diff --git a/IMX6ULL/doc_pic/07_GPIO/09_GPIO子系统与Pinctrl子系统的交互.md b/IMX6ULL/doc_pic/07_GPIO/09_GPIO子系统与Pinctrl子系统的交互.md
new file mode 100644
index 0000000..34e0c19
--- /dev/null
+++ b/IMX6ULL/doc_pic/07_GPIO/09_GPIO子系统与Pinctrl子系统的交互.md
@@ -0,0 +1,227 @@
+## GPIO子系统与Pinctrl子系统的交互
+
+参考资料：
+
+* Linux 5.x内核文档
+  * Linux-5.4\Documentation\driver-api
+  * Linux-5.4\Documentation\devicetree\bindings\gpio\gpio.txt
+  * Linux-5.4\drivers\gpio\gpio-74x164.c
+  
+* Linux 4.x内核文档
+  * Linux-4.9.88\Documentation\gpio
+  * Linux-4.9.88\Documentation\devicetree\bindings\gpio\gpio.txt
+  * Linux-4.9.88\drivers\gpio\gpio-74x164.c
+  
+
+### 1. 使用GPIO前应该设置Pinctrl
+
+假设使用这个虚拟的GPIO Controller的pinA来控制LED：
+
+![image-20210528163702792](pic/07_GPIO/11_virtual_gpio_led.png)
+
+
+
+要使用pinA来控制LED，首先要通过Pinctrl子系统把它设置为GPIO功能，然后才能设置它为输出引脚、设置它的输出值。
+
+所以在设备树文件里，应该添加Pinctrl的内容：
+
+```shell
+virtual_pincontroller {
+	compatible = "100ask,virtual_pinctrl";
+	myled_pin: myled_pin {
+			functions = "gpio";
+			groups = "pin0";
+			configs = <0x11223344>;
+	};
+};
+
+gpio_virt: virtual_gpiocontroller {
+	compatible = "100ask,virtual_gpio";
+    gpio-controller;
+    #gpio-cells = <2>;
+    ngpios = <4>;
+};
+
+myled {
+	compatible = "100ask,leddrv";
+	led-gpios = <&gpio_virt 0 GPIO_ACTIVE_LOW>;
+	pinctrl-names = "default";
+	pinctrl-0 = <&myled_pin>;	
+};
+```
+
+
+
+但是很多芯片，并不要求在设备树中把把引脚复用为GPIO功能。
+
+比如STM32MP157，在它的设备树工具`STM32CubeMX`即使把引脚配置为GPIO功能，它也不会在设备树中出现。
+
+原因在于：GPIO走了后门。
+
+现实的芯片中，并没有Pinctrl这样的硬件，它的功能大部分是在GPIO模块中实现的。
+
+Pinctrl是一个软件虚拟处理的概念，它的实现本来就跟GPIO密切相关。
+
+甚至一些引脚默认就是GPIO功能。
+
+按理说：
+
+一个引脚可能被用作GPIO，也可能被用作I2C，GPIO和I2C这些功能时相同低位的。
+
+要用作GPIO，需要先通过Pinctrl把引脚复用为GPIO功能。
+
+但是Pinctrl和GPIO关系密切，当你使用gpiod_get获得GPIO引脚时，它就`偷偷地`通过Pinctrl把引脚复用为GPIO功能了。
+
+
+
+### 2. GPIO和Pinctrl的映射关系
+
+#### 2.1 示例
+
+![image-20210529094937479](pic/07_GPIO/12_gpio_and_pinctrl_range.png)
+
+从上图可知：
+
+* 左边的Pinctrl支持8个引脚，在Pinctrl的内部编号为0~7
+* 图中有2个GPIO控制器
+  * GPIO0内部引脚编号为0~3，假设在GPIO子系统中全局编号为100~103
+  * GPIO1内部引脚编号为0~3，假设在GPIO子系统中全局编号为104~107
+
+* 假设我们要使用pin1_1，应该这样做：
+  * 根据GPIO1的内部编号1，可以换算为Pinctrl子系统中的编号5
+  * 使用Pinctrl的函数，把第5个引脚配置为GPIO功能
+
+
+
+#### 2.2 数据结构
+
+![image-20210529101049897](pic/07_GPIO/13_gpio_pin_range.png)
+
+
+
+### 3. GPIO调用Pinctrl的过程
+
+GPIO子系统中的request函数，用来申请某个GPIO引脚，
+
+它会导致Pinctrl子系统中的这2个函数之一被调用：`pmxops->gpio_request_enable`或`pmxops->request`
+
+![image-20210529101834908](pic/07_GPIO/14_gpio_request.png)
+
+调用关系如下：
+
+```c
+gpiod_get
+    gpiod_get_index
+    	desc = of_find_gpio(dev, con_id, idx, &lookupflags);
+		ret = gpiod_request(desc, con_id ? con_id : devname);
+					ret = gpiod_request_commit(desc, label);
+								if (chip->request) {
+                                    ret = chip->request(chip, offset);
+                                }
+```
+
+
+
+我们编写GPIO驱动程序时，所设置`chip->request`函数，一般直接调用`gpiochip_generic_request`，它导致Pinctrl把引脚复用为GPIO功能。
+
+```c
+gpiochip_generic_request(struct gpio_chip *chip, unsigned offset)
+    pinctrl_request_gpio(chip->gpiodev->base + offset)
+		ret = pinctrl_get_device_gpio_range(gpio, &pctldev, &range); // gpio是引脚的全局编号
+
+		/* Convert to the pin controllers number space */
+		pin = gpio_to_pin(range, gpio);
+    	
+		ret = pinmux_request_gpio(pctldev, range, pin, gpio);
+					ret = pin_request(pctldev, pin, owner, range);
+```
+
+
+
+Pinctrl子系统中的pin_request函数就会把引脚配置为GPIO功能：
+
+```c
+static int pin_request(struct pinctrl_dev *pctldev,
+		       int pin, const char *owner,
+		       struct pinctrl_gpio_range *gpio_range)
+{
+    const struct pinmux_ops *ops = pctldev->desc->pmxops;
+    
+	/*
+	 * If there is no kind of request function for the pin we just assume
+	 * we got it by default and proceed.
+	 */
+	if (gpio_range && ops->gpio_request_enable)
+		/* This requests and enables a single GPIO pin */
+		status = ops->gpio_request_enable(pctldev, gpio_range, pin);
+	else if (ops->request)
+		status = ops->request(pctldev, pin);
+	else
+		status = 0;
+}
+```
+
+
+
+### 3. 我们要做什么
+
+如果不想在使用GPIO引脚时，在设备树中设置Pinctrl信息，
+
+如果想让GPIO和Pinctrl之间建立联系，
+
+我们需要做这些事情：
+
+#### 3.1 表明GPIO和Pinctrl间的联系
+
+在GPIO设备树中使用`gpio-ranges`来描述它们之间的联系：
+
+  * GPIO系统中有引脚号
+
+  * Pinctrl子系统中也有自己的引脚号
+
+  * 2个号码要建立映射关系
+
+  * 在GPIO设备树中使用如下代码建立映射关系
+
+    ```shell
+    // 当前GPIO控制器的0号引脚, 对应pinctrlA中的128号引脚, 数量为12
+    gpio-ranges = <&pinctrlA 0 128 12>; 
+    ```
+
+#### 3.2 解析这些联系
+
+在GPIO驱动程序中，解析跟Pinctrl之间的联系：处理`gpio-ranges`:
+
+  * 这不需要我们自己写代码
+
+  * 注册gpio_chip时会自动调用
+
+    ```c
+    int gpiochip_add_data(struct gpio_chip *chip, void *data)
+        status = of_gpiochip_add(chip);
+    				status = of_gpiochip_add_pin_range(chip);
+    
+    of_gpiochip_add_pin_range
+    	for (;; index++) {
+    		ret = of_parse_phandle_with_fixed_args(np, "gpio-ranges", 3,
+    				index, &pinspec);
+    
+        	pctldev = of_pinctrl_get(pinspec.np); // 根据gpio-ranges的第1个参数找到pctldev
+    
+            // 增加映射关系	
+            /* npins != 0: linear range */
+            ret = gpiochip_add_pin_range(chip,
+                                         pinctrl_dev_get_devname(pctldev),
+                                         pinspec.args[0],
+                                         pinspec.args[1],
+                                         pinspec.args[2]);
+    ```
+    
+
+
+#### 3.3 编程
+* 在GPIO驱动程序中，提供`gpio_chip->request`
+
+* 在Pinctrl驱动程序中，提供`pmxops->gpio_request_enable`或`pmxops->request`
+
+
diff --git a/IMX6ULL/doc_pic/07_GPIO/09_GPIO子系统与Pinctrl子系统的交互.tif b/IMX6ULL/doc_pic/07_GPIO/09_GPIO子系统与Pinctrl子系统的交互.tif
new file mode 100644
index 0000000..b432dad
Binary files /dev/null and b/IMX6ULL/doc_pic/07_GPIO/09_GPIO子系统与Pinctrl子系统的交互.tif differ
diff --git a/IMX6ULL/doc_pic/07_GPIO/10_编程_GPIO使用Pinctrl.md b/IMX6ULL/doc_pic/07_GPIO/10_编程_GPIO使用Pinctrl.md
new file mode 100644
index 0000000..9283c07
--- /dev/null
+++ b/IMX6ULL/doc_pic/07_GPIO/10_编程_GPIO使用Pinctrl.md
@@ -0,0 +1,396 @@
+## 编程_GPIO使用Pinctrl
+
+参考资料：
+
+* Linux 5.x内核文档
+  * Linux-5.4\Documentation\driver-api
+  * Linux-5.4\Documentation\devicetree\bindings\gpio\gpio.txt
+  * Linux-5.4\drivers\gpio\gpio-74x164.c
+  
+* Linux 4.x内核文档
+  * Linux-4.9.88\Documentation\gpio
+  * Linux-4.9.88\Documentation\devicetree\bindings\gpio\gpio.txt
+  * Linux-4.9.88\drivers\gpio\gpio-74x164.c
+  
+* 本节视频代码在GIT仓库中
+
+  ```shell
+  doc_and_source_for_drivers\IMX6ULL\source\07_GPIO\04_gpio_use_pinctrl_ok
+  doc_and_source_for_drivers\STM32MP157\source\A7\07_GPIO\04_gpio_use_pinctrl_ok
+  ```
+
+  
+
+### 1. 我们要做什么
+
+假设使用这个虚拟的GPIO Controller的pinA来控制LED：
+
+![image-20210528163702792](pic/07_GPIO/11_virtual_gpio_led.png)
+
+如果不想在使用GPIO引脚时，在设备树中设置Pinctrl信息，
+
+如果想让GPIO和Pinctrl之间建立联系，
+
+我们需要做这些事情：
+
+#### 1.1 表明GPIO和Pinctrl间的联系
+
+在GPIO设备树中使用`gpio-ranges`来描述它们之间的联系：
+
+  * GPIO系统中有引脚号
+
+  * Pinctrl子系统中也有自己的引脚号
+
+  * 2个号码要建立映射关系
+
+  * 在GPIO设备树中使用如下代码建立映射关系
+
+    ```shell
+    // 当前GPIO控制器的0号引脚, 对应pinctrlA中的128号引脚, 数量为12
+    gpio-ranges = <&pinctrlA 0 128 12>; 
+    ```
+
+#### 1.2 解析这些联系
+
+在GPIO驱动程序中，解析跟Pinctrl之间的联系：处理`gpio-ranges`:
+
+  * 这不需要我们自己写代码
+
+  * 注册gpio_chip时会自动调用
+
+    ```c
+    int gpiochip_add_data(struct gpio_chip *chip, void *data)
+        status = of_gpiochip_add(chip);
+    				status = of_gpiochip_add_pin_range(chip);
+    
+    of_gpiochip_add_pin_range
+    	for (;; index++) {
+    		ret = of_parse_phandle_with_fixed_args(np, "gpio-ranges", 3,
+    				index, &pinspec);
+    
+        	pctldev = of_pinctrl_get(pinspec.np); // 根据gpio-ranges的第1个参数找到pctldev
+    
+            // 增加映射关系	
+            /* npins != 0: linear range */
+            ret = gpiochip_add_pin_range(chip,
+                                         pinctrl_dev_get_devname(pctldev),
+                                         pinspec.args[0],
+                                         pinspec.args[1],
+                                         pinspec.args[2]);
+    ```
+
+
+#### 1.3 编程
+
+* 在GPIO驱动程序中，提供`gpio_chip->request`
+
+* 在Pinctrl驱动程序中，提供`pmxops->gpio_request_enable`或`pmxops->request`
+
+
+
+### 2. 编写设备树
+
+```shell
+pinctrl_virt: virtual_pincontroller {
+	compatible = "100ask,virtual_pinctrl";
+};
+
+gpio_virt: virtual_gpiocontroller {
+	compatible = "100ask,virtual_gpio";
+    gpio-controller;
+    #gpio-cells = <2>;
+    ngpios = <4>;
+    gpio-ranges = <&pinctrl_virt 0 0 4>; 
+};
+
+myled {
+	compatible = "100ask,leddrv";
+	led-gpios = <&gpio_virt 0 GPIO_ACTIVE_LOW>;
+};
+```
+
+
+
+### 3. 编程
+
+#### 3.1 GPIO控制器编程
+
+gpio_chip中提供request函数：
+
+```c
+chip->request = gpiochip_generic_request;
+```
+
+
+
+#### 3.2 Pinctrl编程
+
+```c
+static const struct pinmux_ops virtual_pmx_ops = {
+	.get_functions_count = virtual_pmx_get_funcs_count,
+	.get_function_name = virtual_pmx_get_func_name,
+	.get_function_groups = virtual_pmx_get_groups,
+	.set_mux = virtual_pmx_set,
+    .gpio_request_enable = virtual_pmx_gpio_request_enable,
+};
+```
+
+
+
+### 4. 上机实验
+
+#### 4.1 设置工具链
+
+##### 1. STM32MP157
+
+  **注意**：对于STM32MP157，以前说编译内核/驱动、编译APP的工具链不一样，其实编译APP用的工具链也能用来编译内核。
+
+  ```shell
+  export ARCH=arm
+  export CROSS_COMPILE=arm-buildroot-linux-gnueabihf-
+  export PATH=$PATH:/home/book/100ask_stm32mp157_pro-sdk/ToolChain/arm-buildroot-linux-gnueabihf_sdk-buildroot/bin
+  ```
+
+##### 2. IMX6ULL
+
+  ```shell
+  export ARCH=arm
+  export CROSS_COMPILE=arm-linux-gnueabihf-
+  export PATH=$PATH:/home/book/100ask_imx6ull-sdk/ToolChain/gcc-linaro-6.2.1-2016.11-x86_64_arm-linux-gnueabihf/bin
+  ```
+
+
+
+#### 4.2 编译、替换设备树
+
+##### 1. STM32MP157
+
+  * 修改`arch/arm/boot/dts/stm32mp157c-100ask-512d-lcd-v1.dts`，添加如下代码：
+
+    ```shell
+    / {
+       pinctrl_virt: virtual_pincontroller {
+            compatible = "100ask,virtual_pinctrl";
+            myled_pin: myled_pin {
+                            functions = "gpio";
+                            groups = "pin0";
+                            configs = <0x11223344>;
+            };
+            i2cgrp: i2cgrp {
+                    functions = "i2c", "i2c";
+                    groups = "pin0", "pin1";
+                    configs = <0x11223344  0x55667788>;
+            };
+        };
+    
+        gpio_virt: virtual_gpiocontroller {
+            compatible = "100ask,virtual_gpio";
+            gpio-controller;
+            #gpio-cells = <2>;
+            ngpios = <4>;
+            gpio-ranges = <&pinctrl_virt 0 0 4>; 
+        };
+    
+        myled {
+            compatible = "100ask,leddrv";
+            led-gpios = <&gpio_virt 2 GPIO_ACTIVE_LOW>;
+        };
+    };
+    ```
+
+    
+
+  * 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
+
+    * vmware使用NAT(假设windowsIP为192.168.1.100)
+
+      ```shell
+      [root@100ask:~]# mount -t nfs -o nolock,vers=3,port=2049,mountport=9999 
+      192.168.1.100:/home/book/nfs_rootfs /mnt
+      ```
+
+    * vmware使用桥接，或者不使用vmware而是直接使用服务器：假设Ubuntu IP为192.168.1.137
+
+      ```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`
+
+    ![](../04_I2C/pic/04_I2C/057_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
+
+  
+
+
+
+##### 2. IMX6ULL
+
+  * 修改`arch/arm/boot/dts/100ask_imx6ull-14x14.dts`，添加如下代码：
+
+    ```shell
+    / {
+       pinctrl_virt: virtual_pincontroller {
+            compatible = "100ask,virtual_pinctrl";
+            myled_pin: myled_pin {
+                            functions = "gpio";
+                            groups = "pin0";
+                            configs = <0x11223344>;
+            };
+            i2cgrp: i2cgrp {
+                    functions = "i2c", "i2c";
+                    groups = "pin0", "pin1";
+                    configs = <0x11223344  0x55667788>;
+            };
+        };
+    
+        gpio_virt: virtual_gpiocontroller {
+            compatible = "100ask,virtual_gpio";
+            gpio-controller;
+            #gpio-cells = <2>;
+            ngpios = <4>;
+            gpio-ranges = <&pinctrl_virt 0 0 4>; 
+        };
+    
+        myled {
+            compatible = "100ask,leddrv";
+            led-gpios = <&gpio_virt 2 GPIO_ACTIVE_LOW>;
+        };
+    };
+    ```
+
+    
+
+  * 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
+
+  * vmware使用NAT(假设windowsIP为192.168.1.100)
+
+    ```shell
+    [root@100ask:~]# mount -t nfs -o nolock,vers=3,port=2049,mountport=9999 
+    192.168.1.100:/home/book/nfs_rootfs /mnt
+    ```
+
+  * vmware使用桥接，或者不使用vmware而是直接使用服务器：假设Ubuntu IP为192.168.1.137
+
+    ```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
+
+
+
+#### 4.3 编译、安装驱动程序
+
+* 编译：
+
+  * 在Ubuntu上
+  * 进入`04_gpio_use_pinctrl_ok`下的3个驱动目录，都执行make命令
+
+* 安装：
+
+  * 在开发板上
+
+  * 挂载NFS，复制文件，insmod，类似如下命令：
+
+    ```shell
+    mount -t nfs -o nolock,vers=3 192.168.1.137:/home/book/nfs_rootfs /mnt
+    // 对于IMX6ULL，想看到驱动打印信息，需要先执行
