代码：

//驱动程序
#include<linux/init.h>
#include<linux/module.h>
#include<linux/of.h>
#include<linux/of_gpio.h>
#include<linux/gpio.h>
#include<linux/timer.h>

struct device_node *dnode;
//unsigned int gpiono;
char kbuf[128] = {0};
//定义定时器对象
struct timer_list mytimer;
struct gpio_desc *gpiono;


int major;
struct class *cls;
struct device *dev;
int mycdev_open(struct inode *inode, struct file *file)
{

    printk("%s:%s:%d\n", __FILE__, __func__, __LINE__);
    return 0;
}

ssize_t mycdev_write(struct file *file, const char *ubuf, size_t size, loff_t *lof)
{
    printk("%s:%s:%d\n", __FILE__, __func__, __LINE__);
    int ret=copy_from_user(kbuf,ubuf,size);

    if(ret)
    {
        printk("copy_from_user filed\n");
        return -EIO;
    }
    printk("%d\n",kbuf[0] - 48);
    gpiod_set_value(gpiono,kbuf[0] - 48);
    return 0;
}
int mycdev_close(struct inode *inode, struct file *file)
{

    printk("%s:%s:%d\n", __FILE__, __func__, __LINE__);
    return 0;
}

// 定义操作方法结构体变量并赋值
struct file_operations fops = {

    .open = mycdev_open,
    .write = mycdev_write,
    .release = mycdev_close,
};

void handler(struct timer_list *timer)
{
    printk("hello world\n");
    mod_timer(timer,jiffies + 5 * HZ);
}


static int __init mycdev_init(void)
{
    dnode = of_find_node_by_path("/myled");

    if(NULL == dnode)
    {
        printk("解析设备节点信息失败\n");
        return  -ENXIO;
    }
    //获取LED1 GPIO编号
    gpiono = gpiod_get_from_of_node(dnode,"led1-gpio",0,GPIOD_OUT_LOW,NULL);
    if(IS_ERR(gpiono))
    {
        printk("申请gpio信息失败\n");
        return -PTR_ERR(gpiono);
    }
    //初始化定时器对象
    timer_setup(&mytimer,handler,0);
    mytimer.expires = jiffies + HZ;
    //注册定时器
    add_timer(&mytimer);
    
     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++)
    {
        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");



    return 0;
}

static void __exit mycdev_exit(void)
{
    del_timer(&mytimer);
    
    //gpio_free(gpiono);
    
    gpiod_put(gpiono);

    // 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");
}


module_init(mycdev_init);
module_exit(mycdev_exit);
MODULE_LICENSE("GPL");

//应用程序
#include<stdio.h>
#include<stdlib.h>
#include<sys/ioctl.h>
#include<string.h>
#include<sys/stat.h>
#include<sys/types.h>
#include<unistd.h>
#include<fcntl.h>
int main(int argc, char const *argv[])
{
    char buf[128] = {0};
    int fd = open("/dev/myled0",O_RDWR);
    while(1)
    {
        printf("请输入>>>");
        scanf("%s",buf);
        write(fd,buf,1);
    }
    
    return 0;
}

 实验现象：