本程序采用动态映射的方法控制led，硬件平台为飞凌的ok6410

led.h：定义控制命令

#ifndef  _LED_H
#define  _LED_H

#define LED_MAGIC 'M'
#define LED_ON  _IO(LED_MAGIC, 0)
#define LED_OFF _IO(LED_MAGIC, 1)

#endif  

#include <linux/module.h>
#include <linux/init.h>
#include <linux/cdev.h>
#include <linux/fs.h>
#include <asm/uaccess.h>
#include <asm/io.h>
#include "led.h"

#define  LEDCON 0x7f008820//与具体平台相关
#define  LEDDAT 0x7f008824

unsigned int *led_config;
unsigned int *led_data;

struct cdev leddev;
dev_t devno;

static int led_open(struct inode *inode, struct file *filp)
{
	return 0;	
}


static int led_close(struct inode *inode, struct file *filp)
{
	return 0;
}

static long led_ioctl(struct file* filp, unsigned int cmd, unsigned long arg)
{
	switch (cmd)
	{
		case LED_ON:
			writel(0x00, led_data);
			break;
		case LED_OFF:
			writel(0xff, led_data);
			break;
		default:
			return -EINVAL;
	}
	return 0;
}

struct file_operations ledfops = {
	.open = led_open,
	.unlocked_ioctl = led_ioctl,
	.release = led_close,
};

static int led_init(void)
{
	/*注册字符设备*/
	cdev_init(&leddev, &ledfops);
	alloc_chrdev_region(&devno, 0, 1, "leddev");
	cdev_add(&leddev, devno, 1);
	
	/*映射配置寄存器*/
	led_config = ioremap(LEDCON, 4);
	/*低四位设置为输出模式，这里暴力简单的解决没做处理*/
	writel(0x00001111, led_config);
	/*映射数据寄存器*/
	led_data = http://www.mamicode.com/ioremap(LEDDAT, 4);>
应用程序led_app.c
#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <sys/ioctl.h>
#include "led.h"

int main(int argc, char *argv[])
{
	int cmd;
	if (argc < 2)
	{
		printf("Usage:%s <cmd>\n", argv[0]);
		return 0;
	}
	cmd = atoi(argv[1]);

	int fd = open("/dev/leddev", O_RDWR);
	if (fd == -1)
	{
		perror("open");
		return -1;
	}
	if (cmd == 1)
		ioctl(fd, LED_ON);
	else
		ioctl(fd, LED_OFF);

	close(fd);
	return 0;
}

编译程序，使用命令mknod /dev/leddev c 252 0创建设备节点，主设备号可通过cat /proc/devices
运行应用程序
./led_app 0                   熄灭led
./led_app 1                   点亮led
Linux下的led驱动程序，ok6410