驱动代码

#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 *vir1_moder;
unsigned int *vir1_odr;
unsigned int *vir1_rcc;
unsigned int *vir2_moder;
unsigned int *vir2_odr;
unsigned int *vir2_rcc;
unsigned int *vir3_moder;
unsigned int *vir3_odr;
unsigned int *vir3_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)
{
    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 = 0;
    ret = copy_from_user(kbuf,ubuf,size);
    if (ret)
    {
        printk("copy_from_user err\n");
        return -EIO;
    }
    switch(kbuf[0])
    {
    case '1':
        (*vir1_odr) |= (0x1 << 10);
        break;
    case '2':   
        (*vir1_odr) &= (~(0x1 << 10));
        break;
    case '3':
        (*vir2_odr) |= (0x1 << 10);
        break;
    case '4':   
        (*vir2_odr) &= (~(0x1 << 10));
        break;
    case '5':
        (*vir3_odr) |= (0x1 << 8);
        break;
    case '6':   
        (*vir3_odr) &= (~(0x1 << 8));
        break;
        default:
        printk("输入错误\n");
        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)
{
    //字符设备驱动注册
    major = register_chrdev(0,"mychrdev",&fops);
    if(major < 0)
    {
        printk("字符串设备驱动注册失败\n");
    }
    printk("字符设备驱动注册成功 major = %d\n",major);
    //相关寄存器内存映射
    vir1_odr = ioremap(LED1_ODR,4);
    if (vir1_odr == NULL)  
    {   
        printk("物理内存映射失败%d\n",__LINE__);
        return -EFAULT;
    }
    vir1_rcc = ioremap(LED1_RCC,4);
    if (vir1_rcc == NULL)  
    {   
        printk("物理内存映射失败%d\n",__LINE__);
        return -EFAULT;
    }
    vir1_moder = ioremap(LED1_MODER,4);
    if (vir1_moder == NULL)  
    {   
        printk("物理内存映射失败%d\n",__LINE__);
        return -EFAULT;
    }
     vir2_odr = ioremap(LED2_ODR,4);
    if (vir2_odr == NULL)  
    {   
        printk("物理内存映射失败%d\n",__LINE__);
        return -EFAULT;
    }
    vir2_rcc = ioremap(LED2_RCC,4);
    if (vir2_rcc == NULL)  
    {   
        printk("物理内存映射失败%d\n",__LINE__);
        return -EFAULT;
    }
    vir2_moder = ioremap(LED2_MODER,4);
    if (vir2_moder == NULL)  
    {   
        printk("物理内存映射失败%d\n",__LINE__);
        return -EFAULT;
    }
     vir3_odr = ioremap(LED3_ODR,4);
    if (vir3_odr == NULL)  
    {   
        printk("物理内存映射失败%d\n",__LINE__);
        return -EFAULT;
    }
    vir3_rcc = ioremap(LED3_RCC,4);
    if (vir3_rcc == NULL)  
    {   
        printk("物理内存映射失败%d\n",__LINE__);
        return -EFAULT;
    }
    vir3_moder = ioremap(LED3_MODER,4);
    if (vir3_moder == 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
    (*vir1_rcc) |= (0x1 << 4);
    //设置PE10为输出
    (*vir1_moder) &= (~(0x3 << 20));
    (*vir1_moder) |= (0x1 << 20);
    //默认关灯
    (*vir1_odr) &= (~(0x1 << 10));
     //RCC使能
    (*vir2_rcc) |= (0x1 << 5);
    //设置PE10为输出
    (*vir2_moder) &= (~(0x3 << 20));
    (*vir2_moder) |= (0x1 << 20);
    //默认关灯
    (*vir1_odr) &= (~(0x1 << 10));
     //RCC使能
    (*vir1_rcc) |= (0x1 << 4);
    //设置PE10为输出
    (*vir1_moder) &= (~(0x3 << 16));
    (*vir1_moder) |= (0x1 << 16);
    //默认关灯
    (*vir1_odr) &= (~(0x1 << 8));
    
    return 0;
}
static void __exit mycdev_exit(void)
{
    //取消物理内存映射
    iounmap(vir1_moder);
    iounmap(vir1_rcc);
    iounmap(vir1_odr);
    iounmap(vir2_moder);
    iounmap(vir2_rcc);
    iounmap(vir2_odr);
    iounmap(vir3_moder);
    iounmap(vir3_rcc);
    iounmap(vir3_odr);
    //字符设备驱动注销
    unregister_chrdev(major,"mychrdev");

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

应用层代码

#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,const char * 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)
    {
        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);//在终端输入数据到buf
        buf[strlen(buf)-1] = '\0';
        write(fd,buf,sizeof(buf));
        memset(buf,0,sizeof(buf));
    }
    close(fd);
    return 0;
}