+    echo "7 4 1 7" > /proc/sys/kernel/printk
+    
+    insmod -f /mnt/virtual_pinctrl_driver.ko
+    insmod -f /mnt/virtual_gpio_driver.ko
+    insmod -f /mnt/leddrv.ko
+    
+    ls /dev/100ask_led0
+    /mnt/ledtest /dev/100ask_led0 on
+    /mnt/ledtest /dev/100ask_led0 off
+    ```
+
+* 观察内核打印的信息
+
+
+
+### 5. 再次开后门
+
+在STM32MP157的内核中，
+
+Pinctrl驱动中并没有提供`pmxops->gpio_request_enable`或`pmxops->request`，
+
+为什么也可一直接使用GPIO功能？
+
+它的gpio_chip结构体中，有`direction_input`、`direction_output`，这2个函数的调用关系如下:
+
+```c
+direction_output/direction_input
+    pinctrl_gpio_direction
+    	ret = pinmux_gpio_direction(pctldev, range, pin, input);
+					ret = ops->gpio_set_direction(pctldev, range, pin, input);
+								stm32_pmx_gpio_set_direction
+                                    stm32_pmx_set_mode  // 它会设置引脚为GPIO功能                  
+```
+
+
+
+### 6. IMX6ULL的特殊情况
+
+IMX6ULL使用GPIO时必须设置Pinctrl，如果不设置，只有那些默认就是GPIO功能的引脚可以正常使用。
+
+原因：
+
+* GPIO控制器的设备树中，没有`gpio-ranges`
+* Pinctrl驱动中并没有提供`pmxops->gpio_request_enable`或`pmxops->request`
+* gpio_chip结构体中`direction_input`、`direction_output`，并没有配置引脚为GPIO功能
\ No newline at end of file
diff --git a/IMX6ULL/doc_pic/07_GPIO/11_GPIO子系统的sysfs接口.md b/IMX6ULL/doc_pic/07_GPIO/11_GPIO子系统的sysfs接口.md
new file mode 100644
index 0000000..4438cb0
--- /dev/null
+++ b/IMX6ULL/doc_pic/07_GPIO/11_GPIO子系统的sysfs接口.md
@@ -0,0 +1,110 @@
+## GPIO子系统的sysfs接口
+
+参考资料：
+
+* Linux 5.x内核文档
+  * Linux-5.4\Documentation\driver-api
+  * Linux-5.4\Documentation\devicetree\bindings\gpio\gpio.txt
+  * Linux-5.4\drivers\gpio\gpiolib-sysfs.c
+  
+* Linux 4.x内核文档
+  * Linux-4.9.88\Documentation\gpio
+  * Linux-4.9.88\Documentation\devicetree\bindings\gpio\gpio.txt
+  * Linux-4.9.88\drivers\gpio\gpiolib-sysfs.c
+  
+* 本节视频代码在GIT仓库中
+
+  ```shell
+  doc_and_source_for_drivers\IMX6ULL\source\07_GPIO\04_gpio_use_pinctrl_ok
+  doc_and_source_for_drivers\STM32MP157\source\A7\07_GPIO\04_gpio_use_pinctrl_ok
+  ```
+
+  
+
+### 1. 驱动程序
+
+驱动程序为`drivers\gpio\gpiolib-sysfs.c`，这里不打算分析它。
+
+
+
+### 2. 常用的SYSFS文件
+
+#### 2.1 有哪些GPIO控制器
+
+`/sys/bus/gpio/devices`目录下，列出了所有的GPIO控制器，如下表示有11个GPIO控制器：
+
+```c
+/sys/bus/gpio/devices/gpiochip0
+/sys/bus/gpio/devices/gpiochip1
+/sys/bus/gpio/devices/gpiochip2
+/sys/bus/gpio/devices/gpiochip3
+/sys/bus/gpio/devices/gpiochip4
+/sys/bus/gpio/devices/gpiochip5
+/sys/bus/gpio/devices/gpiochip6
+/sys/bus/gpio/devices/gpiochip7
+/sys/bus/gpio/devices/gpiochip8
+/sys/bus/gpio/devices/gpiochip9
+/sys/bus/gpio/devices/gpiochip10
+```
+
+
+
+#### 2.2 每个GPIO控制器的详细信息
+
+`/sys/class/gpio/gpiochipXXX`下，有这些信息：
+
+```shell
+/sys/class/gpio/gpiochip508]# ls -1
+base     // 这个GPIO控制器的GPIO编号
+device
+label    // 名字
+ngpio    // 引脚个数
+power
+subsystem
+uevent
+```
+
+
+
+#### 2.3 查看GPIO使用情况
+
+```shell
+cat /sys/kernel/debug/gpio
+```
+
+
+
+#### 2.4 通过SYSFS使用GPIO
+
+如果只是简单的引脚控制(比如输出、查询输入值)，可以不编写驱动程序。
+
+但是涉及中断的话，就需要编写驱动程序了。
+
+##### 1. 确定GPIO编号
+
+查看每个`/sys/bus/gpio/devices/gpiochipXXX`目录下的label，确定是你要用的GPIO控制器，也称为GPIO Bank。
+
+根据它名字gpiochipXXX，就可以知道基值是XXX。
+
+基值加上引脚offset，就是这个引脚的编号。
+
+
+
+##### 2. 导出/设置方向/读写值
+
+举例：
+
+```shell
+echo 509 > /sys/class/gpio/export
+echo out > /sys/class/gpio/gpio509/direction
+echo 1 > /sys/class/gpio/gpio509/value
+echo 509 > /sys/class/gpio/unexport
+
+echo 509 > /sys/class/gpio/export
+echo in > /sys/class/gpio/gpio509/direction
+cat /sys/class/gpio/gpio509/value
+echo 509 > /sys/class/gpio/unexport
+```
+
+
+
diff --git a/IMX6ULL/doc_pic/07_GPIO/pic/07_GPIO/12_gpio_and_pinctrl_range.png b/IMX6ULL/doc_pic/07_GPIO/pic/07_GPIO/12_gpio_and_pinctrl_range.png
new file mode 100644
index 0000000..9bb71ec
Binary files /dev/null and b/IMX6ULL/doc_pic/07_GPIO/pic/07_GPIO/12_gpio_and_pinctrl_range.png differ
diff --git a/IMX6ULL/doc_pic/07_GPIO/pic/07_GPIO/13_gpio_pin_range.png b/IMX6ULL/doc_pic/07_GPIO/pic/07_GPIO/13_gpio_pin_range.png
new file mode 100644
index 0000000..3c18b21
Binary files /dev/null and b/IMX6ULL/doc_pic/07_GPIO/pic/07_GPIO/13_gpio_pin_range.png differ
diff --git a/IMX6ULL/doc_pic/07_GPIO/pic/07_GPIO/14_gpio_request.png b/IMX6ULL/doc_pic/07_GPIO/pic/07_GPIO/14_gpio_request.png
new file mode 100644
index 0000000..efed222
Binary files /dev/null and b/IMX6ULL/doc_pic/07_GPIO/pic/07_GPIO/14_gpio_request.png differ
diff --git a/IMX6ULL/source/07_GPIO/04_gpio_use_pinctrl_ok/01_led/Makefile b/IMX6ULL/source/07_GPIO/04_gpio_use_pinctrl_ok/01_led/Makefile
new file mode 100644
index 0000000..ce80d85
--- /dev/null
+++ b/IMX6ULL/source/07_GPIO/04_gpio_use_pinctrl_ok/01_led/Makefile
@@ -0,0 +1,29 @@
+
+# 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 # 板子所用内核源码的目录
+
+all:
+	make -C $(KERN_DIR) M=`pwd` modules 
+	$(CROSS_COMPILE)gcc -o ledtest ledtest.c 
+
+clean:
+	make -C $(KERN_DIR) M=`pwd` modules clean
+	rm -rf modules.order
+	rm -f ledtest
+
+# 参考内核源码drivers/char/ipmi/Makefile
+# 要想把a.c, b.c编译成ab.ko, 可以这样指定:
+# ab-y := a.o b.o
+# obj-m += ab.o
+
+
+
+obj-m += leddrv.o
+
diff --git a/IMX6ULL/source/07_GPIO/04_gpio_use_pinctrl_ok/01_led/leddrv.c b/IMX6ULL/source/07_GPIO/04_gpio_use_pinctrl_ok/01_led/leddrv.c
new file mode 100644
index 0000000..521c65d
--- /dev/null
+++ b/IMX6ULL/source/07_GPIO/04_gpio_use_pinctrl_ok/01_led/leddrv.c
@@ -0,0 +1,161 @@
+#include <linux/module.h>
+#include <linux/platform_device.h>
+
+#include <linux/fs.h>
+#include <linux/errno.h>
+#include <linux/miscdevice.h>
+#include <linux/kernel.h>
+#include <linux/major.h>
+#include <linux/mutex.h>
+#include <linux/proc_fs.h>
+#include <linux/seq_file.h>
+#include <linux/stat.h>
+#include <linux/init.h>
+#include <linux/device.h>
+#include <linux/tty.h>
+#include <linux/kmod.h>
+#include <linux/gfp.h>
+#include <linux/gpio/consumer.h>
+#include <linux/of.h>
+
+
+/* 1. 确定主设备号                                                                 */
+static int major = 0;
+static struct class *led_class;
+static struct gpio_desc *led_gpio;
+
+
+/* 3. 实现对应的open/read/write等函数，填入file_operations结构体                   */
+static ssize_t led_drv_read (struct file *file, char __user *buf, size_t size, loff_t *offset)
+{
+	printk("%s %s line %d\n", __FILE__, __FUNCTION__, __LINE__);
+	return 0;
+}
+
+/* write(fd, &val, 1); */
+static ssize_t led_drv_write (struct file *file, const char __user *buf, size_t size, loff_t *offset)
+{
+	int err;
+	char status;
+	
+	printk("%s %s line %d\n", __FILE__, __FUNCTION__, __LINE__);
+	err = copy_from_user(&status, buf, 1);
+
+	/* 根据次设备号和status控制LED */
+	gpiod_set_value(led_gpio, status);
+	
+	return 1;
+}
+
+static int led_drv_open (struct inode *node, struct file *file)
+{	
+	printk("%s %s line %d\n", __FILE__, __FUNCTION__, __LINE__);
+	/* 根据次设备号初始化LED */
+	gpiod_direction_output(led_gpio, 0);
+	
+	return 0;
+}
+
+static int led_drv_close (struct inode *node, struct file *file)
+{
+	printk("%s %s line %d\n", __FILE__, __FUNCTION__, __LINE__);
+	return 0;
+}
+
+/* 定义自己的file_operations结构体                                              */
+static struct file_operations led_drv = {
+	.owner	 = THIS_MODULE,
+	.open    = led_drv_open,
+	.read    = led_drv_read,
+	.write   = led_drv_write,
+	.release = led_drv_close,
+};
+
+/* 4. 从platform_device获得GPIO
+ *    把file_operations结构体告诉内核：注册驱动程序
+ */
+static int chip_demo_gpio_probe(struct platform_device *pdev)
+{
+	printk("%s %s line %d\n", __FILE__, __FUNCTION__, __LINE__);
+
+	/* 4.1 设备树中定义有: led-gpios=<...>;	*/
+    led_gpio = gpiod_get(&pdev->dev, "led", 0);
+	if (IS_ERR(led_gpio)) {
+		dev_err(&pdev->dev, "Failed to get GPIO for led\n");
+		return PTR_ERR(led_gpio);
+	}
+    
+	/* 4.2 注册file_operations 	*/
+	major = register_chrdev(0, "100ask_led", &led_drv);  /* /dev/led */
+
+	led_class = class_create(THIS_MODULE, "100ask_led_class");
+	if (IS_ERR(led_class)) {
+		printk("%s %s line %d\n", __FILE__, __FUNCTION__, __LINE__);
+		unregister_chrdev(major, "led");
+		gpiod_put(led_gpio);
+		return PTR_ERR(led_class);
+	}
+
+	device_create(led_class, NULL, MKDEV(major, 0), NULL, "100ask_led%d", 0); /* /dev/100ask_led0 */
+        
+    return 0;
+    
+}
+
+static int chip_demo_gpio_remove(struct platform_device *pdev)
+{
+	device_destroy(led_class, MKDEV(major, 0));
+	class_destroy(led_class);
+	unregister_chrdev(major, "100ask_led");
+	gpiod_put(led_gpio);
+    
+    return 0;
+}
+
+
+static const struct of_device_id ask100_leds[] = {
+    { .compatible = "100ask,leddrv" },
+    { },
+};
+
+/* 1. 定义platform_driver */
+static struct platform_driver chip_demo_gpio_driver = {
+    .probe      = chip_demo_gpio_probe,
+    .remove     = chip_demo_gpio_remove,
+    .driver     = {
+        .name   = "100ask_led",
+        .of_match_table = ask100_leds,
+    },
+};
+
+/* 2. 在入口函数注册platform_driver */
+static int __init led_init(void)
+{
+    int err;
+    
+	printk("%s %s line %d\n", __FILE__, __FUNCTION__, __LINE__);
+	
+    err = platform_driver_register(&chip_demo_gpio_driver); 
+	
+	return err;
+}
+
+/* 3. 有入口函数就应该有出口函数：卸载驱动程序时，就会去调用这个出口函数
+ *     卸载platform_driver
+ */
+static void __exit led_exit(void)
+{
+	printk("%s %s line %d\n", __FILE__, __FUNCTION__, __LINE__);
+
+    platform_driver_unregister(&chip_demo_gpio_driver);
+}
+
+
+/* 7. 其他完善：提供设备信息，自动创建设备节点                                     */
+
+module_init(led_init);
+module_exit(led_exit);
+
+MODULE_LICENSE("GPL");
+
+
diff --git a/IMX6ULL/source/07_GPIO/04_gpio_use_pinctrl_ok/01_led/leddrv_未测试的原始版本.c b/IMX6ULL/source/07_GPIO/04_gpio_use_pinctrl_ok/01_led/leddrv_未测试的原始版本.c
new file mode 100644
index 0000000..6ef1a7c
--- /dev/null
+++ b/IMX6ULL/source/07_GPIO/04_gpio_use_pinctrl_ok/01_led/leddrv_未测试的原始版本.c
@@ -0,0 +1,165 @@
+#include <linux/module.h>
+
+#include <linux/fs.h>
+#include <linux/errno.h>
+#include <linux/miscdevice.h>
+#include <linux/kernel.h>
+#include <linux/major.h>
+#include <linux/mutex.h>
+#include <linux/proc_fs.h>
+#include <linux/seq_file.h>
+#include <linux/stat.h>
+#include <linux/init.h>
+#include <linux/device.h>
+#include <linux/tty.h>
+#include <linux/kmod.h>
+#include <linux/gfp.h>
+#include <linux/gpio/consumer.h>
+
+
+/* 1. 确定主设备号                                                                 */
+static int major = 0;
+static struct class *led_class;
+static struct gpio_desc *led_gpio;
+
+
+/* 3. 实现对应的open/read/write等函数，填入file_operations结构体                   */
+static ssize_t led_drv_read (struct file *file, char __user *buf, size_t size, loff_t *offset)
+{
+	printk("%s %s line %d\n", __FILE__, __FUNCTION__, __LINE__);
+	return 0;
+}
+
+/* write(fd, &val, 1); */
+static ssize_t led_drv_write (struct file *file, const char __user *buf, size_t size, loff_t *offset)
+{
+	int err;
+	char status;
+	struct inode *inode = file_inode(file);
+	int minor = iminor(inode);
+	
+	printk("%s %s line %d\n", __FILE__, __FUNCTION__, __LINE__);
+	err = copy_from_user(&status, buf, 1);
+
+	/* 根据次设备号和status控制LED */
+	gpiod_set_value(led_gpio, status);
+	
+	return 1;
+}
+
+static int led_drv_open (struct inode *node, struct file *file)
+{
+	int minor = iminor(node);
+	
+	printk("%s %s line %d\n", __FILE__, __FUNCTION__, __LINE__);
+	/* 根据次设备号初始化LED */
+	gpiod_direction_output(led_gpio, 0);
+	
+	return 0;
+}
+
+static int led_drv_close (struct inode *node, struct file *file)
+{
+	printk("%s %s line %d\n", __FILE__, __FUNCTION__, __LINE__);
+	return 0;
+}
+
+/* 定义自己的file_operations结构体                                              */
+static struct file_operations led_drv = {
+	.owner	 = THIS_MODULE,
+	.open    = led_drv_open,
+	.read    = led_drv_read,
+	.write   = led_drv_write,
+	.release = led_drv_close,
+};
+
+/* 4. 从platform_device获得GPIO
+ *    把file_operations结构体告诉内核：注册驱动程序
+ */
+static int chip_demo_gpio_probe(struct platform_device *pdev)
+{
+	int err;
+	
+	printk("%s %s line %d\n", __FILE__, __FUNCTION__, __LINE__);
+
+	/* 4.1 设备树中定义有: led-gpios=<...>;	*/
+    led_gpio = gpiod_get(&pdev->dev, "led", 0);
+	if (IS_ERR(led_gpio)) {
+		dev_err(&pdev->dev, "Failed to get GPIO for led\n");
+		return PTR_ERR(led_gpio);
+	}
+    
+	/* 4.2 注册file_operations 	*/
+	major = register_chrdev(0, "100ask_led", &led_drv);  /* /dev/led */
+
+	led_class = class_create(THIS_MODULE, "100ask_led_class");
+	if (IS_ERR(led_class)) {
+		printk("%s %s line %d\n", __FILE__, __FUNCTION__, __LINE__);
+		unregister_chrdev(major, "led");
+		gpiod_free(led_gpio);
+		return PTR_ERR(led_class);
+	}
+
+	device_create(led_class, NULL, MKDEV(major, 0), NULL, "100ask_led%d", 0); /* /dev/100ask_led0 */
+        
+    return 0;
+    
+}
+
+static int chip_demo_gpio_remove(struct platform_device *pdev)
+{
+	device_destroy(led_class, MKDEV(major, 0));
+	class_destroy(led_class);
+	unregister_chrdev(major, "100ask_led");
+	gpiod_free(led_gpio);
