jffs2 image
+[y] Download root_yaffs image
+[d] Download to SDRAM & Run
+[z] Download zImage into RAM
+[g] Boot linux from RAM
+[f] Format the Nand Flash
+[s] Set the boot parameters
+[b] Boot the system
+[r] Reboot u-boot
+[q] Quit from menu
+
+����ǰ���Сд��ĸ�����������أ�Ȼ��ʹ��dnw���߷����ļ���
+���磺
+a. ��u-boot��������k��u-boot���ȴ����������ں�ӳ����ʱ�����������С�sudo dnw uImage�����ɷ����ں˸�u-boot��
+b. ��u-boot��������y��u-boot���ȴ���������yaffs�ļ�ϵͳӳ����ʱ�����������С�sudo dnw fs_mini_mdev.yaffs2�����ɷ��͸�u-boot��
+c. ��u-boot��������d��u-boot���ȴ����������ļ�����ʱ�����������С�sudo dnw uart.bin 0x31000000�����ɰ�uart.bin���͸�u-boot��
+   u-boot���յ��ļ�����ַ0x31000000�����uart.bin�����ݴ����0x31000000����Ȼ����תȥִ����
+   
+   
+3. Ҳ���Բ�ʹ��u-boot�IJ˵�������q�˳��˵���Ȼ��ʹ��u-boot��������в�����
+   usb�����ʹ�÷����������롰help usbslave���������
+usbslave [wait] [loadAddress]
+"wait" is 0 or 1, 0 means for return immediately, not waits for the finish of transferring
+
+   ���ʾ������usbslave��������USB���أ�[wait]��[loadAddress]��������ַ�ǿ�ѡ�ģ�
+           ���[wait]��ֵ��0��u-boot�����ȴ�USB������ɣ���ʱ���������������һ��u-boot���
+           ���[wait]��ֵ��1��u-boto���ȴ�USB������ɣ����֮�������������һ��u-boot���
+           ���ָ��[loadAddress]����ô���ص��ļ���������SDRAM��ַ[loadAddress]���������ŵ�ַ��������dnw����ָ��
+   
+
+
+windows�汾��
+1. dnw.exe��һ��USB���ߣ�ͨ��USB�����ļ�������USB���ع��ܵ�bootloader��
+���߱�����ʹ�÷���Ϊ(Ҫ���ͳɹ�������������о���USB���ع��ܵ�bootloader)��
+�� �ڡ�Configuration -> Options�� �˵����������ص�ַ��Download Address��
+�� ͨ����USB Port -> Transmit���˵���ѡ�񡢷����ļ�
+
+2. �������u-boot����ʱ���ڴ��ڹ���������ո����u-boot��������²˵���
+##### 100ask Bootloader for OpenJTAG #####
+[n] Download u-boot to Nand Flash
+[o] Download u-boot to Nor Flash               // �����Nand Flash�����Ļ�������˵���û��
+[k] Download Linux kernel uImage
+[j] Download root_jffs2 image
+[y] Download root_yaffs image
+[d] Download to SDRAM & Run
+[z] Download zImage into RAM
+[g] Boot linux from RAM
+[f] Format the Nand Flash
+[s] Set the boot parameters
+[b] Boot the system
+[r] Reboot u-boot
+[q] Quit from menu
+
+����ǰ���Сд��ĸ�����������أ�Ȼ��ʹ��dnw���߷����ļ���
+���磺
+a. ��u-boot��������k��u-boot���ȴ����������ں�ӳ����ʱ��������ʹ��dnw.exeѡ��uImage���ɷ����ں˸�u-boot��
+b. ��u-boot��������y��u-boot���ȴ���������yaffs�ļ�ϵͳӳ����ʱ��������ʹ��dnw.exeѡ��yaffs�ļ�ϵͳӳ�󼴿ɷ����ں˸�u-boot��
+c. ��u-boot��������d��u-boot���ȴ����������ļ�����ʱ������������dnw.exe�����������ص�ַ��Ϊ0x31000000��Ȼ�����ļ���
+   u-boot���յ��ļ�����ַ0x31000000����Ѵ��ļ����ݴ����0x31000000����Ȼ����תȥִ����
+   
+   
+3. Ҳ���Բ�ʹ��u-boot�IJ˵�������q�˳��˵���Ȼ��ʹ��u-boot��������в�����
+   usb�����ʹ�÷����������롰help usbslave���������
+usbslave [wait] [loadAddress]
+"wait" is 0 or 1, 0 means for return immediately, not waits for the finish of transferring
+
+   ���ʾ������usbslave��������USB���أ�[wait]��[loadAddress]��������ַ�ǿ�ѡ�ģ�
+           ���[wait]��ֵ��0��u-boot�����ȴ�USB������ɣ���ʱ���������������һ��u-boot���
+           ���[wait]��ֵ��1��u-boto���ȴ�USB������ɣ����֮�������������һ��u-boot���
+           ���ָ��[loadAddress]����ô���ص��ļ���������SDRAM��ַ[loadAddress]���������ŵ�ַ��������dnw����ָ��
+   
diff --git a/STM32MP157/source/A7/12_USB/01_libusb示例程序/dnw_for_libusb1.0/libusb-1.0.21.tar.bz2 b/STM32MP157/source/A7/12_USB/01_libusb示例程序/dnw_for_libusb1.0/libusb-1.0.21.tar.bz2
new file mode 100644
index 0000000..c61ba3d
Binary files /dev/null and b/STM32MP157/source/A7/12_USB/01_libusb示例程序/dnw_for_libusb1.0/libusb-1.0.21.tar.bz2 differ
diff --git a/STM32MP157/source/A7/12_USB/01_libusb示例程序/dnw_for_libusb1.0/libusb-1.0.a b/STM32MP157/source/A7/12_USB/01_libusb示例程序/dnw_for_libusb1.0/libusb-1.0.a
new file mode 100644
index 0000000..98af7cc
Binary files /dev/null and b/STM32MP157/source/A7/12_USB/01_libusb示例程序/dnw_for_libusb1.0/libusb-1.0.a differ
diff --git a/STM32MP157/source/A7/12_USB/01_libusb示例程序/dnw_for_libusb1.0/libusb.h b/STM32MP157/source/A7/12_USB/01_libusb示例程序/dnw_for_libusb1.0/libusb.h
new file mode 100644
index 0000000..f73e31c
--- /dev/null
+++ b/STM32MP157/source/A7/12_USB/01_libusb示例程序/dnw_for_libusb1.0/libusb.h
@@ -0,0 +1,2008 @@
+/*
+ * Public libusb header file
+ * Copyright © 2001 Johannes Erdfelt <johannes@erdfelt.com>
+ * Copyright © 2007-2008 Daniel Drake <dsd@gentoo.org>
+ * Copyright © 2012 Pete Batard <pete@akeo.ie>
+ * Copyright © 2012 Nathan Hjelm <hjelmn@cs.unm.edu>
+ * For more information, please visit: http://libusb.info
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#ifndef LIBUSB_H
+#define LIBUSB_H
+
+#ifdef _MSC_VER
+/* on MS environments, the inline keyword is available in C++ only */
+#if !defined(__cplusplus)
+#define inline __inline
+#endif
+/* ssize_t is also not available (copy/paste from MinGW) */
+#ifndef _SSIZE_T_DEFINED
+#define _SSIZE_T_DEFINED
+#undef ssize_t
+#ifdef _WIN64
+  typedef __int64 ssize_t;
+#else
+  typedef int ssize_t;
+#endif /* _WIN64 */
+#endif /* _SSIZE_T_DEFINED */
+#endif /* _MSC_VER */
+
+/* stdint.h is not available on older MSVC */
+#if defined(_MSC_VER) && (_MSC_VER < 1600) && (!defined(_STDINT)) && (!defined(_STDINT_H))
+typedef unsigned __int8   uint8_t;
+typedef unsigned __int16  uint16_t;
+typedef unsigned __int32  uint32_t;
+#else
+#include <stdint.h>
+#endif
+
+#if !defined(_WIN32_WCE)
+#include <sys/types.h>
+#endif
+
+#if defined(__linux) || defined(__APPLE__) || defined(__CYGWIN__) || defined(__HAIKU__)
+#include <sys/time.h>
+#endif
+
+#include <time.h>
+#include <limits.h>
+
+/* 'interface' might be defined as a macro on Windows, so we need to
+ * undefine it so as not to break the current libusb API, because
+ * libusb_config_descriptor has an 'interface' member
+ * As this can be problematic if you include windows.h after libusb.h
+ * in your sources, we force windows.h to be included first. */
+#if defined(_WIN32) || defined(__CYGWIN__) || defined(_WIN32_WCE)
+#include <windows.h>
+#if defined(interface)
+#undef interface
+#endif
+#if !defined(__CYGWIN__)
+#include <winsock.h>
+#endif
+#endif
+
+#if __GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 5)
+#define LIBUSB_DEPRECATED_FOR(f) \
+  __attribute__((deprecated("Use " #f " instead")))
+#else
+#define LIBUSB_DEPRECATED_FOR(f)
+#endif /* __GNUC__ */
+
+/** \def LIBUSB_CALL
+ * \ingroup libusb_misc
+ * libusb's Windows calling convention.
+ *
+ * Under Windows, the selection of available compilers and configurations
+ * means that, unlike other platforms, there is not <em>one true calling
+ * convention</em> (calling convention: the manner in which parameters are
+ * passed to functions in the generated assembly code).
+ *
+ * Matching the Windows API itself, libusb uses the WINAPI convention (which
+ * translates to the <tt>stdcall</tt> convention) and guarantees that the
+ * library is compiled in this way. The public header file also includes
+ * appropriate annotations so that your own software will use the right
+ * convention, even if another convention is being used by default within
+ * your codebase.
+ *
+ * The one consideration that you must apply in your software is to mark
+ * all functions which you use as libusb callbacks with this LIBUSB_CALL
+ * annotation, so that they too get compiled for the correct calling
+ * convention.
+ *
+ * On non-Windows operating systems, this macro is defined as nothing. This
+ * means that you can apply it to your code without worrying about
+ * cross-platform compatibility.
+ */
+/* LIBUSB_CALL must be defined on both definition and declaration of libusb
+ * functions. You'd think that declaration would be enough, but cygwin will
+ * complain about conflicting types unless both are marked this way.
+ * The placement of this macro is important too; it must appear after the
+ * return type, before the function name. See internal documentation for
+ * API_EXPORTED.
+ */
+#if defined(_WIN32) || defined(__CYGWIN__) || defined(_WIN32_WCE)
+#define LIBUSB_CALL WINAPI
+#else
+#define LIBUSB_CALL
+#endif
+
+/** \def LIBUSB_API_VERSION
+ * \ingroup libusb_misc
+ * libusb's API version.
+ *
+ * Since version 1.0.13, to help with feature detection, libusb defines
+ * a LIBUSB_API_VERSION macro that gets increased every time there is a
+ * significant change to the API, such as the introduction of a new call,
+ * the definition of a new macro/enum member, or any other element that
+ * libusb applications may want to detect at compilation time.
+ *
+ * The macro is typically used in an application as follows:
+ * \code
+ * #if defined(LIBUSB_API_VERSION) && (LIBUSB_API_VERSION >= 0x01001234)
+ * // Use one of the newer features from the libusb API
+ * #endif
+ * \endcode
+ *
+ * Internally, LIBUSB_API_VERSION is defined as follows:
+ * (libusb major << 24) | (libusb minor << 16) | (16 bit incremental)
+ */
+#define LIBUSB_API_VERSION 0x01000105
+
+/* The following is kept for compatibility, but will be deprecated in the future */
+#define LIBUSBX_API_VERSION LIBUSB_API_VERSION
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * \ingroup libusb_misc
+ * Convert a 16-bit value from host-endian to little-endian format. On
+ * little endian systems, this function does nothing. On big endian systems,
+ * the bytes are swapped.
