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add 07_GPIO/08_调试与使用虚拟的GPIO控制器
This commit is contained in:
weidongshan
307
IMX6ULL/doc_pic/07_GPIO/08_调试与使用虚拟的GPIO控制器.md
Normal file
307
IMX6ULL/doc_pic/07_GPIO/08_调试与使用虚拟的GPIO控制器.md
Normal file
@@ -0,0 +1,307 @@
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## 调试与使用虚拟的GPIO控制器
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参考资料：
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* Linux 5.x内核文档
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* Linux-5.4\Documentation\driver-api
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* Linux-5.4\Documentation\devicetree\bindings\gpio\gpio.txt
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* Linux-5.4\drivers\gpio\gpio-74x164.c
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* Linux 4.x内核文档
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* Linux-4.9.88\Documentation\gpio
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* Linux-4.9.88\Documentation\devicetree\bindings\gpio\gpio.txt
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* Linux-4.9.88\drivers\gpio\gpio-74x164.c
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* 本章课程源码位于GIT仓库里
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```shell
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doc_and_source_for_drivers\IMX6ULL\source\07_GPIO\03_virtual_gpio_ok
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doc_and_source_for_drivers\STM32MP157\source\A7\07_GPIO\03_virtual_gpio_ok
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```
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### 1. 硬件功能
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假设使用这个虚拟的GPIO Controller的pinA来控制LED：
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### 2. 编写设备树文件
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```shell
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gpio_virt: virtual_gpiocontroller {
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compatible = "100ask,virtual_gpio";
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gpio-controller;
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#gpio-cells = <2>;
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ngpios = <4>;
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};
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myled {
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compatible = "100ask,leddrv";
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led-gpios = <&gpio_virt 0 GPIO_ACTIVE_LOW>;
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};
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```
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### 3. 上机实验
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#### 3.1 设置工具链
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##### 1. STM32MP157
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**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。
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```shell
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export ARCH=arm
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export CROSS_COMPILE=arm-buildroot-linux-gnueabihf-
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export PATH=$PATH:/home/book/100ask_stm32mp157_pro-sdk/ToolChain/arm-buildroot-linux-gnueabihf_sdk-buildroot/bin
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```
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##### 2. IMX6ULL
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```shell
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export ARCH=arm
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export CROSS_COMPILE=arm-linux-gnueabihf-
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export PATH=$PATH:/home/book/100ask_imx6ull-sdk/ToolChain/gcc-linaro-6.2.1-2016.11-x86_64_arm-linux-gnueabihf/bin
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```
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#### 3.2 编译、替换设备树
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##### 1. STM32MP157
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* 修改`arch/arm/boot/dts/stm32mp157c-100ask-512d-lcd-v1.dts`，添加如下代码：
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```shell
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/ {
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gpio_virt: virtual_gpiocontroller {
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compatible = "100ask,virtual_gpio";
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gpio-controller;
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#gpio-cells = <2>;
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ngpios = <4>;
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};
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myled {
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compatible = "100ask,leddrv";
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led-gpios = <&gpio_virt 2 GPIO_ACTIVE_LOW>;
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};
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};
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```
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* 编译设备树：
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在Ubuntu的STM32MP157内核目录下执行如下命令,
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得到设备树文件：`arch/arm/boot/dts/stm32mp157c-100ask-512d-lcd-v1.dtb`
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```shell
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make dtbs
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```
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* 复制到NFS目录：
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```shell
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$ cp arch/arm/boot/dts/stm32mp157c-100ask-512d-lcd-v1.dtb ~/nfs_rootfs/
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```
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* 开发板上挂载NFS文件系统
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* vmware使用NAT(假设windowsIP为192.168.1.100)
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```shell
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[root@100ask:~]# mount -t nfs -o nolock,vers=3,port=2049,mountport=9999
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192.168.1.100:/home/book/nfs_rootfs /mnt
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```
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* 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
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```shell
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[root@100ask:~]# mount -t nfs -o nolock,vers=3 192.168.1.137:/home/book/nfs_rootfs /mnt
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```
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* 确定设备树分区挂载在哪里
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由于版本变化，STM32MP157单板上烧录的系统可能有细微差别。
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在开发板上执行`cat /proc/mounts`后，可以得到两种结果(见下图)：
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* 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
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* mmcblk2p2挂载在/mnt目录下(下图右边)
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* 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：
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* `mount /dev/mmcblk2p2 /boot`
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* 更新设备树
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```shell
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[root@100ask:~]# cp /mnt/stm32mp157c-100ask-512d-lcd-v1.dtb /boot
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[root@100ask:~]# sync
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```
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* 重启开发板
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##### 2. IMX6ULL