+    
+    return 0;
+}
+
+
+static const struct of_device_id ask100_leds[] = {
+    { .compatible = "100ask,leddrv" },
+    { },
+};
+
+/* 1. 定义platform_driver */
+static struct platform_driver chip_demo_gpio_driver = {
+    .probe      = chip_demo_gpio_probe,
+    .remove     = chip_demo_gpio_remove,
+    .driver     = {
+        .name   = "100ask_led",
+        .of_match_table = ask100_leds,
+    },
+};
+
+/* 2. 在入口函数注册platform_driver */
+static int __init led_init(void)
+{
+    int err;
+    
+	printk("%s %s line %d\n", __FILE__, __FUNCTION__, __LINE__);
+	
+    err = platform_driver_register(&chip_demo_gpio_driver); 
+	
+	return err;
+}
+
+/* 3. 有入口函数就应该有出口函数：卸载驱动程序时，就会去调用这个出口函数
+ *     卸载platform_driver
+ */
+static void __exit led_exit(void)
+{
+	printk("%s %s line %d\n", __FILE__, __FUNCTION__, __LINE__);
+
+    platform_driver_unregister(&chip_demo_gpio_driver);
+}
+
+
+/* 7. 其他完善：提供设备信息，自动创建设备节点                                     */
+
+module_init(led_init);
+module_exit(led_exit);
+
+MODULE_LICENSE("GPL");
+
+
diff --git a/IMX6ULL/source/07_GPIO/04_gpio_use_pinctrl_ok/01_led/ledtest.c b/IMX6ULL/source/07_GPIO/04_gpio_use_pinctrl_ok/01_led/ledtest.c
new file mode 100644
index 0000000..099eb11
--- /dev/null
+++ b/IMX6ULL/source/07_GPIO/04_gpio_use_pinctrl_ok/01_led/ledtest.c
@@ -0,0 +1,50 @@
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <stdio.h>
+#include <string.h>
+
+/*
+ * ./ledtest /dev/100ask_led0 on
+ * ./ledtest /dev/100ask_led0 off
+ */
+int main(int argc, char **argv)
+{
+	int fd;
+	char status;
+	
+	/* 1. 判断参数 */
+	if (argc != 3) 
+	{
+		printf("Usage: %s <dev> <on | off>\n", argv[0]);
+		return -1;
+	}
+
+	/* 2. 打开文件 */
+	fd = open(argv[1], O_RDWR);
+	if (fd == -1)
+	{
+		printf("can not open file %s\n", argv[1]);
+		return -1;
+	}
+
+	/* 3. 写文件 */
+	if (0 == strcmp(argv[2], "on"))
+	{
+		status = 1;
+		write(fd, &status, 1);
+	}
+	else
+	{
+		status = 0;
+		write(fd, &status, 1);
+	}
+	
+	close(fd);
+	
+	return 0;
+}
+
+
diff --git a/IMX6ULL/source/07_GPIO/04_gpio_use_pinctrl_ok/02_virtual_pinctrl_ok/Makefile b/IMX6ULL/source/07_GPIO/04_gpio_use_pinctrl_ok/02_virtual_pinctrl_ok/Makefile
new file mode 100644
index 0000000..dbd4e41
--- /dev/null
+++ b/IMX6ULL/source/07_GPIO/04_gpio_use_pinctrl_ok/02_virtual_pinctrl_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 
+
+clean:
+	make -C $(KERN_DIR) M=`pwd` modules clean
+	rm -rf modules.order
+
+obj-m	+= virtual_pinctrl_driver.o
+obj-m	+= virtual_pinctrl_client.o
+
+
diff --git a/IMX6ULL/source/07_GPIO/04_gpio_use_pinctrl_ok/02_virtual_pinctrl_ok/core.h b/IMX6ULL/source/07_GPIO/04_gpio_use_pinctrl_ok/02_virtual_pinctrl_ok/core.h
new file mode 100644
index 0000000..747c423
--- /dev/null
+++ b/IMX6ULL/source/07_GPIO/04_gpio_use_pinctrl_ok/02_virtual_pinctrl_ok/core.h
@@ -0,0 +1,205 @@
+/*
+ * Core private header for the pin control subsystem
+ *
+ * Copyright (C) 2011 ST-Ericsson SA
+ * Written on behalf of Linaro for ST-Ericsson
+ *
+ * Author: Linus Walleij <linus.walleij@linaro.org>
+ *
+ * License terms: GNU General Public License (GPL) version 2
+ */
+
+#include <linux/kref.h>
+#include <linux/mutex.h>
+#include <linux/radix-tree.h>
+#include <linux/pinctrl/pinconf.h>
+#include <linux/pinctrl/machine.h>
+
+struct pinctrl_gpio_range;
+
+/**
+ * struct pinctrl_dev - pin control class device
+ * @node: node to include this pin controller in the global pin controller list
+ * @desc: the pin controller descriptor supplied when initializing this pin
+ *	controller
+ * @pin_desc_tree: each pin descriptor for this pin controller is stored in
+ *	this radix tree
+ * @gpio_ranges: a list of GPIO ranges that is handled by this pin controller,
+ *	ranges are added to this list at runtime
+ * @dev: the device entry for this pin controller
+ * @owner: module providing the pin controller, used for refcounting
+ * @driver_data: driver data for drivers registering to the pin controller
+ *	subsystem
+ * @p: result of pinctrl_get() for this device
+ * @hog_default: default state for pins hogged by this device
+ * @hog_sleep: sleep state for pins hogged by this device
+ * @mutex: mutex taken on each pin controller specific action
+ * @device_root: debugfs root for this device
+ */
+struct pinctrl_dev {
+	struct list_head node;
+	struct pinctrl_desc *desc;
+	struct radix_tree_root pin_desc_tree;
+	struct list_head gpio_ranges;
+	struct device *dev;
+	struct module *owner;
+	void *driver_data;
+	struct pinctrl *p;
+	struct pinctrl_state *hog_default;
+	struct pinctrl_state *hog_sleep;
+	struct mutex mutex;
+#ifdef CONFIG_DEBUG_FS
+	struct dentry *device_root;
+#endif
+};
+
+/**
+ * struct pinctrl - per-device pin control state holder
+ * @node: global list node
+ * @dev: the device using this pin control handle
+ * @states: a list of states for this device
+ * @state: the current state
+ * @dt_maps: the mapping table chunks dynamically parsed from device tree for
+ *	this device, if any
+ * @users: reference count
+ */
+struct pinctrl {
+	struct list_head node;
+	struct device *dev;
+	struct list_head states;
+	struct pinctrl_state *state;
+	struct list_head dt_maps;
+	struct kref users;
+};
+
+/**
+ * struct pinctrl_state - a pinctrl state for a device
+ * @node: list node for struct pinctrl's @states field
+ * @name: the name of this state
+ * @settings: a list of settings for this state
+ */
+struct pinctrl_state {
+	struct list_head node;
+	const char *name;
+	struct list_head settings;
+};
+
+/**
+ * struct pinctrl_setting_mux - setting data for MAP_TYPE_MUX_GROUP
+ * @group: the group selector to program
+ * @func: the function selector to program
+ */
+struct pinctrl_setting_mux {
+	unsigned group;
+	unsigned func;
+};
+
+/**
+ * struct pinctrl_setting_configs - setting data for MAP_TYPE_CONFIGS_*
+ * @group_or_pin: the group selector or pin ID to program
+ * @configs: a pointer to an array of config parameters/values to program into
+ *	hardware. Each individual pin controller defines the format and meaning
+ *	of config parameters.
+ * @num_configs: the number of entries in array @configs
+ */
+struct pinctrl_setting_configs {
+	unsigned group_or_pin;
+	unsigned long *configs;
+	unsigned num_configs;
+};
+
+/**
+ * struct pinctrl_setting - an individual mux or config setting
+ * @node: list node for struct pinctrl_settings's @settings field
+ * @type: the type of setting
+ * @pctldev: pin control device handling to be programmed. Not used for
+ *   PIN_MAP_TYPE_DUMMY_STATE.
+ * @dev_name: the name of the device using this state
+ * @data: Data specific to the setting type
+ */
+struct pinctrl_setting {
+	struct list_head node;
+	enum pinctrl_map_type type;
+	struct pinctrl_dev *pctldev;
+	const char *dev_name;
+	union {
+		struct pinctrl_setting_mux mux;
+		struct pinctrl_setting_configs configs;
+	} data;
+};
+
+/**
+ * struct pin_desc - pin descriptor for each physical pin in the arch
+ * @pctldev: corresponding pin control device
+ * @name: a name for the pin, e.g. the name of the pin/pad/finger on a
+ *	datasheet or such
+ * @dynamic_name: if the name of this pin was dynamically allocated
+ * @drv_data: driver-defined per-pin data. pinctrl core does not touch this
+ * @mux_usecount: If zero, the pin is not claimed, and @owner should be NULL.
+ *	If non-zero, this pin is claimed by @owner. This field is an integer
+ *	rather than a boolean, since pinctrl_get() might process multiple
+ *	mapping table entries that refer to, and hence claim, the same group
+ *	or pin, and each of these will increment the @usecount.
+ * @mux_owner: The name of device that called pinctrl_get().
+ * @mux_setting: The most recent selected mux setting for this pin, if any.
+ * @gpio_owner: If pinctrl_request_gpio() was called for this pin, this is
+ *	the name of the GPIO that "owns" this pin.
+ */
+struct pin_desc {
+	struct pinctrl_dev *pctldev;
+	const char *name;
+	bool dynamic_name;
+	void *drv_data;
+	/* These fields only added when supporting pinmux drivers */
+#ifdef CONFIG_PINMUX
+	unsigned mux_usecount;
+	const char *mux_owner;
+	const struct pinctrl_setting_mux *mux_setting;
+	const char *gpio_owner;
+#endif
+};
+
+/**
+ * struct pinctrl_maps - a list item containing part of the mapping table
+ * @node: mapping table list node
+ * @maps: array of mapping table entries
+ * @num_maps: the number of entries in @maps
+ */
+struct pinctrl_maps {
+	struct list_head node;
+	struct pinctrl_map const *maps;
+	unsigned num_maps;
+};
+
+struct pinctrl_dev *get_pinctrl_dev_from_devname(const char *dev_name);
+struct pinctrl_dev *get_pinctrl_dev_from_of_node(struct device_node *np);
+int pin_get_from_name(struct pinctrl_dev *pctldev, const char *name);
+const char *pin_get_name(struct pinctrl_dev *pctldev, const unsigned pin);
+int pinctrl_get_group_selector(struct pinctrl_dev *pctldev,
+			       const char *pin_group);
+
+static inline struct pin_desc *pin_desc_get(struct pinctrl_dev *pctldev,
+					    unsigned int pin)
+{
+	return radix_tree_lookup(&pctldev->pin_desc_tree, pin);
+}
+
+extern struct pinctrl_gpio_range *
+pinctrl_find_gpio_range_from_pin_nolock(struct pinctrl_dev *pctldev,
+					unsigned int pin);
+
+int pinctrl_register_map(struct pinctrl_map const *maps, unsigned num_maps,
+			 bool dup);
+void pinctrl_unregister_map(struct pinctrl_map const *map);
+
+extern int pinctrl_force_sleep(struct pinctrl_dev *pctldev);
+extern int pinctrl_force_default(struct pinctrl_dev *pctldev);
+
+extern struct mutex pinctrl_maps_mutex;
+extern struct list_head pinctrl_maps;
+
+#define for_each_maps(_maps_node_, _i_, _map_) \
+	list_for_each_entry(_maps_node_, &pinctrl_maps, node) \
+		for (_i_ = 0, _map_ = &_maps_node_->maps[_i_]; \
+			_i_ < _maps_node_->num_maps; \
+			_i_++, _map_ = &_maps_node_->maps[_i_])
diff --git a/IMX6ULL/source/07_GPIO/04_gpio_use_pinctrl_ok/02_virtual_pinctrl_ok/virtual_pinctrl_client.c b/IMX6ULL/source/07_GPIO/04_gpio_use_pinctrl_ok/02_virtual_pinctrl_ok/virtual_pinctrl_client.c
new file mode 100644
index 0000000..bced33e
--- /dev/null
+++ b/IMX6ULL/source/07_GPIO/04_gpio_use_pinctrl_ok/02_virtual_pinctrl_ok/virtual_pinctrl_client.c
@@ -0,0 +1,67 @@
+#include <linux/module.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/mfd/syscon.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/of_address.h>
+#include <linux/pinctrl/machine.h>
+#include <linux/pinctrl/pinconf.h>
+#include <linux/pinctrl/pinctrl.h>
+#include <linux/pinctrl/pinmux.h>
+#include <linux/slab.h>
+#include <linux/regmap.h>
+
+static const struct of_device_id virtual_client_of_match[] = {
+	{ .compatible = "100ask,virtual_i2c", },
+	{ },
+};
+
+static int virtual_client_probe(struct platform_device *pdev)
+{
+	printk("%s %s %d\n", __FILE__, __FUNCTION__, __LINE__);
+	return 0;
+}
+static int virtual_client_remove(struct platform_device *pdev)
+{
+
+	printk("%s %s %d\n", __FILE__, __FUNCTION__, __LINE__);
+	return 0;
+}
+
+
+static struct platform_driver virtual_client_driver = {
+	.probe		= virtual_client_probe,
+	.remove		= virtual_client_remove,
+	.driver		= {
+		.name	= "100ask_virtual_client",
+		.of_match_table = of_match_ptr(virtual_client_of_match),
+	}
+};
+
+
+/* 1. 入口函数 */
+static int __init virtual_client_init(void)
+{	
+	printk("%s %s %d\n", __FILE__, __FUNCTION__, __LINE__);
+	/* 1.1 注册一个platform_driver */
+	return platform_driver_register(&virtual_client_driver);
+}
+
+
+/* 2. 出口函数 */
+static void __exit virtual_client_exit(void)
+{
+	printk("%s %s %d\n", __FILE__, __FUNCTION__, __LINE__);
+	/* 2.1 反注册platform_driver */
+	platform_driver_unregister(&virtual_client_driver);
+}
+
+module_init(virtual_client_init);
+module_exit(virtual_client_exit);
+
+MODULE_LICENSE("GPL");
+
+
+
diff --git a/IMX6ULL/source/07_GPIO/04_gpio_use_pinctrl_ok/02_virtual_pinctrl_ok/virtual_pinctrl_driver.c b/IMX6ULL/source/07_GPIO/04_gpio_use_pinctrl_ok/02_virtual_pinctrl_ok/virtual_pinctrl_driver.c
new file mode 100644
index 0000000..80c60e8
--- /dev/null
+++ b/IMX6ULL/source/07_GPIO/04_gpio_use_pinctrl_ok/02_virtual_pinctrl_ok/virtual_pinctrl_driver.c
@@ -0,0 +1,329 @@
+
+#include <linux/module.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/mfd/syscon.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/of_address.h>
+#include <linux/pinctrl/machine.h>
+#include <linux/pinctrl/pinconf.h>
+#include <linux/pinctrl/pinctrl.h>
+#include <linux/pinctrl/pinmux.h>
+#include <linux/slab.h>
+#include <linux/regmap.h>
+
+#include "core.h"
+
+
+static struct pinctrl_dev *g_pinctrl_dev;
+
+static const struct pinctrl_pin_desc pins[] = {
+	{0, "pin0", NULL},
+	{1, "pin1", NULL},
+	{2, "pin2", NULL},
+	{3, "pin3", NULL},
+};
