编写应用程序控制三盏灯的亮灭

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;

//LED灯的寄存器地址
#define LED1_ADDR 0X50006000
#define LED2_ADDR 0X50007000
#define LED3_ADDR 0X50006000
#define RCC_ADDR 0X50000A28

#endif

demo.c：

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

char kbuf[128] = {};
unsigned int major;
gpio_t *vir_led1;
gpio_t *vir_led2;
gpio_t *vir_led3;
// 定义指针指向映射后的虚拟内存
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__);
    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__);
    int 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__);
    int ret;
    ret = copy_from_user(kbuf, ubuf, size);
    if (ret)
    {
        printk("copy_from_user filed\n");
        return -EIO;
    }
    switch (kbuf[0])
    {
    case '1':
        if (kbuf[1] == '1')      // 开灯
            vir_led1->ODR |= (0x1 << 10);
        else if (kbuf[1] == '0') // 关灯
            vir_led1->ODR &= (~(0x1 << 10));
        break;
    case '2':
        if (kbuf[1] == '1')      // 开灯
            vir_led2->ODR |= (0x1 << 10);
        else if (kbuf[1] == '0') // 关灯
            vir_led2->ODR &= (~(0x1 << 10));
        break;
    case '3':
        if (kbuf[1] == '1')      // 开灯
            vir_led3->ODR |= (0x1 << 8);
        else if (kbuf[1] == '0') // 关灯
            vir_led3->ODR &= (~(0x1 << 8));
        break;
    default:
        printk("输入错误\n");
    }
    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对象
struct file_operations fops = {
    .open = mycdev_open,
    .read = mycdev_read,
    .write = mycdev_write,
    .release = mycdev_close,
};
static int __init mycdev_init(void)
{
    // 注册字符设备驱动
    major = register_chrdev(0, "mychrdev", &fops);
    if (major < 0)
    {
        printk("字符设备驱动注册失败\n");
        return major;
    }
    printk("注册字符设备驱动成功major=%d\n", major);
    // 进行寄存器的地址映射
    vir_led1 = ioremap(LED1_ADDR, sizeof(gpio_t));
    if (vir_led1 == NULL)
    {
        printk("物理内存地址映射失败%d\n", __LINE__);
        return -EFAULT;
    }
    vir_led2 = ioremap(LED2_ADDR, sizeof(gpio_t));
    if (vir_led2 == NULL)
    {
        printk("物理内存地址映射失败%d\n", __LINE__);
        return -EFAULT;
    }
    vir_led3 = ioremap(LED3_ADDR, sizeof(gpio_t));
    if (vir_led3 == NULL)
    {
        printk("物理内存地址映射失败%d\n", __LINE__);
        return -EFAULT;
    }
    vir_rcc=ioremap(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");

    // 寄存器初始化
    (*vir_rcc) |= (0x3 << 4); // GPIOE控制器时钟使能
    // 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));

    printk("寄存器初始化成功\n");
    return 0;
}
static void __exit mycdev_exit(void)
{
    // 取消内存映射
    iounmap(vir_led1);
    iounmap(vir_led2);
    iounmap(vir_rcc);
    // 注销字符设备驱动
    unregister_chrdev(major, "mychrdev");
    return 0;
}
module_init(mycdev_init);
module_exit(mycdev_exit);
MODULE_LICENSE("GPL");

test.c：

#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <string.h>
#include <stdlib.h>
int main(int argc, char const *argv[])
{
    char buf[128] = {0};
    int fd = open("/dev/mychrdev", O_RDWR);
    if (fd < 0)
    {
        printf("打开设备文件失败\n");
        return -1;
    }
    printf("打开设备文件成功\n");
    while (1)
    {
        printf("请输入要控制的灯：1(LED1) 2(LED2) 3(LED3)  >>>\n");
        printf("请输入您要进行的操作：1(开灯) 0(关灯)       >>>\n");
        printf("请输入控制灯的两个字符  >>> ");
        fgets(buf, sizeof(buf), stdin);    //在终端读一个字符串
        buf[strlen(buf) - 1] = '\0';
        write(fd, buf, sizeof(buf));       //将数据传递给内核
    }
    close(fd);
    return 0;
}