发布SPI: 12_编写SPI_DAC模块驱动程序,13_编写DAC驱动_上机实验_IMX6ULL,13_编写DAC驱动_上机实验_STM32MP157

IMX6ULL/doc_pic/11_SPI/12_编写SPI_DAC模块驱动程序.md

@@ -4,12 +4,25 @@
 
 * DAC芯片手册：`TLC5615.pdf`
 
-  
 
 
-## 1. 硬件
 
-### 1.1 原理图
+## 1. 要做什么事情
+
+![](pic/09_spi_drv_frame.png)
+
+
+
+* 查看原理图，编写设备树
+* 编写驱动程序，注册一个spidrv
+* 编写测试程序
+
+
+
+
+## 2. 硬件
+
+### 2.1 原理图
 
 IMX6ULL:
 
@@ -27,9 +40,9 @@ STM32MP157:
 
 
 
-### 1.2 连接
+### 2.2 连接
 
-#### 1.2.1 IMX6ULL
+#### 2.2.1 IMX6ULL
 
 DAC模块接到IMX6ULL扩展板的SPI_A插座上：
 
@@ -37,11 +50,11 @@ DAC模块接到IMX6ULL扩展板的SPI_A插座上：
 
 
 
-#### 1.2.2 STM32MP157
+#### 2.2.2 STM32MP157
 
 
 
-## 2. 编写设备树
+## 3. 编写设备树
 
 确认SPI时钟最大频率：
 
@@ -66,7 +79,7 @@ F = 20000000 = 20MHz
 
 
 
-### 2.1 IMX6ULL
+### 3.1 IMX6ULL
 
 ![image-20220311101017666](pic/44_imx6ull_pro_extend_spi_a.png)
 
@@ -95,7 +108,7 @@ DAC模块接在这个插座上，那么要在设备树里spi1的节点下创建
 
 
 
-### 2.2 STM32MP157
+### 3.2 STM32MP157
 
 ![image-20220311101127305](pic/45_stm32mp157_pro_extend_spi_a.png)
 
@@ -129,7 +142,7 @@ DAC模块接在这个插座上，那么要在设备树里spi5的节点下创建
 
 
 
-## 3. 编写驱动程序
+## 4. 编写驱动程序
 
 以前我们基于spidev编写过DAC的应用程序，可以参考它：
 
@@ -139,5 +152,5 @@ DAC模块接在这个插座上，那么要在设备树里spi5的节点下创建
 
 
 
