通过字符设备驱动分步注册方式编写LED驱动，完成设备文件和设备的绑定，发布CSDN

 头文件

#ifndef __HEAD_H__
#define __HEAD_H__ 
typedef struct{
    unsigned int MODER;
    unsigned int OTYPER;
    unsigned int OSPEEDR;
    unsigned int PUPDR;
    unsigned int IDR;
    unsigned int ODR;
}gpio_t;
#define PHY_LED1_ADDR 0X50006000
#define PHY_LED2_ADDR    0X50007000
#define PHY_LED3_ADDR 0X50006000
#define PHY_RCC_ADDR    0X50000A28


#define LED_ON _IO('l',1)
#define LED_OFF _IO('l',0)



#endif 

驱动文件

#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include "head.h"

struct cdev *cdev;
char kbuf[128] = {0};
unsigned int major = 0;
unsigned int minor = 0;
dev_t devno;
module_param(major,uint,0664);  //方便在命令行传递major的值
struct class *cls;
struct device *dev;
gpio_t *vir_led1;
gpio_t *vir_led2;
gpio_t *vir_led3;
unsigned int *vir_rcc;


int mycdev_open(struct inode *inode, struct file *file)
{
    int min = MINOR(inode->i_rdev);
    file->private_data = (void *)min;
    printk("%s:%s:%d\n",__FILE__,__func__,__LINE__);
    return 0;
}


long mycdev_ioctl(struct file *file, unsigned int cmd,unsigned long arg)
{
    int min=(int)file->private_data;
    switch (min)
    {
    case 0: // 控制LED1
        switch (cmd)
        {
        case LED_ON: 
            //开灯
            vir_led1->ODR |= (0x1 << 10);
            break;
        case LED_OFF:
            //关灯
            vir_led1->ODR &= (~(0x1 << 10));
            break;
        }
        break;
    case 1: // 控制LED2
        switch (cmd)
        {
        case LED_ON: 
            //开灯
            vir_led2->ODR |= (0x1 << 10);
            break;
        case LED_OFF:
            //关灯
            vir_led2->ODR &= (~(0x1 << 10));
            break;
        }
        break;
    case 2: // 控制LED3
        switch (cmd)
        {
        case LED_ON: 
            //开灯
            vir_led3->ODR |= (0x1 << 8);
            break;
        case LED_OFF:
            //关灯
            vir_led3->ODR |= (~(0x1 << 8));
            break;
        }
        break;
    }
    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,
    .unlocked_ioctl = mycdev_ioctl,
    .release=mycdev_close,
};

int all_led_init(void)
{
    //寄存器地址的映射
    vir_led1=ioremap(PHY_LED1_ADDR,sizeof(gpio_t));
    if(vir_led1==NULL)
    {
        printk("ioremap filed:%d\n",__LINE__);
        return -ENOMEM;
    }
     vir_led2=ioremap(PHY_LED2_ADDR,sizeof(gpio_t));
    if(vir_led2==NULL)
    {
        printk("ioremap filed:%d\n",__LINE__);
        return -ENOMEM;
    }
     vir_led3=vir_led1;
    vir_rcc=ioremap(PHY_RCC_ADDR,4);
    if(vir_rcc==NULL)
    {
        printk("ioremap filed:%d\n",__LINE__);
        return -ENOMEM;
    }
    printk("物理地址映射成功\n");
    //寄存器的初始化
    //rcc
    (*vir_rcc) |= (0X3<<4);
    //led1
    vir_led1->MODER &= (~(3<<20));
    vir_led1->MODER |= (1<<20);
    vir_led1->ODR &= (~(1<<10));
    //led2
    vir_led2->MODER &= (~(3<<20));
    vir_led2->MODER |= (1<<20);
    vir_led2->ODR &= (~(1<<10));
    //led3
    vir_led3->MODER &= (~(3<<16));
    vir_led3->MODER |= (1<<16);
    vir_led3->ODR &= (~(1<<8));
    printk("寄存器初始化成功\n");