+ * \param x the host-endian value to convert
+ * \returns the value in little-endian byte order
+ */
+static inline uint16_t libusb_cpu_to_le16(const uint16_t x)
+{
+	union {
+		uint8_t  b8[2];
+		uint16_t b16;
+	} _tmp;
+	_tmp.b8[1] = (uint8_t) (x >> 8);
+	_tmp.b8[0] = (uint8_t) (x & 0xff);
+	return _tmp.b16;
+}
+
+/** \def libusb_le16_to_cpu
+ * \ingroup libusb_misc
+ * Convert a 16-bit value from little-endian to host-endian format. On
+ * little endian systems, this function does nothing. On big endian systems,
+ * the bytes are swapped.
+ * \param x the little-endian value to convert
+ * \returns the value in host-endian byte order
+ */
+#define libusb_le16_to_cpu libusb_cpu_to_le16
+
+/* standard USB stuff */
+
+/** \ingroup libusb_desc
+ * Device and/or Interface Class codes */
+enum libusb_class_code {
+	/** In the context of a \ref libusb_device_descriptor "device descriptor",
+	 * this bDeviceClass value indicates that each interface specifies its
+	 * own class information and all interfaces operate independently.
+	 */
+	LIBUSB_CLASS_PER_INTERFACE = 0,
+
+	/** Audio class */
+	LIBUSB_CLASS_AUDIO = 1,
+
+	/** Communications class */
+	LIBUSB_CLASS_COMM = 2,
+
+	/** Human Interface Device class */
+	LIBUSB_CLASS_HID = 3,
+
+	/** Physical */
+	LIBUSB_CLASS_PHYSICAL = 5,
+
+	/** Printer class */
+	LIBUSB_CLASS_PRINTER = 7,
+
+	/** Image class */
+	LIBUSB_CLASS_PTP = 6, /* legacy name from libusb-0.1 usb.h */
+	LIBUSB_CLASS_IMAGE = 6,
+
+	/** Mass storage class */
+	LIBUSB_CLASS_MASS_STORAGE = 8,
+
+	/** Hub class */
+	LIBUSB_CLASS_HUB = 9,
+
+	/** Data class */
+	LIBUSB_CLASS_DATA = 10,
+
+	/** Smart Card */
+	LIBUSB_CLASS_SMART_CARD = 0x0b,
+
+	/** Content Security */
+	LIBUSB_CLASS_CONTENT_SECURITY = 0x0d,
+
+	/** Video */
+	LIBUSB_CLASS_VIDEO = 0x0e,
+
+	/** Personal Healthcare */
+	LIBUSB_CLASS_PERSONAL_HEALTHCARE = 0x0f,
+
+	/** Diagnostic Device */
+	LIBUSB_CLASS_DIAGNOSTIC_DEVICE = 0xdc,
+
+	/** Wireless class */
+	LIBUSB_CLASS_WIRELESS = 0xe0,
+
+	/** Application class */
+	LIBUSB_CLASS_APPLICATION = 0xfe,
+
+	/** Class is vendor-specific */
+	LIBUSB_CLASS_VENDOR_SPEC = 0xff
+};
+
+/** \ingroup libusb_desc
+ * Descriptor types as defined by the USB specification. */
+enum libusb_descriptor_type {
+	/** Device descriptor. See libusb_device_descriptor. */
+	LIBUSB_DT_DEVICE = 0x01,
+
+	/** Configuration descriptor. See libusb_config_descriptor. */
+	LIBUSB_DT_CONFIG = 0x02,
+
+	/** String descriptor */
+	LIBUSB_DT_STRING = 0x03,
+
+	/** Interface descriptor. See libusb_interface_descriptor. */
+	LIBUSB_DT_INTERFACE = 0x04,
+
+	/** Endpoint descriptor. See libusb_endpoint_descriptor. */
+	LIBUSB_DT_ENDPOINT = 0x05,
+
+	/** BOS descriptor */
+	LIBUSB_DT_BOS = 0x0f,
+
+	/** Device Capability descriptor */
+	LIBUSB_DT_DEVICE_CAPABILITY = 0x10,
+
+	/** HID descriptor */
+	LIBUSB_DT_HID = 0x21,
+
+	/** HID report descriptor */
+	LIBUSB_DT_REPORT = 0x22,
+
+	/** Physical descriptor */
+	LIBUSB_DT_PHYSICAL = 0x23,
+
+	/** Hub descriptor */
+	LIBUSB_DT_HUB = 0x29,
+
+	/** SuperSpeed Hub descriptor */
+	LIBUSB_DT_SUPERSPEED_HUB = 0x2a,
+
+	/** SuperSpeed Endpoint Companion descriptor */
+	LIBUSB_DT_SS_ENDPOINT_COMPANION = 0x30
+};
+
+/* Descriptor sizes per descriptor type */
+#define LIBUSB_DT_DEVICE_SIZE			18
+#define LIBUSB_DT_CONFIG_SIZE			9
+#define LIBUSB_DT_INTERFACE_SIZE		9
+#define LIBUSB_DT_ENDPOINT_SIZE			7
+#define LIBUSB_DT_ENDPOINT_AUDIO_SIZE		9	/* Audio extension */
+#define LIBUSB_DT_HUB_NONVAR_SIZE		7
+#define LIBUSB_DT_SS_ENDPOINT_COMPANION_SIZE	6
+#define LIBUSB_DT_BOS_SIZE			5
+#define LIBUSB_DT_DEVICE_CAPABILITY_SIZE	3
+
+/* BOS descriptor sizes */
+#define LIBUSB_BT_USB_2_0_EXTENSION_SIZE	7
+#define LIBUSB_BT_SS_USB_DEVICE_CAPABILITY_SIZE	10
+#define LIBUSB_BT_CONTAINER_ID_SIZE		20
+
+/* We unwrap the BOS => define its max size */
+#define LIBUSB_DT_BOS_MAX_SIZE		((LIBUSB_DT_BOS_SIZE)     +\
+					(LIBUSB_BT_USB_2_0_EXTENSION_SIZE)       +\
+					(LIBUSB_BT_SS_USB_DEVICE_CAPABILITY_SIZE) +\
+					(LIBUSB_BT_CONTAINER_ID_SIZE))
+
+#define LIBUSB_ENDPOINT_ADDRESS_MASK	0x0f    /* in bEndpointAddress */
+#define LIBUSB_ENDPOINT_DIR_MASK		0x80
+
+/** \ingroup libusb_desc
+ * Endpoint direction. Values for bit 7 of the
+ * \ref libusb_endpoint_descriptor::bEndpointAddress "endpoint address" scheme.
+ */
+enum libusb_endpoint_direction {
+	/** In: device-to-host */
+	LIBUSB_ENDPOINT_IN = 0x80,
+
+	/** Out: host-to-device */
+	LIBUSB_ENDPOINT_OUT = 0x00
+};
+
+#define LIBUSB_TRANSFER_TYPE_MASK			0x03    /* in bmAttributes */
+
+/** \ingroup libusb_desc
+ * Endpoint transfer type. Values for bits 0:1 of the
+ * \ref libusb_endpoint_descriptor::bmAttributes "endpoint attributes" field.
+ */
+enum libusb_transfer_type {
+	/** Control endpoint */
+	LIBUSB_TRANSFER_TYPE_CONTROL = 0,
+
+	/** Isochronous endpoint */
+	LIBUSB_TRANSFER_TYPE_ISOCHRONOUS = 1,
+
+	/** Bulk endpoint */
+	LIBUSB_TRANSFER_TYPE_BULK = 2,
+
+	/** Interrupt endpoint */
+	LIBUSB_TRANSFER_TYPE_INTERRUPT = 3,
+
+	/** Stream endpoint */
+	LIBUSB_TRANSFER_TYPE_BULK_STREAM = 4,
+};
+
+/** \ingroup libusb_misc
+ * Standard requests, as defined in table 9-5 of the USB 3.0 specifications */
+enum libusb_standard_request {
+	/** Request status of the specific recipient */
+	LIBUSB_REQUEST_GET_STATUS = 0x00,
+
+	/** Clear or disable a specific feature */
+	LIBUSB_REQUEST_CLEAR_FEATURE = 0x01,
+
+	/* 0x02 is reserved */
+
+	/** Set or enable a specific feature */
+	LIBUSB_REQUEST_SET_FEATURE = 0x03,
+
+	/* 0x04 is reserved */
+
+	/** Set device address for all future accesses */
+	LIBUSB_REQUEST_SET_ADDRESS = 0x05,
+
+	/** Get the specified descriptor */
+	LIBUSB_REQUEST_GET_DESCRIPTOR = 0x06,
+
+	/** Used to update existing descriptors or add new descriptors */
+	LIBUSB_REQUEST_SET_DESCRIPTOR = 0x07,
+
+	/** Get the current device configuration value */
+	LIBUSB_REQUEST_GET_CONFIGURATION = 0x08,
+
+	/** Set device configuration */
+	LIBUSB_REQUEST_SET_CONFIGURATION = 0x09,
+
+	/** Return the selected alternate setting for the specified interface */
+	LIBUSB_REQUEST_GET_INTERFACE = 0x0A,
+
+	/** Select an alternate interface for the specified interface */
+	LIBUSB_REQUEST_SET_INTERFACE = 0x0B,
+
+	/** Set then report an endpoint's synchronization frame */
+	LIBUSB_REQUEST_SYNCH_FRAME = 0x0C,
+
+	/** Sets both the U1 and U2 Exit Latency */
+	LIBUSB_REQUEST_SET_SEL = 0x30,
+
+	/** Delay from the time a host transmits a packet to the time it is
+	  * received by the device. */
+	LIBUSB_SET_ISOCH_DELAY = 0x31,
+};
+
+/** \ingroup libusb_misc
+ * Request type bits of the
+ * \ref libusb_control_setup::bmRequestType "bmRequestType" field in control
+ * transfers. */
+enum libusb_request_type {
+	/** Standard */
+	LIBUSB_REQUEST_TYPE_STANDARD = (0x00 << 5),
+
+	/** Class */
+	LIBUSB_REQUEST_TYPE_CLASS = (0x01 << 5),
+
+	/** Vendor */
+	LIBUSB_REQUEST_TYPE_VENDOR = (0x02 << 5),
+
+	/** Reserved */
+	LIBUSB_REQUEST_TYPE_RESERVED = (0x03 << 5)
+};
+
+/** \ingroup libusb_misc
+ * Recipient bits of the
+ * \ref libusb_control_setup::bmRequestType "bmRequestType" field in control
+ * transfers. Values 4 through 31 are reserved. */
+enum libusb_request_recipient {
+	/** Device */
+	LIBUSB_RECIPIENT_DEVICE = 0x00,
+
+	/** Interface */
+	LIBUSB_RECIPIENT_INTERFACE = 0x01,
+
+	/** Endpoint */
+	LIBUSB_RECIPIENT_ENDPOINT = 0x02,
+
+	/** Other */
+	LIBUSB_RECIPIENT_OTHER = 0x03,
+};
+
+#define LIBUSB_ISO_SYNC_TYPE_MASK		0x0C
+
+/** \ingroup libusb_desc
+ * Synchronization type for isochronous endpoints. Values for bits 2:3 of the
+ * \ref libusb_endpoint_descriptor::bmAttributes "bmAttributes" field in
+ * libusb_endpoint_descriptor.