-## 4. 编写测试程序
+## 5. 编写测试程序
 

IMX6ULL/doc_pic/11_SPI/13_编写DAC驱动_上机实验.md

@@ -0,0 +1,286 @@
+# 编写DAC驱动_上机实验 #
+
+* 源码
+
+![image-20220426095853618](pic/73_src_dac_drv.png)
+
+
+
+## 1. 硬件
+
+### 1.1 原理图
+
+IMX6ULL:
+
+![image-20220309150927785](pic/33_imx6ull_dac.png)
+
+STM32MP157:
+
+![image-20220309151025637](pic/34_stm32mp157_dac.png)
+
+
+
+原理图：
+
+![image-20220309151636533](pic/35_dac_sch.png)
+
+
+
+### 1.2 连接
+
+#### 1.2.1 IMX6ULL
+
+DAC模块接到IMX6ULL扩展板的SPI_A插座上：
+
+![image-20220309164031109](pic/40_dac_on_imx6ull.png)
+
+
+
+#### 1.2.2 STM32MP157
+
+DAC模块接到STM32MP157扩展板的SPI_A插座上：
+
+![image-20220311100618477](pic/43_dac_on_stm32mp157.png)
+
+
+
+
+
+## 2. 编写设备树
+
+确认SPI时钟最大频率：
+
+![image-20220309163435541](pic/39_dac_time_param.png)
+
+```shell
+T = 25 + 25 = 50ns
+F = 20000000 = 20MHz
+```
+
+
+
+设备树如下：
+
+```shell
+    dac: dac {
+        compatible = "100ask,dac";
+        reg = <0>;
+        spi-max-frequency = <20000000>;
+    };
+```
+
+
+
+### 2.1 IMX6ULL
+
+![image-20220311101017666](pic/44_imx6ull_pro_extend_spi_a.png)
+
+DAC模块接在这个插座上，那么要在设备树里spi1的节点下创建子节点。
+
+代码在`arch/arm/boot/dts/100ask_imx6ull-14x14.dts`中，如下：
+
+```shell
+&ecspi1 {
+    pinctrl-names = "default";
+    pinctrl-0 = <&pinctrl_ecspi1>;
+
+    fsl,spi-num-chipselects = <2>;
+    cs-gpios = <&gpio4 26 GPIO_ACTIVE_LOW>, <&gpio4 24 GPIO_ACTIVE_LOW>;
+    status = "okay";
+
+    dac: dac {
+        compatible = "100ask,dac";
+        reg = <0>;
+        spi-max-frequency = <20000000>;
+    };
+};
+```
+
+
+
+
+
+### 2.2 STM32MP157
+
+![image-20220311101127305](pic/45_stm32mp157_pro_extend_spi_a.png)
+
+DAC模块接在这个插座上，那么要在设备树里spi5的节点下创建子节点。
+
+代码在`arch/arm/boot/dts/stm32mp157c-100ask-512d-lcd-v1.dts`中，如下：
+
+```shell
+&spi5 {
+        pinctrl-names = "default", "sleep";
+        pinctrl-0 = <&spi5_pins_a>;
+        pinctrl-1 = <&spi5_sleep_pins_a>;
+        status = "okay";
+        cs-gpios = <&gpioh 5 GPIO_ACTIVE_LOW>, <&gpioz 4 GPIO_ACTIVE_LOW>;
+        spidev: icm20608@0{
+                compatible = "invensense,icm20608";
+                interrupts = <0 IRQ_TYPE_EDGE_FALLING>;
+                interrupt-parent = <&gpioz>;
+                spi-max-frequency = <8000000>;
+                reg = <0>;
+        };
+        dac_test: dac_test@1{
+                compatible = "100ask,dac";
+                spi-max-frequency = <20000000>;
+                reg = <1>;
+        };
+};
+```
+
+
+
+
+
+## 3. 编译替换设备树
+
+### 3.1 IMX6ULL
+
+#### 3.1.1 设置工具链
+
+```shell
+export ARCH=arm
+export CROSS_COMPILE=arm-buildroot-linux-gnueabihf-
+ export PATH=$PATH:/home/book/100ask_imx6ull-sdk/ToolChain/arm-buildroot-linux-gnueabihf_sdk-buildroot/bin
+```
+
+
+#### 3.1.2 编译、替换设备树
+
+  * 编译设备树：
+    在Ubuntu的IMX6ULL内核目录下执行如下命令,
+    得到设备树文件：`arch/arm/boot/dts/100ask_imx6ull-14x14.dtb`
+
+    ```shell
+    make dtbs
+    ```
+
+  * 复制到NFS目录：
+
+    ```shell
+    $ cp arch/arm/boot/dts/100ask_imx6ull-14x14.dtb ~/nfs_rootfs/
+    ```
+
+  * 开发板上挂载NFS文件系统
+
+    ```shell
+    [root@100ask:~]#  mount -t nfs -o nolock,vers=3 192.168.1.137:/home/book/nfs_rootfs /mnt
+    ```
+
+* 更新设备树
+
+    ```shell
+    [root@100ask:~]# cp /mnt/100ask_imx6ull-14x14.dtb /boot
+    [root@100ask:~]# sync
+    ```
+
+* 重启开发板
+
+
+
+### 3.2 STM32MP157
+
+#### 3.2.1 设置工具链
+
+```shell
+export ARCH=arm
+export CROSS_COMPILE=arm-buildroot-linux-gnueabihf-
+export PATH=$PATH:/home/book/100ask_stm32mp157_pro-sdk/ToolChain/arm-buildroot-linux-gnueabihf_sdk-buildroot/bin
+```
+
+
+#### 3.2.2 编译、替换设备树
+
+  * 编译设备树：
+    在Ubuntu的STM32MP157内核目录下执行如下命令,
+    得到设备树文件：`arch/arm/boot/dts/stm32mp157c-100ask-512d-lcd-v1.dtb`
+
+    ```shell
+    make dtbs
+    ```
+
+  * 复制到NFS目录：
+
+    ```shell
+    $ cp arch/arm/boot/dts/stm32mp157c-100ask-512d-lcd-v1.dtb ~/nfs_rootfs/
+    ```
+
+  * 开发板上挂载NFS文件系统
+
+    ```shell
+    [root@100ask:~]#  mount -t nfs -o nolock,vers=3 192.168.1.137:/home/book/nfs_rootfs /mnt
+    ```
+
+* 确定设备树分区挂载在哪里
+
+  由于版本变化，STM32MP157单板上烧录的系统可能有细微差别。
+  在开发板上执行`cat /proc/mounts`后，可以得到两种结果(见下图)：
+
+  * mmcblk2p2分区挂载在/boot目录下(下图左边)：无需特殊操作，下面把文件复制到/boot目录即可
+
+  * mmcblk2p2挂载在/mnt目录下(下图右边)
+
+    * 在视频里、后面文档里，都是更新/boot目录下的文件，所以要先执行以下命令重新挂载：
+      * `mount  /dev/mmcblk2p2  /boot`
+
+    ![](pic/46_boot_mount.png)
+
+* 更新设备树
+
+  ```shell
+  [root@100ask:~]# cp /mnt/stm32mp157c-100ask-512d-lcd-v1.dtb /boot/
+  [root@100ask:~]# sync
+  ```
+
+* 重启开发板
+
+
+
+## 4. 编译DAC驱动
+
+
+
+## 5. 编译APP
+
+```shell
+arm-buildroot-linux-gnueabihf-gcc  -o  dac_test  dac_test.c
+```
+
+
+
+## 6. 上机实验
+
+如果spidev没有被编译进内核，那么先执行：
+
+```shell
+insmod dac_drv.ko
+```
+
+
+
+确定设备节点：
+
+```shell
+ls /dev/100ask_dac
+```
+
+
+
+假设设备节点为`/dev/100ask_dac`，执行测试程序：
+
+```shell
+./dac_test  /dev/100ask_dac  500
+./dac_test  /dev/100ask_dac  600
+./dac_test  /dev/100ask_dac  1000
+```
+
+
+
+
+
+
+
+
+

IMX6ULL/source/11_SPI/05_dac_use_mydrv/Makefile

@@ -0,0 +1,22 @@
+
+# 1. 使用不同的开发板内核时, 一定要修改KERN_DIR
+# 2. KERN_DIR中的内核要事先配置、编译, 为了能编译内核, 要先设置下列环境变量:
+# 2.1 ARCH,          比如: export ARCH=arm64
+# 2.2 CROSS_COMPILE, 比如: export CROSS_COMPILE=aarch64-linux-gnu-
+# 2.3 PATH,          比如: export PATH=$PATH:/home/book/100ask_roc-rk3399-pc/ToolChain-6.3.1/gcc-linaro-6.3.1-2017.05-x86_64_aarch64-linux-gnu/bin 
+# 注意: 不同的开发板不同的编译器上述3个环境变量不一定相同,
+#       请参考各开发板的高级用户使用手册
+
+KERN_DIR = /home/book/100ask_imx6ull-sdk/Linux-4.9.88
+
+all:
+	make -C $(KERN_DIR) M=`pwd` modules 
+	$(CROSS_COMPILE)gcc -o dac_test dac_test.c
+
+clean:
+	make -C $(KERN_DIR) M=`pwd` modules clean
+	rm -rf modules.order dac_test
+
+obj-m	+= dac_drv.o
+
+