+
+static unsigned long g_configs[4];
+
+struct virtual_functions_desc {
+	const char *func_name;
+	const char **groups;
+	int num_groups;
+};
+
+
+static const char *func0_grps[] = {"pin0", "pin1", "pin2", "pin3"};
+static const char *func1_grps[] = {"pin0", "pin1"};
+static const char *func2_grps[] = {"pin2", "pin3"};
+
+static struct virtual_functions_desc g_funcs_des[] = {
+	{"gpio", func0_grps, 4},
+	{"i2c",  func1_grps, 2},
+	{"uart", func2_grps, 2},
+};
+
+
+static const struct of_device_id virtual_pinctrl_of_match[] = {
+	{ .compatible = "100ask,virtual_pinctrl", },
+	{ },
+};
+
+static int virtual_get_groups_count(struct pinctrl_dev *pctldev)
+{
+	return pctldev->desc->npins;
+}
+
+static const char *virtual_get_group_name(struct pinctrl_dev *pctldev,
+				       unsigned selector)
+{
+	return pctldev->desc->pins[selector].name;
+}
+
+static int virtual_get_group_pins(struct pinctrl_dev *pctldev, unsigned selector,
+				  const unsigned **pins,
+				  unsigned *npins)
+{
+   if (selector >= pctldev->desc->npins)
+	   return -EINVAL;
+
+   *pins = &pctldev->desc->pins[selector].number;
+   *npins = 1;
+
+   return 0;
+}
+
+static void virtual_pin_dbg_show(struct pinctrl_dev *pctldev, struct seq_file *s,
+		 unsigned offset)
+{
+  seq_printf(s, "%s", dev_name(pctldev->dev));
+}
+
+/*
+ i2cgrp {
+		 functions = "i2c", "i2c";
+		 groups = "pin0", "pin1";
+		 configs = <0x11223344	0x55667788>;
+ };
+
+ one pin ==> two pinctrl_map (one for mux, one for config)
+
+ */
+static int virtual_dt_node_to_map(struct pinctrl_dev *pctldev,
+		 struct device_node *np,
+		 struct pinctrl_map **map, unsigned *num_maps)
+{
+	int i;
+	int num_pins = 0;
+	const char *pin;
+	const char *function;
+	unsigned int config;
+	struct pinctrl_map *new_map;
+	unsigned long *configs;
+	
+	/* 1. 确定pin个数/分配pinctrl_map */
+	while (1)
+	{
+		if (of_property_read_string_index(np, "groups", num_pins, &pin) == 0)
+			num_pins++;
+		else
+			break;
+	}
+
+	new_map = kmalloc(sizeof(struct pinctrl_map) * num_pins * 2, GFP_KERNEL);
+	
+
+	for (i = 0; i < num_pins; i++)
+	{
+		/* 2. get pin/function/config */
+		of_property_read_string_index(np, "groups", i, &pin);
+		of_property_read_string_index(np, "functions", i, &function);
+		of_property_read_u32_index(np, "configs", i, &config);
+		
+
+		/* 3. 存入pinctrl_map   */
+		configs = kmalloc(sizeof(*configs), GFP_KERNEL);
+
+		new_map[i*2].type = PIN_MAP_TYPE_MUX_GROUP;
+		new_map[i*2].data.mux.function = function;
+		new_map[i*2].data.mux.group = pin;
+
+		new_map[i*2+1].type = PIN_MAP_TYPE_CONFIGS_PIN;
+ 		new_map[i*2+1].data.configs.group_or_pin = pin;
+ 		new_map[i*2+1].data.configs.configs = configs;
+		configs[0] = config;
+		new_map[i*2+1].data.configs.num_configs = 1;
+
+	}
+
+	*map = new_map;
+	*num_maps = num_pins * 2;
+
+	return 0;
+}
+static void virtual_dt_free_map(struct pinctrl_dev *pctldev,
+			 struct pinctrl_map *map, unsigned num_maps)
+{
+	while (num_maps--)
+	{
+		if (map->type == PIN_MAP_TYPE_CONFIGS_PIN)
+			kfree(map->data.configs.configs);
+
+		 kfree(map);
+		 map++;
+	}
+}
+
+static const struct pinctrl_ops virtual_pctrl_ops = {
+	.get_groups_count = virtual_get_groups_count,
+	.get_group_name = virtual_get_group_name,
+	.get_group_pins = virtual_get_group_pins,
+	.pin_dbg_show = virtual_pin_dbg_show,
+	.dt_node_to_map = virtual_dt_node_to_map,
+	.dt_free_map = virtual_dt_free_map,
+
+};
+
+static int virtual_pmx_get_funcs_count(struct pinctrl_dev *pctldev)
+{
+	return ARRAY_SIZE(g_funcs_des);
+}
+
+static const char *virtual_pmx_get_func_name(struct pinctrl_dev *pctldev,
+					  unsigned selector)
+{
+	return g_funcs_des[selector].func_name;
+}
+
+static int virtual_pmx_get_groups(struct pinctrl_dev *pctldev, unsigned selector,
+				 const char * const **groups,
+				 unsigned * const num_groups)
+{
+  *groups = g_funcs_des[selector].groups;
+  *num_groups = g_funcs_des[selector].num_groups;
+
+  return 0;
+}
+
+static int virtual_pmx_set(struct pinctrl_dev *pctldev, unsigned selector,
+			unsigned group)
+{
+	printk("set %s as %s\n", pctldev->desc->pins[group].name, g_funcs_des[selector].func_name);
+	return 0;
+}
+
+static int virtual_pmx_gpio_request_enable (struct pinctrl_dev *pctldev,
+				struct pinctrl_gpio_range *range,
+				unsigned offset)
+{
+	printk("set and enable pin %s as GPIO\n", pctldev->desc->pins[offset].name);
+	return 0;
+}
+
+
+static const struct pinmux_ops virtual_pmx_ops = {
+	.get_functions_count = virtual_pmx_get_funcs_count,
+	.get_function_name = virtual_pmx_get_func_name,
+	.get_function_groups = virtual_pmx_get_groups,
+	.set_mux = virtual_pmx_set,
+	.gpio_request_enable = virtual_pmx_gpio_request_enable,
+};
+
+
+static int virtual_pinconf_get(struct pinctrl_dev *pctldev,
+			     unsigned pin_id, unsigned long *config)
+{
+	*config = g_configs[pin_id];
+	return 0;
+}
+
+
+static int virtual_pinconf_set(struct pinctrl_dev *pctldev,
+			  unsigned pin_id, unsigned long *configs,
+			  unsigned num_configs)
+{
+	if (num_configs != 1)
+		return -EINVAL;
+	
+	g_configs[pin_id] = *configs;
+	
+	printk("config %s as 0x%lx\n", pctldev->desc->pins[pin_id].name, *configs);
+	
+	return 0;
+}
+
+static void virtual_pinconf_dbg_show(struct pinctrl_dev *pctldev,
+				 struct seq_file *s, unsigned pin_id)
+{
+	  seq_printf(s, "0x%lx", g_configs[pin_id]);
+}
+
+static void virtual_pinconf_group_dbg_show(struct pinctrl_dev *pctldev,
+			  struct seq_file *s, unsigned pin_id)
+{
+   seq_printf(s, "0x%lx", g_configs[pin_id]);
+}
+
+
+static const struct pinconf_ops virtual_pinconf_ops = {
+	.pin_config_get = virtual_pinconf_get,
+	.pin_config_set = virtual_pinconf_set,
+	.pin_config_dbg_show = virtual_pinconf_dbg_show,
+	.pin_config_group_dbg_show = virtual_pinconf_group_dbg_show,
+};
+
+
+
+static int virtual_pinctrl_probe(struct platform_device *pdev)
+{
+	struct pinctrl_desc *pictrl;
+	
+	printk("%s %s %d\n", __FILE__, __FUNCTION__, __LINE__);
+
+	/* a. 分配pinctrl_desc */
+	pictrl = devm_kzalloc(&pdev->dev, sizeof(*pictrl), GFP_KERNEL);
+	
+	/* b. 设置pinctrl_desc */
+	pictrl->name = dev_name(&pdev->dev);
+	pictrl->owner = THIS_MODULE;
+	
+	/* b.1 pins and group */
+	pictrl->pins = pins;
+	pictrl->npins = ARRAY_SIZE(pins);
+
+	pictrl->pctlops = &virtual_pctrl_ops;
+	
+	/* b.2 pin mux */
+	pictrl->pmxops = &virtual_pmx_ops;
+	
+	/* b.3 pin config */
+	pictrl->confops = &virtual_pinconf_ops;
+	
+	/* c. 注册pinctrl_desc */
+	g_pinctrl_dev = devm_pinctrl_register(&pdev->dev, pictrl, NULL);
+	
+	return 0;
+}
+static int virtual_pinctrl_remove(struct platform_device *pdev)
+{
+
+	printk("%s %s %d\n", __FILE__, __FUNCTION__, __LINE__);
+	return 0;
+}
+
+
+static struct platform_driver virtual_pinctrl_driver = {
+	.probe		= virtual_pinctrl_probe,
+	.remove		= virtual_pinctrl_remove,
+	.driver		= {
+		.name	= "100ask_virtual_pinctrl",
+		.of_match_table = of_match_ptr(virtual_pinctrl_of_match),
+	}
+};
+
+
+/* 1. 入口函数 */
+static int __init virtual_pinctrl_init(void)
+{	
+	printk("%s %s %d\n", __FILE__, __FUNCTION__, __LINE__);
+	/* 1.1 注册一个platform_driver */
+	return platform_driver_register(&virtual_pinctrl_driver);
+}
+
+
+/* 2. 出口函数 */
+static void __exit virtual_pinctrl_exit(void)
+{
+	printk("%s %s %d\n", __FILE__, __FUNCTION__, __LINE__);
+	/* 2.1 反注册platform_driver */
+	platform_driver_unregister(&virtual_pinctrl_driver);
+}
+
+module_init(virtual_pinctrl_init);
+module_exit(virtual_pinctrl_exit);
+
+MODULE_LICENSE("GPL");
+
+
diff --git a/IMX6ULL/source/07_GPIO/04_gpio_use_pinctrl_ok/03_virtual_gpio_ok/Makefile b/IMX6ULL/source/07_GPIO/04_gpio_use_pinctrl_ok/03_virtual_gpio_ok/Makefile
new file mode 100644
index 0000000..95163c6
--- /dev/null
+++ b/IMX6ULL/source/07_GPIO/04_gpio_use_pinctrl_ok/03_virtual_gpio_ok/Makefile
@@ -0,0 +1,21 @@
+
+# 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 
+
+clean:
+	make -C $(KERN_DIR) M=`pwd` modules clean
+	rm -rf modules.order
+
+obj-m	+= virtual_gpio_driver.o
+
+
diff --git a/IMX6ULL/source/07_GPIO/04_gpio_use_pinctrl_ok/03_virtual_gpio_ok/virtual_gpio_driver.c b/IMX6ULL/source/07_GPIO/04_gpio_use_pinctrl_ok/03_virtual_gpio_ok/virtual_gpio_driver.c
new file mode 100644
index 0000000..4585219
--- /dev/null
+++ b/IMX6ULL/source/07_GPIO/04_gpio_use_pinctrl_ok/03_virtual_gpio_ok/virtual_gpio_driver.c
@@ -0,0 +1,128 @@
+
+#include <linux/module.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/mfd/syscon.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/of_address.h>
+#include <linux/gpio/consumer.h>
+#include <linux/gpio/driver.h>
+#include <linux/slab.h>
+#include <linux/regmap.h>
+
+static struct gpio_chip * g_virt_gpio;
+static int g_gpio_val = 0;
+
+static const struct of_device_id virtual_gpio_of_match[] = {
+	{ .compatible = "100ask,virtual_gpio", },
+	{ },
+};
+
+static int virt_gpio_direction_output(struct gpio_chip *gc,
+		unsigned offset, int val)
+{
+	printk("set pin %d as output %s\n", offset, val ? "high" : "low");
+	return 0;
+}
+
+static int virt_gpio_direction_input(struct gpio_chip *chip,
+					unsigned offset)
+{
+	printk("set pin %d as input\n", offset);
+	return 0;
+}
+
+
+static int virt_gpio_get_value(struct gpio_chip *gc, unsigned offset)
+{
+	int val;
+	val = (g_gpio_val & (1<<offset)) ? 1 : 0;
+	printk("get pin %d, it's val = %d\n", offset, val);
+	return val;
+}
+
+static void virt_gpio_set_value(struct gpio_chip *gc,
+		unsigned offset, int val)
+{
+	printk("set pin %d as %d\n", offset, val);
+	if (val)
+		g_gpio_val |= (1 << offset);
+	else
+		g_gpio_val &= ~(1 << offset);
+}
+
+static int virtual_gpio_probe(struct platform_device *pdev)
+{
+	int ret;
+	unsigned int val;
+	
+	printk("%s %s %d\n", __FILE__, __FUNCTION__, __LINE__);
+	
+	/* 1. 分配gpio_chip */
+	g_virt_gpio = devm_kzalloc(&pdev->dev, sizeof(*g_virt_gpio), GFP_KERNEL);
+	
+	/* 2. 设置gpio_chip */
+	
+	/* 2.1 设置函数 */
+	g_virt_gpio->label = pdev->name;
+	g_virt_gpio->direction_output = virt_gpio_direction_output;
+	g_virt_gpio->direction_input  = virt_gpio_direction_input;
+	g_virt_gpio->get = virt_gpio_get_value;
+	g_virt_gpio->set = virt_gpio_set_value;
+	g_virt_gpio->request = gpiochip_generic_request;
+	
+	g_virt_gpio->parent = &pdev->dev;
+	g_virt_gpio->owner = THIS_MODULE;
+	
+	/* 2.2 设置base、ngpio值 */
+	g_virt_gpio->base = -1;
+	ret = of_property_read_u32(pdev->dev.of_node, "ngpios", &val);
+	g_virt_gpio->ngpio = val;
+	
+	/* 3. 注册gpio_chip */
+	ret = devm_gpiochip_add_data(&pdev->dev, g_virt_gpio, NULL);
+	
+	return 0;
+}
+static int virtual_gpio_remove(struct platform_device *pdev)
+{
+	printk("%s %s %d\n", __FILE__, __FUNCTION__, __LINE__);
+	return 0;
+}
+
+
+static struct platform_driver virtual_gpio_driver = {
+	.probe		= virtual_gpio_probe,
+	.remove		= virtual_gpio_remove,
+	.driver		= {
+		.name	= "100ask_virtual_gpio",
+		.of_match_table = of_match_ptr(virtual_gpio_of_match),
+	}
+};
+
+
+/* 1. 入口函数 */
+static int __init virtual_gpio_init(void)
+{	
+	printk("%s %s %d\n", __FILE__, __FUNCTION__, __LINE__);
+	/* 1.1 注册一个platform_driver */
+	return platform_driver_register(&virtual_gpio_driver);
+}
+
+
+/* 2. 出口函数 */
+static void __exit virtual_gpio_exit(void)
+{
+	printk("%s %s %d\n", __FILE__, __FUNCTION__, __LINE__);
+	/* 2.1 反注册platform_driver */
+	platform_driver_unregister(&virtual_gpio_driver);
+}
+
+module_init(virtual_gpio_init);
+module_exit(virtual_gpio_exit);
+
+MODULE_LICENSE("GPL");
+
+
diff --git a/README.md b/README.md
index 002eec6..22bb448 100644
--- a/README.md
+++ b/README.md
@@ -243,6 +243,17 @@ git clone https://e.coding.net/weidongshan/linux/doc_and_source_for_drivers.git
   07_编写一个虚拟GPIO控制器的驱动程序
   08_调试与使用虚拟的GPIO控制器
   ```
+  
+* 2021.05.29 完结"GPIO子系统": 
+
+  ```shell
+  09_GPIO子系统与Pinctrl子系统的交互
+  10_编程_GPIO使用Pinctrl
+  11_GPIO子系统的sysfs接口
+  ```
+
+  
+
 
 
 ## 6. 联系方式
diff --git a/STM32MP157/doc_pic/07_GPIO/09_GPIO子系统与Pinctrl子系统的交互.md b/STM32MP157/doc_pic/07_GPIO/09_GPIO子系统与Pinctrl子系统的交互.md
new file mode 100644
index 0000000..34e0c19
--- /dev/null
+++ b/STM32MP157/doc_pic/07_GPIO/09_GPIO子系统与Pinctrl子系统的交互.md
@@ -0,0 +1,227 @@
+## GPIO子系统与Pinctrl子系统的交互
+
+参考资料：
+
+* Linux 5.x内核文档
+  * Linux-5.4\Documentation\driver-api
+  * Linux-5.4\Documentation\devicetree\bindings\gpio\gpio.txt
+  * Linux-5.4\drivers\gpio\gpio-74x164.c
+  
+* Linux 4.x内核文档
+  * Linux-4.9.88\Documentation\gpio
+  * Linux-4.9.88\Documentation\devicetree\bindings\gpio\gpio.txt
+  * Linux-4.9.88\drivers\gpio\gpio-74x164.c
+  
+
+### 1. 使用GPIO前应该设置Pinctrl
+
+假设使用这个虚拟的GPIO Controller的pinA来控制LED：
+
+![image-20210528163702792](pic/07_GPIO/11_virtual_gpio_led.png)
+
+
+
+要使用pinA来控制LED，首先要通过Pinctrl子系统把它设置为GPIO功能，然后才能设置它为输出引脚、设置它的输出值。
+
+所以在设备树文件里，应该添加Pinctrl的内容：
+
+```shell
