应用程序：

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

int main(int argc, char const *argv[])
{
    /* code */
    char buf[128]={0};
    int fd=open("/dev/demo0", O_RDWR);
    if(fd<0){
        printf("打开设备文件失败\n");
        exit(-1);
    }
    printf("成功打开设备文件\n");
    while(1){
        printf("请输入要实现的逻辑》\n");
        printf("11:LED1亮\n");
        printf("10:LED1灭\n");
        printf("21:LED2亮\n");
        printf("20:LED2灭\n");
        printf("31:LED3亮\n");
        printf("30:LED3灭\n");
        fgets(buf,sizeof(buf),stdin);
        buf[strlen(buf)-1]='\0';
        write(fd,buf,sizeof(buf));
    }
    close(fd);
    return 0;
}

驱动程序：

        头文件

#ifndef __HEAD_H__
#define __HEAD_H__

typedef struct{
    volatile unsigned int MODER;
    volatile unsigned int OTYPER;
    volatile unsigned int OSPEEDR;
    volatile unsigned int PUPDR;
    volatile unsigned int IDR;
    volatile unsigned int ODR;
}gpio_t;
#define GPIOE 0x50006000
#define GPIOF 0x50007000
#define PHY_LED_RCC 0x50000A28
#endif

        驱动文件

#include <linux/init.h>
#include <linux/module.h>
#include <linux/fs.h>
#include <linux/uaccess.h>
#include <linux/io.h>
#include <linux/device.h>
#include "head.h"

// extern int add(int i,int j);

int major;
char kbuf[128]={0};
struct class *cls;
struct device *dev;
//定义指针接收映射成功的虚拟内存首地址
gpio_t *vir_gpioe;
gpio_t *vir_gpiof;
unsigned int *vir_rcc;

// 封装操作方法
int mycdev_open(struct inode *inode, struct file *file)
{
    printk("%s:%s:%d\n", __FILE__, __func__, __LINE__);
    return 0;
}
ssize_t mycdev_read(struct file *file, char *ubuf, size_t size, loff_t *lof)
{
    int ret;
    ret=copy_to_user(ubuf, kbuf, size);
    if(ret){
        printk("copy_to_user failed\n");
        return ret;
    }

    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)
{
    int ret;
    ret=copy_from_user(kbuf, ubuf, size);
    if(ret){
        printk("copy_from_user failed\n");
        return ret;
    }
    //开关灯逻辑
    //LED1
    if(kbuf[0]=='1'&&kbuf[1]=='1'){
        printk("开灯\n");
        vir_gpioe->ODR|=(0x1<<10);
    }else if(kbuf[0]=='1'&&kbuf[1]=='0'){
        printk("关灯\n");
        vir_gpioe->ODR&=(~(0x1<<10));
    }
    //LED2
    if(kbuf[0]=='2'&&kbuf[1]=='1'){
        printk("开灯\n");
        vir_gpiof->ODR|=(0x1<<10);
    }else if(kbuf[0]=='2'&&kbuf[1]=='0'){
        printk("关灯\n");
        vir_gpiof->ODR&=(~(0x1<<10));
    }
    //LED3
    if(kbuf[0]=='3'&&kbuf[1]=='1'){
        printk("开灯\n");
        vir_gpioe->ODR|=(0x1<<8);
    }else if(kbuf[0]=='3'&&kbuf[1]=='0'){
        printk("关灯\n");
        vir_gpioe->ODR&=(~(0x1<<8));
    }
    printk("%s:%s:%d\n", __FILE__, __func__, __LINE__);
    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遍历并且初始化
struct file_operations fops = {
    .open = mycdev_open,
    .read = mycdev_read,
    .write = mycdev_write,
    .release = mycdev_close,
};
static int __init mycdev_init(void)
{
    // 注册字符设备驱动
    major = register_chrdev(0, "demo0", &fops);
    if (major < 0)
    {
        printk("字符设备驱动组测失败\n");
        return major;
    }
    printk("字符设备驱动注册成功major=%d\n", major);
    //物理内存映射首地址
    vir_gpioe=ioremap(GPIOE,sizeof(gpio_t));
    if(vir_gpioe==NULL){
        printk("物理内存映射失败\n");
        return -EFAULT;
    }
    vir_gpiof=ioremap(GPIOF,sizeof(gpio_t));
    if(vir_gpiof==NULL){
        printk("物理内存映射失败\n");
        return -EFAULT;
    }   
    vir_rcc=ioremap(PHY_LED_RCC,4);
    if(vir_rcc==NULL){
        printk("物理内存映射失败%d\n",__LINE__);
        return -EFAULT;
    }
    printk("物理内存映射成功\n");
    //硬件寄存器初始化
    //gpioe、gpiof寄存器组使能
    (*vir_rcc)|=(0x3<<4);
    //LED1设置---PE10
    vir_gpioe->MODER&=(~(0x3<<20));
    vir_gpioe->MODER|=(0x1<<20);
    vir_gpioe->ODR&=(~(0x1<<10));
    //LED2设置---PF10
    vir_gpiof->MODER&=(~(0x3<<20));
    vir_gpiof->MODER|=(0x1<<20);
    vir_gpiof->ODR&=(~(0x1<<10));
    //LED3设置---PE8
    vir_gpioe->MODER&=(~(0x3<<16));
    vir_gpioe->MODER|=(0x1<<16);
    vir_gpioe->ODR&=(~(0x1<<8));

    //创建设备节点文件
    //向上提交目录信息
    cls=class_create(THIS_MODULE,"demo0");
    if(IS_ERR(cls)){
        printk("向上提交目录信息失败\n");
        return -PTR_ERR(cls);
    }
    printk("向上提交目录信息成功");
    //向上提交设备信息
    int i;
    for(i=0;i<3;i++){
        dev=device_create(cls,NULL,MKDEV(major,i),NULL,"demo%d",i);
        if(IS_ERR(dev)){
            printk("向上提交设备信息失败\n");
            return -PTR_ERR(dev);
        }     
    }
    printk("向上提交设备信息成功\n");
    return 0;
}

static void __exit mycdev_exit(void)
{
    //取消物理内存的映射
    iounmap(vir_gpioe);
    iounmap(vir_gpiof);
    iounmap(vir_rcc);

    //销毁设备信息
    int i;
    for(i=0;i<3;i++){
        device_destroy(cls,MKDEV(major,i));
    }
    //销毁目录信息
    class_destroy(cls);

    // 字符设备驱动注销
    unregister_chrdev(major, "demo0");
}

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