IMX6ULL/source/11_SPI/05_dac_use_mydrv/dac_drv.c

@@ -0,0 +1,174 @@
+/*
+ * Simple synchronous userspace interface to SPI devices
+ *
+ * Copyright (C) 2006 SWAPP
+ *	Andrea Paterniani <a.paterniani@swapp-eng.it>
+ * Copyright (C) 2007 David Brownell (simplification, cleanup)
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program 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 General Public License for more details.
+ */
+
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/ioctl.h>
+#include <linux/fs.h>
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/list.h>
+#include <linux/errno.h>
+#include <linux/mutex.h>
+#include <linux/slab.h>
+#include <linux/compat.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/acpi.h>
+
+#include <linux/spi/spi.h>
+#include <linux/spi/spidev.h>
+
+#include <linux/uaccess.h>
+
+#define SPI_IOC_WR 123
+
+/*-------------------------------------------------------------------------*/
+
+static struct spi_device *dac;
+static int major;
+
+static long
+spidev_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
+{
+	int val;
+	int err;
+	int old_val = 0;
+
+	struct spi_message	msg;
+	struct spi_transfer	xfer;
+	int status;
+	
+	/* copy_from_user */
+	err = copy_from_user(&val, (const void __user *)arg, sizeof(int));
+
+	/* 发起SPI传输:     */
+
+	/* 1. 把val修改为正确的格式 */
+	val <<= 2;     /* bit0,bit1 = 0b00 */
+	val &= 0xFFC;  /* 只保留10bit */
+
+	/* 2. 发起SPI传输同时写\读 */
+	/* 2.1 构造transfer
+	 * 2.2 加入message
+	 * 2.3 调用spi_sync
+	 */
+	xfer[0].tx_buf = &val;
+	xfer[0].rx_buf = &old_val;
+	xfer[0].len = 2;
+
+	spi_message_init(&msg);
+	spi_message_add_tail(&[0], &msg);
+	
+	status = spi_sync(dac, &msg);
+
+	/* 3. 修改读到的数据的格式 */
+	old_val >>= 2;
+
+	/* copy_to_user */
+	err = copy_to_user((void __user *)arg, &old_val, sizeof(int));
+	
+	return 0;
+}
+
+
+static const struct file_operations spidev_fops = {
+	.owner =	THIS_MODULE,
+	/* REVISIT switch to aio primitives, so that userspace
+	 * gets more complete API coverage.  It'll simplify things
+	 * too, except for the locking.
+	 */
+	.unlocked_ioctl = spidev_ioctl,
+};
+
+/*-------------------------------------------------------------------------*/
+
+/* The main reason to have this class is to make mdev/udev create the
+ * /dev/spidevB.C character device nodes exposing our userspace API.
+ * It also simplifies memory management.
+ */
+
+static struct class *spidev_class;
+
+static const struct of_device_id spidev_dt_ids[] = {
+	{ .compatible = "100ask,dac" },
+	{},
+};
+
+
+/*-------------------------------------------------------------------------*/
+
+static int spidev_probe(struct spi_device *spi)
+{
+	/* 1. 记录spi_device */
+	dac = spi;
+
+	/* 2. 注册字符设备 */
+	major = register_chrdev(0, "100ask_dac", &spidev_fops);
+	spidev_class = class_create(THIS_MODULE, "100ask_dac");
+	device_create(spidev_class, NULL, MKDEV(major, 0), NULL, "100ask_dac");	
+
+	return 0;
+}
+
+static int spidev_remove(struct spi_device *spi)
+{
+	/* 反注册字符设备 */
+	device_destroy(spidev_class, MKDEV(major, 0));
+	class_destroy(spidev_class);
+	unregister_chrdev(major, "100ask_dac");
+
+	return 0;
+}
+
+static struct spi_driver spidev_spi_driver = {
+	.driver = {
+		.name =		"100ask_spi_dac_drv",
+		.of_match_table = of_match_ptr(spidev_dt_ids),
+	},
+	.probe =	spidev_probe,
+	.remove =	spidev_remove,
+
+	/* NOTE:  suspend/resume methods are not necessary here.
+	 * We don't do anything except pass the requests to/from
+	 * the underlying controller.  The refrigerator handles
+	 * most issues; the controller driver handles the rest.
+	 */
+};
+
+/*-------------------------------------------------------------------------*/
+
+static int __init spidev_init(void)
+{
+	int status;
+
+	status = spi_register_driver(&spidev_spi_driver);
+	if (status < 0) {
+	}
+	return status;
+}
+module_init(spidev_init);
+
+static void __exit spidev_exit(void)
+{
+	spi_unregister_driver(&spidev_spi_driver);
+}
+module_exit(spidev_exit);
+
+MODULE_LICENSE("GPL");
+

IMX6ULL/source/11_SPI/05_dac_use_mydrv/dac_test.c

@@ -0,0 +1,56 @@
+
+
+/* 参考: tools\spi\spidev_fdx.c */
+
+#include <stdio.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <fcntl.h>
+#include <string.h>
+
+#include <sys/ioctl.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+
+#include <linux/types.h>
+
+#define SPI_IOC_WR 123
+
+/* dac_test /dev/100ask_dac <val> */
+
+int main(int argc, char **argv)
+{
+	int fd;
+	unsigned int val;
+	int status;
+
+	unsigned char tx_buf[2];	
+	unsigned char rx_buf[2];	
+	
+	if (argc != 3)
+	{
+		printf("Usage: %s /dev/100ask_dac <val>\n", argv[0]);
+		return 0;
+	}
+
+	fd = open(argv[1], O_RDWR);
+	if (fd < 0) {
+		printf("can not open %s\n", argv[1]);
+		return 1;
+	}
+
+	val = strtoul(argv[2], NULL, 0);
+
+	status = ioctl(fd, SPI_IOC_WR, &val);
+	if (status < 0) {
+		printf("SPI_IOC_WR\n");
+		return -1;
+	}
+
+	/* 打印 */
+	printf("Pre val = %d\n", val);
+	
+	
+	return 0;
+}
+

IMX6ULL/source/11_SPI/06_dac_use_mydrv_ok/Makefile

@@ -0,0 +1,22 @@
+
+# 1. 使用不同的开发板内核时, 一定要修改KERN_DIR
+# 2. KERN_DIR中的内核要事先配置、编译, 为了能编译内核, 要先设置下列环境变量:
+# 2.1 ARCH,          比如: export ARCH=arm64
+# 2.2 CROSS_COMPILE, 比如: export CROSS_COMPILE=aarch64-linux-gnu-
+# 2.3 PATH,          比如: export PATH=$PATH:/home/book/100ask_roc-rk3399-pc/ToolChain-6.3.1/gcc-linaro-6.3.1-2017.05-x86_64_aarch64-linux-gnu/bin 
+# 注意: 不同的开发板不同的编译器上述3个环境变量不一定相同,
+#       请参考各开发板的高级用户使用手册
+
+KERN_DIR = /home/book/100ask_imx6ull-sdk/Linux-4.9.88
+
+all:
+	make -C $(KERN_DIR) M=`pwd` modules 
+	$(CROSS_COMPILE)gcc -o dac_test dac_test.c
+
+clean:
+	make -C $(KERN_DIR) M=`pwd` modules clean
+	rm -rf modules.order dac_test
+
+obj-m	+= dac_drv.o
+
+

