效果图

设备树代码

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>;
	}; 

应用程序

#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;
}

驱动程序

#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");