head.h
#ifndef __HEAD_H__
#define __HEAD_H__
//LED1:PE10
//LED2:PF10
//LED3:PE8
#define LED_RCC 0X50000A28 //使能GPIO
#define LED_MODER 0X50006000 //设置输出模式
#define LED_ODR 0X50006014 //设置输出高低电平
#define LED2_MODER 0X50007000 //设置输出模式
#define LED2_ODR 0X50007014 //设置输出高低电平
#endifmychrdev.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] = {0};
unsigned int *vir_rcc;
unsigned int *vir_moder;
unsigned int *vir_odr;
unsigned int *vir_moder_led2;
unsigned int *vir_odr_led2;
//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 err\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 err\n");
return -EIO;
}
//控制LED1-LED3开和关
if(kbuf[0] == '1') //开灯
{
(*vir_odr) |= (0x1<<10); //输出高电平
(*vir_odr_led2) |= (0x1<<10); //输出高电平
(*vir_odr) |= (0x1<<8); //输出高电平
}
else if(kbuf[0] == '0') //关灯
{
(*vir_odr) &= (~(0x1<<10)); //输出低电平
(*vir_odr_led2) &= (~(0x1<<10)); //输出高电平
(*vir_odr) &= (~(0x1<<8)); //输出高电平
}
return 0;
}
int mycdev_close(struct inode *inode,struct file *file)
{
printk("%s:%s:%d\n",__FILE__,__func__,__LINE__);
return 0;
}
struct file_operations fops={ //定义一个操作方法结构体对象并初始化
.open = mycdev_open,
.read = mycdev_read,
.write = mycdev_write,
.release = mycdev_close,
};
static int __init mycdev_init(void) //入口函数 安装内核模块时执行
{
major=register_chrdev(0,"mychrdev",&fops); //字符设备驱动的注册
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LED控制相关寄存器的内存映射
vir_rcc = ioremap(LED_RCC,4);
if(vir_rcc == NULL)
{
printk("物理内存映射失败%d\n",__LINE__);
return -EFAULT;
}
vir_moder = ioremap(LED_MODER,4);
if(vir_moder == NULL)
{
printk("物理内存映射失败%d\n",__LINE__);
return -EFAULT;
}
vir_odr = ioremap(LED_ODR,4);
if(vir_odr == NULL)
{
printk("物理内存映射失败%d\n",__LINE__);
return -EFAULT;
}
vir_moder_led2 = ioremap(LED2_MODER,4);
if(vir_moder_led2 == NULL)
{
printk("物理内存映射失败%d\n",__LINE__);
return -EFAULT;
}
vir_odr_led2 = ioremap(LED2_ODR,4);
if(vir_odr_led2 == 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");
//控制led1-led3硬件寄存器的初始化
(*vir_rcc) |= (0x1<<4); //RCC使能GPIO E组
(*vir_rcc) |= (0x1<<5); //RCC使能GPIO F组
(*vir_moder) &= (~(0x3<<20)); //设置PE10为输出
(*vir_moder) |= (0x1<<20);
(*vir_moder_led2) &= (~(0x3<<20)); //设置PF10为输出
(*vir_moder_led2) |= (0x1<<20);
(*vir_moder) &= (~(0x3<<16)); //设置PE8为输出
(*vir_moder) |= (0x1<<16);
(*vir_odr) &= (~(0x1<<10)); //设置led1默认关灯
(*vir_odr_led2) &= (~(0x1<<10)); //设置led2默认关灯
(*vir_odr) &= (~(0x1<<8)); //设置led3默认关灯
return 0;
}
static void __exit mycdev_exit(void) //出口函数，卸载内核模块时执行
{
iounmap(vir_moder); //取消物理内存映射
iounmap(vir_moder_led2); //取消物理内存映射
iounmap(vir_odr); //取消物理内存映射
iounmap(vir_odr_led2); //取消物理内存映射
iounmap(vir_rcc); //取消物理内存映射
unregister_chrdev(major,"mychrdev"); //注销字符设备驱动
}
module_init(mycdev_init); //用于声明当前内核模块入口函数的地址
module_exit(mycdev_exit); //用于声明当前内核模块出口函数的地址
MODULE_LICENSE("GPL"); //声明当前内核模块遵循GPL协议
led_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(int argc, char const *argv[])
{
char buf[128] = {0};
int fd=open("/dev/mychrdev",O_RDWR);
if(fd < 0)
{
printf("设备文件打开失败\n");
exit(-1);
}
while(1)
{ //控制LED亮和灭
printf("请输入LED的控制命令：1(开灯)，0(关灯) >>");
fgets(buf,sizeof(buf),stdin); //从终端输入数据传递到buf中
buf[strlen(buf)-1] = '\0'; //末尾替换\n
write(fd,buf,sizeof(buf));
}
return 0;
}
测试结果如下：