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* 修改`arch/arm/boot/dts/100ask_imx6ull-14x14.dts`，添加如下代码：
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```shell
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/ {
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gpio_virt: virtual_gpiocontroller {
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compatible = "100ask,virtual_gpio";
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gpio-controller;
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#gpio-cells = <2>;
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ngpios = <4>;
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};
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myled {
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compatible = "100ask,leddrv";
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led-gpios = <&gpio_virt 2 GPIO_ACTIVE_LOW>;
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};
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};
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```
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* 编译设备树：
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在Ubuntu的IMX6ULL内核目录下执行如下命令,
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得到设备树文件：`arch/arm/boot/dts/100ask_imx6ull-14x14.dtb`
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```shell
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make dtbs
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```
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* 复制到NFS目录：
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```shell
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$ cp arch/arm/boot/dts/100ask_imx6ull-14x14.dtb ~/nfs_rootfs/
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```
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* 开发板上挂载NFS文件系统
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* vmware使用NAT(假设windowsIP为192.168.1.100)
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```shell
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[root@100ask:~]# mount -t nfs -o nolock,vers=3,port=2049,mountport=9999
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192.168.1.100:/home/book/nfs_rootfs /mnt
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```
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* 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
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```shell
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[root@100ask:~]# mount -t nfs -o nolock,vers=3 192.168.1.137:/home/book/nfs_rootfs /mnt
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```
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* 更新设备树
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```shell
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[root@100ask:~]# cp /mnt/100ask_imx6ull-14x14.dtb /boot
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[root@100ask:~]# sync
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```
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* 重启开发板
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#### 3.3 编译、安装驱动程序
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* 编译：
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* 在Ubuntu上
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* 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。
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* 安装：
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* 在开发板上
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* 挂载NFS，复制文件，insmod，类似如下命令：
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```shell
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mount -t nfs -o nolock,vers=3 192.168.1.137:/home/book/nfs_rootfs /mnt
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// 对于IMX6ULL，想看到驱动打印信息，需要先执行
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echo "7 4 1 7" > /proc/sys/kernel/printk
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insmod -f /mnt/virtual_gpio_driver.ko
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insmod -f /mnt/leddrv.ko
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ls /dev/100ask_led0
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/mnt/ledtest /dev/100ask_led0 on
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/mnt/ledtest /dev/100ask_led0 off
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```
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* 观察内核打印的信息
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### 4. STM32MP157上的bug
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在STM32MP157上做如下实验时：
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```shell
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echo 509 > /sys/class/gpio/export
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echo out > /sys/class/gpio/gpio509/direction
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cat /sys/class/gpio/gpio509/value
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```
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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：
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```shell
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cat /sys/class/gpio/gpio509/value
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[ 96.283263] get pin 1, it's val = 0
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[ 96.297803] get pin 1, it's val = 0
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[ 96.312604] get pin 1, it's val = 0
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```
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`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。
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value_show只会调用一次GPIO Controller中的get函数。
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所以，我们编写了一个read.c程序，源码如下：
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```c
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#include <stdio.h>
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <fcntl.h>
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#include <unistd.h>
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int main(int argc, char **argv)
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{
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int fd = open(argv[1], O_RDONLY);
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char buf[10];
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read(fd, buf, 10);
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printf("%s\n", buf);
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return 0;
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}
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```
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编译read.c:
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```shell
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arm-buildroot-linux-gnueabihf-gcc -o read read.c
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```
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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：
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```shell
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# ./read /sys/class/gpio/gpio509/value
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[ 298.663613] get pin 1, it's val = 0
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1
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```
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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。
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至于cat的bug在哪，无关紧要，先不花时间去查。
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BIN
IMX6ULL/doc_pic/07_GPIO/pic/07_GPIO/11_virtual_gpio_led.png
Normal file
BIN
IMX6ULL/doc_pic/07_GPIO/pic/07_GPIO/11_virtual_gpio_led.png
Normal file
Binary file not shown.
