作业：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

驱动程序：myled.c

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

char kbuf[128] = "";
struct cdev *cdev;
unsigned int major = 0;
unsigned int minor = 0;
dev_t devno;
module_param(major, uint, 0664); //方便命令行传递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); //根据打开的文件对应的设备号获取次设备号
    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; //传递次设备号

    //设备文件和设备的绑定，根据次设备号决定打开的设备文件，根据打开的设备文件，控制相应的设备
    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;
}
ssize_t mycdev_read(struct file *file, char *ubuf, size_t size, loff_t *lof)
{

    return 0;
}

ssize_t mycdev_write(struct file *file, const char *ubuf, size_t size, loff_t *lof)
{

    return 0;
}

int mycdev_close(struct inode *inode, struct file *file)
{
    printk("%s:%s:%d\n", __FILE__, __func__, __LINE__);
    return 0;
}

//定义一个操作方法结构体对象并初始化
struct file_operations fops = {
    .open = mycdev_open,
    .unlocked_ioctl = mycdev_ioctl,
    .read = mycdev_read,
    .write = mycdev_write,
    .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)
{
    //寄存器内存地址映射以及初始化
	all_led_init();
    
    int ret;
    //1.为字符设备驱动对象申请空间
    cdev = cdev_alloc();
    if (cdev == NULL)
    {
        printk("申请字符设备驱动对象空间失败\n");
        ret = -EFAULT;
        goto out1;
    }
    printk("申请字符设备驱动对象空间成功\n");

    //2.初始化字符设备驱动对象
    cdev_init(cdev, &fops);
    printk("初始化字符设备驱动对象成功\n");

    //3.申请设备号
    if (major > 0) //静态指定设备号
    {
        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); //获取次设备号
    }
    printk("申请设备号成功 major= %d\n", major);

    //4.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
    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:
    //注销字符设备驱动对象
    cdev_del(cdev);
out3:
    //释放设备号
    unregister_chrdev_region(MKDEV(major, minor), 3);
out2:
    //释放设备驱动对象空间
    kfree(cdev);
out1:
    return ret;
}
static void __exit mycdev_exit(void)
{
    int i;
    //释放设备节点信息
    for (i = 0; i < 0; i++)
    {
        device_destroy(cls, MKDEV(major, i));
    }
    //销毁目录
    class_destroy(cls);
    //注销字符设备驱动对象
    cdev_del(cdev);
    //释放设备号
    unregister_chrdev_region(MKDEV(major, minor), 3);
    //释放设备驱动对象空间
    kfree(cdev);
}
module_init(mycdev_init);
module_exit(mycdev_exit);
MODULE_LICENSE("GPL");

应用程序：test.c

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

int main()
{
	int a, b;
	char buf[128] = "";
	int fd1, fd2, fd3;
	while (1)
	{
		printf("请输入要控制的灯：0(LED1) 1(LED2) 2(LED3) >");
		scanf("%d", &a);
		switch (a)
		{
		case 0:
			fd1 = open("/dev/myled0", O_RDWR);
			if (fd1 < 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(fd1, LED_OFF); //关灯
				close(fd1);
				break;
			case 1:
				ioctl(fd1, LED_ON); //开灯
				close(fd1);
				break;
			}
			break;

		case 1:
			fd2 = open("/dev/myled1", O_RDWR);
			if (fd2 < 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(fd2, LED_OFF); //关灯
				close(fd2);
				break;
			case 1:
				ioctl(fd2, LED_ON); //开灯
				close(fd2);
				break;
			}
			break;

		case 2:
			fd3 = open("/dev/myled2", O_RDWR);
			if (fd3 < 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(fd3, LED_OFF); //关灯
				close(fd3);
				break;
			case 1:
				ioctl(fd3, LED_ON); //开灯
				close(fd3);
				break;
			}
			break;
		}
	}

	close(fd1);
	close(fd2);
	close(fd3);

	return 0;
}

头文件：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，不添加ioctl第三个参数
#define LED_ON _IO('l', 1)
#define LED_OFF _IO('l', 0)

#endif