+virtual_pincontroller {
+	compatible = "100ask,virtual_pinctrl";
+	myled_pin: myled_pin {
+			functions = "gpio";
+			groups = "pin0";
+			configs = <0x11223344>;
+	};
+};
+
+gpio_virt: virtual_gpiocontroller {
+	compatible = "100ask,virtual_gpio";
+    gpio-controller;
+    #gpio-cells = <2>;
+    ngpios = <4>;
+};
+
+myled {
+	compatible = "100ask,leddrv";
+	led-gpios = <&gpio_virt 0 GPIO_ACTIVE_LOW>;
+	pinctrl-names = "default";
+	pinctrl-0 = <&myled_pin>;	
+};
+```
+
+
+
+但是很多芯片，并不要求在设备树中把把引脚复用为GPIO功能。
+
+比如STM32MP157，在它的设备树工具`STM32CubeMX`即使把引脚配置为GPIO功能，它也不会在设备树中出现。
+
+原因在于：GPIO走了后门。
+
+现实的芯片中，并没有Pinctrl这样的硬件，它的功能大部分是在GPIO模块中实现的。
+
+Pinctrl是一个软件虚拟处理的概念，它的实现本来就跟GPIO密切相关。
+
+甚至一些引脚默认就是GPIO功能。
+
+按理说：
+
+一个引脚可能被用作GPIO，也可能被用作I2C，GPIO和I2C这些功能时相同低位的。
+
+要用作GPIO，需要先通过Pinctrl把引脚复用为GPIO功能。
+
+但是Pinctrl和GPIO关系密切，当你使用gpiod_get获得GPIO引脚时，它就`偷偷地`通过Pinctrl把引脚复用为GPIO功能了。
+
+
+
+### 2. GPIO和Pinctrl的映射关系
+
+#### 2.1 示例
+
+![image-20210529094937479](pic/07_GPIO/12_gpio_and_pinctrl_range.png)
+
+从上图可知：
+
+* 左边的Pinctrl支持8个引脚，在Pinctrl的内部编号为0~7
+* 图中有2个GPIO控制器
+  * GPIO0内部引脚编号为0~3，假设在GPIO子系统中全局编号为100~103
+  * GPIO1内部引脚编号为0~3，假设在GPIO子系统中全局编号为104~107
+
+* 假设我们要使用pin1_1，应该这样做：
+  * 根据GPIO1的内部编号1，可以换算为Pinctrl子系统中的编号5
+  * 使用Pinctrl的函数，把第5个引脚配置为GPIO功能
+
+
+
+#### 2.2 数据结构
+
+![image-20210529101049897](pic/07_GPIO/13_gpio_pin_range.png)
+
+
+
+### 3. GPIO调用Pinctrl的过程
+
+GPIO子系统中的request函数，用来申请某个GPIO引脚，
+
+它会导致Pinctrl子系统中的这2个函数之一被调用：`pmxops->gpio_request_enable`或`pmxops->request`
+
+![image-20210529101834908](pic/07_GPIO/14_gpio_request.png)
+
+调用关系如下：
+
+```c
+gpiod_get
+    gpiod_get_index
+    	desc = of_find_gpio(dev, con_id, idx, &lookupflags);
+		ret = gpiod_request(desc, con_id ? con_id : devname);
+					ret = gpiod_request_commit(desc, label);
+								if (chip->request) {
+                                    ret = chip->request(chip, offset);
+                                }
+```
+
+
+
+我们编写GPIO驱动程序时，所设置`chip->request`函数，一般直接调用`gpiochip_generic_request`，它导致Pinctrl把引脚复用为GPIO功能。
+
+```c
+gpiochip_generic_request(struct gpio_chip *chip, unsigned offset)
+    pinctrl_request_gpio(chip->gpiodev->base + offset)
+		ret = pinctrl_get_device_gpio_range(gpio, &pctldev, &range); // gpio是引脚的全局编号
+
+		/* Convert to the pin controllers number space */
+		pin = gpio_to_pin(range, gpio);
+    	
+		ret = pinmux_request_gpio(pctldev, range, pin, gpio);
+					ret = pin_request(pctldev, pin, owner, range);
+```
+
+
+
+Pinctrl子系统中的pin_request函数就会把引脚配置为GPIO功能：
+
+```c
+static int pin_request(struct pinctrl_dev *pctldev,
+		       int pin, const char *owner,
+		       struct pinctrl_gpio_range *gpio_range)
+{
+    const struct pinmux_ops *ops = pctldev->desc->pmxops;
+    
+	/*
+	 * If there is no kind of request function for the pin we just assume
+	 * we got it by default and proceed.
+	 */
+	if (gpio_range && ops->gpio_request_enable)
+		/* This requests and enables a single GPIO pin */
+		status = ops->gpio_request_enable(pctldev, gpio_range, pin);
+	else if (ops->request)
+		status = ops->request(pctldev, pin);
+	else
+		status = 0;
+}
+```
+
+
+
+### 3. 我们要做什么
+
+如果不想在使用GPIO引脚时，在设备树中设置Pinctrl信息，
+
+如果想让GPIO和Pinctrl之间建立联系，
+
+我们需要做这些事情：
+
+#### 3.1 表明GPIO和Pinctrl间的联系
+
+在GPIO设备树中使用`gpio-ranges`来描述它们之间的联系：
+
+  * GPIO系统中有引脚号
+
+  * Pinctrl子系统中也有自己的引脚号
+
+  * 2个号码要建立映射关系
+
+  * 在GPIO设备树中使用如下代码建立映射关系
+
+    ```shell
+    // 当前GPIO控制器的0号引脚, 对应pinctrlA中的128号引脚, 数量为12
+    gpio-ranges = <&pinctrlA 0 128 12>; 
+    ```
+
+#### 3.2 解析这些联系
+
+在GPIO驱动程序中，解析跟Pinctrl之间的联系：处理`gpio-ranges`:
+
+  * 这不需要我们自己写代码
+
+  * 注册gpio_chip时会自动调用
+
+    ```c
+    int gpiochip_add_data(struct gpio_chip *chip, void *data)
+        status = of_gpiochip_add(chip);
+    				status = of_gpiochip_add_pin_range(chip);
+    
+    of_gpiochip_add_pin_range
+    	for (;; index++) {
+    		ret = of_parse_phandle_with_fixed_args(np, "gpio-ranges", 3,
+    				index, &pinspec);
+    
+        	pctldev = of_pinctrl_get(pinspec.np); // 根据gpio-ranges的第1个参数找到pctldev
+    
+            // 增加映射关系	
+            /* npins != 0: linear range */
+            ret = gpiochip_add_pin_range(chip,
+                                         pinctrl_dev_get_devname(pctldev),
+                                         pinspec.args[0],
+                                         pinspec.args[1],
+                                         pinspec.args[2]);
+    ```
+    
+
+
+#### 3.3 编程
+* 在GPIO驱动程序中，提供`gpio_chip->request`
+
+* 在Pinctrl驱动程序中，提供`pmxops->gpio_request_enable`或`pmxops->request`
+
+
diff --git a/STM32MP157/doc_pic/07_GPIO/09_GPIO子系统与Pinctrl子系统的交互.tif b/STM32MP157/doc_pic/07_GPIO/09_GPIO子系统与Pinctrl子系统的交互.tif
new file mode 100644
index 0000000..b432dad
Binary files /dev/null and b/STM32MP157/doc_pic/07_GPIO/09_GPIO子系统与Pinctrl子系统的交互.tif differ
diff --git a/STM32MP157/doc_pic/07_GPIO/10_编程_GPIO使用Pinctrl.md b/STM32MP157/doc_pic/07_GPIO/10_编程_GPIO使用Pinctrl.md
new file mode 100644
index 0000000..9283c07
--- /dev/null
+++ b/STM32MP157/doc_pic/07_GPIO/10_编程_GPIO使用Pinctrl.md
@@ -0,0 +1,396 @@
+## 编程_GPIO使用Pinctrl
+
+参考资料：
+
+* Linux 5.x内核文档
+  * Linux-5.4\Documentation\driver-api
+  * Linux-5.4\Documentation\devicetree\bindings\gpio\gpio.txt
+  * Linux-5.4\drivers\gpio\gpio-74x164.c
+  
+* Linux 4.x内核文档
+  * Linux-4.9.88\Documentation\gpio
+  * Linux-4.9.88\Documentation\devicetree\bindings\gpio\gpio.txt
+  * Linux-4.9.88\drivers\gpio\gpio-74x164.c
+  
+* 本节视频代码在GIT仓库中
+
+  ```shell
+  doc_and_source_for_drivers\IMX6ULL\source\07_GPIO\04_gpio_use_pinctrl_ok
+  doc_and_source_for_drivers\STM32MP157\source\A7\07_GPIO\04_gpio_use_pinctrl_ok
+  ```
+
+  
+
+### 1. 我们要做什么
+
+假设使用这个虚拟的GPIO Controller的pinA来控制LED：
+
+![image-20210528163702792](pic/07_GPIO/11_virtual_gpio_led.png)
+
+如果不想在使用GPIO引脚时，在设备树中设置Pinctrl信息，
+
+如果想让GPIO和Pinctrl之间建立联系，
+
+我们需要做这些事情：
+
+#### 1.1 表明GPIO和Pinctrl间的联系
+
+在GPIO设备树中使用`gpio-ranges`来描述它们之间的联系：
+
+  * GPIO系统中有引脚号
+
+  * Pinctrl子系统中也有自己的引脚号
+
+  * 2个号码要建立映射关系
+
+  * 在GPIO设备树中使用如下代码建立映射关系
+
+    ```shell
+    // 当前GPIO控制器的0号引脚, 对应pinctrlA中的128号引脚, 数量为12
+    gpio-ranges = <&pinctrlA 0 128 12>; 
+    ```
+
+#### 1.2 解析这些联系
+
+在GPIO驱动程序中，解析跟Pinctrl之间的联系：处理`gpio-ranges`:
+
+  * 这不需要我们自己写代码
+
+  * 注册gpio_chip时会自动调用
+
+    ```c
+    int gpiochip_add_data(struct gpio_chip *chip, void *data)
+        status = of_gpiochip_add(chip);
+    				status = of_gpiochip_add_pin_range(chip);
+    
+    of_gpiochip_add_pin_range
+    	for (;; index++) {
+    		ret = of_parse_phandle_with_fixed_args(np, "gpio-ranges", 3,
+    				index, &pinspec);
+    
+        	pctldev = of_pinctrl_get(pinspec.np); // 根据gpio-ranges的第1个参数找到pctldev
+    
+            // 增加映射关系	
+            /* npins != 0: linear range */
+            ret = gpiochip_add_pin_range(chip,
+                                         pinctrl_dev_get_devname(pctldev),
+                                         pinspec.args[0],
+                                         pinspec.args[1],
+                                         pinspec.args[2]);
+    ```
+
+
+#### 1.3 编程
+
+* 在GPIO驱动程序中，提供`gpio_chip->request`
+
+* 在Pinctrl驱动程序中，提供`pmxops->gpio_request_enable`或`pmxops->request`
+
+
+
+### 2. 编写设备树
+
+```shell
+pinctrl_virt: virtual_pincontroller {
+	compatible = "100ask,virtual_pinctrl";
+};
+
+gpio_virt: virtual_gpiocontroller {
+	compatible = "100ask,virtual_gpio";
+    gpio-controller;
+    #gpio-cells = <2>;
+    ngpios = <4>;
+    gpio-ranges = <&pinctrl_virt 0 0 4>; 
+};
+
+myled {
+	compatible = "100ask,leddrv";
+	led-gpios = <&gpio_virt 0 GPIO_ACTIVE_LOW>;
+};
+```
+
+
+
+### 3. 编程
+
+#### 3.1 GPIO控制器编程
+
+gpio_chip中提供request函数：
+
+```c
+chip->request = gpiochip_generic_request;
+```
+
+
+
+#### 3.2 Pinctrl编程
+
+```c
+static const struct pinmux_ops virtual_pmx_ops = {
+	.get_functions_count = virtual_pmx_get_funcs_count,
+	.get_function_name = virtual_pmx_get_func_name,
+	.get_function_groups = virtual_pmx_get_groups,
+	.set_mux = virtual_pmx_set,
+    .gpio_request_enable = virtual_pmx_gpio_request_enable,
+};
+```
+
+
+
+### 4. 上机实验
+
+#### 4.1 设置工具链
+
+##### 1. STM32MP157
+
+  **注意**：对于STM32MP157，以前说编译内核/驱动、编译APP的工具链不一样，其实编译APP用的工具链也能用来编译内核。
+
+  ```shell
+  export ARCH=arm
+  export CROSS_COMPILE=arm-buildroot-linux-gnueabihf-
+  export PATH=$PATH:/home/book/100ask_stm32mp157_pro-sdk/ToolChain/arm-buildroot-linux-gnueabihf_sdk-buildroot/bin
+  ```
+
+##### 2. IMX6ULL
+
+  ```shell
+  export ARCH=arm
+  export CROSS_COMPILE=arm-linux-gnueabihf-
+  export PATH=$PATH:/home/book/100ask_imx6ull-sdk/ToolChain/gcc-linaro-6.2.1-2016.11-x86_64_arm-linux-gnueabihf/bin
+  ```
+
+
+
+#### 4.2 编译、替换设备树
+
+##### 1. STM32MP157
+
+  * 修改`arch/arm/boot/dts/stm32mp157c-100ask-512d-lcd-v1.dts`，添加如下代码：
+
+    ```shell
+    / {
+       pinctrl_virt: virtual_pincontroller {
+            compatible = "100ask,virtual_pinctrl";
+            myled_pin: myled_pin {
+                            functions = "gpio";
+                            groups = "pin0";
+                            configs = <0x11223344>;
+            };
+            i2cgrp: i2cgrp {
+                    functions = "i2c", "i2c";
+                    groups = "pin0", "pin1";
+                    configs = <0x11223344  0x55667788>;
+            };
+        };
+    
+        gpio_virt: virtual_gpiocontroller {
+            compatible = "100ask,virtual_gpio";
+            gpio-controller;
+            #gpio-cells = <2>;
+            ngpios = <4>;
+            gpio-ranges = <&pinctrl_virt 0 0 4>; 
+        };
+    
+        myled {
+            compatible = "100ask,leddrv";
+            led-gpios = <&gpio_virt 2 GPIO_ACTIVE_LOW>;
+        };
+    };
+    ```
+
+    
+
+  * 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
+
+    * vmware使用NAT(假设windowsIP为192.168.1.100)
+
+      ```shell
+      [root@100ask:~]# mount -t nfs -o nolock,vers=3,port=2049,mountport=9999 
+      192.168.1.100:/home/book/nfs_rootfs /mnt
+      ```
+
+    * vmware使用桥接，或者不使用vmware而是直接使用服务器：假设Ubuntu IP为192.168.1.137
+
+      ```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`
+
+    ![](../04_I2C/pic/04_I2C/057_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
+
+  
+
+
+
+##### 2. IMX6ULL
+
+  * 修改`arch/arm/boot/dts/100ask_imx6ull-14x14.dts`，添加如下代码：
+
+    ```shell
+    / {
+       pinctrl_virt: virtual_pincontroller {
+            compatible = "100ask,virtual_pinctrl";
+            myled_pin: myled_pin {
+                            functions = "gpio";
+                            groups = "pin0";
+                            configs = <0x11223344>;
+            };
+            i2cgrp: i2cgrp {
+                    functions = "i2c", "i2c";
+                    groups = "pin0", "pin1";
+                    configs = <0x11223344  0x55667788>;
+            };
+        };
+    
+        gpio_virt: virtual_gpiocontroller {
+            compatible = "100ask,virtual_gpio";
+            gpio-controller;
+            #gpio-cells = <2>;
+            ngpios = <4>;
+            gpio-ranges = <&pinctrl_virt 0 0 4>; 
+        };
+    
+        myled {
+            compatible = "100ask,leddrv";
+            led-gpios = <&gpio_virt 2 GPIO_ACTIVE_LOW>;
+        };
+    };
+    ```
+
+    
+
+  * 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
+
+  * vmware使用NAT(假设windowsIP为192.168.1.100)
+
+    ```shell
+    [root@100ask:~]# mount -t nfs -o nolock,vers=3,port=2049,mountport=9999 
+    192.168.1.100:/home/book/nfs_rootfs /mnt
+    ```
+
+  * vmware使用桥接，或者不使用vmware而是直接使用服务器：假设Ubuntu IP为192.168.1.137
+
+    ```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
+
+
+
+#### 4.3 编译、安装驱动程序
+
+* 编译：
+
+  * 在Ubuntu上
+  * 进入`04_gpio_use_pinctrl_ok`下的3个驱动目录，都执行make命令
+
+* 安装：
+
+  * 在开发板上
+
+  * 挂载NFS，复制文件，insmod，类似如下命令：
+
+    ```shell
+    mount -t nfs -o nolock,vers=3 192.168.1.137:/home/book/nfs_rootfs /mnt
+    // 对于IMX6ULL，想看到驱动打印信息，需要先执行
+    echo "7 4 1 7" > /proc/sys/kernel/printk
+    
+    insmod -f /mnt/virtual_pinctrl_driver.ko
+    insmod -f /mnt/virtual_gpio_driver.ko
+    insmod -f /mnt/leddrv.ko
+    
+    ls /dev/100ask_led0
+    /mnt/ledtest /dev/100ask_led0 on
+    /mnt/ledtest /dev/100ask_led0 off
+    ```
+
+* 观察内核打印的信息
+
+
+
+### 5. 再次开后门
+
+在STM32MP157的内核中，
+
+Pinctrl驱动中并没有提供`pmxops->gpio_request_enable`或`pmxops->request`，
+
+为什么也可一直接使用GPIO功能？
+
+它的gpio_chip结构体中，有`direction_input`、`direction_output`，这2个函数的调用关系如下:
+
+```c
+direction_output/direction_input
+    pinctrl_gpio_direction
+    	ret = pinmux_gpio_direction(pctldev, range, pin, input);
+					ret = ops->gpio_set_direction(pctldev, range, pin, input);
+								stm32_pmx_gpio_set_direction
+                                    stm32_pmx_set_mode  // 它会设置引脚为GPIO功能                  
+```
+
+
