在串口工具进行输入：   
    echo 1 > /dev/myled0 ---->led1灯点亮
    echo 0 > /dev/myled0 ---->led1灯熄灭
    echo 1 > /dev/myled1 ---->led2灯点亮
    echo 0 > /dev/myled1 ---->led2灯熄灭
    echo 1 > /dev/myled2 ---->led3灯点亮
    echo 0 > /dev/myled2 ---->led3灯熄灭
要求：
    1）分部实现注册字符设备驱动
    2）自动创建设备节点
    3）通过结构体对led灯地址进行映射
    4）次设备号完成私有数据传参

#ifndef __LED_H__
#define __LED_H__
#define CNAME "myled"
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 RCC (0x50000A28)
 
#endif

#include <linux/init.h>
#include <linux/module.h>
#include <linux/cdev.h>
#include <linux/fs.h>
#include <linux/device.h> 
#include <linux/slab.h>
#include <linux/uaccess.h>
#include <linux/io.h>
#include "led.h"
 
struct cdev *cdev;
struct class *cls;
struct device *dev;
#if 1
unsigned int major=0;
#else
unsigned int major=500;
#endif
int minor = 0;
const int count = 3;
volatile unsigned int* vir_rcc;
volatile gpio_t* vir_gpioe;
volatile gpio_t* vir_gpiof;
 
int mycdev_open(struct inode *inode,struct file *file)
{
    file->private_data = (void*)(MINOR(inode->i_rdev));
    printk("%s:%s:%d\n",__FILE__,__func__,__LINE__);
    return 0;
}
ssize_t mycdev_read(struct file *file,char __user *ubuf,size_t size,loff_t *loffs)
{
    printk("%s:%s:%d\n",__FILE__,__func__,__LINE__);
    return 0;
}
ssize_t mycdev_write(struct file *file,const char __user *ubuf,size_t size,loff_t *loffs)
{
    char kbuf;
    int ret;
    int a;
    a = (int)file->private_data;
    
    ret = copy_from_user(&kbuf,ubuf,sizeof(char));
    if(ret)
    {
        printk("copy from user is error...\n");
        return -EIO;
    }
    if(kbuf=='1')
    {
        switch (a)
        {
        case 0:
            vir_gpioe->ODR |= (0x1<<10); 
            break;
        case 1:
            vir_gpiof->ODR |= (0x1<<10);
            break;
        case 2:
            vir_gpioe->ODR |= (0x1<<8);
            break;
        default:
            break;
        }
    }   
    else
    {
        switch (a)
        {
        case 0:
            vir_gpioe->ODR &= (~(0x1<<10)); 
            break;
        case 1:
            vir_gpiof->ODR &= (~(0x1<<10));
            break;
        case 2:
            vir_gpioe->ODR &= (~(0x1<<8));
            break;
        default:
            break;
        }
    }
    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;
}
const struct file_operations fops = {
    .open=mycdev_open,
    .write=mycdev_write,
    .read=mycdev_read,
    .release=mycdev_close,
};
static int __init mycdev_init(void)
{
    int i;
    int ret;
    dev_t devt;
    //分步实现字符设备驱动
    cdev = cdev_alloc();
    if(NULL==cdev)
    {
        printk("cdev alloc is error...\n");
        goto ERR1;
    }
    cdev_init(cdev,&fops);
    if(major>0)
    {
        ret = register_chrdev_region(MKDEV(major,minor),count,CNAME);
        if(ret)
        {
            printk("register chrdev region is error...\n");
            goto ERR2;
        }
    }
    else
    {
        ret = alloc_chrdev_region(&devt,0,count,CNAME);
        if(ret)
        {
            printk("alloc chrdev region is error\n");
            goto ERR2;
        }
        major=MAJOR(devt);
        minor=MINOR(devt);
    }
    ret = cdev_add(cdev,MKDEV(major,minor),count);
    if(ret)
    {
        printk("cdev add is error...\n");
        goto ERR3;
    }
    //自动创建设备节点
    cls = class_create(THIS_MODULE,CNAME);
    if(IS_ERR(cls))
    {
        printk("class create is error...\n");
        ret = PTR_ERR(cls);
        goto ERR4;
    }
    for(i=0;i<count;i++)
    {
        dev = device_create(cls,NULL,MKDEV(major,i),NULL,"myled%d",i);
        if(IS_ERR(dev))
        {
            printk("device create is error...\n");
            goto ERR5;
        }
    }
    //对LED灯地址进行映射
    vir_rcc = ioremap(RCC,4);
    if(NULL==vir_rcc)
    {
        printk("rcc ioremap is error\n");
        return -ENOMEM;
    }
    vir_gpioe = ioremap(GPIOE,sizeof(GPIOE));
    if(NULL==vir_gpioe)
    {
        printk("gpioe ioremap is error\n");
        return -ENOMEM;
    }
    vir_gpiof = ioremap(GPIOF,sizeof(GPIOF));
    if(NULL==vir_gpiof)
    {
        printk("gpiof ioremap is error\n");
        return -ENOMEM;
    }
    *vir_rcc |= (0x3<<4);
    vir_gpioe->MODER &= (~(0x3<<20));
    vir_gpioe->MODER |= (0x1<<20);
    vir_gpiof->MODER &= (~(0x3<<20));
    vir_gpiof->MODER |= (0x1<<20);
    vir_gpioe->MODER &= (~(0x3<<16));
    vir_gpioe->MODER |= (0x1<<16);
    return 0;
 
ERR5:
    for(--i;i>=0;i--)
    {
        device_destroy(cls,MKDEV(major,i));
    }
    class_destroy(cls);   
ERR4:
    cdev_del(cdev);
ERR3:
    unregister_chrdev_region(MKDEV(major,minor),count);
ERR2:
    kfree(cdev);
ERR1:
    return -EIO;
}
static void __exit mycdev_exit(void)
{
    int i;
    for(i=0;i<count;i++)
    {
        device_destroy(cls,MKDEV(major,i));
    }
    class_destroy(cls);
    cdev_del(cdev);
    unregister_chrdev_region(MKDEV(major,minor),count);
    kfree(cdev);
    //取消映射
    iounmap(vir_rcc);
    iounmap(vir_gpioe);
    iounmap(vir_gpiof);
}
module_init(mycdev_init);
module_exit(mycdev_exit);
MODULE_LICENSE("GPL");

现象：