IMX6ULL/source/11_SPI/06_dac_use_mydrv_ok/dac_drv.c

@@ -0,0 +1,186 @@
+/*
+ * Simple synchronous userspace interface to SPI devices
+ *
+ * Copyright (C) 2006 SWAPP
+ *	Andrea Paterniani <a.paterniani@swapp-eng.it>
+ * Copyright (C) 2007 David Brownell (simplification, cleanup)
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program 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 General Public License for more details.
+ */
+
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/ioctl.h>
+#include <linux/fs.h>
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/list.h>
+#include <linux/errno.h>
+#include <linux/mutex.h>
+#include <linux/slab.h>
+#include <linux/compat.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/acpi.h>
+
+#include <linux/spi/spi.h>
+#include <linux/spi/spidev.h>
+
+#include <linux/uaccess.h>
+
+#define SPI_IOC_WR 123
+
+/*-------------------------------------------------------------------------*/
+
+static struct spi_device *dac;
+static int major;
+
+static long
+spidev_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
+{
+	int val;
+	int err;
+	unsigned char tx_buf[2];	
+	unsigned char rx_buf[2];	
+
+	struct spi_message	msg;
+	struct spi_transfer	xfer[1];
+	int status;
+
+	memset(&xfer[0], 0, sizeof(xfer));
+	
+	/* copy_from_user */
+	err = copy_from_user(&val, (const void __user *)arg, sizeof(int));
+
+	printk("spidev_ioctl get val from user: %d\n", val);
+
+	/* 发起SPI传输:     */
+
+	/* 1. 把val修改为正确的格式 */
+	val <<= 2;     /* bit0,bit1 = 0b00 */
+	val &= 0xFFC;  /* 只保留10bit */
+
+	tx_buf[1] = val & 0xff;
+	tx_buf[0] = (val>>8) & 0xff;	
+
+	/* 2. 发起SPI传输同时写\读 */
+	/* 2.1 构造transfer
+	 * 2.2 加入message
+	 * 2.3 调用spi_sync
+	 */
+	xfer[0].tx_buf = tx_buf;
+	xfer[0].rx_buf = rx_buf;
+	xfer[0].len = 2;
+
+	spi_message_init(&msg);
+	spi_message_add_tail(&xfer[0], &msg);
+	
+	status = spi_sync(dac, &msg);
+
+	/* 3. 修改读到的数据的格式 */
+	val = (rx_buf[0] << 8) | (rx_buf[1]);
+	val >>= 2;
+
+	/* copy_to_user */
+	err = copy_to_user((void __user *)arg, &val, sizeof(int));
+	
+	return 0;
+}
+
+
+static const struct file_operations spidev_fops = {
+	.owner =	THIS_MODULE,
+	/* REVISIT switch to aio primitives, so that userspace
+	 * gets more complete API coverage.  It'll simplify things
+	 * too, except for the locking.
+	 */
+	.unlocked_ioctl = spidev_ioctl,
+};
+
+/*-------------------------------------------------------------------------*/
+
+/* The main reason to have this class is to make mdev/udev create the
+ * /dev/spidevB.C character device nodes exposing our userspace API.
+ * It also simplifies memory management.
+ */
+
+static struct class *spidev_class;
+
+static const struct of_device_id spidev_dt_ids[] = {
+	{ .compatible = "100ask,dac" },
+	{},
+};
+
+
+/*-------------------------------------------------------------------------*/
+
+static int spidev_probe(struct spi_device *spi)
+{
+	/* 1. 记录spi_device */
+	dac = spi;
+
+	/* 2. 注册字符设备 */
+	major = register_chrdev(0, "100ask_dac", &spidev_fops);
+	spidev_class = class_create(THIS_MODULE, "100ask_dac");
+	device_create(spidev_class, NULL, MKDEV(major, 0), NULL, "100ask_dac");	
+
+	return 0;
+}
+
+static int spidev_remove(struct spi_device *spi)
+{
+	/* 反注册字符设备 */
+	device_destroy(spidev_class, MKDEV(major, 0));
+	class_destroy(spidev_class);
+	unregister_chrdev(major, "100ask_dac");
+
+	return 0;
+}
+
+static struct spi_driver spidev_spi_driver = {
+	.driver = {
+		.name =		"100ask_spi_dac_drv",
+		.of_match_table = of_match_ptr(spidev_dt_ids),
+	},
+	.probe =	spidev_probe,
+	.remove =	spidev_remove,
+
+	/* NOTE:  suspend/resume methods are not necessary here.
+	 * We don't do anything except pass the requests to/from
+	 * the underlying controller.  The refrigerator handles
+	 * most issues; the controller driver handles the rest.
+	 */
+};
+
+/*-------------------------------------------------------------------------*/
+
+static int __init spidev_init(void)
+{
+	int status;
+
+	printk("%s %s %d\n", __FILE__, __FUNCTION__, __LINE__);
+
+	status = spi_register_driver(&spidev_spi_driver);
+	if (status < 0) {
+	}
+	return status;
+}
+module_init(spidev_init);
+
+static void __exit spidev_exit(void)
+{
+	printk("%s %s %d\n", __FILE__, __FUNCTION__, __LINE__);
+	spi_unregister_driver(&spidev_spi_driver);
+}
+module_exit(spidev_exit);
+
+MODULE_LICENSE("GPL");
+

IMX6ULL/source/11_SPI/06_dac_use_mydrv_ok/dac_test.c

@@ -0,0 +1,56 @@
+
+
+/* 参考: tools\spi\spidev_fdx.c */
+
+#include <stdio.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <fcntl.h>
+#include <string.h>
+
+#include <sys/ioctl.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+
+#include <linux/types.h>
+
+#define SPI_IOC_WR 123
+
+/* dac_test /dev/100ask_dac <val> */
+
+int main(int argc, char **argv)
+{
+	int fd;
+	unsigned int val;
+	int status;
+
+	unsigned char tx_buf[2];	
+	unsigned char rx_buf[2];	
+	
+	if (argc != 3)
+	{
+		printf("Usage: %s /dev/100ask_dac <val>\n", argv[0]);
+		return 0;
+	}
+
+	fd = open(argv[1], O_RDWR);
+	if (fd < 0) {
+		printf("can not open %s\n", argv[1]);
+		return 1;
+	}
+
+	val = strtoul(argv[2], NULL, 0);
+
+	status = ioctl(fd, SPI_IOC_WR, &val);
+	if (status < 0) {
+		printf("SPI_IOC_WR\n");
+		return -1;
+	}
+
+	/* 打印 */
+	printf("Pre val = %d\n", val);
+	
+	
+	return 0;
+}
+

