驱动day4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，不添加ioctl第三个参数 
#define LED_ON _IO('l',1)
#define  LED_OFF _IO('l',0)

#endif 

mychrdev.c

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

struct cdev *cdev;
struct class *cls;
struct device *dev;
unsigned int major = 500;
unsigned int minor = 0; // 次设备号的起始值
dev_t devno;
char kbuf[128] = {0};
module_param(major,uint,0664);

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)
{
    printk("%s:%s:%d\n", __FILE__, __func__, __LINE__);
    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;
    return 0;
}

ssize_t mycdev_read(struct file *file, char *ubuf, size_t size, loff_t *lof)
{
    printk("%s:%s:%d\n", __FILE__, __func__, __LINE__);
    if (size > sizeof(kbuf)) // 用户的需求内核满足不了
    {
        size = sizeof(kbuf);
    }
    long ret;
    ret = copy_to_user(ubuf, kbuf, size);
    if (ret)
    {
        printk("copy_to_user filed\n");
        return -EIO;
    }
    return 0;
}

ssize_t mycdev_write(struct file *file, const char *ubuf, size_t size, loff_t *lof)
{
    printk("%s:%s:%d\n", __FILE__, __func__, __LINE__);
    if (size > sizeof(kbuf)) // 用户的需求内核满足不了
    {
        size = sizeof(kbuf);
    }
    long ret;
    ret = copy_from_user(kbuf, ubuf, size);
    if (ret)
    {
        printk("copy_from_user filed\n");
        return -EIO;
    }
    return 0;
}

long mycdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg){
    int min = (int)file->private_data;
    switch(min){
        case 0://led1
            switch (cmd)
            {
            case LED_ON:
                vir_led1->ODR |= 1 << 10;
                break;
            case LED_OFF:
                vir_led1->ODR &= (~(1 << 10));
                break;
            }
            break;
        case 1:
            switch (cmd)
            {
            case LED_ON:
                vir_led2->ODR |= 1 << 10;
                break;
            case LED_OFF:
                vir_led2->ODR &= (~(1 << 10));
                break;
            }
            break;
        case 2:
            switch (cmd)
            {
            case LED_ON:
                vir_led3->ODR |= 1 << 10;
                break;
            case LED_OFF:
                vir_led3->ODR &= (~(1 << 10));
                break;
            }
            break;    
    }
    return 0;
}

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

// 定义一个操作方法结构体变量并且初始化
struct file_operations fops = {
    .open = mycdev_open,
    .release = mycdev_close,
    .read = mycdev_read,
    .write = mycdev_write,
    .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_led1->MODER |= (1 << 16);
    vir_led1->ODR &= (~(1 << 8));
    printk("寄存器初始化成功\n");
 
    return 0;
}

static int __init mycdev_init(void)
{
    int ret;
    // 1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("字符设备驱动对象申请空间成功\n");

    // 2初始化对象 c_dev_init
    cdev_init(cdev, &fops);

    // 3申请设备号
    if (major == 0)
    { // 动态申请
        ret = alloc_chrdev_region(&devno, minor, 3, "myled");
        if (ret)
        {
            printk("动态申请设备号失败\n");
            goto OUT2;
        }
        // 统一后面的操作
        major = MAJOR(devno);
        minor = MINOR(devno);
    }
    else
    { // 静态申请
        ret = register_chrdev_region(MKDEV(major, minor), 3, "myled");
        if (ret)
        {
            printk("静态指定设备号失败\n");
            goto OUT2;
        }
    }
    printk("设备号申请成功\n");

    // 4注册字符设备驱动对象
    ret = cdev_add(cdev, MKDEV(major, minor), 3);
    if (ret)
    {
        printk("注册设备驱动对象失败\n");
        goto OUT3;
    }
    printk("注册设备驱动对象成功\n");

    // 5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");

    // 6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, "myled%d", i);
        if (IS_ERR(dev))
        {
            printk("向上提交设备节点失败\n");
            ret = -PTR_ERR(dev);
            goto OUT5;
        }
    }
    printk("向上提交设备信息成功\n");

    return 0;

OUT5:
    // 将之前提交成功的设备信息销毁
    for (--i;i>=0;i--)
    {
        device_destroy(cls, MKDEV(major, i));
    }
    class_destroy(cls);
OUT4:
    cdev_del(cdev);
OUT3:
    unregister_chrdev_region(MKDEV(major, minor), 3);
OUT2:
     kfree(cdev);
OUT1:
    return ret;
}

static void __exit mycdev_exit(void)
{
    // 1销毁设备节点信息
    int i;
    for (i=0;i<3;i++)
    {
        device_destroy(cls, MKDEV(major, i));
    }

    // 2销毁目录信息
    class_destroy(cls);

    // 3注销驱动对象 cdev_del
    cdev_del(cdev);

    // 4释放设备号
    unregister_chrdev_region(MKDEV(major, minor), 3);

    // 5释放空间
    kfree(cdev);
}

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

app.c

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

int main(int argc, char const *argv[])
{
    int a;
    char buf[128]={0};
    int fd=open("/dev/myled0",O_RDWR);
    if(fd<0)
    {
        printf("打开设备文件失败\n");
        exit(-1);
    }
    while(1)
    {
        //从终端读取
        printf("请输入对LED灯的控制:1(开灯) 0(关灯)");
        scanf("%d",&a);
        switch(a){
            case 1:
                ioctl(fd,LED_ON);//开灯
                break;
            case 0:
                ioctl(fd,LED_OFF);//关灯
                break;
        }
    }
    
    close(fd);

    return 0;
}