目录
作业要求：
通过platform总线驱动框架编写LED灯的驱动，编写应用程序测试，发布到CSDN
作业答案：
代码效果：
Platform总线驱动代码：
cs
#include <linux/init.h>
#include <linux/module.h>
#include <linux/of_gpio.h>
#include <linux/gpio.h>
#include <linux/platform_device.h>
#include <linux/mod_devicetable.h>
//主设备号
int major;
//用于上传目录和设备节点信息
struct class *cls;
struct device *device;
// led设备号
struct gpio_desc *gpiono1;
struct gpio_desc *gpiono2;
struct gpio_desc *gpiono3;
// 创建功能码
#define LED_ON _IOW('l', 1, int)
#define LED_OFF _IOW('l', 0, int)
// ioctl函数，用于控制led设备
long mycdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
switch (cmd)
{
case LED_ON:
switch (arg)
{
case 1:
gpiod_set_value(gpiono1, 1);
break;
case 2:
gpiod_set_value(gpiono2, 1);
break;
case 3:
gpiod_set_value(gpiono3, 1);
break;
}
break;
case LED_OFF:
switch (arg)
{
case 1:
gpiod_set_value(gpiono1, 0);
break;
case 2:
gpiod_set_value(gpiono2, 0);
break;
case 3:
gpiod_set_value(gpiono3, 0);
break;
}
break;
}
return 0;
}
// 定义操作方法结构体变量并赋值
struct file_operations fops = {
.unlocked_ioctl = mycdev_ioctl,
};
// 封装probe函数，当设备和驱动匹配成功之后执行
int pdrv_probe(struct platform_device *dev)
{
printk("%s:%s:%d\n", __FILE__, __func__, __LINE__);
// 字符设备驱动注册
major = register_chrdev(0, "mychrdev", &fops);
if (major < 0)
{
printk("字符设备驱动注册失败\n");
return major;
}
printk("字符设备驱动注册成功:major=%d\n", major);
// 向上提交目录
cls = class_create(THIS_MODULE, "mychrdev");
if (IS_ERR(cls))
{
printk("向上提交目录失败\n");
return -PTR_ERR(cls);
}
printk("向上提交目录成功\n");
// 向上提交设备节点信息
int i; // 向上提交三次设备节点信息
for (i = 0; i < 3; i++)
{
device = device_create(cls, NULL, MKDEV(major, i), NULL, "myled%d", i);
if (IS_ERR(dev))
{
printk("向上提交设备节点失败\n");
return -PTR_ERR(dev);
}
}
printk("向上提交设备节点成功\n");
// 解析LED1的gpio编号
gpiono1 = gpiod_get_from_of_node(dev->dev.of_node, "led1-gpio", 0, GPIOD_OUT_LOW, NULL);
if (gpiono1 == NULL)
{
printk("解析led1对应gpio编号失败\n");
return -ENXIO;
}
printk("解析led1对应gpio编号成功\n");
// 解析LED1的gpio编号
gpiono2 = gpiod_get_from_of_node(dev->dev.of_node, "led2-gpio", 0, GPIOD_OUT_LOW, NULL);
if (gpiono2 == NULL)
{
printk("解析led2对应gpio编号失败\n");
return -ENXIO;
}
printk("解析led2对应gpio编号成功\n");
// 解析LED1的gpio编号
gpiono3 = gpiod_get_from_of_node(dev->dev.of_node, "led3-gpio", 0, GPIOD_OUT_LOW, NULL);
if (gpiono3 == NULL)
{
printk("解析led3对应gpio编号失败\n");
return -ENXIO;
}
printk("解析led3对应gpio编号成功\n");
return 0;
}
// 封装remove函数，用于驱动和设备卸载时执行
int pdrv_remove(struct platform_device *dev)
{
// 销毁设备节点信息
device_destroy(cls, MKDEV(major, 0));
// 销毁设备节点信息
int i;
for (i = 0; i < 3; i++)
{
device_destroy(cls, MKDEV(major, i));
}
// 释放gpio编号
gpiod_put(gpiono1);
gpiod_put(gpiono2);
gpiod_put(gpiono3);
// 销毁目录
class_destroy(cls);
// 注销字符设备驱动
unregister_chrdev(major, "mychrdev");
printk("%s:%s:%d\n", __FILE__, __func__, __LINE__);
return 0;
}
// 构建用于匹配的设备树表
struct of_device_id oftable[] = {
{
.compatible = "hqyj,myplatform",
},
{/* end node */}, // 防止数组越界
};
// 分配驱动对象并初始化
struct platform_driver pdrv = {
.probe = pdrv_probe,
.remove = pdrv_remove,
.driver = {
.name = "bbbbb",
.of_match_table = oftable, // 设置设备树匹配
},
};
// 一键注册宏
module_platform_driver(pdrv);
MODULE_LICENSE("GPL");应用程序代码：
cs
#include<stdlib.h>
#include<stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include<unistd.h>
#include<string.h>
#include<sys/ioctl.h>
//创建功能码
#define LED_ON _IOW('l',1,int)
#define LED_OFF _IOW('l',0,int)
int main(int argc, char const *argv[])
{
int a,b;
int fd=open("/dev/myled0",O_RDWR);
if(fd<0)
{
printf("打开设备文件失败\n");
exit(-1);
}
while(1)
{
//从终端读取
printf("请输入要实现的功能\n");
printf("0(关灯) 1(开灯)\n");
printf("请输入>");
scanf("%d",&a);
printf("请输入要控制的灯\n");
printf("1(LED1) 2(LED2) 3(LED3)\n");
printf("请输入>");
scanf("%d",&b);
switch(a)
{
case 1:
ioctl(fd,LED_ON,b);
break;
case 0:
ioctl(fd,LED_OFF,b);
break;
}
}
close(fd);
return 0;
}设备树配置：
cs
/dts-v1/;
#include "stm32mp157.dtsi"
#include "stm32mp15xa.dtsi"
#include "stm32mp15-pinctrl.dtsi"
#include "stm32mp15xxac-pinctrl.dtsi"
#include "stm32mp15xx-fsmp1x.dtsi"
/ {
model = "HQYJ STM32MP157 FSMP1A Discovery Board";
compatible = "st,stm32mp157a-dk1", "st,stm32mp157";
aliases {
serial0 = &uart4;
serial5 = &usart3;
};
chosen {
stdout-path = "serial0:115200n8";
};
reserved-memory {
gpu_reserved: gpu@d4000000 {
reg = <0xd4000000 0x4000000>;
no-map;
};
optee_memory: optee@0xde000000 {
reg = <0xde000000 0x02000000>;
no-map;
};
};
mynode@0x12345678{
compatible = "hqyj,mynode";
astring="hello 23091";
uint =<0xaabbccdd 0x11223344>;
binarry=[00 0c 29 7b f9 be];
mixed ="hello",[11 22],<0x12345678>;
};
myled
{
led1-gpio=<&gpioe 10 0>;
led2-gpio=<&gpiof 10 0>;
led3-gpio=<&gpioe 8 0>;
};
myirq{
compatible = "hqyj,myirq";
interrupt-parent = <&gpiof>;
interrupts=<9 0>,<7 0>,<8 0>;
};
myplatform{
compatible = "hqyj,myplatform";
led1-gpio=<&gpioe 10 0>;
led2-gpio=<&gpiof 10 0>;
led3-gpio=<&gpioe 8 0>;
interrupt-parent = <&gpiof>;
interrupts=<9 0>;
reg=<0X12345678 0X400>;
};
};