README.md

@@ -545,13 +545,18 @@ git clone https://e.coding.net/weidongshan/linux/doc_and_source_for_drivers.git
   ```
   
 * 2021.04.25 发布"SPI子系统"：
-    
+  
   ```shell
   10_OLED模块上机实验_STM32MP157
   ```
   
+* 2021.04.26 发布"SPI子系统"：
   
-  
+  ```shell
+  12_编写SPI_DAC模块驱动程序
+  13_编写DAC驱动_上机实验_IMX6ULL
+  13_编写DAC驱动_上机实验_STM32MP157
+  ```
   
   
   

STM32MP157/doc_pic/11_SPI/12_编写SPI_DAC模块驱动程序.md

@@ -4,12 +4,25 @@
 
 * DAC芯片手册：`TLC5615.pdf`
 
-  
 
 
-## 1. 硬件
 
-### 1.1 原理图
+## 1. 要做什么事情
+
+![](pic/09_spi_drv_frame.png)
+
+
+
+* 查看原理图，编写设备树
+* 编写驱动程序，注册一个spidrv
+* 编写测试程序
+
+
+
+
+## 2. 硬件
+
+### 2.1 原理图
 
 IMX6ULL:
 
@@ -27,9 +40,9 @@ STM32MP157:
 
 
 
-### 1.2 连接
+### 2.2 连接
 
-#### 1.2.1 IMX6ULL
+#### 2.2.1 IMX6ULL
 
 DAC模块接到IMX6ULL扩展板的SPI_A插座上：
 
@@ -37,11 +50,11 @@ DAC模块接到IMX6ULL扩展板的SPI_A插座上：
 
 
 
-#### 1.2.2 STM32MP157
+#### 2.2.2 STM32MP157
 
 
 
-## 2. 编写设备树
+## 3. 编写设备树
 
 确认SPI时钟最大频率：
 
@@ -66,7 +79,7 @@ F = 20000000 = 20MHz
 
 
 
-### 2.1 IMX6ULL
+### 3.1 IMX6ULL
 
 ![image-20220311101017666](pic/44_imx6ull_pro_extend_spi_a.png)
 
@@ -95,7 +108,7 @@ DAC模块接在这个插座上，那么要在设备树里spi1的节点下创建
 
 
 
-### 2.2 STM32MP157
+### 3.2 STM32MP157
 
 ![image-20220311101127305](pic/45_stm32mp157_pro_extend_spi_a.png)
 
@@ -129,7 +142,7 @@ DAC模块接在这个插座上，那么要在设备树里spi5的节点下创建
 
 
 
-## 3. 编写驱动程序
+## 4. 编写驱动程序
 
 以前我们基于spidev编写过DAC的应用程序，可以参考它：
 
@@ -139,5 +152,5 @@ DAC模块接在这个插座上，那么要在设备树里spi5的节点下创建
 
 
 
-## 4. 编写测试程序
+## 5. 编写测试程序
 

STM32MP157/doc_pic/11_SPI/13_编写DAC驱动_上机实验.md

@@ -0,0 +1,286 @@
+# 编写DAC驱动_上机实验 #
+
+* 源码
+
+![image-20220426095853618](pic/73_src_dac_drv.png)
+
+
+
+## 1. 硬件
+
+### 1.1 原理图
+
+IMX6ULL:
+
+![image-20220309150927785](pic/33_imx6ull_dac.png)
+
+STM32MP157:
+
+![image-20220309151025637](pic/34_stm32mp157_dac.png)
+
+
+
+原理图：
+
+![image-20220309151636533](pic/35_dac_sch.png)
+
+
+
+### 1.2 连接
+
+#### 1.2.1 IMX6ULL
+
+DAC模块接到IMX6ULL扩展板的SPI_A插座上：
+
+![image-20220309164031109](pic/40_dac_on_imx6ull.png)
+
+
+
+#### 1.2.2 STM32MP157
+
+DAC模块接到STM32MP157扩展板的SPI_A插座上：
+
+![image-20220311100618477](pic/43_dac_on_stm32mp157.png)
+
+
+
+
+
+## 2. 编写设备树
+
+确认SPI时钟最大频率：
+
+![image-20220309163435541](pic/39_dac_time_param.png)
+
+```shell
+T = 25 + 25 = 50ns
+F = 20000000 = 20MHz
+```
+
+
+
+设备树如下：
+
+```shell
+    dac: dac {
+        compatible = "100ask,dac";
+        reg = <0>;
+        spi-max-frequency = <20000000>;
+    };
+```
+
+
+
+### 2.1 IMX6ULL
+
+![image-20220311101017666](pic/44_imx6ull_pro_extend_spi_a.png)
+
+DAC模块接在这个插座上，那么要在设备树里spi1的节点下创建子节点。
+
+代码在`arch/arm/boot/dts/100ask_imx6ull-14x14.dts`中，如下：
+
+```shell
+&ecspi1 {
+    pinctrl-names = "default";
+    pinctrl-0 = <&pinctrl_ecspi1>;
+
+    fsl,spi-num-chipselects = <2>;
+    cs-gpios = <&gpio4 26 GPIO_ACTIVE_LOW>, <&gpio4 24 GPIO_ACTIVE_LOW>;
+    status = "okay";
+
+    dac: dac {
+        compatible = "100ask,dac";
+        reg = <0>;
+        spi-max-frequency = <20000000>;
+    };
+};
+```
+
+
+
+
+
+### 2.2 STM32MP157
+
+![image-20220311101127305](pic/45_stm32mp157_pro_extend_spi_a.png)
+
+DAC模块接在这个插座上，那么要在设备树里spi5的节点下创建子节点。
+
+代码在`arch/arm/boot/dts/stm32mp157c-100ask-512d-lcd-v1.dts`中，如下：
+
+```shell
+&spi5 {
+        pinctrl-names = "default", "sleep";
+        pinctrl-0 = <&spi5_pins_a>;
+        pinctrl-1 = <&spi5_sleep_pins_a>;
+        status = "okay";
+        cs-gpios = <&gpioh 5 GPIO_ACTIVE_LOW>, <&gpioz 4 GPIO_ACTIVE_LOW>;
+        spidev: icm20608@0{
+                compatible = "invensense,icm20608";
+                interrupts = <0 IRQ_TYPE_EDGE_FALLING>;
+                interrupt-parent = <&gpioz>;
+                spi-max-frequency = <8000000>;
+                reg = <0>;
+        };
+        dac_test: dac_test@1{
+                compatible = "100ask,dac";
+                spi-max-frequency = <20000000>;
+                reg = <1>;
+        };
+};
+```
+
+
+
+
+
+## 3. 编译替换设备树
+
+### 3.1 IMX6ULL
+
+#### 3.1.1 设置工具链
+
+```shell
+export ARCH=arm
+export CROSS_COMPILE=arm-buildroot-linux-gnueabihf-
+ export PATH=$PATH:/home/book/100ask_imx6ull-sdk/ToolChain/arm-buildroot-linux-gnueabihf_sdk-buildroot/bin
+```
+
+
+#### 3.1.2 编译、替换设备树
+
+  * 编译设备树：
+    在Ubuntu的IMX6ULL内核目录下执行如下命令,
+    得到设备树文件：`arch/arm/boot/dts/100ask_imx6ull-14x14.dtb`
+
+    ```shell
+    make dtbs
+    ```
+
+  * 复制到NFS目录：
+
+    ```shell
+    $ cp arch/arm/boot/dts/100ask_imx6ull-14x14.dtb ~/nfs_rootfs/
+    ```
+
+  * 开发板上挂载NFS文件系统
+
+    ```shell
+    [root@100ask:~]#  mount -t nfs -o nolock,vers=3 192.168.1.137:/home/book/nfs_rootfs /mnt