+ */
+enum libusb_iso_sync_type {
+	/** No synchronization */
+	LIBUSB_ISO_SYNC_TYPE_NONE = 0,
+
+	/** Asynchronous */
+	LIBUSB_ISO_SYNC_TYPE_ASYNC = 1,
+
+	/** Adaptive */
+	LIBUSB_ISO_SYNC_TYPE_ADAPTIVE = 2,
+
+	/** Synchronous */
+	LIBUSB_ISO_SYNC_TYPE_SYNC = 3
+};
+
+#define LIBUSB_ISO_USAGE_TYPE_MASK 0x30
+
+/** \ingroup libusb_desc
+ * Usage type for isochronous endpoints. Values for bits 4:5 of the
+ * \ref libusb_endpoint_descriptor::bmAttributes "bmAttributes" field in
+ * libusb_endpoint_descriptor.
+ */
+enum libusb_iso_usage_type {
+	/** Data endpoint */
+	LIBUSB_ISO_USAGE_TYPE_DATA = 0,
+
+	/** Feedback endpoint */
+	LIBUSB_ISO_USAGE_TYPE_FEEDBACK = 1,
+
+	/** Implicit feedback Data endpoint */
+	LIBUSB_ISO_USAGE_TYPE_IMPLICIT = 2,
+};
+
+/** \ingroup libusb_desc
+ * A structure representing the standard USB device descriptor. This
+ * descriptor is documented in section 9.6.1 of the USB 3.0 specification.
+ * All multiple-byte fields are represented in host-endian format.
+ */
+struct libusb_device_descriptor {
+	/** Size of this descriptor (in bytes) */
+	uint8_t  bLength;
+
+	/** Descriptor type. Will have value
+	 * \ref libusb_descriptor_type::LIBUSB_DT_DEVICE LIBUSB_DT_DEVICE in this
+	 * context. */
+	uint8_t  bDescriptorType;
+
+	/** USB specification release number in binary-coded decimal. A value of
+	 * 0x0200 indicates USB 2.0, 0x0110 indicates USB 1.1, etc. */
+	uint16_t bcdUSB;
+
+	/** USB-IF class code for the device. See \ref libusb_class_code. */
+	uint8_t  bDeviceClass;
+
+	/** USB-IF subclass code for the device, qualified by the bDeviceClass
+	 * value */
+	uint8_t  bDeviceSubClass;
+
+	/** USB-IF protocol code for the device, qualified by the bDeviceClass and
+	 * bDeviceSubClass values */
+	uint8_t  bDeviceProtocol;
+
+	/** Maximum packet size for endpoint 0 */
+	uint8_t  bMaxPacketSize0;
+
+	/** USB-IF vendor ID */
+	uint16_t idVendor;
+
+	/** USB-IF product ID */
+	uint16_t idProduct;
+
+	/** Device release number in binary-coded decimal */
+	uint16_t bcdDevice;
+
+	/** Index of string descriptor describing manufacturer */
+	uint8_t  iManufacturer;
+
+	/** Index of string descriptor describing product */
+	uint8_t  iProduct;
+
+	/** Index of string descriptor containing device serial number */
+	uint8_t  iSerialNumber;
+
+	/** Number of possible configurations */
+	uint8_t  bNumConfigurations;
+};
+
+/** \ingroup libusb_desc
+ * A structure representing the standard USB endpoint descriptor. This
+ * descriptor is documented in section 9.6.6 of the USB 3.0 specification.
+ * All multiple-byte fields are represented in host-endian format.
+ */
+struct libusb_endpoint_descriptor {
+	/** Size of this descriptor (in bytes) */
+	uint8_t  bLength;
+
+	/** Descriptor type. Will have value
+	 * \ref libusb_descriptor_type::LIBUSB_DT_ENDPOINT LIBUSB_DT_ENDPOINT in
+	 * this context. */
+	uint8_t  bDescriptorType;
+
+	/** The address of the endpoint described by this descriptor. Bits 0:3 are
+	 * the endpoint number. Bits 4:6 are reserved. Bit 7 indicates direction,
+	 * see \ref libusb_endpoint_direction.
+	 */
+	uint8_t  bEndpointAddress;
+
+	/** Attributes which apply to the endpoint when it is configured using
+	 * the bConfigurationValue. Bits 0:1 determine the transfer type and
+	 * correspond to \ref libusb_transfer_type. Bits 2:3 are only used for
+	 * isochronous endpoints and correspond to \ref libusb_iso_sync_type.
+	 * Bits 4:5 are also only used for isochronous endpoints and correspond to
+	 * \ref libusb_iso_usage_type. Bits 6:7 are reserved.
+	 */
+	uint8_t  bmAttributes;
+
+	/** Maximum packet size this endpoint is capable of sending/receiving. */
+	uint16_t wMaxPacketSize;
+
+	/** Interval for polling endpoint for data transfers. */
+	uint8_t  bInterval;
+
+	/** For audio devices only: the rate at which synchronization feedback
+	 * is provided. */
+	uint8_t  bRefresh;
+
+	/** For audio devices only: the address if the synch endpoint */
+	uint8_t  bSynchAddress;
+
+	/** Extra descriptors. If libusb encounters unknown endpoint descriptors,
+	 * it will store them here, should you wish to parse them. */
+	const unsigned char *extra;
+
+	/** Length of the extra descriptors, in bytes. */
+	int extra_length;
+};
+
+/** \ingroup libusb_desc
+ * A structure representing the standard USB interface descriptor. This
+ * descriptor is documented in section 9.6.5 of the USB 3.0 specification.
+ * All multiple-byte fields are represented in host-endian format.
+ */
+struct libusb_interface_descriptor {
+	/** Size of this descriptor (in bytes) */
+	uint8_t  bLength;
+
+	/** Descriptor type. Will have value
+	 * \ref libusb_descriptor_type::LIBUSB_DT_INTERFACE LIBUSB_DT_INTERFACE
+	 * in this context. */
+	uint8_t  bDescriptorType;
+
+	/** Number of this interface */
+	uint8_t  bInterfaceNumber;
+
+	/** Value used to select this alternate setting for this interface */
+	uint8_t  bAlternateSetting;
+
+	/** Number of endpoints used by this interface (excluding the control
+	 * endpoint). */
+	uint8_t  bNumEndpoints;
+
+	/** USB-IF class code for this interface. See \ref libusb_class_code. */
+	uint8_t  bInterfaceClass;
+
+	/** USB-IF subclass code for this interface, qualified by the
+	 * bInterfaceClass value */
+	uint8_t  bInterfaceSubClass;
+
+	/** USB-IF protocol code for this interface, qualified by the
+	 * bInterfaceClass and bInterfaceSubClass values */
+	uint8_t  bInterfaceProtocol;
+
+	/** Index of string descriptor describing this interface */
+	uint8_t  iInterface;
+
+	/** Array of endpoint descriptors. This length of this array is determined
+	 * by the bNumEndpoints field. */
+	const struct libusb_endpoint_descriptor *endpoint;
+
+	/** Extra descriptors. If libusb encounters unknown interface descriptors,
+	 * it will store them here, should you wish to parse them. */
+	const unsigned char *extra;
+
+	/** Length of the extra descriptors, in bytes. */
+	int extra_length;
+};
+
+/** \ingroup libusb_desc
+ * A collection of alternate settings for a particular USB interface.
+ */
+struct libusb_interface {
+	/** Array of interface descriptors. The length of this array is determined
+	 * by the num_altsetting field. */
+	const struct libusb_interface_descriptor *altsetting;
+
+	/** The number of alternate settings that belong to this interface */
+	int num_altsetting;
+};
+
+/** \ingroup libusb_desc
+ * A structure representing the standard USB configuration descriptor. This
+ * descriptor is documented in section 9.6.3 of the USB 3.0 specification.
+ * All multiple-byte fields are represented in host-endian format.
+ */
+struct libusb_config_descriptor {
+	/** Size of this descriptor (in bytes) */
+	uint8_t  bLength;
+
+	/** Descriptor type. Will have value
+	 * \ref libusb_descriptor_type::LIBUSB_DT_CONFIG LIBUSB_DT_CONFIG
+	 * in this context. */
+	uint8_t  bDescriptorType;
+
+	/** Total length of data returned for this configuration */
+	uint16_t wTotalLength;
+
+	/** Number of interfaces supported by this configuration */
+	uint8_t  bNumInterfaces;
+
+	/** Identifier value for this configuration */
+	uint8_t  bConfigurationValue;
+
+	/** Index of string descriptor describing this configuration */
+	uint8_t  iConfiguration;
+
+	/** Configuration characteristics */
+	uint8_t  bmAttributes;
+
+	/** Maximum power consumption of the USB device from this bus in this
+	 * configuration when the device is fully operation. Expressed in units
+	 * of 2 mA when the device is operating in high-speed mode and in units
+	 * of 8 mA when the device is operating in super-speed mode. */
+	uint8_t  MaxPower;
+
+	/** Array of interfaces supported by this configuration. The length of
+	 * this array is determined by the bNumInterfaces field. */
+	const struct libusb_interface *interface;
+
+	/** Extra descriptors. If libusb encounters unknown configuration
+	 * descriptors, it will store them here, should you wish to parse them. */
+	const unsigned char *extra;
+
+	/** Length of the extra descriptors, in bytes. */
+	int extra_length;
+};
+
+/** \ingroup libusb_desc
+ * A structure representing the superspeed endpoint companion
+ * descriptor. This descriptor is documented in section 9.6.7 of
+ * the USB 3.0 specification. All multiple-byte fields are represented in
+ * host-endian format.
+ */
+struct libusb_ss_endpoint_companion_descriptor {
+
+	/** Size of this descriptor (in bytes) */
+	uint8_t  bLength;
+
+	/** Descriptor type. Will have value
+	 * \ref libusb_descriptor_type::LIBUSB_DT_SS_ENDPOINT_COMPANION in
+	 * this context. */
+	uint8_t  bDescriptorType;
+
+
+	/** The maximum number of packets the endpoint can send or
+	 *  receive as part of a burst. */
+	uint8_t  bMaxBurst;
+
+	/** In bulk EP:	bits 4:0 represents the	maximum	number of
+	 *  streams the	EP supports. In	isochronous EP:	bits 1:0
+	 *  represents the Mult	- a zero based value that determines
+	 *  the	maximum	number of packets within a service interval  */
+	uint8_t  bmAttributes;
+
+	/** The	total number of bytes this EP will transfer every
+	 *  service interval. valid only for periodic EPs. */
+	uint16_t wBytesPerInterval;
+};
+
+/** \ingroup libusb_desc
+ * A generic representation of a BOS Device Capability descriptor. It is
+ * advised to check bDevCapabilityType and call the matching
+ * libusb_get_*_descriptor function to get a structure fully matching the type.
+ */
+struct libusb_bos_dev_capability_descriptor {
+	/** Size of this descriptor (in bytes) */
+	uint8_t bLength;
+	/** Descriptor type. Will have value
+	 * \ref libusb_descriptor_type::LIBUSB_DT_DEVICE_CAPABILITY
+	 * LIBUSB_DT_DEVICE_CAPABILITY in this context. */
+	uint8_t bDescriptorType;
+	/** Device Capability type */
+	uint8_t bDevCapabilityType;
+	/** Device Capability data (bLength - 3 bytes) */
+	uint8_t dev_capability_data
+#if defined(__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L)
+	[] /* valid C99 code */
+#else
+	[0] /* non-standard, but usually working code */
+#endif
+	;
+};
+
+/** \ingroup libusb_desc
+ * A structure representing the Binary Device Object Store (BOS) descriptor.
