diff --git a/IMX6ULL/doc_pic/07_GPIO/08_调试与使用虚拟的GPIO控制器.md b/IMX6ULL/doc_pic/07_GPIO/08_调试与使用虚拟的GPIO控制器.md new file mode 100644 index 0000000..8d4ac82 --- /dev/null +++ b/IMX6ULL/doc_pic/07_GPIO/08_调试与使用虚拟的GPIO控制器.md @@ -0,0 +1,307 @@ +## 调试与使用虚拟的GPIO控制器 + +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 + +* 本章课程源码位于GIT仓库里 + + ```shell + doc_and_source_for_drivers\IMX6ULL\source\07_GPIO\03_virtual_gpio_ok + doc_and_source_for_drivers\STM32MP157\source\A7\07_GPIO\03_virtual_gpio_ok + ``` + + + +### 1. 硬件功能 + +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) + + + +### 2. 编写设备树文件 + +```shell +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>; +}; +``` + + + +### 3. 上机实验 + +#### 3.1 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 + ``` + + + +#### 3.2 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 + / { + gpio_virt: virtual_gpiocontroller { + compatible = "100ask,virtual_gpio"; + gpio-controller; + #gpio-cells = <2>; + ngpios = <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 + / { + gpio_virt: virtual_gpiocontroller { + compatible = "100ask,virtual_gpio"; + gpio-controller; + #gpio-cells = <2>; + ngpios = <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 + + + +#### 3.3 编译、安装驱动程序 + +* 编译： + + * 在Ubuntu上 + * 修改`01_led`、`02_virtual_gpio`中的Makefile，指定内核路径`KERN_DIR`，在执行`make`命令即可。 + +* 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_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 + + + + +### 4. STM32MP157上的bug + +在STM32MP157上做如下实验时： + +```shell +echo 509 > /sys/class/gpio/export +echo out > /sys/class/gpio/gpio509/direction +cat /sys/class/gpio/gpio509/value +``` + +发现对于`value`执行一次cat操作，导致`virt_gpio_get_value`函数被调用3次，如下： + +```shell +cat /sys/class/gpio/gpio509/value +[ 96.283263] get pin 1, it's val = 0 +[ 96.297803] get pin 1, it's val = 0 +[ 96.312604] get pin 1, it's val = 0 +``` + +`cat value`这个操作，会导致驱动`drivers/gpio/gpiolib-sysfs.c`中的value_show函数被调用。 + +value_show只会调用一次GPIO Controller中的get函数。 + +所以，我们编写了一个read.c程序，源码如下： + +```c +#include +#include +#include +#include +#include + +int main(int argc, char **argv) +{ + int fd = open(argv[1], O_RDONLY); + + char buf[10]; + + read(fd, buf, 10); + printf("%s\n", buf); + return 0; +} +``` + +编译read.c: + +```shell +arm-buildroot-linux-gnueabihf-gcc -o read read.c +``` + +放到板子上执行，发现读取value文件一次，只会导致get函数被调用一次，如下： + +```shell +# ./read /sys/class/gpio/gpio509/value +[ 298.663613] get pin 1, it's val = 0 +1 +``` + + + +所以：问题在于cat命令，虽然我们执行了一次cat操作，但是它发起了3次读value文件的操作。 + +至于cat的bug在哪，无关紧要，先不花时间去查。 \ No newline at end of file diff --git a/IMX6ULL/doc_pic/07_GPIO/pic/07_GPIO/11_virtual_gpio_led.png b/IMX6ULL/doc_pic/07_GPIO/pic/07_GPIO/11_virtual_gpio_led.png new file mode 100644 index 0000000..1d5edf3 Binary files /dev/null and b/IMX6ULL/doc_pic/07_GPIO/pic/07_GPIO/11_virtual_gpio_led.png differ diff --git a/IMX6ULL/source/07_GPIO/01_led/Makefile b/IMX6ULL/source/07_GPIO/01_led/Makefile index 090f6cd..ce80d85 100644 --- a/IMX6ULL/source/07_GPIO/01_led/Makefile +++ b/IMX6ULL/source/07_GPIO/01_led/Makefile @@ -7,7 +7,7 @@ # 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 = # 板子所用内核源码的目录 +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 $(KERN_DIR) M=`pwd` modules diff --git a/IMX6ULL/source/07_GPIO/03_virtual_gpio_ok/Makefile b/IMX6ULL/source/07_GPIO/03_virtual_gpio_ok/Makefile new file mode 100644 index 0000000..95163c6 --- /dev/null +++ b/IMX6ULL/source/07_GPIO/03_virtual_gpio_ok/Makefile @@ -0,0 +1,21 @@ + +# 1. 使用不同的开发板内核时, 一定要修改KERN_DIR +# 2. KERN_DIR中的内核要事先配置、编译, 为了能编译内核, 要先设置下列环境变量: +# 2.1 ARCH, 比如: export ARCH=arm64 +# 2.2 CROSS_COMPILE, 比如: export CROSS_COMPILE=aarch64-linux-gnu- +# 2.3 PATH, 比如: export PATH=$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/03_virtual_gpio_ok/virtual_gpio_driver.c b/IMX6ULL/source/07_GPIO/03_virtual_gpio_ok/virtual_gpio_driver.c new file mode 100644 index 0000000..b646719 --- /dev/null +++ b/IMX6ULL/source/07_GPIO/03_virtual_gpio_ok/virtual_gpio_driver.c @@ -0,0 +1,127 @@ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +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<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->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 00d03dd..002eec6 100644 --- a/README.md +++ b/README.md @@ -241,13 +241,9 @@ git clone https://e.coding.net/weidongshan/linux/doc_and_source_for_drivers.git 06_IMX6ULL的GPIO驱动源码分析 06_STM32MP157的GPIO驱动源码分析 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 + ``` - - - - ## 6. 联系方式 @@ -260,4 +256,7 @@ git clone https://e.coding.net/weidongshan/linux/doc_and_source_for_drivers.git * 公众号： ![](wechat.jpg) - \ No newline at end of file + +``` + +``` \ No newline at end of file diff --git a/STM32MP157/doc_pic/07_GPIO/08_调试与使用虚拟的GPIO控制器.md b/STM32MP157/doc_pic/07_GPIO/08_调试与使用虚拟的GPIO控制器.md new file mode 100644 index 0000000..8d4ac82 --- /dev/null +++ b/STM32MP157/doc_pic/07_GPIO/08_调试与使用虚拟的GPIO控制器.md @@ -0,0 +1,307 @@ +## 调试与使用虚拟的GPIO控制器 + +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 + +* 本章课程源码位于GIT仓库里 + + ```shell + doc_and_source_for_drivers\IMX6ULL\source\07_GPIO\03_virtual_gpio_ok + doc_and_source_for_drivers\STM32MP157\source\A7\07_GPIO\03_virtual_gpio_ok + ``` + + + +### 1. 硬件功能 + +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) + + + +### 2. 编写设备树文件 + +```shell +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>; +}; +``` + + + +### 3. 上机实验 + +#### 3.1 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 + ``` + + + +#### 3.2 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 + / { + gpio_virt: virtual_gpiocontroller { + compatible = "100ask,virtual_gpio"; + gpio-controller; + #gpio-cells = <2>; + ngpios = <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 + / { + gpio_virt: virtual_gpiocontroller { + compatible = "100ask,virtual_gpio"; + gpio-controller; + #gpio-cells = <2>; + ngpios = <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 + + + +#### 3.3 编译、安装驱动程序 + +* 编译： + + * 在Ubuntu上 + * 修改`01_led`、`02_virtual_gpio`中的Makefile，指定内核路径`KERN_DIR`，在执行`make`命令即可。 + +* 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_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 + + + + +### 4. STM32MP157上的bug + +在STM32MP157上做如下实验时： + +```shell +echo 509 > /sys/class/gpio/export +echo out > /sys/class/gpio/gpio509/direction +cat /sys/class/gpio/gpio509/value +``` + +发现对于`value`执行一次cat操作，导致`virt_gpio_get_value`函数被调用3次，如下： + +```shell +cat /sys/class/gpio/gpio509/value +[ 96.283263] get pin 1, it's val = 0 +[ 96.297803] get pin 1, it's val = 0 +[ 96.312604] get pin 1, it's val = 0 +``` + +`cat value`这个操作，会导致驱动`drivers/gpio/gpiolib-sysfs.c`中的value_show函数被调用。 + +value_show只会调用一次GPIO Controller中的get函数。 + +所以，我们编写了一个read.c程序，源码如下： + +```c +#include +#include +#include +#include +#include + +int main(int argc, char **argv) +{ + int fd = open(argv[1], O_RDONLY); + + char buf[10]; + + read(fd, buf, 10); + printf("%s\n", buf); + return 0; +} +``` + +编译read.c: + +```shell +arm-buildroot-linux-gnueabihf-gcc -o read read.c +``` + +放到板子上执行，发现读取value文件一次，只会导致get函数被调用一次，如下： + +```shell +# ./read /sys/class/gpio/gpio509/value +[ 298.663613] get pin 1, it's val = 0 +1 +``` + + + +所以：问题在于cat命令，虽然我们执行了一次cat操作，但是它发起了3次读value文件的操作。 + +至于cat的bug在哪，无关紧要，先不花时间去查。 \ No newline at end of file diff --git a/STM32MP157/doc_pic/07_GPIO/pic/07_GPIO/11_virtual_gpio_led.png b/STM32MP157/doc_pic/07_GPIO/pic/07_GPIO/11_virtual_gpio_led.png new file mode 100644 index 0000000..1d5edf3 Binary files /dev/null and b/STM32MP157/doc_pic/07_GPIO/pic/07_GPIO/11_virtual_gpio_led.png differ diff --git a/STM32MP157/source/A7/07_GPIO/01_led/Makefile b/STM32MP157/source/A7/07_GPIO/01_led/Makefile index 090f6cd..b519dab 100644 --- a/STM32MP157/source/A7/07_GPIO/01_led/Makefile +++ b/STM32MP157/source/A7/07_GPIO/01_led/Makefile @@ -7,7 +7,7 @@ # 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 = # 板子所用内核源码的目录 +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 $(KERN_DIR) M=`pwd` modules diff --git a/STM32MP157/source/A7/07_GPIO/03_virtual_gpio_ok/Makefile b/STM32MP157/source/A7/07_GPIO/03_virtual_gpio_ok/Makefile new file mode 100644 index 0000000..7581388 --- /dev/null +++ b/STM32MP157/source/A7/07_GPIO/03_virtual_gpio_ok/Makefile @@ -0,0 +1,21 @@ + +# 1. 使用不同的开发板内核时, 一定要修改KERN_DIR +# 2. KERN_DIR中的内核要事先配置、编译, 为了能编译内核, 要先设置下列环境变量: +# 2.1 ARCH, 比如: export ARCH=arm64 +# 2.2 CROSS_COMPILE, 比如: export CROSS_COMPILE=aarch64-linux-gnu- +# 2.3 PATH, 比如: export PATH=$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/03_virtual_gpio_ok/virtual_gpio_driver.c b/STM32MP157/source/A7/07_GPIO/03_virtual_gpio_ok/virtual_gpio_driver.c new file mode 100644 index 0000000..b646719 --- /dev/null +++ b/STM32MP157/source/A7/07_GPIO/03_virtual_gpio_ok/virtual_gpio_driver.c @@ -0,0 +1,127 @@ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +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<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->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"); + +