+    ```
+
+* 更新设备树
+
+    ```shell
+    [root@100ask:~]# cp /mnt/100ask_imx6ull-14x14.dtb /boot
+    [root@100ask:~]# sync
+    ```
+
+* 重启开发板
+
+
+
+### 3.2 STM32MP157
+
+#### 3.2.1 设置工具链
+
+```shell
+export ARCH=arm
+export CROSS_COMPILE=arm-buildroot-linux-gnueabihf-
+export PATH=$PATH:/home/book/100ask_stm32mp157_pro-sdk/ToolChain/arm-buildroot-linux-gnueabihf_sdk-buildroot/bin
+```
+
+
+#### 3.2.2 编译、替换设备树
+
+  * 编译设备树：
+    在Ubuntu的STM32MP157内核目录下执行如下命令,
+    得到设备树文件：`arch/arm/boot/dts/stm32mp157c-100ask-512d-lcd-v1.dtb`
+
+    ```shell
+    make dtbs
+    ```
+
+  * 复制到NFS目录：
+
+    ```shell
+    $ cp arch/arm/boot/dts/stm32mp157c-100ask-512d-lcd-v1.dtb ~/nfs_rootfs/
+    ```
+
+  * 开发板上挂载NFS文件系统
+
+    ```shell
+    [root@100ask:~]#  mount -t nfs -o nolock,vers=3 192.168.1.137:/home/book/nfs_rootfs /mnt
+    ```
+
+* 确定设备树分区挂载在哪里
+
+  由于版本变化，STM32MP157单板上烧录的系统可能有细微差别。
+  在开发板上执行`cat /proc/mounts`后，可以得到两种结果(见下图)：
+
+  * mmcblk2p2分区挂载在/boot目录下(下图左边)：无需特殊操作，下面把文件复制到/boot目录即可
+
+  * mmcblk2p2挂载在/mnt目录下(下图右边)
+
+    * 在视频里、后面文档里，都是更新/boot目录下的文件，所以要先执行以下命令重新挂载：
+      * `mount  /dev/mmcblk2p2  /boot`
+
+    ![](pic/46_boot_mount.png)
+
+* 更新设备树
+
+  ```shell
+  [root@100ask:~]# cp /mnt/stm32mp157c-100ask-512d-lcd-v1.dtb /boot/
+  [root@100ask:~]# sync
+  ```
+
+* 重启开发板
+
+
+
+## 4. 编译DAC驱动
+
+
+
+## 5. 编译APP
+
+```shell
+arm-buildroot-linux-gnueabihf-gcc  -o  dac_test  dac_test.c
+```
+
+
+
+## 6. 上机实验
+
+如果spidev没有被编译进内核，那么先执行：
+
+```shell
+insmod dac_drv.ko
+```
+
+
+
+确定设备节点：
+
+```shell
+ls /dev/100ask_dac
+```
+
+
+
+假设设备节点为`/dev/100ask_dac`，执行测试程序：
+
+```shell
+./dac_test  /dev/100ask_dac  500
+./dac_test  /dev/100ask_dac  600
+./dac_test  /dev/100ask_dac  1000
+```
+
+
+
+
+
+
+
+
+

STM32MP157/source/A7/11_SPI/05_dac_use_mydrv/Makefile

@@ -0,0 +1,22 @@
+
+# 1. 使用不同的开发板内核时, 一定要修改KERN_DIR
+# 2. KERN_DIR中的内核要事先配置、编译, 为了能编译内核, 要先设置下列环境变量:
+# 2.1 ARCH,          比如: export ARCH=arm64
+# 2.2 CROSS_COMPILE, 比如: export CROSS_COMPILE=aarch64-linux-gnu-
+# 2.3 PATH,          比如: export PATH=$PATH:/home/book/100ask_roc-rk3399-pc/ToolChain-6.3.1/gcc-linaro-6.3.1-2017.05-x86_64_aarch64-linux-gnu/bin 
+# 注意: 不同的开发板不同的编译器上述3个环境变量不一定相同,
+#       请参考各开发板的高级用户使用手册
+
+KERN_DIR = /home/book/100ask_stm32mp157_pro-sdk/Linux-5.4
+
+all:
+	make -C $(KERN_DIR) M=`pwd` modules 
+	$(CROSS_COMPILE)gcc -o dac_test dac_test.c
+
+clean:
+	make -C $(KERN_DIR) M=`pwd` modules clean
+	rm -rf modules.order dac_test
+
+obj-m	+= dac_drv.o
+
+

STM32MP157/source/A7/11_SPI/05_dac_use_mydrv/dac_drv.c

@@ -0,0 +1,174 @@
+/*
+ * Simple synchronous userspace interface to SPI devices
+ *
+ * Copyright (C) 2006 SWAPP
+ *	Andrea Paterniani <a.paterniani@swapp-eng.it>
+ * Copyright (C) 2007 David Brownell (simplification, cleanup)
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program 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 General Public License for more details.
+ */
+
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/ioctl.h>
+#include <linux/fs.h>
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/list.h>
+#include <linux/errno.h>
+#include <linux/mutex.h>
+#include <linux/slab.h>
+#include <linux/compat.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/acpi.h>
+
+#include <linux/spi/spi.h>
+#include <linux/spi/spidev.h>
+
+#include <linux/uaccess.h>
+
+#define SPI_IOC_WR 123
+
+/*-------------------------------------------------------------------------*/
+
+static struct spi_device *dac;
+static int major;
+
+static long
+spidev_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
+{
+	int val;
+	int err;
+	int old_val = 0;
+
+	struct spi_message	msg;
+	struct spi_transfer	xfer;
+	int status;
+	
+	/* copy_from_user */
+	err = copy_from_user(&val, (const void __user *)arg, sizeof(int));
+
+	/* 发起SPI传输:     */
+
+	/* 1. 把val修改为正确的格式 */
+	val <<= 2;     /* bit0,bit1 = 0b00 */
+	val &= 0xFFC;  /* 只保留10bit */
+
+	/* 2. 发起SPI传输同时写\读 */
+	/* 2.1 构造transfer
+	 * 2.2 加入message
+	 * 2.3 调用spi_sync
+	 */
+	xfer[0].tx_buf = &val;
+	xfer[0].rx_buf = &old_val;
+	xfer[0].len = 2;
+
+	spi_message_init(&msg);
+	spi_message_add_tail(&[0], &msg);
+	
+	status = spi_sync(dac, &msg);
+
+	/* 3. 修改读到的数据的格式 */
+	old_val >>= 2;
+
+	/* copy_to_user */
+	err = copy_to_user((void __user *)arg, &old_val, sizeof(int));
+	
+	return 0;
+}
+
+
+static const struct file_operations spidev_fops = {
+	.owner =	THIS_MODULE,
+	/* REVISIT switch to aio primitives, so that userspace
+	 * gets more complete API coverage.  It'll simplify things