+ * This descriptor is documented in section 9.6.2 of the USB 3.0 specification.
+ * All multiple-byte fields are represented in host-endian format.
+ */
+struct libusb_bos_descriptor {
+	/** Size of this descriptor (in bytes) */
+	uint8_t  bLength;
+
+	/** Descriptor type. Will have value
+	 * \ref libusb_descriptor_type::LIBUSB_DT_BOS LIBUSB_DT_BOS
+	 * in this context. */
+	uint8_t  bDescriptorType;
+
+	/** Length of this descriptor and all of its sub descriptors */
+	uint16_t wTotalLength;
+
+	/** The number of separate device capability descriptors in
+	 * the BOS */
+	uint8_t  bNumDeviceCaps;
+
+	/** bNumDeviceCap Device Capability Descriptors */
+	struct libusb_bos_dev_capability_descriptor *dev_capability
+#if defined(__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L)
+	[] /* valid C99 code */
+#else
+	[0] /* non-standard, but usually working code */
+#endif
+	;
+};
+
+/** \ingroup libusb_desc
+ * A structure representing the USB 2.0 Extension descriptor
+ * This descriptor is documented in section 9.6.2.1 of the USB 3.0 specification.
+ * All multiple-byte fields are represented in host-endian format.
+ */
+struct libusb_usb_2_0_extension_descriptor {
+	/** Size of this descriptor (in bytes) */
+	uint8_t  bLength;
+
+	/** Descriptor type. Will have value
+	 * \ref libusb_descriptor_type::LIBUSB_DT_DEVICE_CAPABILITY
+	 * LIBUSB_DT_DEVICE_CAPABILITY in this context. */
+	uint8_t  bDescriptorType;
+
+	/** Capability type. Will have value
+	 * \ref libusb_capability_type::LIBUSB_BT_USB_2_0_EXTENSION
+	 * LIBUSB_BT_USB_2_0_EXTENSION in this context. */
+	uint8_t  bDevCapabilityType;
+
+	/** Bitmap encoding of supported device level features.
+	 * A value of one in a bit location indicates a feature is
+	 * supported; a value of zero indicates it is not supported.
+	 * See \ref libusb_usb_2_0_extension_attributes. */
+	uint32_t  bmAttributes;
+};
+
+/** \ingroup libusb_desc
+ * A structure representing the SuperSpeed USB Device Capability descriptor
+ * This descriptor is documented in section 9.6.2.2 of the USB 3.0 specification.
+ * All multiple-byte fields are represented in host-endian format.
+ */
+struct libusb_ss_usb_device_capability_descriptor {
+	/** Size of this descriptor (in bytes) */
+	uint8_t  bLength;
+
+	/** Descriptor type. Will have value
+	 * \ref libusb_descriptor_type::LIBUSB_DT_DEVICE_CAPABILITY
+	 * LIBUSB_DT_DEVICE_CAPABILITY in this context. */
+	uint8_t  bDescriptorType;
+
+	/** Capability type. Will have value
+	 * \ref libusb_capability_type::LIBUSB_BT_SS_USB_DEVICE_CAPABILITY
+	 * LIBUSB_BT_SS_USB_DEVICE_CAPABILITY in this context. */
+	uint8_t  bDevCapabilityType;
+
+	/** Bitmap encoding of supported device level features.
+	 * A value of one in a bit location indicates a feature is
+	 * supported; a value of zero indicates it is not supported.
+	 * See \ref libusb_ss_usb_device_capability_attributes. */
+	uint8_t  bmAttributes;
+
+	/** Bitmap encoding of the speed supported by this device when
+	 * operating in SuperSpeed mode. See \ref libusb_supported_speed. */
+	uint16_t wSpeedSupported;
+
+	/** The lowest speed at which all the functionality supported
+	 * by the device is available to the user. For example if the
+	 * device supports all its functionality when connected at
+	 * full speed and above then it sets this value to 1. */
+	uint8_t  bFunctionalitySupport;
+
+	/** U1 Device Exit Latency. */
+	uint8_t  bU1DevExitLat;
+
+	/** U2 Device Exit Latency. */
+	uint16_t bU2DevExitLat;
+};
+
+/** \ingroup libusb_desc
+ * A structure representing the Container ID descriptor.
+ * This descriptor is documented in section 9.6.2.3 of the USB 3.0 specification.
+ * All multiple-byte fields, except UUIDs, are represented in host-endian format.
+ */
+struct libusb_container_id_descriptor {
+	/** Size of this descriptor (in bytes) */
+	uint8_t  bLength;
+
+	/** Descriptor type. Will have value
+	 * \ref libusb_descriptor_type::LIBUSB_DT_DEVICE_CAPABILITY
+	 * LIBUSB_DT_DEVICE_CAPABILITY in this context. */
+	uint8_t  bDescriptorType;
+
+	/** Capability type. Will have value
+	 * \ref libusb_capability_type::LIBUSB_BT_CONTAINER_ID
+	 * LIBUSB_BT_CONTAINER_ID in this context. */
+	uint8_t  bDevCapabilityType;
+
+	/** Reserved field */
+	uint8_t bReserved;
+
+	/** 128 bit UUID */
+	uint8_t  ContainerID[16];
+};
+
+/** \ingroup libusb_asyncio
+ * Setup packet for control transfers. */
+struct libusb_control_setup {
+	/** Request type. Bits 0:4 determine recipient, see
+	 * \ref libusb_request_recipient. Bits 5:6 determine type, see
+	 * \ref libusb_request_type. Bit 7 determines data transfer direction, see
+	 * \ref libusb_endpoint_direction.
+	 */
+	uint8_t  bmRequestType;
+
+	/** Request. If the type bits of bmRequestType are equal to
+	 * \ref libusb_request_type::LIBUSB_REQUEST_TYPE_STANDARD
+	 * "LIBUSB_REQUEST_TYPE_STANDARD" then this field refers to
+	 * \ref libusb_standard_request. For other cases, use of this field is
+	 * application-specific. */
+	uint8_t  bRequest;
+
+	/** Value. Varies according to request */
+	uint16_t wValue;
+
+	/** Index. Varies according to request, typically used to pass an index
+	 * or offset */
+	uint16_t wIndex;
+
+	/** Number of bytes to transfer */
+	uint16_t wLength;
+};
+
+#define LIBUSB_CONTROL_SETUP_SIZE (sizeof(struct libusb_control_setup))
+
+/* libusb */
+
+struct libusb_context;
+struct libusb_device;
+struct libusb_device_handle;
+
+/** \ingroup libusb_lib
+ * Structure providing the version of the libusb runtime
+ */
+struct libusb_version {
+	/** Library major version. */
+	const uint16_t major;
+
+	/** Library minor version. */
+	const uint16_t minor;
+
+	/** Library micro version. */
+	const uint16_t micro;
+
+	/** Library nano version. */
+	const uint16_t nano;
+
+	/** Library release candidate suffix string, e.g. "-rc4". */
+	const char *rc;
+
+	/** For ABI compatibility only. */
+	const char* describe;
+};
+
+/** \ingroup libusb_lib
+ * Structure representing a libusb session. The concept of individual libusb
+ * sessions allows for your program to use two libraries (or dynamically
+ * load two modules) which both independently use libusb. This will prevent
+ * interference between the individual libusb users - for example
+ * libusb_set_debug() will not affect the other user of the library, and
+ * libusb_exit() will not destroy resources that the other user is still
+ * using.
+ *
+ * Sessions are created by libusb_init() and destroyed through libusb_exit().
+ * If your application is guaranteed to only ever include a single libusb
+ * user (i.e. you), you do not have to worry about contexts: pass NULL in
+ * every function call where a context is required. The default context
+ * will be used.
+ *
+ * For more information, see \ref libusb_contexts.
+ */
+typedef struct libusb_context libusb_context;
+
+/** \ingroup libusb_dev
+ * Structure representing a USB device detected on the system. This is an
+ * opaque type for which you are only ever provided with a pointer, usually
+ * originating from libusb_get_device_list().
+ *
+ * Certain operations can be performed on a device, but in order to do any
+ * I/O you will have to first obtain a device handle using libusb_open().
+ *
+ * Devices are reference counted with libusb_ref_device() and
+ * libusb_unref_device(), and are freed when the reference count reaches 0.
+ * New devices presented by libusb_get_device_list() have a reference count of
+ * 1, and libusb_free_device_list() can optionally decrease the reference count
+ * on all devices in the list. libusb_open() adds another reference which is
+ * later destroyed by libusb_close().
+ */
+typedef struct libusb_device libusb_device;
+
+
+/** \ingroup libusb_dev
+ * Structure representing a handle on a USB device. This is an opaque type for
+ * which you are only ever provided with a pointer, usually originating from
+ * libusb_open().
+ *
+ * A device handle is used to perform I/O and other operations. When finished
+ * with a device handle, you should call libusb_close().
+ */
+typedef struct libusb_device_handle libusb_device_handle;
+
+/** \ingroup libusb_dev
+ * Speed codes. Indicates the speed at which the device is operating.
+ */
+enum libusb_speed {
+	/** The OS doesn't report or know the device speed. */
+	LIBUSB_SPEED_UNKNOWN = 0,
+
+	/** The device is operating at low speed (1.5MBit/s). */
+	LIBUSB_SPEED_LOW = 1,
+
+	/** The device is operating at full speed (12MBit/s). */
+	LIBUSB_SPEED_FULL = 2,
+
+	/** The device is operating at high speed (480MBit/s). */
+	LIBUSB_SPEED_HIGH = 3,
+
+	/** The device is operating at super speed (5000MBit/s). */
+	LIBUSB_SPEED_SUPER = 4,
+};
+
+/** \ingroup libusb_dev
+ * Supported speeds (wSpeedSupported) bitfield. Indicates what
+ * speeds the device supports.
+ */
+enum libusb_supported_speed {
+	/** Low speed operation supported (1.5MBit/s). */
+	LIBUSB_LOW_SPEED_OPERATION   = 1,
+
+	/** Full speed operation supported (12MBit/s). */
+	LIBUSB_FULL_SPEED_OPERATION  = 2,
+
+	/** High speed operation supported (480MBit/s). */
+	LIBUSB_HIGH_SPEED_OPERATION  = 4,
+
+	/** Superspeed operation supported (5000MBit/s). */
+	LIBUSB_SUPER_SPEED_OPERATION = 8,
+};
+
+/** \ingroup libusb_dev
+ * Masks for the bits of the
+ * \ref libusb_usb_2_0_extension_descriptor::bmAttributes "bmAttributes" field
+ * of the USB 2.0 Extension descriptor.
+ */
+enum libusb_usb_2_0_extension_attributes {
+	/** Supports Link Power Management (LPM) */
+	LIBUSB_BM_LPM_SUPPORT = 2,
+};
+
+/** \ingroup libusb_dev
+ * Masks for the bits of the
+ * \ref libusb_ss_usb_device_capability_descriptor::bmAttributes "bmAttributes" field
+ * field of the SuperSpeed USB Device Capability descriptor.