+
+### 6. IMX6ULL的特殊情况
+
+IMX6ULL使用GPIO时必须设置Pinctrl，如果不设置，只有那些默认就是GPIO功能的引脚可以正常使用。
+
+原因：
+
+* GPIO控制器的设备树中，没有`gpio-ranges`
+* Pinctrl驱动中并没有提供`pmxops->gpio_request_enable`或`pmxops->request`
+* gpio_chip结构体中`direction_input`、`direction_output`，并没有配置引脚为GPIO功能
\ No newline at end of file
diff --git a/STM32MP157/doc_pic/07_GPIO/11_GPIO子系统的sysfs接口.md b/STM32MP157/doc_pic/07_GPIO/11_GPIO子系统的sysfs接口.md
new file mode 100644
index 0000000..4438cb0
--- /dev/null
+++ b/STM32MP157/doc_pic/07_GPIO/11_GPIO子系统的sysfs接口.md
@@ -0,0 +1,110 @@
+## GPIO子系统的sysfs接口
+
+参考资料：
+
+* Linux 5.x内核文档
+  * Linux-5.4\Documentation\driver-api
+  * Linux-5.4\Documentation\devicetree\bindings\gpio\gpio.txt
+  * Linux-5.4\drivers\gpio\gpiolib-sysfs.c
+  
+* Linux 4.x内核文档
+  * Linux-4.9.88\Documentation\gpio
+  * Linux-4.9.88\Documentation\devicetree\bindings\gpio\gpio.txt
+  * Linux-4.9.88\drivers\gpio\gpiolib-sysfs.c
+  
+* 本节视频代码在GIT仓库中
+
+  ```shell
+  doc_and_source_for_drivers\IMX6ULL\source\07_GPIO\04_gpio_use_pinctrl_ok
+  doc_and_source_for_drivers\STM32MP157\source\A7\07_GPIO\04_gpio_use_pinctrl_ok
+  ```
+
+  
+
+### 1. 驱动程序
+
+驱动程序为`drivers\gpio\gpiolib-sysfs.c`，这里不打算分析它。
+
+
+
+### 2. 常用的SYSFS文件
+
+#### 2.1 有哪些GPIO控制器
+
+`/sys/bus/gpio/devices`目录下，列出了所有的GPIO控制器，如下表示有11个GPIO控制器：
+
+```c
+/sys/bus/gpio/devices/gpiochip0
+/sys/bus/gpio/devices/gpiochip1
+/sys/bus/gpio/devices/gpiochip2
+/sys/bus/gpio/devices/gpiochip3
+/sys/bus/gpio/devices/gpiochip4
+/sys/bus/gpio/devices/gpiochip5
+/sys/bus/gpio/devices/gpiochip6
+/sys/bus/gpio/devices/gpiochip7
+/sys/bus/gpio/devices/gpiochip8
+/sys/bus/gpio/devices/gpiochip9
+/sys/bus/gpio/devices/gpiochip10
+```
+
+
+
+#### 2.2 每个GPIO控制器的详细信息
+
+`/sys/class/gpio/gpiochipXXX`下，有这些信息：
+
+```shell
+/sys/class/gpio/gpiochip508]# ls -1
+base     // 这个GPIO控制器的GPIO编号
+device
+label    // 名字
+ngpio    // 引脚个数
+power
+subsystem
+uevent
+```
+
+
+
+#### 2.3 查看GPIO使用情况
+
+```shell
+cat /sys/kernel/debug/gpio
+```
+
+
+
+#### 2.4 通过SYSFS使用GPIO
+
+如果只是简单的引脚控制(比如输出、查询输入值)，可以不编写驱动程序。
+
+但是涉及中断的话，就需要编写驱动程序了。
+
+##### 1. 确定GPIO编号
+
+查看每个`/sys/bus/gpio/devices/gpiochipXXX`目录下的label，确定是你要用的GPIO控制器，也称为GPIO Bank。
+
+根据它名字gpiochipXXX，就可以知道基值是XXX。
+
+基值加上引脚offset，就是这个引脚的编号。
+
+
+
+##### 2. 导出/设置方向/读写值
+
+举例：
+
+```shell
+echo 509 > /sys/class/gpio/export
+echo out > /sys/class/gpio/gpio509/direction
+echo 1 > /sys/class/gpio/gpio509/value
+echo 509 > /sys/class/gpio/unexport
+
+echo 509 > /sys/class/gpio/export
+echo in > /sys/class/gpio/gpio509/direction
+cat /sys/class/gpio/gpio509/value
+echo 509 > /sys/class/gpio/unexport
+```
+
+
+
diff --git a/STM32MP157/doc_pic/07_GPIO/pic/07_GPIO/09_imx6ull_gpio_chip_set.png b/STM32MP157/doc_pic/07_GPIO/pic/07_GPIO/09_imx6ull_gpio_chip_set.png
new file mode 100644
index 0000000..13f431e
Binary files /dev/null and b/STM32MP157/doc_pic/07_GPIO/pic/07_GPIO/09_imx6ull_gpio_chip_set.png differ
diff --git a/STM32MP157/doc_pic/07_GPIO/pic/07_GPIO/12_gpio_and_pinctrl_range.png b/STM32MP157/doc_pic/07_GPIO/pic/07_GPIO/12_gpio_and_pinctrl_range.png
new file mode 100644
index 0000000..9bb71ec
Binary files /dev/null and b/STM32MP157/doc_pic/07_GPIO/pic/07_GPIO/12_gpio_and_pinctrl_range.png differ
diff --git a/STM32MP157/doc_pic/07_GPIO/pic/07_GPIO/13_gpio_pin_range.png b/STM32MP157/doc_pic/07_GPIO/pic/07_GPIO/13_gpio_pin_range.png
new file mode 100644
index 0000000..3c18b21
Binary files /dev/null and b/STM32MP157/doc_pic/07_GPIO/pic/07_GPIO/13_gpio_pin_range.png differ
diff --git a/STM32MP157/doc_pic/07_GPIO/pic/07_GPIO/14_gpio_request.png b/STM32MP157/doc_pic/07_GPIO/pic/07_GPIO/14_gpio_request.png
new file mode 100644
index 0000000..efed222
Binary files /dev/null and b/STM32MP157/doc_pic/07_GPIO/pic/07_GPIO/14_gpio_request.png differ
diff --git a/STM32MP157/source/A7/07_GPIO/04_gpio_use_pinctrl_ok/01_led/Makefile b/STM32MP157/source/A7/07_GPIO/04_gpio_use_pinctrl_ok/01_led/Makefile
new file mode 100644
index 0000000..b519dab
--- /dev/null
+++ b/STM32MP157/source/A7/07_GPIO/04_gpio_use_pinctrl_ok/01_led/Makefile
@@ -0,0 +1,29 @@
+
+# 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 # 板子所用内核源码的目录
+
+all:
+	make -C $(KERN_DIR) M=`pwd` modules 
+	$(CROSS_COMPILE)gcc -o ledtest ledtest.c 
+
+clean:
+	make -C $(KERN_DIR) M=`pwd` modules clean
+	rm -rf modules.order
+	rm -f ledtest
+
+# 参考内核源码drivers/char/ipmi/Makefile
+# 要想把a.c, b.c编译成ab.ko, 可以这样指定:
+# ab-y := a.o b.o
+# obj-m += ab.o
+
+
+
+obj-m += leddrv.o
+
diff --git a/STM32MP157/source/A7/07_GPIO/04_gpio_use_pinctrl_ok/01_led/leddrv.c b/STM32MP157/source/A7/07_GPIO/04_gpio_use_pinctrl_ok/01_led/leddrv.c
new file mode 100644
index 0000000..521c65d
--- /dev/null
+++ b/STM32MP157/source/A7/07_GPIO/04_gpio_use_pinctrl_ok/01_led/leddrv.c
@@ -0,0 +1,161 @@
+#include <linux/module.h>
+#include <linux/platform_device.h>
+
+#include <linux/fs.h>
+#include <linux/errno.h>
+#include <linux/miscdevice.h>
+#include <linux/kernel.h>
+#include <linux/major.h>
+#include <linux/mutex.h>
+#include <linux/proc_fs.h>
+#include <linux/seq_file.h>
+#include <linux/stat.h>
+#include <linux/init.h>
+#include <linux/device.h>
+#include <linux/tty.h>
+#include <linux/kmod.h>
+#include <linux/gfp.h>
+#include <linux/gpio/consumer.h>
+#include <linux/of.h>
+
+
+/* 1. 确定主设备号                                                                 */
+static int major = 0;
+static struct class *led_class;
+static struct gpio_desc *led_gpio;
+
+
+/* 3. 实现对应的open/read/write等函数，填入file_operations结构体                   */
+static ssize_t led_drv_read (struct file *file, char __user *buf, size_t size, loff_t *offset)
+{
+	printk("%s %s line %d\n", __FILE__, __FUNCTION__, __LINE__);
+	return 0;
+}
+
+/* write(fd, &val, 1); */
+static ssize_t led_drv_write (struct file *file, const char __user *buf, size_t size, loff_t *offset)
+{
+	int err;
+	char status;
+	
+	printk("%s %s line %d\n", __FILE__, __FUNCTION__, __LINE__);
+	err = copy_from_user(&status, buf, 1);
+
+	/* 根据次设备号和status控制LED */
+	gpiod_set_value(led_gpio, status);
+	
+	return 1;
+}
+
+static int led_drv_open (struct inode *node, struct file *file)
+{	
+	printk("%s %s line %d\n", __FILE__, __FUNCTION__, __LINE__);
+	/* 根据次设备号初始化LED */
+	gpiod_direction_output(led_gpio, 0);
+	
+	return 0;
+}
+
+static int led_drv_close (struct inode *node, struct file *file)
+{
+	printk("%s %s line %d\n", __FILE__, __FUNCTION__, __LINE__);
+	return 0;
+}
+
+/* 定义自己的file_operations结构体                                              */
+static struct file_operations led_drv = {
+	.owner	 = THIS_MODULE,
+	.open    = led_drv_open,
+	.read    = led_drv_read,
+	.write   = led_drv_write,
+	.release = led_drv_close,
+};
+
+/* 4. 从platform_device获得GPIO
+ *    把file_operations结构体告诉内核：注册驱动程序
+ */
+static int chip_demo_gpio_probe(struct platform_device *pdev)
+{
+	printk("%s %s line %d\n", __FILE__, __FUNCTION__, __LINE__);
+
+	/* 4.1 设备树中定义有: led-gpios=<...>;	*/
+    led_gpio = gpiod_get(&pdev->dev, "led", 0);
+	if (IS_ERR(led_gpio)) {
+		dev_err(&pdev->dev, "Failed to get GPIO for led\n");
+		return PTR_ERR(led_gpio);
+	}
+    
+	/* 4.2 注册file_operations 	*/
+	major = register_chrdev(0, "100ask_led", &led_drv);  /* /dev/led */
+
+	led_class = class_create(THIS_MODULE, "100ask_led_class");
+	if (IS_ERR(led_class)) {
+		printk("%s %s line %d\n", __FILE__, __FUNCTION__, __LINE__);
+		unregister_chrdev(major, "led");
+		gpiod_put(led_gpio);
+		return PTR_ERR(led_class);
+	}
+
+	device_create(led_class, NULL, MKDEV(major, 0), NULL, "100ask_led%d", 0); /* /dev/100ask_led0 */
+        
+    return 0;
+    
+}
+
+static int chip_demo_gpio_remove(struct platform_device *pdev)
+{
+	device_destroy(led_class, MKDEV(major, 0));
+	class_destroy(led_class);
+	unregister_chrdev(major, "100ask_led");
+	gpiod_put(led_gpio);
+    
+    return 0;
+}
+
+
+static const struct of_device_id ask100_leds[] = {
+    { .compatible = "100ask,leddrv" },
+    { },
+};
+
+/* 1. 定义platform_driver */
+static struct platform_driver chip_demo_gpio_driver = {
+    .probe      = chip_demo_gpio_probe,
+    .remove     = chip_demo_gpio_remove,
+    .driver     = {
+        .name   = "100ask_led",
+        .of_match_table = ask100_leds,
+    },
+};
+
+/* 2. 在入口函数注册platform_driver */
+static int __init led_init(void)
+{
+    int err;
+    
+	printk("%s %s line %d\n", __FILE__, __FUNCTION__, __LINE__);
+	
+    err = platform_driver_register(&chip_demo_gpio_driver); 
+	
+	return err;
+}
+
+/* 3. 有入口函数就应该有出口函数：卸载驱动程序时，就会去调用这个出口函数
+ *     卸载platform_driver
+ */
+static void __exit led_exit(void)
+{
+	printk("%s %s line %d\n", __FILE__, __FUNCTION__, __LINE__);
+
+    platform_driver_unregister(&chip_demo_gpio_driver);
+}
+
+
+/* 7. 其他完善：提供设备信息，自动创建设备节点                                     */
+
+module_init(led_init);
+module_exit(led_exit);
+
+MODULE_LICENSE("GPL");
+
+
diff --git a/STM32MP157/source/A7/07_GPIO/04_gpio_use_pinctrl_ok/01_led/leddrv_未测试的原始版本.c b/STM32MP157/source/A7/07_GPIO/04_gpio_use_pinctrl_ok/01_led/leddrv_未测试的原始版本.c
new file mode 100644
index 0000000..6ef1a7c
--- /dev/null
+++ b/STM32MP157/source/A7/07_GPIO/04_gpio_use_pinctrl_ok/01_led/leddrv_未测试的原始版本.c
@@ -0,0 +1,165 @@
+#include <linux/module.h>
+
+#include <linux/fs.h>
+#include <linux/errno.h>
+#include <linux/miscdevice.h>
+#include <linux/kernel.h>
+#include <linux/major.h>
+#include <linux/mutex.h>
+#include <linux/proc_fs.h>
+#include <linux/seq_file.h>
+#include <linux/stat.h>
+#include <linux/init.h>
+#include <linux/device.h>
+#include <linux/tty.h>
+#include <linux/kmod.h>
+#include <linux/gfp.h>
+#include <linux/gpio/consumer.h>
+
+
+/* 1. 确定主设备号                                                                 */
+static int major = 0;
+static struct class *led_class;
+static struct gpio_desc *led_gpio;
+
+
+/* 3. 实现对应的open/read/write等函数，填入file_operations结构体                   */
+static ssize_t led_drv_read (struct file *file, char __user *buf, size_t size, loff_t *offset)
+{
+	printk("%s %s line %d\n", __FILE__, __FUNCTION__, __LINE__);
+	return 0;
+}
+
+/* write(fd, &val, 1); */
+static ssize_t led_drv_write (struct file *file, const char __user *buf, size_t size, loff_t *offset)
+{
+	int err;
+	char status;
+	struct inode *inode = file_inode(file);
+	int minor = iminor(inode);
+	
+	printk("%s %s line %d\n", __FILE__, __FUNCTION__, __LINE__);
+	err = copy_from_user(&status, buf, 1);
+
+	/* 根据次设备号和status控制LED */
+	gpiod_set_value(led_gpio, status);
+	
+	return 1;
+}
+
+static int led_drv_open (struct inode *node, struct file *file)
+{
+	int minor = iminor(node);
+	
+	printk("%s %s line %d\n", __FILE__, __FUNCTION__, __LINE__);
+	/* 根据次设备号初始化LED */
+	gpiod_direction_output(led_gpio, 0);
+	
+	return 0;
+}
+
+static int led_drv_close (struct inode *node, struct file *file)
+{
+	printk("%s %s line %d\n", __FILE__, __FUNCTION__, __LINE__);
+	return 0;
+}
+
+/* 定义自己的file_operations结构体                                              */
+static struct file_operations led_drv = {
+	.owner	 = THIS_MODULE,
+	.open    = led_drv_open,
+	.read    = led_drv_read,
+	.write   = led_drv_write,
+	.release = led_drv_close,
+};
+
+/* 4. 从platform_device获得GPIO
+ *    把file_operations结构体告诉内核：注册驱动程序
+ */
+static int chip_demo_gpio_probe(struct platform_device *pdev)
+{
+	int err;
+	
+	printk("%s %s line %d\n", __FILE__, __FUNCTION__, __LINE__);
+
+	/* 4.1 设备树中定义有: led-gpios=<...>;	*/
+    led_gpio = gpiod_get(&pdev->dev, "led", 0);
+	if (IS_ERR(led_gpio)) {
+		dev_err(&pdev->dev, "Failed to get GPIO for led\n");
+		return PTR_ERR(led_gpio);
+	}
+    
+	/* 4.2 注册file_operations 	*/
+	major = register_chrdev(0, "100ask_led", &led_drv);  /* /dev/led */
+
+	led_class = class_create(THIS_MODULE, "100ask_led_class");
+	if (IS_ERR(led_class)) {
+		printk("%s %s line %d\n", __FILE__, __FUNCTION__, __LINE__);
+		unregister_chrdev(major, "led");
+		gpiod_free(led_gpio);
+		return PTR_ERR(led_class);
+	}
+
+	device_create(led_class, NULL, MKDEV(major, 0), NULL, "100ask_led%d", 0); /* /dev/100ask_led0 */
+        
+    return 0;
+    
+}
+
+static int chip_demo_gpio_remove(struct platform_device *pdev)
+{
+	device_destroy(led_class, MKDEV(major, 0));
+	class_destroy(led_class);
+	unregister_chrdev(major, "100ask_led");
+	gpiod_free(led_gpio);
+    
+    return 0;
+}
+
+
+static const struct of_device_id ask100_leds[] = {
+    { .compatible = "100ask,leddrv" },
+    { },
+};
+
+/* 1. 定义platform_driver */
+static struct platform_driver chip_demo_gpio_driver = {
+    .probe      = chip_demo_gpio_probe,
+    .remove     = chip_demo_gpio_remove,
+    .driver     = {
+        .name   = "100ask_led",
+        .of_match_table = ask100_leds,
+    },
+};
+
+/* 2. 在入口函数注册platform_driver */
+static int __init led_init(void)