+	 * too, except for the locking.
+	 */
+	.unlocked_ioctl = spidev_ioctl,
+};
+
+/*-------------------------------------------------------------------------*/
+
+/* The main reason to have this class is to make mdev/udev create the
+ * /dev/spidevB.C character device nodes exposing our userspace API.
+ * It also simplifies memory management.
+ */
+
+static struct class *spidev_class;
+
+static const struct of_device_id spidev_dt_ids[] = {
+	{ .compatible = "100ask,dac" },
+	{},
+};
+
+
+/*-------------------------------------------------------------------------*/
+
+static int spidev_probe(struct spi_device *spi)
+{
+	/* 1. 记录spi_device */
+	dac = spi;
+
+	/* 2. 注册字符设备 */
+	major = register_chrdev(0, "100ask_dac", &spidev_fops);
+	spidev_class = class_create(THIS_MODULE, "100ask_dac");
+	device_create(spidev_class, NULL, MKDEV(major, 0), NULL, "100ask_dac");	
+
+	return 0;
+}
+
+static int spidev_remove(struct spi_device *spi)
+{
+	/* 反注册字符设备 */
+	device_destroy(spidev_class, MKDEV(major, 0));
+	class_destroy(spidev_class);
+	unregister_chrdev(major, "100ask_dac");
+
+	return 0;
+}
+
+static struct spi_driver spidev_spi_driver = {
+	.driver = {
+		.name =		"100ask_spi_dac_drv",
+		.of_match_table = of_match_ptr(spidev_dt_ids),
+	},
+	.probe =	spidev_probe,
+	.remove =	spidev_remove,
+
+	/* NOTE:  suspend/resume methods are not necessary here.
+	 * We don't do anything except pass the requests to/from
+	 * the underlying controller.  The refrigerator handles
+	 * most issues; the controller driver handles the rest.
+	 */
+};
+
+/*-------------------------------------------------------------------------*/
+
+static int __init spidev_init(void)
+{
+	int status;
+
+	status = spi_register_driver(&spidev_spi_driver);
+	if (status < 0) {
+	}
+	return status;
+}
+module_init(spidev_init);
+
+static void __exit spidev_exit(void)
+{
+	spi_unregister_driver(&spidev_spi_driver);
+}
+module_exit(spidev_exit);
+
+MODULE_LICENSE("GPL");
+

STM32MP157/source/A7/11_SPI/05_dac_use_mydrv/dac_test.c

@@ -0,0 +1,56 @@
+
+
+/* 参考: tools\spi\spidev_fdx.c */
+
+#include <stdio.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <fcntl.h>
+#include <string.h>
+
+#include <sys/ioctl.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+
+#include <linux/types.h>
+
+#define SPI_IOC_WR 123
+
+/* dac_test /dev/100ask_dac <val> */
+
+int main(int argc, char **argv)
+{
+	int fd;
+	unsigned int val;
+	int status;
+
+	unsigned char tx_buf[2];	
+	unsigned char rx_buf[2];	
+	
+	if (argc != 3)
+	{
+		printf("Usage: %s /dev/100ask_dac <val>\n", argv[0]);
+		return 0;
+	}
+
+	fd = open(argv[1], O_RDWR);
+	if (fd < 0) {
+		printf("can not open %s\n", argv[1]);
+		return 1;
+	}
+
+	val = strtoul(argv[2], NULL, 0);
+
+	status = ioctl(fd, SPI_IOC_WR, &val);
+	if (status < 0) {
+		printf("SPI_IOC_WR\n");
+		return -1;
+	}
+
+	/* 打印 */
+	printf("Pre val = %d\n", val);
+	
+	
+	return 0;
+}
+

STM32MP157/source/A7/11_SPI/06_dac_use_mydrv_ok/Makefile

@@ -0,0 +1,22 @@
+
+# 1. 使用不同的开发板内核时, 一定要修改KERN_DIR
+# 2. KERN_DIR中的内核要事先配置、编译, 为了能编译内核, 要先设置下列环境变量:
+# 2.1 ARCH,          比如: export ARCH=arm64
+# 2.2 CROSS_COMPILE, 比如: export CROSS_COMPILE=aarch64-linux-gnu-
+# 2.3 PATH,          比如: export PATH=$PATH:/home/book/100ask_roc-rk3399-pc/ToolChain-6.3.1/gcc-linaro-6.3.1-2017.05-x86_64_aarch64-linux-gnu/bin 
+# 注意: 不同的开发板不同的编译器上述3个环境变量不一定相同,
+#       请参考各开发板的高级用户使用手册
+
+KERN_DIR = /home/book/100ask_stm32mp157_pro-sdk/Linux-5.4
+
+all:
+	make -C $(KERN_DIR) M=`pwd` modules 
+	$(CROSS_COMPILE)gcc -o dac_test dac_test.c
+
+clean:
+	make -C $(KERN_DIR) M=`pwd` modules clean
+	rm -rf modules.order dac_test
+
+obj-m	+= dac_drv.o
+
+

STM32MP157/source/A7/11_SPI/06_dac_use_mydrv_ok/dac_drv.c

@@ -0,0 +1,186 @@
+/*
+ * Simple synchronous userspace interface to SPI devices
+ *
+ * Copyright (C) 2006 SWAPP
+ *	Andrea Paterniani <a.paterniani@swapp-eng.it>
+ * Copyright (C) 2007 David Brownell (simplification, cleanup)
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program 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 General Public License for more details.
+ */
+
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/ioctl.h>
+#include <linux/fs.h>
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/list.h>
+#include <linux/errno.h>
+#include <linux/mutex.h>
+#include <linux/slab.h>
+#include <linux/compat.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/acpi.h>
+
+#include <linux/spi/spi.h>
+#include <linux/spi/spidev.h>