+ */
+enum libusb_ss_usb_device_capability_attributes {
+	/** Supports Latency Tolerance Messages (LTM) */
+	LIBUSB_BM_LTM_SUPPORT = 2,
+};
+
+/** \ingroup libusb_dev
+ * USB capability types
+ */
+enum libusb_bos_type {
+	/** Wireless USB device capability */
+	LIBUSB_BT_WIRELESS_USB_DEVICE_CAPABILITY	= 1,
+
+	/** USB 2.0 extensions */
+	LIBUSB_BT_USB_2_0_EXTENSION			= 2,
+
+	/** SuperSpeed USB device capability */
+	LIBUSB_BT_SS_USB_DEVICE_CAPABILITY		= 3,
+
+	/** Container ID type */
+	LIBUSB_BT_CONTAINER_ID				= 4,
+};
+
+/** \ingroup libusb_misc
+ * Error codes. Most libusb functions return 0 on success or one of these
+ * codes on failure.
+ * You can call libusb_error_name() to retrieve a string representation of an
+ * error code or libusb_strerror() to get an end-user suitable description of
+ * an error code.
+ */
+enum libusb_error {
+	/** Success (no error) */
+	LIBUSB_SUCCESS = 0,
+
+	/** Input/output error */
+	LIBUSB_ERROR_IO = -1,
+
+	/** Invalid parameter */
+	LIBUSB_ERROR_INVALID_PARAM = -2,
+
+	/** Access denied (insufficient permissions) */
+	LIBUSB_ERROR_ACCESS = -3,
+
+	/** No such device (it may have been disconnected) */
+	LIBUSB_ERROR_NO_DEVICE = -4,
+
+	/** Entity not found */
+	LIBUSB_ERROR_NOT_FOUND = -5,
+
+	/** Resource busy */
+	LIBUSB_ERROR_BUSY = -6,
+
+	/** Operation timed out */
+	LIBUSB_ERROR_TIMEOUT = -7,
+
+	/** Overflow */
+	LIBUSB_ERROR_OVERFLOW = -8,
+
+	/** Pipe error */
+	LIBUSB_ERROR_PIPE = -9,
+
+	/** System call interrupted (perhaps due to signal) */
+	LIBUSB_ERROR_INTERRUPTED = -10,
+
+	/** Insufficient memory */
+	LIBUSB_ERROR_NO_MEM = -11,
+
+	/** Operation not supported or unimplemented on this platform */
+	LIBUSB_ERROR_NOT_SUPPORTED = -12,
+
+	/* NB: Remember to update LIBUSB_ERROR_COUNT below as well as the
+	   message strings in strerror.c when adding new error codes here. */
+
+	/** Other error */
+	LIBUSB_ERROR_OTHER = -99,
+};
+
+/* Total number of error codes in enum libusb_error */
+#define LIBUSB_ERROR_COUNT 14
+
+/** \ingroup libusb_asyncio
+ * Transfer status codes */
+enum libusb_transfer_status {
+	/** Transfer completed without error. Note that this does not indicate
+	 * that the entire amount of requested data was transferred. */
+	LIBUSB_TRANSFER_COMPLETED,
+
+	/** Transfer failed */
+	LIBUSB_TRANSFER_ERROR,
+
+	/** Transfer timed out */
+	LIBUSB_TRANSFER_TIMED_OUT,
+
+	/** Transfer was cancelled */
+	LIBUSB_TRANSFER_CANCELLED,
+
+	/** For bulk/interrupt endpoints: halt condition detected (endpoint
+	 * stalled). For control endpoints: control request not supported. */
+	LIBUSB_TRANSFER_STALL,
+
+	/** Device was disconnected */
+	LIBUSB_TRANSFER_NO_DEVICE,
+
+	/** Device sent more data than requested */
+	LIBUSB_TRANSFER_OVERFLOW,
+
+	/* NB! Remember to update libusb_error_name()
+	   when adding new status codes here. */
+};
+
+/** \ingroup libusb_asyncio
+ * libusb_transfer.flags values */
+enum libusb_transfer_flags {
+	/** Report short frames as errors */
+	LIBUSB_TRANSFER_SHORT_NOT_OK = 1<<0,
+
+	/** Automatically free() transfer buffer during libusb_free_transfer().
+	 * Note that buffers allocated with libusb_dev_mem_alloc() should not
+	 * be attempted freed in this way, since free() is not an appropriate
+	 * way to release such memory. */
+	LIBUSB_TRANSFER_FREE_BUFFER = 1<<1,
+
+	/** Automatically call libusb_free_transfer() after callback returns.
+	 * If this flag is set, it is illegal to call libusb_free_transfer()
+	 * from your transfer callback, as this will result in a double-free
+	 * when this flag is acted upon. */
+	LIBUSB_TRANSFER_FREE_TRANSFER = 1<<2,
+
+	/** Terminate transfers that are a multiple of the endpoint's
+	 * wMaxPacketSize with an extra zero length packet. This is useful
+	 * when a device protocol mandates that each logical request is
+	 * terminated by an incomplete packet (i.e. the logical requests are
+	 * not separated by other means).
+	 *
+	 * This flag only affects host-to-device transfers to bulk and interrupt
+	 * endpoints. In other situations, it is ignored.
+	 *
+	 * This flag only affects transfers with a length that is a multiple of
+	 * the endpoint's wMaxPacketSize. On transfers of other lengths, this
+	 * flag has no effect. Therefore, if you are working with a device that
+	 * needs a ZLP whenever the end of the logical request falls on a packet
+	 * boundary, then it is sensible to set this flag on <em>every</em>
+	 * transfer (you do not have to worry about only setting it on transfers
+	 * that end on the boundary).
+	 *
+	 * This flag is currently only supported on Linux.
+	 * On other systems, libusb_submit_transfer() will return
+	 * LIBUSB_ERROR_NOT_SUPPORTED for every transfer where this flag is set.
+	 *
+	 * Available since libusb-1.0.9.
+	 */
+	LIBUSB_TRANSFER_ADD_ZERO_PACKET = 1 << 3,
+};
+
+/** \ingroup libusb_asyncio
+ * Isochronous packet descriptor. */
+struct libusb_iso_packet_descriptor {
+	/** Length of data to request in this packet */
+	unsigned int length;
+
+	/** Amount of data that was actually transferred */
+	unsigned int actual_length;
+
+	/** Status code for this packet */
+	enum libusb_transfer_status status;
+};
+
+struct libusb_transfer;
+
+/** \ingroup libusb_asyncio
+ * Asynchronous transfer callback function type. When submitting asynchronous
+ * transfers, you pass a pointer to a callback function of this type via the
+ * \ref libusb_transfer::callback "callback" member of the libusb_transfer
+ * structure. libusb will call this function later, when the transfer has
+ * completed or failed. See \ref libusb_asyncio for more information.
+ * \param transfer The libusb_transfer struct the callback function is being
+ * notified about.
+ */
+typedef void (LIBUSB_CALL *libusb_transfer_cb_fn)(struct libusb_transfer *transfer);
+
+/** \ingroup libusb_asyncio
+ * The generic USB transfer structure. The user populates this structure and
+ * then submits it in order to request a transfer. After the transfer has
+ * completed, the library populates the transfer with the results and passes
+ * it back to the user.
+ */
+struct libusb_transfer {
+	/** Handle of the device that this transfer will be submitted to */
+	libusb_device_handle *dev_handle;
+
+	/** A bitwise OR combination of \ref libusb_transfer_flags. */
+	uint8_t flags;
+
+	/** Address of the endpoint where this transfer will be sent. */
+	unsigned char endpoint;
+
+	/** Type of the endpoint from \ref libusb_transfer_type */
+	unsigned char type;
+
+	/** Timeout for this transfer in millseconds. A value of 0 indicates no
+	 * timeout. */
+	unsigned int timeout;
+
+	/** The status of the transfer. Read-only, and only for use within
+	 * transfer callback function.
+	 *
+	 * If this is an isochronous transfer, this field may read COMPLETED even
+	 * if there were errors in the frames. Use the
+	 * \ref libusb_iso_packet_descriptor::status "status" field in each packet
+	 * to determine if errors occurred. */
+	enum libusb_transfer_status status;
+
+	/** Length of the data buffer */
+	int length;
+
+	/** Actual length of data that was transferred. Read-only, and only for
+	 * use within transfer callback function. Not valid for isochronous
+	 * endpoint transfers. */
+	int actual_length;
+
+	/** Callback function. This will be invoked when the transfer completes,
+	 * fails, or is cancelled. */
+	libusb_transfer_cb_fn callback;
+
+	/** User context data to pass to the callback function. */
+	void *user_data;
+
+	/** Data buffer */
+	unsigned char *buffer;
+
+	/** Number of isochronous packets. Only used for I/O with isochronous
+	 * endpoints. */
+	int num_iso_packets;
+
+	/** Isochronous packet descriptors, for isochronous transfers only. */
+	struct libusb_iso_packet_descriptor iso_packet_desc
+#if defined(__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L)
+	[] /* valid C99 code */
+#else
+	[0] /* non-standard, but usually working code */
+#endif
+	;
+};
+
+/** \ingroup libusb_misc
+ * Capabilities supported by an instance of libusb on the current running
+ * platform. Test if the loaded library supports a given capability by calling
+ * \ref libusb_has_capability().
+ */
+enum libusb_capability {
+	/** The libusb_has_capability() API is available. */
+	LIBUSB_CAP_HAS_CAPABILITY = 0x0000,
+	/** Hotplug support is available on this platform. */
+	LIBUSB_CAP_HAS_HOTPLUG = 0x0001,
+	/** The library can access HID devices without requiring user intervention.
+	 * Note that before being able to actually access an HID device, you may
+	 * still have to call additional libusb functions such as
+	 * \ref libusb_detach_kernel_driver(). */
+	LIBUSB_CAP_HAS_HID_ACCESS = 0x0100,
+	/** The library supports detaching of the default USB driver, using 
+	 * \ref libusb_detach_kernel_driver(), if one is set by the OS kernel */
+	LIBUSB_CAP_SUPPORTS_DETACH_KERNEL_DRIVER = 0x0101
+};
+
+/** \ingroup libusb_lib
+ *  Log message levels.
