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

head.h

#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

//构建LED开关的功能码，添加ioctl第三个参数int 
#define LED_ON  _IOW('l',1,int)
#define LED_OFF _IOW('l',0,int)

#endif 

cdev.c

#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;
// 封装操作方法
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;
}

int mycdev_close(struct inode *inode, struct file *file)
{
    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:
					vir_led1->ODR |= 1 << 10;
                    //开灯
                    break;
                case LED_OFF:
					vir_led1->ODR &= (~(1 << 10));
                    //关灯
                    break;                                
            }
            break;
    case 1://控制LED2
            switch(cmd)
            {
                case LED_ON:
					vir_led2->ODR |= 1 << 10;
                    //开灯
                    break;
                case LED_OFF:
					vir_led2->ODR &= (~(1 << 10));
                    //关灯
                    break;                                
            }
            break;
       case 2://控制LED3
            switch(cmd)
            {
                case LED_ON:
					vir_led3->ODR |= 1 << 8;
                    //开灯
                    break;
                case LED_OFF:
					vir_led3->ODR &= (~(1 << 8));
                    //关灯
                    break;                                
            }
            break;
    }
    return 0;
}

// 定义一个操作方法结构体对象并且初始化
struct file_operations fops = {
    .open=mycdev_open,
    .unlocked_ioctl = mycdev_ioctl,
    .release=mycdev_close,
};

int all_led_init(void)
{
 
	//进行相关寄存器的内存映射
	//GPIOE组寄存器内存映射
	vir_led1 = ioremap(PHY_LED1_ADDR, sizeof(gpio_t));
	if (vir_led1 == NULL)
	{
		printk("物理内存映射失败%d\n", __LINE__);
		return -EFAULT;
	}
 
	vir_led2 = ioremap(PHY_LED2_ADDR, sizeof(gpio_t));
	if (vir_led2 == NULL)
	{
		printk("物理内存映射失败%d\n", __LINE__);
		return -EFAULT;
	}
 
	vir_led3 = vir_led1;
 
	vir_rcc = ioremap(PHY_RCC_ADDR, 4);
	if (vir_rcc == NULL)
	{
		printk("物理内存映射失败%d\n", __LINE__);
		return -EFAULT;
	}
 
	printk("寄存器内存映射成功\n");
 
	//硬件寄存器的初始化
	//RCC使能
	(*vir_rcc) |= (0x3 << 4); //GPIOE(PE10 PE8)使能 GPIOF(PF10)使能
 
	//设置PE10为输出模式 --> LED1
	(vir_led1->MODER) &= (~(0x3 << 20));
	(vir_led1->MODER) |= (0x1 << 20);
	//设置PF10为输出模式 --> LED2
	(vir_led2->MODER) &= (~(0x3 << 20));
	(vir_led2->MODER) |= (0x1 << 20);
	//设置PE8为输出模式 --> LED3
	(vir_led3->MODER) &= (~(0x3 << 16));
	(vir_led3->MODER) |= (0x1 << 16);
 
	//默认LED1关灯
	(vir_led1->ODR) &= (~(0x1 << 10));
	//默认LED2关灯
	(vir_led2->ODR) &= (~(0x1 << 10));
	//默认LED1关灯
	(vir_led3->ODR) &= (~(0x1 << 8));
	printk("寄存器初始化成功\n");
 
	return 0;
}

static int __init mycdev_init(void)
{
	int ret;
	//为字符设备驱动对象申请空间
	cdev = cdev_alloc();
	if(cdev==NULL)
	{
		printk("字符设备驱动对象申请空间失败\n");
		ret=-EFAULT;
		goto out1;
	}
	printk("申请对象空间成功\n");
	//初始化字符设备驱动对象
	cdev_init(cdev,&fops);
	//申请设备号
	if(major>0)
	{
		ret=register_chrdev_region(MKDEV(major,minor),3,"myled");
		if(ret)
		{
			printk("静态申请设备号失败\n");
			goto out2;
		}
	}
	else if(major==0)//动态申请设备号
	{
		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);//获取主设备号
		minor=MINOR(devno);//获取此设备号
	
	}
	printk("申请设备号成功\n");
	//注册字符设备驱动对象
	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("注册字符设备驱动对象成功\n");
	//向上提交目录信息
	all_led_init();
	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");

test.c

#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include "head.h"
 
int main()
{
	int a, b;
	char buf[128] = "";
	int fd;
	while (1)
	{
		printf("请输入要控制的灯：0(LED1) 1(LED2) 2(LED3) >");
		scanf("%d", &a);
		switch (a)
		{
		case 0:
			fd = open("/dev/myled0", O_RDWR);
			if (fd < 0)
			{
				printf("设备文件打开失败\n");
				exit(-1);
			}
			printf("请输入对LED的控制命令:0(关灯) 1(开灯)  >");
			scanf("%d", &b);
			switch (b)
			{
			case 0:
				ioctl(fd, LED_OFF); //关灯
				break;
			case 1:
				ioctl(fd, LED_ON); //开灯
				break;
			}
			break;
 
		case 1:
			fd = open("/dev/myled1", O_RDWR);
			if (fd < 0)
			{
				printf("设备文件打开失败\n");
				exit(-1);
			}
			printf("请输入对LED的控制命令：0(关灯) 1(开灯)  >");
			scanf("%d", &b);
			switch (b)
			{
			case 0:
				ioctl(fd, LED_OFF); //关灯
				break;
			case 1:
				ioctl(fd, LED_ON); //开灯
				break;
			}
			break;
 
		case 2:
			fd = open("/dev/myled2", O_RDWR);
			if (fd < 0)
			{
				printf("设备文件打开失败\n");
				exit(-1);
			}
			printf("请输入对LED的控制命令：0(关灯) 1(开灯)  >");
			scanf("%d", &b);
			switch (b)
			{
			case 0:
				ioctl(fd, LED_OFF); //关灯
				break;
			case 1:
				ioctl(fd, LED_ON); //开灯
				break;
			}
			break;
		}
	}
 
	close(fd);
 
	return 0;
}