基于platform驱动模型实现LED灯点亮

驱动代码

#include <linux/init.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/mod_devicetable.h>
#include <linux/fs.h>
#include <linux/of.h>
#include <linux/of_gpio.h>
#include <linux/gpio.h>

struct resource *res;
unsigned int irqno;
struct cdev *cdev;
int major;
struct class *cls;
struct device *dev;
struct gpio_desc *gpiono1;
struct gpio_desc *gpiono2;
struct gpio_desc *gpiono3;

int mycdev_open(struct inode *inode, struct file *file)
{
    return 0;
}
int mycdev_release(struct inode *inode, struct file *file)
{
    return 0;
}
long mycdev__ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
    switch (cmd)
    {
    case _IOW('l', 1, int): // 开灯
        switch (arg)
        {
        case 1: // LED1
            gpiod_set_value(gpiono1,1);
            break;
        case 2:
            gpiod_set_value(gpiono2,1);
            break;
        case 3:
            gpiod_set_value(gpiono3,1);
            break;
        }
        break;
    case _IOW('l', 0, int): // 关灯
        switch (arg)
        {
        case 1: // LED1
            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;
    return 0;
}

// 操作方法结构体指针
struct file_operations fops = {
    .open = mycdev_open,
    .unlocked_ioctl = mycdev__ioctl,
    .release = mycdev_release};

int pdrv_probe(struct platform_device *pdev)
{
    major = register_chrdev(0, "mychrdev", &fops);
    if (major < 0)
    {
        printk("字符设备驱动注册失败\n");
        return 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++)
    {
        dev = 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");
    gpiono1 = gpiod_get_from_of_node(pdev->dev.of_node, "led1-gpio", 0, GPIOD_OUT_LOW, NULL);
    if (IS_ERR(gpiono1))
    {
        printk("解析GPIO信息失败\n");
        return -PTR_ERR(gpiono1);
    }
    gpiono2 = gpiod_get_from_of_node(pdev->dev.of_node, "led2-gpio", 0, GPIOD_OUT_LOW, NULL);
    if (IS_ERR(gpiono2))
    {
        printk("解析GPIO信息失败\n");
        return -PTR_ERR(gpiono2);
    }
    gpiono3 = gpiod_get_from_of_node(pdev->dev.of_node, "led3-gpio", 0, GPIOD_OUT_LOW, NULL);
    if (IS_ERR(gpiono3))
    {
        printk("解析GPIO信息失败\n");
        return -PTR_ERR(gpiono3);
    }
    return 0;
}
int pdrv_remove(struct platform_device *pdev)
{
    // 销毁设备节点信息
    int i;
    for (i = 0; i < 3; i++)
    {
        device_destroy(cls, MKDEV(major, i));
    }

    // 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;
}

// 构建设备树匹配表
struct of_device_id oftable[] = {
    {.compatible = "hqyj,myled"},
    {},
};
// 1.分配驱动信息对象
struct platform_driver pdrv = {
    .probe = pdrv_probe,
    .remove = pdrv_remove,
    .driver = {
        .name = "ccc",
        .of_match_table = oftable,
    },
};

module_platform_driver(pdrv);
MODULE_LICENSE("GPL");

应用程序

#include<stdlib.h>
#include<stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/ioctl.h>
#include <fcntl.h>
#include<unistd.h>
#include<string.h>


int main(int argc, char const *argv[])
{
    char buf[128]={0};
    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 ");
        printf("0(关灯) 1(开灯)\n");
        printf("请输入>");
        scanf("%d",&a);
        printf("请选择要控制的灯：1（LED1）2(LED2) 3(LED3)\n");
        printf("请输入>");
        scanf("%d",&b);
        switch(a)
        {
            case 1:
                ioctl(fd,_IOW('l', 1,int),b);
                break;
            case 0:
                ioctl(fd,_IOW('l', 0,int),b);
                break;
        }
    }

    
    close(fd);

    return 0;
}