+ *  - LIBUSB_LOG_LEVEL_NONE (0)    : no messages ever printed by the library (default)
+ *  - LIBUSB_LOG_LEVEL_ERROR (1)   : error messages are printed to stderr
+ *  - LIBUSB_LOG_LEVEL_WARNING (2) : warning and error messages are printed to stderr
+ *  - LIBUSB_LOG_LEVEL_INFO (3)    : informational messages are printed to stdout, warning
+ *    and error messages are printed to stderr
+ *  - LIBUSB_LOG_LEVEL_DEBUG (4)   : debug and informational messages are printed to stdout,
+ *    warnings and errors to stderr
+ */
+enum libusb_log_level {
+	LIBUSB_LOG_LEVEL_NONE = 0,
+	LIBUSB_LOG_LEVEL_ERROR,
+	LIBUSB_LOG_LEVEL_WARNING,
+	LIBUSB_LOG_LEVEL_INFO,
+	LIBUSB_LOG_LEVEL_DEBUG,
+};
+
+int LIBUSB_CALL libusb_init(libusb_context **ctx);
+void LIBUSB_CALL libusb_exit(libusb_context *ctx);
+void LIBUSB_CALL libusb_set_debug(libusb_context *ctx, int level);
+const struct libusb_version * LIBUSB_CALL libusb_get_version(void);
+int LIBUSB_CALL libusb_has_capability(uint32_t capability);
+const char * LIBUSB_CALL libusb_error_name(int errcode);
+int LIBUSB_CALL libusb_setlocale(const char *locale);
+const char * LIBUSB_CALL libusb_strerror(enum libusb_error errcode);
+
+ssize_t LIBUSB_CALL libusb_get_device_list(libusb_context *ctx,
+	libusb_device ***list);
+void LIBUSB_CALL libusb_free_device_list(libusb_device **list,
+	int unref_devices);
+libusb_device * LIBUSB_CALL libusb_ref_device(libusb_device *dev);
+void LIBUSB_CALL libusb_unref_device(libusb_device *dev);
+
+int LIBUSB_CALL libusb_get_configuration(libusb_device_handle *dev,
+	int *config);
+int LIBUSB_CALL libusb_get_device_descriptor(libusb_device *dev,
+	struct libusb_device_descriptor *desc);
+int LIBUSB_CALL libusb_get_active_config_descriptor(libusb_device *dev,
+	struct libusb_config_descriptor **config);
+int LIBUSB_CALL libusb_get_config_descriptor(libusb_device *dev,
+	uint8_t config_index, struct libusb_config_descriptor **config);
+int LIBUSB_CALL libusb_get_config_descriptor_by_value(libusb_device *dev,
+	uint8_t bConfigurationValue, struct libusb_config_descriptor **config);
+void LIBUSB_CALL libusb_free_config_descriptor(
+	struct libusb_config_descriptor *config);
+int LIBUSB_CALL libusb_get_ss_endpoint_companion_descriptor(
+	struct libusb_context *ctx,
+	const struct libusb_endpoint_descriptor *endpoint,
+	struct libusb_ss_endpoint_companion_descriptor **ep_comp);
+void LIBUSB_CALL libusb_free_ss_endpoint_companion_descriptor(
+	struct libusb_ss_endpoint_companion_descriptor *ep_comp);
+int LIBUSB_CALL libusb_get_bos_descriptor(libusb_device_handle *dev_handle,
+	struct libusb_bos_descriptor **bos);
+void LIBUSB_CALL libusb_free_bos_descriptor(struct libusb_bos_descriptor *bos);
+int LIBUSB_CALL libusb_get_usb_2_0_extension_descriptor(
+	struct libusb_context *ctx,
+	struct libusb_bos_dev_capability_descriptor *dev_cap,
+	struct libusb_usb_2_0_extension_descriptor **usb_2_0_extension);
+void LIBUSB_CALL libusb_free_usb_2_0_extension_descriptor(
+	struct libusb_usb_2_0_extension_descriptor *usb_2_0_extension);
+int LIBUSB_CALL libusb_get_ss_usb_device_capability_descriptor(
+	struct libusb_context *ctx,
+	struct libusb_bos_dev_capability_descriptor *dev_cap,
+	struct libusb_ss_usb_device_capability_descriptor **ss_usb_device_cap);
+void LIBUSB_CALL libusb_free_ss_usb_device_capability_descriptor(
+	struct libusb_ss_usb_device_capability_descriptor *ss_usb_device_cap);
+int LIBUSB_CALL libusb_get_container_id_descriptor(struct libusb_context *ctx,
+	struct libusb_bos_dev_capability_descriptor *dev_cap,
+	struct libusb_container_id_descriptor **container_id);
+void LIBUSB_CALL libusb_free_container_id_descriptor(
+	struct libusb_container_id_descriptor *container_id);
+uint8_t LIBUSB_CALL libusb_get_bus_number(libusb_device *dev);
+uint8_t LIBUSB_CALL libusb_get_port_number(libusb_device *dev);
+int LIBUSB_CALL libusb_get_port_numbers(libusb_device *dev, uint8_t* port_numbers, int port_numbers_len);
+LIBUSB_DEPRECATED_FOR(libusb_get_port_numbers)
+int LIBUSB_CALL libusb_get_port_path(libusb_context *ctx, libusb_device *dev, uint8_t* path, uint8_t path_length);
+libusb_device * LIBUSB_CALL libusb_get_parent(libusb_device *dev);
+uint8_t LIBUSB_CALL libusb_get_device_address(libusb_device *dev);
+int LIBUSB_CALL libusb_get_device_speed(libusb_device *dev);
+int LIBUSB_CALL libusb_get_max_packet_size(libusb_device *dev,
+	unsigned char endpoint);
+int LIBUSB_CALL libusb_get_max_iso_packet_size(libusb_device *dev,
+	unsigned char endpoint);
+
+int LIBUSB_CALL libusb_open(libusb_device *dev, libusb_device_handle **dev_handle);
+void LIBUSB_CALL libusb_close(libusb_device_handle *dev_handle);
+libusb_device * LIBUSB_CALL libusb_get_device(libusb_device_handle *dev_handle);
+
+int LIBUSB_CALL libusb_set_configuration(libusb_device_handle *dev_handle,
+	int configuration);
+int LIBUSB_CALL libusb_claim_interface(libusb_device_handle *dev_handle,
+	int interface_number);
+int LIBUSB_CALL libusb_release_interface(libusb_device_handle *dev_handle,
+	int interface_number);
+
+libusb_device_handle * LIBUSB_CALL libusb_open_device_with_vid_pid(
+	libusb_context *ctx, uint16_t vendor_id, uint16_t product_id);
+
+int LIBUSB_CALL libusb_set_interface_alt_setting(libusb_device_handle *dev_handle,
+	int interface_number, int alternate_setting);
+int LIBUSB_CALL libusb_clear_halt(libusb_device_handle *dev_handle,
+	unsigned char endpoint);
+int LIBUSB_CALL libusb_reset_device(libusb_device_handle *dev_handle);
+
+int LIBUSB_CALL libusb_alloc_streams(libusb_device_handle *dev_handle,
+	uint32_t num_streams, unsigned char *endpoints, int num_endpoints);
+int LIBUSB_CALL libusb_free_streams(libusb_device_handle *dev_handle,
+	unsigned char *endpoints, int num_endpoints);
+
+unsigned char * LIBUSB_CALL libusb_dev_mem_alloc(libusb_device_handle *dev_handle,
+	size_t length);
+int LIBUSB_CALL libusb_dev_mem_free(libusb_device_handle *dev_handle,
+	unsigned char *buffer, size_t length);
+
+int LIBUSB_CALL libusb_kernel_driver_active(libusb_device_handle *dev_handle,
+	int interface_number);
+int LIBUSB_CALL libusb_detach_kernel_driver(libusb_device_handle *dev_handle,
+	int interface_number);
+int LIBUSB_CALL libusb_attach_kernel_driver(libusb_device_handle *dev_handle,
+	int interface_number);
+int LIBUSB_CALL libusb_set_auto_detach_kernel_driver(
+	libusb_device_handle *dev_handle, int enable);
+
+/* async I/O */
+
+/** \ingroup libusb_asyncio
+ * Get the data section of a control transfer. This convenience function is here
+ * to remind you that the data does not start until 8 bytes into the actual
+ * buffer, as the setup packet comes first.
+ *
+ * Calling this function only makes sense from a transfer callback function,
+ * or situations where you have already allocated a suitably sized buffer at
+ * transfer->buffer.
+ *
+ * \param transfer a transfer
+ * \returns pointer to the first byte of the data section
+ */
+static inline unsigned char *libusb_control_transfer_get_data(
+	struct libusb_transfer *transfer)
+{
+	return transfer->buffer + LIBUSB_CONTROL_SETUP_SIZE;
+}
+
+/** \ingroup libusb_asyncio
+ * Get the control setup packet of a control transfer. This convenience
+ * function is here to remind you that the control setup occupies the first
+ * 8 bytes of the transfer data buffer.
+ *
+ * Calling this function only makes sense from a transfer callback function,
+ * or situations where you have already allocated a suitably sized buffer at
+ * transfer->buffer.
+ *
+ * \param transfer a transfer
+ * \returns a casted pointer to the start of the transfer data buffer
+ */
+static inline struct libusb_control_setup *libusb_control_transfer_get_setup(
+	struct libusb_transfer *transfer)
+{
+	return (struct libusb_control_setup *)(void *) transfer->buffer;
+}
+
+/** \ingroup libusb_asyncio
+ * Helper function to populate the setup packet (first 8 bytes of the data
+ * buffer) for a control transfer. The wIndex, wValue and wLength values should
+ * be given in host-endian byte order.
+ *
+ * \param buffer buffer to output the setup packet into
+ * This pointer must be aligned to at least 2 bytes boundary.
+ * \param bmRequestType see the
+ * \ref libusb_control_setup::bmRequestType "bmRequestType" field of
+ * \ref libusb_control_setup
+ * \param bRequest see the
+ * \ref libusb_control_setup::bRequest "bRequest" field of
+ * \ref libusb_control_setup
+ * \param wValue see the
+ * \ref libusb_control_setup::wValue "wValue" field of
+ * \ref libusb_control_setup
+ * \param wIndex see the
+ * \ref libusb_control_setup::wIndex "wIndex" field of
+ * \ref libusb_control_setup
+ * \param wLength see the
+ * \ref libusb_control_setup::wLength "wLength" field of
+ * \ref libusb_control_setup
+ */
+static inline void libusb_fill_control_setup(unsigned char *buffer,
+	uint8_t bmRequestType, uint8_t bRequest, uint16_t wValue, uint16_t wIndex,
+	uint16_t wLength)
+{
+	struct libusb_control_setup *setup = (struct libusb_control_setup *)(void *) buffer;
+	setup->bmRequestType = bmRequestType;
+	setup->bRequest = bRequest;
+	setup->wValue = libusb_cpu_to_le16(wValue);
+	setup->wIndex = libusb_cpu_to_le16(wIndex);
+	setup->wLength = libusb_cpu_to_le16(wLength);
+}
+
+struct libusb_transfer * LIBUSB_CALL libusb_alloc_transfer(int iso_packets);
+int LIBUSB_CALL libusb_submit_transfer(struct libusb_transfer *transfer);
+int LIBUSB_CALL libusb_cancel_transfer(struct libusb_transfer *transfer);
+void LIBUSB_CALL libusb_free_transfer(struct libusb_transfer *transfer);
+void LIBUSB_CALL libusb_transfer_set_stream_id(
+	struct libusb_transfer *transfer, uint32_t stream_id);
+uint32_t LIBUSB_CALL libusb_transfer_get_stream_id(
+	struct libusb_transfer *transfer);
+
+/** \ingroup libusb_asyncio
+ * Helper function to populate the required \ref libusb_transfer fields
+ * for a control transfer.
+ *
+ * If you pass a transfer buffer to this function, the first 8 bytes will
+ * be interpreted as a control setup packet, and the wLength field will be
+ * used to automatically populate the \ref libusb_transfer::length "length"
+ * field of the transfer. Therefore the recommended approach is:
+ * -# Allocate a suitably sized data buffer (including space for control setup)
+ * -# Call libusb_fill_control_setup()
+ * -# If this is a host-to-device transfer with a data stage, put the data
+ *    in place after the setup packet
+ * -# Call this function
+ * -# Call libusb_submit_transfer()
+ *
+ * It is also legal to pass a NULL buffer to this function, in which case this
+ * function will not attempt to populate the length field. Remember that you
+ * must then populate the buffer and length fields later.
+ *
+ * \param transfer the transfer to populate
+ * \param dev_handle handle of the device that will handle the transfer
+ * \param buffer data buffer. If provided, this function will interpret the
+ * first 8 bytes as a setup packet and infer the transfer length from that.
+ * This pointer must be aligned to at least 2 bytes boundary.