    return 0;
}

static int __init mycdev_init(void)
{
    all_led_init();
    int ret;
    //申请字符设备对象空间
    cdev = cdev_alloc();
    if (NULL == cdev)
    {
        printk("申请字符设备空间失败\n");
        ret = -EFAULT;
        goto out1;
    }
    printk("申请对象空间成功\n");
    //字符设备驱动对象初始化
    cdev_init(cdev,&fops);
    //申请设备号
    if(major > 0)
    ret = register_chrdev_region(MKDEV(major,minor),3,"myled");
    if(ret)
    {
        printk("静态设备申请设备号失败\n");
        goto out2;
    }
    else if(0 == major)
    {
       ret = alloc_chrdev_region(&devno,minor,3,"myled");
    if(ret)
    {
        printk("动态申请设备号失败\n");
        goto out2;
    } 
    major = MAJOR(devno);
    minor = MINOR(devno);
    }
    printk("申请设备号成功\n");

    //注册驱动
    ret = cdev_add(cdev,MKDEV(major,minor),3);
    if(ret)
    {
        printk("注册字符设备驱动对象失败\n");
        goto out3;
    }
    printk("注册支付设备驱动对象成功\n");
    //向上提交目录信息
    cls = class_create(THIS_MODULE,"myled");
if(IS_ERR(cls))
    {
        printk("向上提交目录失败\n");
        ret=-PTR_ERR(cls);
        goto out4;
    }
    printk("向上提交目录成功\n");
    //向上提交设备节点信息
    int i;
    for(i=0;i<3;i++)
    {
        dev=device_create(cls,NULL,MKDEV(major,i),NULL,"myled%d",i);
        if(IS_ERR(dev))
        {
            printk("向上提交设备节点信息失败\n");
            ret=-PTR_ERR(dev);
            goto out5;
        }
    }
    printk("向上提交设备信息成功\n");
    return 0;
out5:
    //释放前一次提交成功的设备信息
    for(--i;i>=0;i--)
    {
        device_destroy(cls,MKDEV(major,i));
    }
    class_destroy(cls);//释放目录
out4:
    cdev_del(cdev);
out3:
    unregister_chrdev_region(MKDEV(major,minor),3);
out2:
    kfree(cdev);
out1:
    return ret;
}
static void __exit mycdev_exit(void)
{
    //释放节点信息
    int i;
    for(i=0;i<3;i++)
    {
        device_destroy(cls,MKDEV(major,i));
    }
    //销毁目录
    class_destroy(cls);
    //注销驱动对象
    cdev_del(cdev);
    //释放设备号
    unregister_chrdev_region(MKDEV(major,minor),3);
    //释放对象空间
    kfree(cdev);

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

应用程序文件

#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include "head.h"

int main(int argc, char const *argv[])
{
    int a,b,fd;
    char buf[128] = {0};
    while (1)
    {
        printf("请输入要控制的灯:1(LED1) 2(LED2) 3(LED3)>");
        scanf("%d", &a);
        switch (a)
        {
        case 1:
            fd = open("/dev/myled0", O_RDWR);
            if (fd < 0)
            {
                printf("打开设备文件失败\n");
                exit(-1);
            }
            break;
        case 2:
            fd = open("/dev/myled1", O_RDWR);
            if (fd < 0)
            {
                printf("打开设备文件失败\n");
                exit(-1);
            }
            break;
        case 3:
            fd = open("/dev/myled2", O_RDWR);
            if (fd < 0)
            {
                printf("打开设备文件失败\n");
                exit(-1);
            }
            break; 
        }
        printf("请输入对LED灯的控制:1(开灯)0(关灯)>");
        scanf("%d",&b); 
        switch (b)
            {
            case 1:
                ioctl(fd,LED_ON); // 开灯
                break;
            case 0:
                ioctl(fd,LED_OFF); // 关灯
                break;
            }         
    }

    close(fd);
 

    return 0;
}