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嵌入式：驱动开发 Day2

news 2025/8/4 1:07:26

作业：字符设备驱动，完成三盏LED灯的控制

驱动代码： mychrdev.c

#include <linux/init.h>
#include <linux/module.h>
#include <linux/fs.h>
#include <linux/uaccess.h>
#include <linux/io.h>
#include "head.h"unsigned int major;   //保存主设备号
char kbuf[128] = "";unsigned int *vir_moder_e;
unsigned int *vir_odr_e;
unsigned int *vir_rcc_e;unsigned int *vir_moder_f;
unsigned int *vir_odr_f;
unsigned int *vir_rcc_f;//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){int ret;ret = copy_to_user(ubuf, kbuf, size);if(ret){printk("copy_to_user err\n");return -EIO;}return 0;
}ssize_t mycdev_write(struct file *file, const char *ubuf, size_t size, loff_t *lof){int ret;ret = copy_from_user(kbuf, ubuf, size);if(ret){printk("copy_from_user err\n");return -EIO;}if(kbuf[0] == '1')  	//led1开灯{//开灯逻辑(*vir_odr_e) |= (0x1 << 10);}else if(kbuf[0] == '2'){   //led1关灯//关灯逻辑(*vir_odr_e) &= (~(0x1 << 10));}else if(kbuf[0] == '3'){   //led2开灯//开灯逻辑(*vir_odr_f) |= (0x1 << 10);}else if(kbuf[0] == '4'){   //led2关灯//关灯逻辑(*vir_odr_f) &= (~(0x1 << 10));}else if(kbuf[0] == '5'){   //led3开灯//开灯逻辑(*vir_odr_e) |= (0x1 << 8);}else if(kbuf[0] == '6'){   //led3关灯//关灯逻辑(*vir_odr_e) &= (~(0x1 << 8));}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,.read = mycdev_read,.write = mycdev_write,.release = mycdev_close,
};static int __init mycdev_init(void){//字符设备驱动的注册major = register_chrdev(0, "mychrdev", &fops);if(major < 0){printk("字符设备驱动注册失败\n");return major;}printk("字符设备驱动注册成功 major = %d\n", major);//进行相关寄存器的内存映射//GPIOE组寄存器内存映射vir_odr_e = ioremap(GPIOE_ODR, 4);if(vir_odr_e == NULL){printk("物理内存映射失败%d\n", __LINE__);return -EFAULT;}vir_rcc_e = ioremap(GPIOE_RCC, 4);if(vir_rcc_e == NULL){printk("物理内存映射失败%d\n", __LINE__);return -EFAULT;}vir_moder_e = ioremap(GPIOE_MODER, 4);if(vir_moder_e == NULL){printk("物理内存映射失败%d\n", __LINE__);return -EFAULT;}//GPIOF组寄存器内存映射vir_odr_f = ioremap(GPIOF_ODR, 4);if(vir_odr_f == NULL){printk("物理内存映射失败%d\n", __LINE__);return -EFAULT;}vir_rcc_f = ioremap(GPIOF_RCC, 4);if(vir_rcc_f == NULL){printk("物理内存映射失败%d\n", __LINE__);return -EFAULT;}vir_moder_f = ioremap(GPIOF_MODER, 4);if(vir_moder_f == 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_e) |= (0x1 << 4);     //GPIOE(PE10 PE8)使能(*vir_rcc_f) |= (0x1 << 5);     //GPIOF(PF10)使能//设置PE10为输出模式 --> LED1(*vir_moder_e) &= (~(0x3 << 20));(*vir_moder_e) |= (0x1 << 20);//设置PF10为输出模式 --> LED2(*vir_moder_f) &= (~(0x3 << 20));(*vir_moder_f) |= (0x1 << 20);//设置PE8为输出模式 --> LED3(*vir_moder_e) &= (~(0x3 << 16));(*vir_moder_e) |= (0x1 << 16);//默认LED1关灯(*vir_odr_e) &= (~(0x1 << 10));//默认LED2关灯(*vir_odr_f) &= (~(0x1 << 10));//默认LED1关灯(*vir_odr_e) &= (~(0x1 << 8));return 0;
}static void __exit mycdev_exit(void){//取消物理内存映射iounmap(vir_moder_e);iounmap(vir_odr_e);iounmap(vir_rcc_e);iounmap(vir_moder_f);iounmap(vir_odr_f);iounmap(vir_rcc_f);//字符设备驱动注销unregister_chrdev(major, "mychrdev");
}module_init(mycdev_init);
module_exit(mycdev_exit);
MODULE_LICENSE("GPL");

应用代码：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>int main(){char buf[128] = "";int fd = open("/dev/mychrdev", O_RDWR);if(fd < 0){printf("设备文件打开失败\n");exit(-1);}while(1){printf("请输入对LED的控制命令：1(LED1开灯) 2(LED1关灯) 3(LED2开灯) 4(LED2关灯) 5(LED3开灯) 6(LED3关灯) >");fgets(buf, sizeof(buf), stdin); //在终端输入数据传递到bufbuf[strlen(buf) - 1] = '\0'; 	//替换末尾的'\n'write(fd, buf, sizeof(buf));}close(fd);return 0;
}

头文件：head.h

#ifndef __HEAD_H__
#define __HEAD_H__#define GPIOE_MODER 0x50006000
#define GPIOE_ODR 0x50006014
#define GPIOE_RCC 0x50000A28#define GPIOF_MODER 0x50007000
#define GPIOF_ODR 0x50007014
#define GPIOF_RCC 0x50000A28#endif