+ * \param callback callback function to be invoked on transfer completion
+ * \param user_data user data to pass to callback function
+ * \param timeout timeout for the transfer in milliseconds
+ */
+static inline void libusb_fill_control_transfer(
+	struct libusb_transfer *transfer, libusb_device_handle *dev_handle,
+	unsigned char *buffer, libusb_transfer_cb_fn callback, void *user_data,
+	unsigned int timeout)
+{
+	struct libusb_control_setup *setup = (struct libusb_control_setup *)(void *) buffer;
+	transfer->dev_handle = dev_handle;
+	transfer->endpoint = 0;
+	transfer->type = LIBUSB_TRANSFER_TYPE_CONTROL;
+	transfer->timeout = timeout;
+	transfer->buffer = buffer;
+	if (setup)
+		transfer->length = (int) (LIBUSB_CONTROL_SETUP_SIZE
+			+ libusb_le16_to_cpu(setup->wLength));
+	transfer->user_data = user_data;
+	transfer->callback = callback;
+}
+
+/** \ingroup libusb_asyncio
+ * Helper function to populate the required \ref libusb_transfer fields
+ * for a bulk transfer.
+ *
+ * \param transfer the transfer to populate
+ * \param dev_handle handle of the device that will handle the transfer
+ * \param endpoint address of the endpoint where this transfer will be sent
+ * \param buffer data buffer
+ * \param length length of data buffer
+ * \param callback callback function to be invoked on transfer completion
+ * \param user_data user data to pass to callback function
+ * \param timeout timeout for the transfer in milliseconds
+ */
+static inline void libusb_fill_bulk_transfer(struct libusb_transfer *transfer,
+	libusb_device_handle *dev_handle, unsigned char endpoint,
+	unsigned char *buffer, int length, libusb_transfer_cb_fn callback,
+	void *user_data, unsigned int timeout)
+{
+	transfer->dev_handle = dev_handle;
+	transfer->endpoint = endpoint;
+	transfer->type = LIBUSB_TRANSFER_TYPE_BULK;
+	transfer->timeout = timeout;
+	transfer->buffer = buffer;
+	transfer->length = length;
+	transfer->user_data = user_data;
+	transfer->callback = callback;
+}
+
+/** \ingroup libusb_asyncio
+ * Helper function to populate the required \ref libusb_transfer fields
+ * for a bulk transfer using bulk streams.
+ *
+ * Since version 1.0.19, \ref LIBUSB_API_VERSION >= 0x01000103
+ *
+ * \param transfer the transfer to populate
+ * \param dev_handle handle of the device that will handle the transfer
+ * \param endpoint address of the endpoint where this transfer will be sent
+ * \param stream_id bulk stream id for this transfer
+ * \param buffer data buffer
+ * \param length length of data buffer
+ * \param callback callback function to be invoked on transfer completion
+ * \param user_data user data to pass to callback function
+ * \param timeout timeout for the transfer in milliseconds
+ */
+static inline void libusb_fill_bulk_stream_transfer(
+	struct libusb_transfer *transfer, libusb_device_handle *dev_handle,
+	unsigned char endpoint, uint32_t stream_id,
+	unsigned char *buffer, int length, libusb_transfer_cb_fn callback,
+	void *user_data, unsigned int timeout)
+{
+	libusb_fill_bulk_transfer(transfer, dev_handle, endpoint, buffer,
+				  length, callback, user_data, timeout);
+	transfer->type = LIBUSB_TRANSFER_TYPE_BULK_STREAM;
+	libusb_transfer_set_stream_id(transfer, stream_id);
+}
+
+/** \ingroup libusb_asyncio
+ * Helper function to populate the required \ref libusb_transfer fields
+ * for an interrupt transfer.
+ *
+ * \param transfer the transfer to populate
+ * \param dev_handle handle of the device that will handle the transfer
+ * \param endpoint address of the endpoint where this transfer will be sent
+ * \param buffer data buffer
+ * \param length length of data buffer
+ * \param callback callback function to be invoked on transfer completion
+ * \param user_data user data to pass to callback function
+ * \param timeout timeout for the transfer in milliseconds
+ */
+static inline void libusb_fill_interrupt_transfer(
+	struct libusb_transfer *transfer, libusb_device_handle *dev_handle,
+	unsigned char endpoint, unsigned char *buffer, int length,
+	libusb_transfer_cb_fn callback, void *user_data, unsigned int timeout)
+{
+	transfer->dev_handle = dev_handle;
+	transfer->endpoint = endpoint;
+	transfer->type = LIBUSB_TRANSFER_TYPE_INTERRUPT;
+	transfer->timeout = timeout;
+	transfer->buffer = buffer;
+	transfer->length = length;
+	transfer->user_data = user_data;
+	transfer->callback = callback;
+}
+
+/** \ingroup libusb_asyncio
+ * Helper function to populate the required \ref libusb_transfer fields
+ * for an isochronous transfer.
+ *
+ * \param transfer the transfer to populate
+ * \param dev_handle handle of the device that will handle the transfer
+ * \param endpoint address of the endpoint where this transfer will be sent
+ * \param buffer data buffer
+ * \param length length of data buffer
+ * \param num_iso_packets the number of isochronous packets
+ * \param callback callback function to be invoked on transfer completion
+ * \param user_data user data to pass to callback function
+ * \param timeout timeout for the transfer in milliseconds
+ */
+static inline void libusb_fill_iso_transfer(struct libusb_transfer *transfer,
+	libusb_device_handle *dev_handle, unsigned char endpoint,
+	unsigned char *buffer, int length, int num_iso_packets,
+	libusb_transfer_cb_fn callback, void *user_data, unsigned int timeout)
+{
+	transfer->dev_handle = dev_handle;
+	transfer->endpoint = endpoint;
+	transfer->type = LIBUSB_TRANSFER_TYPE_ISOCHRONOUS;
+	transfer->timeout = timeout;
+	transfer->buffer = buffer;
+	transfer->length = length;
+	transfer->num_iso_packets = num_iso_packets;
+	transfer->user_data = user_data;
+	transfer->callback = callback;
+}
+
+/** \ingroup libusb_asyncio
+ * Convenience function to set the length of all packets in an isochronous
+ * transfer, based on the num_iso_packets field in the transfer structure.
+ *
+ * \param transfer a transfer
+ * \param length the length to set in each isochronous packet descriptor
+ * \see libusb_get_max_packet_size()
+ */
+static inline void libusb_set_iso_packet_lengths(
+	struct libusb_transfer *transfer, unsigned int length)
+{
+	int i;
+	for (i = 0; i < transfer->num_iso_packets; i++)
+		transfer->iso_packet_desc[i].length = length;
+}
+
+/** \ingroup libusb_asyncio
+ * Convenience function to locate the position of an isochronous packet
+ * within the buffer of an isochronous transfer.
+ *
+ * This is a thorough function which loops through all preceding packets,
+ * accumulating their lengths to find the position of the specified packet.
+ * Typically you will assign equal lengths to each packet in the transfer,
+ * and hence the above method is sub-optimal. You may wish to use
+ * libusb_get_iso_packet_buffer_simple() instead.
+ *
+ * \param transfer a transfer
+ * \param packet the packet to return the address of
+ * \returns the base address of the packet buffer inside the transfer buffer,
+ * or NULL if the packet does not exist.
+ * \see libusb_get_iso_packet_buffer_simple()
+ */
+static inline unsigned char *libusb_get_iso_packet_buffer(
+	struct libusb_transfer *transfer, unsigned int packet)
+{
+	int i;
+	size_t offset = 0;
+	int _packet;
+
+	/* oops..slight bug in the API. packet is an unsigned int, but we use
+	 * signed integers almost everywhere else. range-check and convert to
+	 * signed to avoid compiler warnings. FIXME for libusb-2. */
+	if (packet > INT_MAX)
+		return NULL;
+	_packet = (int) packet;
+
+	if (_packet >= transfer->num_iso_packets)
+		return NULL;
+
+	for (i = 0; i < _packet; i++)
+		offset += transfer->iso_packet_desc[i].length;
+
+	return transfer->buffer + offset;
+}
+
+/** \ingroup libusb_asyncio
+ * Convenience function to locate the position of an isochronous packet
+ * within the buffer of an isochronous transfer, for transfers where each
+ * packet is of identical size.
+ *
+ * This function relies on the assumption that every packet within the transfer
+ * is of identical size to the first packet. Calculating the location of
+ * the packet buffer is then just a simple calculation:
+ * <tt>buffer + (packet_size * packet)</tt>
+ *
+ * Do not use this function on transfers other than those that have identical
+ * packet lengths for each packet.
+ *
+ * \param transfer a transfer
+ * \param packet the packet to return the address of
+ * \returns the base address of the packet buffer inside the transfer buffer,
+ * or NULL if the packet does not exist.
+ * \see libusb_get_iso_packet_buffer()
+ */
+static inline unsigned char *libusb_get_iso_packet_buffer_simple(
+	struct libusb_transfer *transfer, unsigned int packet)
+{
+	int _packet;
+
+	/* oops..slight bug in the API. packet is an unsigned int, but we use
+	 * signed integers almost everywhere else. range-check and convert to
+	 * signed to avoid compiler warnings. FIXME for libusb-2. */
+	if (packet > INT_MAX)
+		return NULL;
+	_packet = (int) packet;
+
+	if (_packet >= transfer->num_iso_packets)
+		return NULL;
+
+	return transfer->buffer + ((int) transfer->iso_packet_desc[0].length * _packet);
+}
+
+/* sync I/O */
+
+int LIBUSB_CALL libusb_control_transfer(libusb_device_handle *dev_handle,
+	uint8_t request_type, uint8_t bRequest, uint16_t wValue, uint16_t wIndex,
+	unsigned char *data, uint16_t wLength, unsigned int timeout);
+
+int LIBUSB_CALL libusb_bulk_transfer(libusb_device_handle *dev_handle,
+	unsigned char endpoint, unsigned char *data, int length,
+	int *actual_length, unsigned int timeout);
+
+int LIBUSB_CALL libusb_interrupt_transfer(libusb_device_handle *dev_handle,
+	unsigned char endpoint, unsigned char *data, int length,
+	int *actual_length, unsigned int timeout);
+
+/** \ingroup libusb_desc
+ * Retrieve a descriptor from the default control pipe.
+ * This is a convenience function which formulates the appropriate control
+ * message to retrieve the descriptor.
+ *
+ * \param dev_handle a device handle
+ * \param desc_type the descriptor type, see \ref libusb_descriptor_type
+ * \param desc_index the index of the descriptor to retrieve
+ * \param data output buffer for descriptor
+ * \param length size of data buffer
+ * \returns number of bytes returned in data, or LIBUSB_ERROR code on failure
+ */
+static inline int libusb_get_descriptor(libusb_device_handle *dev_handle,
+	uint8_t desc_type, uint8_t desc_index, unsigned char *data, int length)
+{
+	return libusb_control_transfer(dev_handle, LIBUSB_ENDPOINT_IN,
+		LIBUSB_REQUEST_GET_DESCRIPTOR, (uint16_t) ((desc_type << 8) | desc_index),
+		0, data, (uint16_t) length, 1000);
+}
+
+/** \ingroup libusb_desc
+ * Retrieve a descriptor from a device.
+ * This is a convenience function which formulates the appropriate control
+ * message to retrieve the descriptor. The string returned is Unicode, as
+ * detailed in the USB specifications.