+{
+    int err;
+    
+	printk("%s %s line %d\n", __FILE__, __FUNCTION__, __LINE__);
+	
+    err = platform_driver_register(&chip_demo_gpio_driver); 
+	
+	return err;
+}
+
+/* 3. 有入口函数就应该有出口函数：卸载驱动程序时，就会去调用这个出口函数
+ *     卸载platform_driver
+ */
+static void __exit led_exit(void)
+{
+	printk("%s %s line %d\n", __FILE__, __FUNCTION__, __LINE__);
+
+    platform_driver_unregister(&chip_demo_gpio_driver);
+}
+
+
+/* 7. 其他完善：提供设备信息，自动创建设备节点                                     */
+
+module_init(led_init);
+module_exit(led_exit);
+
+MODULE_LICENSE("GPL");
+
+
diff --git a/STM32MP157/source/A7/07_GPIO/04_gpio_use_pinctrl_ok/01_led/ledtest.c b/STM32MP157/source/A7/07_GPIO/04_gpio_use_pinctrl_ok/01_led/ledtest.c
new file mode 100644
index 0000000..099eb11
--- /dev/null
+++ b/STM32MP157/source/A7/07_GPIO/04_gpio_use_pinctrl_ok/01_led/ledtest.c
@@ -0,0 +1,50 @@
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <stdio.h>
+#include <string.h>
+
+/*
+ * ./ledtest /dev/100ask_led0 on
+ * ./ledtest /dev/100ask_led0 off
+ */
+int main(int argc, char **argv)
+{
+	int fd;
+	char status;
+	
+	/* 1. 判断参数 */
+	if (argc != 3) 
+	{
+		printf("Usage: %s <dev> <on | off>\n", argv[0]);
+		return -1;
+	}
+
+	/* 2. 打开文件 */
+	fd = open(argv[1], O_RDWR);
+	if (fd == -1)
+	{
+		printf("can not open file %s\n", argv[1]);
+		return -1;
+	}
+
+	/* 3. 写文件 */
+	if (0 == strcmp(argv[2], "on"))
+	{
+		status = 1;
+		write(fd, &status, 1);
+	}
+	else
+	{
+		status = 0;
+		write(fd, &status, 1);
+	}
+	
+	close(fd);
+	
+	return 0;
+}
+
+
diff --git a/STM32MP157/source/A7/07_GPIO/04_gpio_use_pinctrl_ok/02_virtual_pinctrl_ok/Makefile b/STM32MP157/source/A7/07_GPIO/04_gpio_use_pinctrl_ok/02_virtual_pinctrl_ok/Makefile
new file mode 100644
index 0000000..bbbccf0
--- /dev/null
+++ b/STM32MP157/source/A7/07_GPIO/04_gpio_use_pinctrl_ok/02_virtual_pinctrl_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 
+
+clean:
+	make -C $(KERN_DIR) M=`pwd` modules clean
+	rm -rf modules.order
+
+obj-m	+= virtual_pinctrl_driver.o
+obj-m	+= virtual_pinctrl_client.o
+
+
diff --git a/STM32MP157/source/A7/07_GPIO/04_gpio_use_pinctrl_ok/02_virtual_pinctrl_ok/core.h b/STM32MP157/source/A7/07_GPIO/04_gpio_use_pinctrl_ok/02_virtual_pinctrl_ok/core.h
new file mode 100644
index 0000000..7f34167
--- /dev/null
+++ b/STM32MP157/source/A7/07_GPIO/04_gpio_use_pinctrl_ok/02_virtual_pinctrl_ok/core.h
@@ -0,0 +1,253 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Core private header for the pin control subsystem
+ *
+ * Copyright (C) 2011 ST-Ericsson SA
+ * Written on behalf of Linaro for ST-Ericsson
+ *
+ * Author: Linus Walleij <linus.walleij@linaro.org>
+ */
+
+#include <linux/kref.h>
+#include <linux/mutex.h>
+#include <linux/radix-tree.h>
+#include <linux/pinctrl/pinconf.h>
+#include <linux/pinctrl/machine.h>
+
+struct pinctrl_gpio_range;
+
+/**
+ * struct pinctrl_dev - pin control class device
+ * @node: node to include this pin controller in the global pin controller list
+ * @desc: the pin controller descriptor supplied when initializing this pin
+ *	controller
+ * @pin_desc_tree: each pin descriptor for this pin controller is stored in
+ *	this radix tree
+ * @pin_group_tree: optionally each pin group can be stored in this radix tree
+ * @num_groups: optionally number of groups can be kept here
+ * @pin_function_tree: optionally each function can be stored in this radix tree
+ * @num_functions: optionally number of functions can be kept here
+ * @gpio_ranges: a list of GPIO ranges that is handled by this pin controller,
+ *	ranges are added to this list at runtime
+ * @dev: the device entry for this pin controller
+ * @owner: module providing the pin controller, used for refcounting
+ * @driver_data: driver data for drivers registering to the pin controller
+ *	subsystem
+ * @p: result of pinctrl_get() for this device
+ * @hog_default: default state for pins hogged by this device
+ * @hog_sleep: sleep state for pins hogged by this device
+ * @mutex: mutex taken on each pin controller specific action
+ * @device_root: debugfs root for this device
+ */
+struct pinctrl_dev {
+	struct list_head node;
+	struct pinctrl_desc *desc;
+	struct radix_tree_root pin_desc_tree;
+#ifdef CONFIG_GENERIC_PINCTRL_GROUPS
+	struct radix_tree_root pin_group_tree;
+	unsigned int num_groups;
+#endif
+#ifdef CONFIG_GENERIC_PINMUX_FUNCTIONS
+	struct radix_tree_root pin_function_tree;
+	unsigned int num_functions;
+#endif
+	struct list_head gpio_ranges;
+	struct device *dev;
+	struct module *owner;
+	void *driver_data;
+	struct pinctrl *p;
+	struct pinctrl_state *hog_default;
+	struct pinctrl_state *hog_sleep;
+	struct mutex mutex;
+#ifdef CONFIG_DEBUG_FS
+	struct dentry *device_root;
+#endif
+};
+
+/**
+ * struct pinctrl - per-device pin control state holder
+ * @node: global list node
+ * @dev: the device using this pin control handle
+ * @states: a list of states for this device
+ * @state: the current state
+ * @dt_maps: the mapping table chunks dynamically parsed from device tree for
+ *	this device, if any
+ * @users: reference count
+ */
+struct pinctrl {
+	struct list_head node;
+	struct device *dev;
+	struct list_head states;
+	struct pinctrl_state *state;
+	struct list_head dt_maps;
+	struct kref users;
+};
+
+/**
+ * struct pinctrl_state - a pinctrl state for a device
+ * @node: list node for struct pinctrl's @states field
+ * @name: the name of this state
+ * @settings: a list of settings for this state
+ */
+struct pinctrl_state {
+	struct list_head node;
+	const char *name;
+	struct list_head settings;
+};
+
+/**
+ * struct pinctrl_setting_mux - setting data for MAP_TYPE_MUX_GROUP
+ * @group: the group selector to program
+ * @func: the function selector to program
+ */
+struct pinctrl_setting_mux {
+	unsigned group;
+	unsigned func;
+};
+
+/**
+ * struct pinctrl_setting_configs - setting data for MAP_TYPE_CONFIGS_*
+ * @group_or_pin: the group selector or pin ID to program
+ * @configs: a pointer to an array of config parameters/values to program into
+ *	hardware. Each individual pin controller defines the format and meaning
+ *	of config parameters.
+ * @num_configs: the number of entries in array @configs
+ */
+struct pinctrl_setting_configs {
+	unsigned group_or_pin;
+	unsigned long *configs;
+	unsigned num_configs;
+};
+
+/**
+ * struct pinctrl_setting - an individual mux or config setting
+ * @node: list node for struct pinctrl_settings's @settings field
+ * @type: the type of setting
+ * @pctldev: pin control device handling to be programmed. Not used for
+ *   PIN_MAP_TYPE_DUMMY_STATE.
+ * @dev_name: the name of the device using this state
+ * @data: Data specific to the setting type
+ */
+struct pinctrl_setting {
+	struct list_head node;
+	enum pinctrl_map_type type;
+	struct pinctrl_dev *pctldev;
+	const char *dev_name;
+	union {
+		struct pinctrl_setting_mux mux;
+		struct pinctrl_setting_configs configs;
+	} data;
+};
+
+/**
+ * struct pin_desc - pin descriptor for each physical pin in the arch
+ * @pctldev: corresponding pin control device
+ * @name: a name for the pin, e.g. the name of the pin/pad/finger on a
+ *	datasheet or such
+ * @dynamic_name: if the name of this pin was dynamically allocated
+ * @drv_data: driver-defined per-pin data. pinctrl core does not touch this
+ * @mux_usecount: If zero, the pin is not claimed, and @owner should be NULL.
+ *	If non-zero, this pin is claimed by @owner. This field is an integer
+ *	rather than a boolean, since pinctrl_get() might process multiple
+ *	mapping table entries that refer to, and hence claim, the same group
+ *	or pin, and each of these will increment the @usecount.
+ * @mux_owner: The name of device that called pinctrl_get().
+ * @mux_setting: The most recent selected mux setting for this pin, if any.
+ * @gpio_owner: If pinctrl_gpio_request() was called for this pin, this is
+ *	the name of the GPIO that "owns" this pin.
+ */
+struct pin_desc {
+	struct pinctrl_dev *pctldev;
+	const char *name;
+	bool dynamic_name;
+	void *drv_data;
+	/* These fields only added when supporting pinmux drivers */
+#ifdef CONFIG_PINMUX
+	unsigned mux_usecount;
+	const char *mux_owner;
+	const struct pinctrl_setting_mux *mux_setting;
+	const char *gpio_owner;
+#endif
+};
+
+/**
+ * struct pinctrl_maps - a list item containing part of the mapping table
+ * @node: mapping table list node
+ * @maps: array of mapping table entries
+ * @num_maps: the number of entries in @maps
+ */
+struct pinctrl_maps {
+	struct list_head node;
+	const struct pinctrl_map *maps;
+	unsigned num_maps;
+};
+
+#ifdef CONFIG_GENERIC_PINCTRL_GROUPS
+
+/**
+ * struct group_desc - generic pin group descriptor
+ * @name: name of the pin group
+ * @pins: array of pins that belong to the group
+ * @num_pins: number of pins in the group
+ * @data: pin controller driver specific data
+ */
+struct group_desc {
+	const char *name;
+	int *pins;
+	int num_pins;
+	void *data;
+};
+
+int pinctrl_generic_get_group_count(struct pinctrl_dev *pctldev);
+
+const char *pinctrl_generic_get_group_name(struct pinctrl_dev *pctldev,
+					   unsigned int group_selector);
+
+int pinctrl_generic_get_group_pins(struct pinctrl_dev *pctldev,
+				   unsigned int group_selector,
+				   const unsigned int **pins,
+				   unsigned int *npins);
+
+struct group_desc *pinctrl_generic_get_group(struct pinctrl_dev *pctldev,
+					     unsigned int group_selector);
+
+int pinctrl_generic_add_group(struct pinctrl_dev *pctldev, const char *name,
+			      int *gpins, int ngpins, void *data);
+
+int pinctrl_generic_remove_group(struct pinctrl_dev *pctldev,
+				 unsigned int group_selector);
+
+#endif	/* CONFIG_GENERIC_PINCTRL_GROUPS */
+
+struct pinctrl_dev *get_pinctrl_dev_from_devname(const char *dev_name);
+struct pinctrl_dev *get_pinctrl_dev_from_of_node(struct device_node *np);
+int pin_get_from_name(struct pinctrl_dev *pctldev, const char *name);
+const char *pin_get_name(struct pinctrl_dev *pctldev, const unsigned pin);
+int pinctrl_get_group_selector(struct pinctrl_dev *pctldev,
+			       const char *pin_group);
+
+static inline struct pin_desc *pin_desc_get(struct pinctrl_dev *pctldev,
+					    unsigned int pin)
+{
+	return radix_tree_lookup(&pctldev->pin_desc_tree, pin);
+}
+
+extern struct pinctrl_gpio_range *
+pinctrl_find_gpio_range_from_pin_nolock(struct pinctrl_dev *pctldev,
+					unsigned int pin);
+
+int pinctrl_register_map(const struct pinctrl_map *maps, unsigned num_maps,
+			 bool dup);
+void pinctrl_unregister_map(const struct pinctrl_map *map);
+
+extern int pinctrl_force_sleep(struct pinctrl_dev *pctldev);
+extern int pinctrl_force_default(struct pinctrl_dev *pctldev);
+
+extern struct mutex pinctrl_maps_mutex;
+extern struct list_head pinctrl_maps;
+
+#define for_each_maps(_maps_node_, _i_, _map_) \
+	list_for_each_entry(_maps_node_, &pinctrl_maps, node) \
+		for (_i_ = 0, _map_ = &_maps_node_->maps[_i_]; \
+			_i_ < _maps_node_->num_maps; \
+			_i_++, _map_ = &_maps_node_->maps[_i_])
diff --git a/STM32MP157/source/A7/07_GPIO/04_gpio_use_pinctrl_ok/02_virtual_pinctrl_ok/virtual_pinctrl_client.c b/STM32MP157/source/A7/07_GPIO/04_gpio_use_pinctrl_ok/02_virtual_pinctrl_ok/virtual_pinctrl_client.c
new file mode 100644
index 0000000..bced33e
--- /dev/null
+++ b/STM32MP157/source/A7/07_GPIO/04_gpio_use_pinctrl_ok/02_virtual_pinctrl_ok/virtual_pinctrl_client.c
@@ -0,0 +1,67 @@
+#include <linux/module.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/mfd/syscon.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/of_address.h>
+#include <linux/pinctrl/machine.h>
+#include <linux/pinctrl/pinconf.h>
+#include <linux/pinctrl/pinctrl.h>
+#include <linux/pinctrl/pinmux.h>
+#include <linux/slab.h>
+#include <linux/regmap.h>
+
+static const struct of_device_id virtual_client_of_match[] = {
+	{ .compatible = "100ask,virtual_i2c", },
+	{ },
+};
+
+static int virtual_client_probe(struct platform_device *pdev)
+{
+	printk("%s %s %d\n", __FILE__, __FUNCTION__, __LINE__);
+	return 0;
+}
+static int virtual_client_remove(struct platform_device *pdev)
+{
+
+	printk("%s %s %d\n", __FILE__, __FUNCTION__, __LINE__);
+	return 0;
+}
+
+
+static struct platform_driver virtual_client_driver = {
+	.probe		= virtual_client_probe,
+	.remove		= virtual_client_remove,
+	.driver		= {
+		.name	= "100ask_virtual_client",
+		.of_match_table = of_match_ptr(virtual_client_of_match),
+	}
+};
+
+
+/* 1. 入口函数 */
+static int __init virtual_client_init(void)
+{	
+	printk("%s %s %d\n", __FILE__, __FUNCTION__, __LINE__);
+	/* 1.1 注册一个platform_driver */
+	return platform_driver_register(&virtual_client_driver);
+}
+
+
+/* 2. 出口函数 */