+
+#include <linux/uaccess.h>
+
+#define SPI_IOC_WR 123
+
+/*-------------------------------------------------------------------------*/
+
+static struct spi_device *dac;
+static int major;
+
+static long
+spidev_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
+{
+	int val;
+	int err;
+	unsigned char tx_buf[2];	
+	unsigned char rx_buf[2];	
+
+	struct spi_message	msg;
+	struct spi_transfer	xfer[1];
+	int status;
+
+	memset(&xfer[0], 0, sizeof(xfer));
+	
+	/* copy_from_user */
+	err = copy_from_user(&val, (const void __user *)arg, sizeof(int));
+
+	printk("spidev_ioctl get val from user: %d\n", val);
+
+	/* 发起SPI传输:     */
+
+	/* 1. 把val修改为正确的格式 */
+	val <<= 2;     /* bit0,bit1 = 0b00 */
+	val &= 0xFFC;  /* 只保留10bit */
+
+	tx_buf[1] = val & 0xff;
+	tx_buf[0] = (val>>8) & 0xff;	
+
+	/* 2. 发起SPI传输同时写\读 */
+	/* 2.1 构造transfer
+	 * 2.2 加入message
+	 * 2.3 调用spi_sync
+	 */
+	xfer[0].tx_buf = tx_buf;
+	xfer[0].rx_buf = rx_buf;
+	xfer[0].len = 2;
+
+	spi_message_init(&msg);
+	spi_message_add_tail(&xfer[0], &msg);
+	
+	status = spi_sync(dac, &msg);
+
+	/* 3. 修改读到的数据的格式 */
+	val = (rx_buf[0] << 8) | (rx_buf[1]);
+	val >>= 2;
+
+	/* copy_to_user */
+	err = copy_to_user((void __user *)arg, &val, sizeof(int));
+	
+	return 0;
+}
+
+
+static const struct file_operations spidev_fops = {
+	.owner =	THIS_MODULE,
+	/* REVISIT switch to aio primitives, so that userspace
+	 * gets more complete API coverage.  It'll simplify things
+	 * too, except for the locking.
+	 */
+	.unlocked_ioctl = spidev_ioctl,
+};
+
+/*-------------------------------------------------------------------------*/
+
+/* The main reason to have this class is to make mdev/udev create the
+ * /dev/spidevB.C character device nodes exposing our userspace API.
+ * It also simplifies memory management.
+ */
+
+static struct class *spidev_class;
+
+static const struct of_device_id spidev_dt_ids[] = {
+	{ .compatible = "100ask,dac" },
+	{},
+};
+
+
+/*-------------------------------------------------------------------------*/
+
+static int spidev_probe(struct spi_device *spi)
+{
+	/* 1. 记录spi_device */
+	dac = spi;
+
+	/* 2. 注册字符设备 */
+	major = register_chrdev(0, "100ask_dac", &spidev_fops);
+	spidev_class = class_create(THIS_MODULE, "100ask_dac");
+	device_create(spidev_class, NULL, MKDEV(major, 0), NULL, "100ask_dac");	
+
+	return 0;
+}
+
+static int spidev_remove(struct spi_device *spi)
+{
+	/* 反注册字符设备 */
+	device_destroy(spidev_class, MKDEV(major, 0));
+	class_destroy(spidev_class);
+	unregister_chrdev(major, "100ask_dac");
+
+	return 0;
+}
+
+static struct spi_driver spidev_spi_driver = {
+	.driver = {
+		.name =		"100ask_spi_dac_drv",
+		.of_match_table = of_match_ptr(spidev_dt_ids),
+	},
+	.probe =	spidev_probe,
+	.remove =	spidev_remove,
+
+	/* NOTE:  suspend/resume methods are not necessary here.
+	 * We don't do anything except pass the requests to/from
+	 * the underlying controller.  The refrigerator handles
+	 * most issues; the controller driver handles the rest.
+	 */
+};
+
+/*-------------------------------------------------------------------------*/
+
+static int __init spidev_init(void)
+{
+	int status;
+
+	printk("%s %s %d\n", __FILE__, __FUNCTION__, __LINE__);
+
+	status = spi_register_driver(&spidev_spi_driver);
+	if (status < 0) {
+	}
+	return status;
+}
+module_init(spidev_init);
+
+static void __exit spidev_exit(void)
+{
+	printk("%s %s %d\n", __FILE__, __FUNCTION__, __LINE__);
+	spi_unregister_driver(&spidev_spi_driver);
+}
+module_exit(spidev_exit);
+
+MODULE_LICENSE("GPL");
+

STM32MP157/source/A7/11_SPI/06_dac_use_mydrv_ok/dac_test.c

@@ -0,0 +1,56 @@
+
+
+/* 参考: tools\spi\spidev_fdx.c */
+
+#include <stdio.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <fcntl.h>
+#include <string.h>
+
+#include <sys/ioctl.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+
+#include <linux/types.h>
+
+#define SPI_IOC_WR 123
+
+/* dac_test /dev/100ask_dac <val> */
+
+int main(int argc, char **argv)
+{
+	int fd;
+	unsigned int val;
+	int status;
+
+	unsigned char tx_buf[2];	
+	unsigned char rx_buf[2];	
+	
+	if (argc != 3)
+	{
+		printf("Usage: %s /dev/100ask_dac <val>\n", argv[0]);
+		return 0;
+	}
+
+	fd = open(argv[1], O_RDWR);
+	if (fd < 0) {
+		printf("can not open %s\n", argv[1]);
+		return 1;
+	}
+
+	val = strtoul(argv[2], NULL, 0);
+
+	status = ioctl(fd, SPI_IOC_WR, &val);
+	if (status < 0) {
+		printf("SPI_IOC_WR\n");
+		return -1;
+	}
+
+	/* 打印 */
+	printf("Pre val = %d\n", val);
+	
+	
+	return 0;
+}
+