+ *
+ * \param dev_handle a device handle
+ * \param desc_index the index of the descriptor to retrieve
+ * \param langid the language ID for the string descriptor
+ * \param data output buffer for descriptor
+ * \param length size of data buffer
+ * \returns number of bytes returned in data, or LIBUSB_ERROR code on failure
+ * \see libusb_get_string_descriptor_ascii()
+ */
+static inline int libusb_get_string_descriptor(libusb_device_handle *dev_handle,
+	uint8_t desc_index, uint16_t langid, unsigned char *data, int length)
+{
+	return libusb_control_transfer(dev_handle, LIBUSB_ENDPOINT_IN,
+		LIBUSB_REQUEST_GET_DESCRIPTOR, (uint16_t)((LIBUSB_DT_STRING << 8) | desc_index),
+		langid, data, (uint16_t) length, 1000);
+}
+
+int LIBUSB_CALL libusb_get_string_descriptor_ascii(libusb_device_handle *dev_handle,
+	uint8_t desc_index, unsigned char *data, int length);
+
+/* polling and timeouts */
+
+int LIBUSB_CALL libusb_try_lock_events(libusb_context *ctx);
+void LIBUSB_CALL libusb_lock_events(libusb_context *ctx);
+void LIBUSB_CALL libusb_unlock_events(libusb_context *ctx);
+int LIBUSB_CALL libusb_event_handling_ok(libusb_context *ctx);
+int LIBUSB_CALL libusb_event_handler_active(libusb_context *ctx);
+void LIBUSB_CALL libusb_interrupt_event_handler(libusb_context *ctx);
+void LIBUSB_CALL libusb_lock_event_waiters(libusb_context *ctx);
+void LIBUSB_CALL libusb_unlock_event_waiters(libusb_context *ctx);
+int LIBUSB_CALL libusb_wait_for_event(libusb_context *ctx, struct timeval *tv);
+
+int LIBUSB_CALL libusb_handle_events_timeout(libusb_context *ctx,
+	struct timeval *tv);
+int LIBUSB_CALL libusb_handle_events_timeout_completed(libusb_context *ctx,
+	struct timeval *tv, int *completed);
+int LIBUSB_CALL libusb_handle_events(libusb_context *ctx);
+int LIBUSB_CALL libusb_handle_events_completed(libusb_context *ctx, int *completed);
+int LIBUSB_CALL libusb_handle_events_locked(libusb_context *ctx,
+	struct timeval *tv);
+int LIBUSB_CALL libusb_pollfds_handle_timeouts(libusb_context *ctx);
+int LIBUSB_CALL libusb_get_next_timeout(libusb_context *ctx,
+	struct timeval *tv);
+
+/** \ingroup libusb_poll
+ * File descriptor for polling
+ */
+struct libusb_pollfd {
+	/** Numeric file descriptor */
+	int fd;
+
+	/** Event flags to poll for from <poll.h>. POLLIN indicates that you
+	 * should monitor this file descriptor for becoming ready to read from,
+	 * and POLLOUT indicates that you should monitor this file descriptor for
+	 * nonblocking write readiness. */
+	short events;
+};
+
+/** \ingroup libusb_poll
+ * Callback function, invoked when a new file descriptor should be added
+ * to the set of file descriptors monitored for events.
+ * \param fd the new file descriptor
+ * \param events events to monitor for, see \ref libusb_pollfd for a
+ * description
+ * \param user_data User data pointer specified in
+ * libusb_set_pollfd_notifiers() call
+ * \see libusb_set_pollfd_notifiers()
+ */
+typedef void (LIBUSB_CALL *libusb_pollfd_added_cb)(int fd, short events,
+	void *user_data);
+
+/** \ingroup libusb_poll
+ * Callback function, invoked when a file descriptor should be removed from
+ * the set of file descriptors being monitored for events. After returning
+ * from this callback, do not use that file descriptor again.
+ * \param fd the file descriptor to stop monitoring
+ * \param user_data User data pointer specified in
+ * libusb_set_pollfd_notifiers() call
+ * \see libusb_set_pollfd_notifiers()
+ */
+typedef void (LIBUSB_CALL *libusb_pollfd_removed_cb)(int fd, void *user_data);
+
+const struct libusb_pollfd ** LIBUSB_CALL libusb_get_pollfds(
+	libusb_context *ctx);
+void LIBUSB_CALL libusb_free_pollfds(const struct libusb_pollfd **pollfds);
+void LIBUSB_CALL libusb_set_pollfd_notifiers(libusb_context *ctx,
+	libusb_pollfd_added_cb added_cb, libusb_pollfd_removed_cb removed_cb,
+	void *user_data);
+
+/** \ingroup libusb_hotplug
+ * Callback handle.
+ *
+ * Callbacks handles are generated by libusb_hotplug_register_callback()
+ * and can be used to deregister callbacks. Callback handles are unique
+ * per libusb_context and it is safe to call libusb_hotplug_deregister_callback()
+ * on an already deregisted callback.
+ *
+ * Since version 1.0.16, \ref LIBUSB_API_VERSION >= 0x01000102
+ *
+ * For more information, see \ref libusb_hotplug.
+ */
+typedef int libusb_hotplug_callback_handle;
+
+/** \ingroup libusb_hotplug
+ *
+ * Since version 1.0.16, \ref LIBUSB_API_VERSION >= 0x01000102
+ *
+ * Flags for hotplug events */
+typedef enum {
+	/** Default value when not using any flags. */
+	LIBUSB_HOTPLUG_NO_FLAGS = 0,
+
+	/** Arm the callback and fire it for all matching currently attached devices. */
+	LIBUSB_HOTPLUG_ENUMERATE = 1<<0,
+} libusb_hotplug_flag;
+
+/** \ingroup libusb_hotplug
+ *
+ * Since version 1.0.16, \ref LIBUSB_API_VERSION >= 0x01000102
+ *
+ * Hotplug events */
+typedef enum {
+	/** A device has been plugged in and is ready to use */
+	LIBUSB_HOTPLUG_EVENT_DEVICE_ARRIVED = 0x01,
+
+	/** A device has left and is no longer available.
+	 * It is the user's responsibility to call libusb_close on any handle associated with a disconnected device.
+	 * It is safe to call libusb_get_device_descriptor on a device that has left */
+	LIBUSB_HOTPLUG_EVENT_DEVICE_LEFT    = 0x02,
+} libusb_hotplug_event;
+
+/** \ingroup libusb_hotplug
+ * Wildcard matching for hotplug events */
+#define LIBUSB_HOTPLUG_MATCH_ANY -1
+
+/** \ingroup libusb_hotplug
+ * Hotplug callback function type. When requesting hotplug event notifications,
+ * you pass a pointer to a callback function of this type.
+ *
+ * This callback may be called by an internal event thread and as such it is
+ * recommended the callback do minimal processing before returning.
+ *
+ * libusb will call this function later, when a matching event had happened on
+ * a matching device. See \ref libusb_hotplug for more information.
+ *
+ * It is safe to call either libusb_hotplug_register_callback() or
+ * libusb_hotplug_deregister_callback() from within a callback function.
+ *
+ * Since version 1.0.16, \ref LIBUSB_API_VERSION >= 0x01000102
+ *
+ * \param ctx            context of this notification
+ * \param device         libusb_device this event occurred on
+ * \param event          event that occurred
+ * \param user_data      user data provided when this callback was registered
+ * \returns bool whether this callback is finished processing events.
+ *                       returning 1 will cause this callback to be deregistered
+ */
+typedef int (LIBUSB_CALL *libusb_hotplug_callback_fn)(libusb_context *ctx,
+						libusb_device *device,
+						libusb_hotplug_event event,
+						void *user_data);
+
+/** \ingroup libusb_hotplug
+ * Register a hotplug callback function
+ *
+ * Register a callback with the libusb_context. The callback will fire
+ * when a matching event occurs on a matching device. The callback is
+ * armed until either it is deregistered with libusb_hotplug_deregister_callback()
+ * or the supplied callback returns 1 to indicate it is finished processing events.
+ *
+ * If the \ref LIBUSB_HOTPLUG_ENUMERATE is passed the callback will be
+ * called with a \ref LIBUSB_HOTPLUG_EVENT_DEVICE_ARRIVED for all devices
+ * already plugged into the machine. Note that libusb modifies its internal
+ * device list from a separate thread, while calling hotplug callbacks from
+ * libusb_handle_events(), so it is possible for a device to already be present
+ * on, or removed from, its internal device list, while the hotplug callbacks
+ * still need to be dispatched. This means that when using \ref
+ * LIBUSB_HOTPLUG_ENUMERATE, your callback may be called twice for the arrival
+ * of the same device, once from libusb_hotplug_register_callback() and once
+ * from libusb_handle_events(); and/or your callback may be called for the
+ * removal of a device for which an arrived call was never made.
+ *
+ * Since version 1.0.16, \ref LIBUSB_API_VERSION >= 0x01000102
+ *
+ * \param[in] ctx context to register this callback with
+ * \param[in] events bitwise or of events that will trigger this callback. See \ref
+ *            libusb_hotplug_event
+ * \param[in] flags hotplug callback flags. See \ref libusb_hotplug_flag
+ * \param[in] vendor_id the vendor id to match or \ref LIBUSB_HOTPLUG_MATCH_ANY
+ * \param[in] product_id the product id to match or \ref LIBUSB_HOTPLUG_MATCH_ANY
+ * \param[in] dev_class the device class to match or \ref LIBUSB_HOTPLUG_MATCH_ANY
+ * \param[in] cb_fn the function to be invoked on a matching event/device
+ * \param[in] user_data user data to pass to the callback function
+ * \param[out] callback_handle pointer to store the handle of the allocated callback (can be NULL)
+ * \returns LIBUSB_SUCCESS on success LIBUSB_ERROR code on failure
+ */
+int LIBUSB_CALL libusb_hotplug_register_callback(libusb_context *ctx,
+						libusb_hotplug_event events,
+						libusb_hotplug_flag flags,
+						int vendor_id, int product_id,
+						int dev_class,
+						libusb_hotplug_callback_fn cb_fn,
+						void *user_data,
+						libusb_hotplug_callback_handle *callback_handle);
+
+/** \ingroup libusb_hotplug
+ * Deregisters a hotplug callback.
+ *
+ * Deregister a callback from a libusb_context. This function is safe to call from within
+ * a hotplug callback.
+ *
+ * Since version 1.0.16, \ref LIBUSB_API_VERSION >= 0x01000102
+ *
+ * \param[in] ctx context this callback is registered with
+ * \param[in] callback_handle the handle of the callback to deregister
+ */
+void LIBUSB_CALL libusb_hotplug_deregister_callback(libusb_context *ctx,
+						libusb_hotplug_callback_handle callback_handle);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif
diff --git a/STM32MP157/source/A7/12_USB/01_libusb示例程序/dnw_for_libusb1.0/说明.txt b/STM32MP157/source/A7/12_USB/01_libusb示例程序/dnw_for_libusb1.0/说明.txt
new file mode 100644
index 0000000..bfe1d37
--- /dev/null
+++ b/STM32MP157/source/A7/12_USB/01_libusb示例程序/dnw_for_libusb1.0/说明.txt
@@ -0,0 +1,22 @@
+1．可以直接使用我们编译好的dnw可执行程序:
+   先把dnw放入ubuntu的/usr/bin目录
+   然后修改属性:
+   sudo chmod +x /usr/bin/dnw
+   最后参考"dnw使用说明.txt"
+   
+2. 我们也提供了源码, 你可以尝试自己编译:
+2.1 先编译libusb1.0库:
+    tar xjf libusb-1.0.21.tar.bz2
+	cd libusb-1.0.21
+	./configure --enable-udev=no
+	make
+
+2.2 把库文件、头文件取出来:	
+	cp  libusb-1.0.21/libusb/.libs/libusb-1.0.a    <dnw.c的目录>
+	cp  libusb-1.0.21/libusb/libusb.h              <dnw.c的目录>
+
+2.3 编译dnw:
+    cd 	<dnw.c的目录>
+	make
+	
+	
\ No newline at end of file
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