+static void __exit virtual_client_exit(void)
+{
+	printk("%s %s %d\n", __FILE__, __FUNCTION__, __LINE__);
+	/* 2.1 反注册platform_driver */
+	platform_driver_unregister(&virtual_client_driver);
+}
+
+module_init(virtual_client_init);
+module_exit(virtual_client_exit);
+
+MODULE_LICENSE("GPL");
+
+
+
diff --git a/STM32MP157/source/A7/07_GPIO/04_gpio_use_pinctrl_ok/02_virtual_pinctrl_ok/virtual_pinctrl_driver.c b/STM32MP157/source/A7/07_GPIO/04_gpio_use_pinctrl_ok/02_virtual_pinctrl_ok/virtual_pinctrl_driver.c
new file mode 100644
index 0000000..80c60e8
--- /dev/null
+++ b/STM32MP157/source/A7/07_GPIO/04_gpio_use_pinctrl_ok/02_virtual_pinctrl_ok/virtual_pinctrl_driver.c
@@ -0,0 +1,329 @@
+
+#include <linux/module.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/mfd/syscon.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/of_address.h>
+#include <linux/pinctrl/machine.h>
+#include <linux/pinctrl/pinconf.h>
+#include <linux/pinctrl/pinctrl.h>
+#include <linux/pinctrl/pinmux.h>
+#include <linux/slab.h>
+#include <linux/regmap.h>
+
+#include "core.h"
+
+
+static struct pinctrl_dev *g_pinctrl_dev;
+
+static const struct pinctrl_pin_desc pins[] = {
+	{0, "pin0", NULL},
+	{1, "pin1", NULL},
+	{2, "pin2", NULL},
+	{3, "pin3", NULL},
+};
+
+static unsigned long g_configs[4];
+
+struct virtual_functions_desc {
+	const char *func_name;
+	const char **groups;
+	int num_groups;
+};
+
+
+static const char *func0_grps[] = {"pin0", "pin1", "pin2", "pin3"};
+static const char *func1_grps[] = {"pin0", "pin1"};
+static const char *func2_grps[] = {"pin2", "pin3"};
+
+static struct virtual_functions_desc g_funcs_des[] = {
+	{"gpio", func0_grps, 4},
+	{"i2c",  func1_grps, 2},
+	{"uart", func2_grps, 2},
+};
+
+
+static const struct of_device_id virtual_pinctrl_of_match[] = {
+	{ .compatible = "100ask,virtual_pinctrl", },
+	{ },
+};
+
+static int virtual_get_groups_count(struct pinctrl_dev *pctldev)
+{
+	return pctldev->desc->npins;
+}
+
+static const char *virtual_get_group_name(struct pinctrl_dev *pctldev,
+				       unsigned selector)
+{
+	return pctldev->desc->pins[selector].name;
+}
+
+static int virtual_get_group_pins(struct pinctrl_dev *pctldev, unsigned selector,
+				  const unsigned **pins,
+				  unsigned *npins)
+{
+   if (selector >= pctldev->desc->npins)
+	   return -EINVAL;
+
+   *pins = &pctldev->desc->pins[selector].number;
+   *npins = 1;
+
+   return 0;
+}
+
+static void virtual_pin_dbg_show(struct pinctrl_dev *pctldev, struct seq_file *s,
+		 unsigned offset)
+{
+  seq_printf(s, "%s", dev_name(pctldev->dev));
+}
+
+/*
+ i2cgrp {
+		 functions = "i2c", "i2c";
+		 groups = "pin0", "pin1";
+		 configs = <0x11223344	0x55667788>;
+ };
+
+ one pin ==> two pinctrl_map (one for mux, one for config)
+
+ */
+static int virtual_dt_node_to_map(struct pinctrl_dev *pctldev,
+		 struct device_node *np,
+		 struct pinctrl_map **map, unsigned *num_maps)
+{
+	int i;
+	int num_pins = 0;
+	const char *pin;
+	const char *function;
+	unsigned int config;
+	struct pinctrl_map *new_map;
+	unsigned long *configs;
+	
+	/* 1. 确定pin个数/分配pinctrl_map */
+	while (1)
+	{
+		if (of_property_read_string_index(np, "groups", num_pins, &pin) == 0)
+			num_pins++;
+		else
+			break;
+	}
+
+	new_map = kmalloc(sizeof(struct pinctrl_map) * num_pins * 2, GFP_KERNEL);
+	
+
+	for (i = 0; i < num_pins; i++)
+	{
+		/* 2. get pin/function/config */
+		of_property_read_string_index(np, "groups", i, &pin);
+		of_property_read_string_index(np, "functions", i, &function);
+		of_property_read_u32_index(np, "configs", i, &config);
+		
+
+		/* 3. 存入pinctrl_map   */
+		configs = kmalloc(sizeof(*configs), GFP_KERNEL);
+
+		new_map[i*2].type = PIN_MAP_TYPE_MUX_GROUP;
+		new_map[i*2].data.mux.function = function;
+		new_map[i*2].data.mux.group = pin;
+
+		new_map[i*2+1].type = PIN_MAP_TYPE_CONFIGS_PIN;
+ 		new_map[i*2+1].data.configs.group_or_pin = pin;
+ 		new_map[i*2+1].data.configs.configs = configs;
+		configs[0] = config;
+		new_map[i*2+1].data.configs.num_configs = 1;
+
+	}
+
+	*map = new_map;
+	*num_maps = num_pins * 2;
+
+	return 0;
+}
+static void virtual_dt_free_map(struct pinctrl_dev *pctldev,
+			 struct pinctrl_map *map, unsigned num_maps)
+{
+	while (num_maps--)
+	{
+		if (map->type == PIN_MAP_TYPE_CONFIGS_PIN)
+			kfree(map->data.configs.configs);
+
+		 kfree(map);
+		 map++;
+	}
+}
+
+static const struct pinctrl_ops virtual_pctrl_ops = {
+	.get_groups_count = virtual_get_groups_count,
+	.get_group_name = virtual_get_group_name,
+	.get_group_pins = virtual_get_group_pins,
+	.pin_dbg_show = virtual_pin_dbg_show,
+	.dt_node_to_map = virtual_dt_node_to_map,
+	.dt_free_map = virtual_dt_free_map,
+
+};
+
+static int virtual_pmx_get_funcs_count(struct pinctrl_dev *pctldev)
+{
+	return ARRAY_SIZE(g_funcs_des);
+}
+
+static const char *virtual_pmx_get_func_name(struct pinctrl_dev *pctldev,
+					  unsigned selector)
+{
+	return g_funcs_des[selector].func_name;
+}
+
+static int virtual_pmx_get_groups(struct pinctrl_dev *pctldev, unsigned selector,
+				 const char * const **groups,
+				 unsigned * const num_groups)
+{
+  *groups = g_funcs_des[selector].groups;
+  *num_groups = g_funcs_des[selector].num_groups;
+
+  return 0;
+}
+
+static int virtual_pmx_set(struct pinctrl_dev *pctldev, unsigned selector,
+			unsigned group)
+{
+	printk("set %s as %s\n", pctldev->desc->pins[group].name, g_funcs_des[selector].func_name);
+	return 0;
+}
+
+static int virtual_pmx_gpio_request_enable (struct pinctrl_dev *pctldev,
+				struct pinctrl_gpio_range *range,
+				unsigned offset)
+{
+	printk("set and enable pin %s as GPIO\n", pctldev->desc->pins[offset].name);
+	return 0;
+}
+
+
+static const struct pinmux_ops virtual_pmx_ops = {
+	.get_functions_count = virtual_pmx_get_funcs_count,
+	.get_function_name = virtual_pmx_get_func_name,
+	.get_function_groups = virtual_pmx_get_groups,
+	.set_mux = virtual_pmx_set,
+	.gpio_request_enable = virtual_pmx_gpio_request_enable,
+};
+
+
+static int virtual_pinconf_get(struct pinctrl_dev *pctldev,
+			     unsigned pin_id, unsigned long *config)
+{
+	*config = g_configs[pin_id];
+	return 0;
+}
+
+
+static int virtual_pinconf_set(struct pinctrl_dev *pctldev,
+			  unsigned pin_id, unsigned long *configs,
+			  unsigned num_configs)
+{
+	if (num_configs != 1)
+		return -EINVAL;
+	
+	g_configs[pin_id] = *configs;
+	
+	printk("config %s as 0x%lx\n", pctldev->desc->pins[pin_id].name, *configs);
+	
+	return 0;
+}
+
+static void virtual_pinconf_dbg_show(struct pinctrl_dev *pctldev,
+				 struct seq_file *s, unsigned pin_id)
+{
+	  seq_printf(s, "0x%lx", g_configs[pin_id]);
+}
+
+static void virtual_pinconf_group_dbg_show(struct pinctrl_dev *pctldev,
+			  struct seq_file *s, unsigned pin_id)
+{
+   seq_printf(s, "0x%lx", g_configs[pin_id]);
+}
+
+
+static const struct pinconf_ops virtual_pinconf_ops = {
+	.pin_config_get = virtual_pinconf_get,
+	.pin_config_set = virtual_pinconf_set,
+	.pin_config_dbg_show = virtual_pinconf_dbg_show,
+	.pin_config_group_dbg_show = virtual_pinconf_group_dbg_show,
+};
+
+
+
+static int virtual_pinctrl_probe(struct platform_device *pdev)
+{
+	struct pinctrl_desc *pictrl;
+	
+	printk("%s %s %d\n", __FILE__, __FUNCTION__, __LINE__);
+
+	/* a. 分配pinctrl_desc */
+	pictrl = devm_kzalloc(&pdev->dev, sizeof(*pictrl), GFP_KERNEL);
+	
+	/* b. 设置pinctrl_desc */
+	pictrl->name = dev_name(&pdev->dev);
+	pictrl->owner = THIS_MODULE;
+	
+	/* b.1 pins and group */
+	pictrl->pins = pins;
+	pictrl->npins = ARRAY_SIZE(pins);
+
+	pictrl->pctlops = &virtual_pctrl_ops;
+	
+	/* b.2 pin mux */
+	pictrl->pmxops = &virtual_pmx_ops;
+	
+	/* b.3 pin config */
+	pictrl->confops = &virtual_pinconf_ops;
+	
+	/* c. 注册pinctrl_desc */
+	g_pinctrl_dev = devm_pinctrl_register(&pdev->dev, pictrl, NULL);
+	
+	return 0;
+}
+static int virtual_pinctrl_remove(struct platform_device *pdev)
+{
+
+	printk("%s %s %d\n", __FILE__, __FUNCTION__, __LINE__);
+	return 0;
+}
+
+
+static struct platform_driver virtual_pinctrl_driver = {
+	.probe		= virtual_pinctrl_probe,
+	.remove		= virtual_pinctrl_remove,
+	.driver		= {
+		.name	= "100ask_virtual_pinctrl",
+		.of_match_table = of_match_ptr(virtual_pinctrl_of_match),
+	}
+};
+
+
+/* 1. 入口函数 */
+static int __init virtual_pinctrl_init(void)
+{	
+	printk("%s %s %d\n", __FILE__, __FUNCTION__, __LINE__);
+	/* 1.1 注册一个platform_driver */
+	return platform_driver_register(&virtual_pinctrl_driver);
+}
+
+
+/* 2. 出口函数 */
+static void __exit virtual_pinctrl_exit(void)
+{
+	printk("%s %s %d\n", __FILE__, __FUNCTION__, __LINE__);
+	/* 2.1 反注册platform_driver */
+	platform_driver_unregister(&virtual_pinctrl_driver);
+}
+
+module_init(virtual_pinctrl_init);
+module_exit(virtual_pinctrl_exit);
+
+MODULE_LICENSE("GPL");
+
+
diff --git a/STM32MP157/source/A7/07_GPIO/04_gpio_use_pinctrl_ok/03_virtual_gpio_ok/Makefile b/STM32MP157/source/A7/07_GPIO/04_gpio_use_pinctrl_ok/03_virtual_gpio_ok/Makefile
new file mode 100644
index 0000000..7581388
--- /dev/null
+++ b/STM32MP157/source/A7/07_GPIO/04_gpio_use_pinctrl_ok/03_virtual_gpio_ok/Makefile
@@ -0,0 +1,21 @@
+
+# 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 
+
+clean:
+	make -C $(KERN_DIR) M=`pwd` modules clean
+	rm -rf modules.order
+
+obj-m	+= virtual_gpio_driver.o
+
+
diff --git a/STM32MP157/source/A7/07_GPIO/04_gpio_use_pinctrl_ok/03_virtual_gpio_ok/virtual_gpio_driver.c b/STM32MP157/source/A7/07_GPIO/04_gpio_use_pinctrl_ok/03_virtual_gpio_ok/virtual_gpio_driver.c
new file mode 100644
index 0000000..4585219
--- /dev/null
+++ b/STM32MP157/source/A7/07_GPIO/04_gpio_use_pinctrl_ok/03_virtual_gpio_ok/virtual_gpio_driver.c
@@ -0,0 +1,128 @@
+
+#include <linux/module.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/mfd/syscon.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/of_address.h>
+#include <linux/gpio/consumer.h>
+#include <linux/gpio/driver.h>
+#include <linux/slab.h>
+#include <linux/regmap.h>
+
+static struct gpio_chip * g_virt_gpio;
+static int g_gpio_val = 0;
+
+static const struct of_device_id virtual_gpio_of_match[] = {
+	{ .compatible = "100ask,virtual_gpio", },
+	{ },
+};
+
+static int virt_gpio_direction_output(struct gpio_chip *gc,
+		unsigned offset, int val)
+{
+	printk("set pin %d as output %s\n", offset, val ? "high" : "low");
+	return 0;
+}
+
+static int virt_gpio_direction_input(struct gpio_chip *chip,
+					unsigned offset)
+{
+	printk("set pin %d as input\n", offset);
+	return 0;
+}
+
+
+static int virt_gpio_get_value(struct gpio_chip *gc, unsigned offset)
+{
+	int val;
+	val = (g_gpio_val & (1<<offset)) ? 1 : 0;
+	printk("get pin %d, it's val = %d\n", offset, val);
+	return val;
+}
+
+static void virt_gpio_set_value(struct gpio_chip *gc,
+		unsigned offset, int val)
+{
+	printk("set pin %d as %d\n", offset, val);
+	if (val)
+		g_gpio_val |= (1 << offset);
+	else
+		g_gpio_val &= ~(1 << offset);
+}
+
+static int virtual_gpio_probe(struct platform_device *pdev)
+{
+	int ret;
+	unsigned int val;
+	
+	printk("%s %s %d\n", __FILE__, __FUNCTION__, __LINE__);
+	
+	/* 1. 分配gpio_chip */
+	g_virt_gpio = devm_kzalloc(&pdev->dev, sizeof(*g_virt_gpio), GFP_KERNEL);
+	
+	/* 2. 设置gpio_chip */
+	
+	/* 2.1 设置函数 */
+	g_virt_gpio->label = pdev->name;
+	g_virt_gpio->direction_output = virt_gpio_direction_output;
+	g_virt_gpio->direction_input  = virt_gpio_direction_input;
+	g_virt_gpio->get = virt_gpio_get_value;
+	g_virt_gpio->set = virt_gpio_set_value;
+	g_virt_gpio->request = gpiochip_generic_request;
+	
+	g_virt_gpio->parent = &pdev->dev;
+	g_virt_gpio->owner = THIS_MODULE;
+	
+	/* 2.2 设置base、ngpio值 */
+	g_virt_gpio->base = -1;
+	ret = of_property_read_u32(pdev->dev.of_node, "ngpios", &val);
+	g_virt_gpio->ngpio = val;
+	
+	/* 3. 注册gpio_chip */
+	ret = devm_gpiochip_add_data(&pdev->dev, g_virt_gpio, NULL);
+	
+	return 0;
+}
+static int virtual_gpio_remove(struct platform_device *pdev)
+{
+	printk("%s %s %d\n", __FILE__, __FUNCTION__, __LINE__);
+	return 0;
+}
+
+
+static struct platform_driver virtual_gpio_driver = {
+	.probe		= virtual_gpio_probe,
+	.remove		= virtual_gpio_remove,
+	.driver		= {
+		.name	= "100ask_virtual_gpio",
+		.of_match_table = of_match_ptr(virtual_gpio_of_match),
+	}
+};
+
+
+/* 1. 入口函数 */
+static int __init virtual_gpio_init(void)
+{	
+	printk("%s %s %d\n", __FILE__, __FUNCTION__, __LINE__);
+	/* 1.1 注册一个platform_driver */
+	return platform_driver_register(&virtual_gpio_driver);
+}
+
+
+/* 2. 出口函数 */
+static void __exit virtual_gpio_exit(void)
+{
+	printk("%s %s %d\n", __FILE__, __FUNCTION__, __LINE__);
+	/* 2.1 反注册platform_driver */
+	platform_driver_unregister(&virtual_gpio_driver);
+}
+
+module_init(virtual_gpio_init);
+module_exit(virtual_gpio_exit);
+
+MODULE_LICENSE("GPL");
+
+