|
After Width: | Height: | Size: 11 KiB |
@@ -7,7 +7,7 @@
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# 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,
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# 请参考各开发板的高级用户使用手册
|
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KERN_DIR = # 板子所用内核源码的目录
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KERN_DIR = /home/book/100ask_imx6ull-sdk/Linux-4.9.88 # 板子所用内核源码的目录
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all:
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make -C $(KERN_DIR) M=`pwd` modules
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21
IMX6ULL/source/07_GPIO/03_virtual_gpio_ok/Makefile
Normal file
21
IMX6ULL/source/07_GPIO/03_virtual_gpio_ok/Makefile
Normal file
@@ -0,0 +1,21 @@
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# 1. 使用不同的开发板内核时, 一定要修改KERN_DIR
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# 2. KERN_DIR中的内核要事先配置、编译, 为了能编译内核, 要先设置下列环境变量:
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# 2.1 ARCH, 比如: export ARCH=arm64
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# 2.2 CROSS_COMPILE, 比如: export CROSS_COMPILE=aarch64-linux-gnu-
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# 2.3 PATH, 比如: export PATH=$PATH:/home/book/100ask_roc-rk3399-pc/ToolChain-6.3.1/gcc-linaro-6.3.1-2017.05-x86_64_aarch64-linux-gnu/bin
|
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# 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
|
||||
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KERN_DIR = /home/book/100ask_imx6ull-sdk/Linux-4.9.88
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all:
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make -C $(KERN_DIR) M=`pwd` modules
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clean:
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make -C $(KERN_DIR) M=`pwd` modules clean
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rm -rf modules.order
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obj-m += virtual_gpio_driver.o
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|
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127
IMX6ULL/source/07_GPIO/03_virtual_gpio_ok/virtual_gpio_driver.c
Normal file
127
IMX6ULL/source/07_GPIO/03_virtual_gpio_ok/virtual_gpio_driver.c
Normal file
@@ -0,0 +1,127 @@
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#include <linux/module.h>
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#include <linux/err.h>
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#include <linux/init.h>
|
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#include <linux/io.h>
|
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#include <linux/mfd/syscon.h>
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#include <linux/of.h>
|
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#include <linux/of_device.h>
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#include <linux/of_address.h>
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#include <linux/gpio/consumer.h>
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#include <linux/gpio/driver.h>
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#include <linux/slab.h>
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#include <linux/regmap.h>
|
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static struct gpio_chip * g_virt_gpio;
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static int g_gpio_val = 0;
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static const struct of_device_id virtual_gpio_of_match[] = {
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{ .compatible = "100ask,virtual_gpio", },
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{ },
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};
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static int virt_gpio_direction_output(struct gpio_chip *gc,
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unsigned offset, int val)
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{
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printk("set pin %d as output %s\n", offset, val ? "high" : "low");
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return 0;
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}
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||||
static int virt_gpio_direction_input(struct gpio_chip *chip,
|
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unsigned offset)
|
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{
|
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printk("set pin %d as input\n", offset);
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return 0;
|
||||
}
|
||||
|
||||
|
||||
static int virt_gpio_get_value(struct gpio_chip *gc, unsigned offset)
|
||||
{
|
||||
int val;
|
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val = (g_gpio_val & (1<<offset)) ? 1 : 0;
|
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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->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");
|
||||
|
||||
|
||||
13
README.md
13
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：
|
||||
|
||||
|
||||
|
||||
|
||||
```
|
||||
|
||||
```
|
||||
307
STM32MP157/doc_pic/07_GPIO/08_调试与使用虚拟的GPIO控制器.md
Normal file
307
STM32MP157/doc_pic/07_GPIO/08_调试与使用虚拟的GPIO控制器.md
Normal file
@@ -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：
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
### 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`
|
||||
|
||||
|
||||
|
||||
* 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 <stdio.h>
|
||||
#include <sys/types.h>
|
||||
#include <sys/stat.h>
|
||||
#include <fcntl.h>
|
||||
#include <unistd.h>
|
||||
|
||||
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。
|
||||
BIN
STM32MP157/doc_pic/07_GPIO/pic/07_GPIO/11_virtual_gpio_led.png
Normal file
BIN
STM32MP157/doc_pic/07_GPIO/pic/07_GPIO/11_virtual_gpio_led.png
Normal file
Binary file not shown.
|
After Width: | Height: | Size: 11 KiB |
@@ -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 $(KERN_DIR) M=`pwd` modules
|
||||
|
||||
21
STM32MP157/source/A7/07_GPIO/03_virtual_gpio_ok/Makefile
Normal file
21
STM32MP157/source/A7/07_GPIO/03_virtual_gpio_ok/Makefile
Normal file
@@ -0,0 +1,21 @@
|
||||
|
||||
# 1. 使用不同的开发板内核时, 一定要修改KERN_DIR
|
||||
# 2. KERN_DIR中的内核要事先配置、编译, 为了能编译内核, 要先设置下列环境变量:
|
||||
# 2.1 ARCH, 比如: export ARCH=arm64
|
||||
# 2.2 CROSS_COMPILE, 比如: export CROSS_COMPILE=aarch64-linux-gnu-
|
||||
# 2.3 PATH, 比如: export PATH=$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
|
||||
|
||||
|
||||
@@ -0,0 +1,127 @@
|
||||
|
||||
#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->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");
|
||||
|
||||
|
||||
Reference in New Issue
Block a user