设备文件和设备绑定

实验目的：使用函数让设备文件和设备绑定，完成对LED的简单控制

在test.c中完成硬件逻辑控制

test.c

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

void LED_CONTROL()
{
    int a, b, fd;
    while (1)
    {
        printf("需要控制的灯1(LED1) 2(LED2) 3(LED3) > \n");
        scanf("%d", &a);
        switch (a)
        {
        case 1:
            fd = open("/dev/mycdev0", O_RDWR);
            break;
        case 2:
            fd = open("/dev/mycdev1", O_RDWR);
            break;
        case 3:
            fd = open("/dev/mycdev2", O_RDWR);
            break;
        default:
            break;
        }

        if (fd < 0)
        {
            printf("打开设备失败\n");
            exit(-1);
        }
        printf("实现功能:1(开灯) 0(关灯) > \n");
        scanf("%d", &b);
        switch (b)
        {
        case 1:
            ioctl(fd, LED_ON, &a);
            break;
        case 0:
            ioctl(fd, LED_OFF, &a);
            break;
        default:
            break;
        }
        close(fd);
    }
}

int main(int argc, const char *argv[])
{
    LED_CONTROL();
    return 0;
}

Character_device.c

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

unsigned int major = 0;
unsigned int minor = 0;

gpio_t *vir_led1;
gpio_t *vir_led2;
gpio_t *vir_led3;
unsigned int *vir_rcc;

struct cdev *cdev;
dev_t devnum;

// 向上申请的结构体目录信息
struct class *cls;
// 向上申请的结构体节点信息
struct device *dev;

spinlock_t lock;

// 封装操作方法
int mycdev_open(struct inode *inode, struct file *file)
{
    printk("%s:%s:%d\n", __FILE__, __func__, __LINE__);
    unsigned int minor = MINOR(inode->i_rdev); // 获取操作的文件的次设备号
    file->private_data = (void *)minor;        // 将次设备号当做file对象的私有数据存放
    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__);
    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__);
    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)
{
    unsigned int which = (unsigned int)file->private_data; // 获取open中得到的文件次设备号
    int ret = copy_from_user(&which, (unsigned int *)arg, 4);
    if (ret)
    {
        printk("copy_from_user is ERR\n");
        return ret;
    }
    spin_lock(&lock);
    switch (which)
    {
    case 1:
        switch (cmd)
        {
        case LED_ON:
            vir_led1->ODR |= 0x1 << 10;
            break;
        case LED_OFF:
            vir_led1->ODR &= (~(0x1 << 10));
            break;
        default:
            break;
        }
        break;
    case 2:
        switch (cmd)
        {
        case LED_ON:
            vir_led2->ODR |= 0x1 << 10;
            break;
        case LED_OFF:
            vir_led2->ODR &= (~(0x1 << 10));
            break;
        default:
            break;
        }
        break;
    case 3:
        switch (cmd)
        {
        case LED_ON:
            vir_led3->ODR |= 0x1 << 8;
            break;
        case LED_OFF:
            vir_led3->ODR &= (~(0x1 << 8));
            break;
        default:
            break;
        }
        break;
    default:
        break;
    }
    spin_unlock(&lock);
    return 0;
}

// 寄存器地址映射
int all_led_init(void)
{
    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("物理内存映射成功\n");
    // rcc
    (*vir_rcc) |= 0x3 << 4;
    // LED1
    vir_led1->MODER &= (~(0x3 << 20));
    vir_led1->MODER |= 0x1 << 20;
    vir_led1->ODR &= (~(0x1 << 10));
    // LED2
    vir_led2->MODER &= (~(0x3 << 20));
    vir_led2->MODER |= 0x1 << 20;
    vir_led2->ODR &= (~(0x1 << 10));
    // LED3
    vir_led3->MODER &= (~(0x3 << 16));
    vir_led3->MODER |= 0x1 << 16;
    vir_led3->ODR &= (~(0x1 << 8));

    return 0;
}

struct file_operations fops = {
    .open = mycdev_open,
    .release = mycdev_close,
    .read = mycdev_read,
    .write = mycdev_write,
    .unlocked_ioctl = mycdev_ioctl,
};

static int __init mycdev_init(void)
{
    int ret;
    // 1.分配字符设备驱动对象
    cdev = cdev_alloc();
    if (cdev == NULL)
    {
        printk("申请字符设备驱动对象失败\n");
        ret = -EFAULT;
        goto OUT1;
    }
    printk("申请字符设备驱动成功\n");
    // 2.初始化字符设备驱动对象
    cdev_init(cdev, &fops);
    // 3.申请设备号
    if (major > 0) // 静态指定
    {
        ret = register_chrdev_region(MKDEV(major, minor), 3, "mycdev");
        if (ret)
        {
            printk("静态指定设备号失败\n");
            goto OUT2;
        }
    }
    else
    {
        ret = alloc_chrdev_region(&devnum, minor, 3, "mycdev");
        if (ret)
        {
            printk("静态指定设备号失败\n");
            goto OUT2;
        }
        minor = MINOR(devnum);
        major = MAJOR(devnum);
    }
    printk("申请设备号成功\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");

    // 寄存器映射函数
    all_led_init();

    // 向上提交目录信息
    cls = class_create(THIS_MODULE, "mycdev");
    if (IS_ERR(cls))
    {
        printk("向上提交目录信息失败\n");
        ret = -PTR_ERR(cls);
        goto OUT4;
    }
    printk("向上提交目录信息成功\n");

    // 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, "mycdev%d", i);
        if (IS_ERR(dev))
        {
            printk("向上提交设备节点失败\n");
            ret = -PTR_ERR(cls);
            goto OUT5;
        }
    }
    printk("向上提交设备节点成功\n");
    return 0;

OUT5:
    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)
{
    // 取消物理映射
    iounmap(vir_led1);
    iounmap(vir_led2);
    iounmap(vir_rcc);

    // 销毁设备信息
    int i;
    for (i = 0; i < 3; i++)
        device_destroy(cls, MKDEV(major, i));

    // 销毁目录信息
    class_destroy(cls);
    // 注销字符设备驱动对象
    unregister_chrdev_region(MKDEV(major, minor), 3);
    // 释放空间对象
    kfree(cdev);
}
module_init(mycdev_init);
module_exit(mycdev_exit);
MODULE_LICENSE("GPL");

实现效果

串口查看：

实际现象：