led.c

嵌入式linux 2.6内核led驱动,也许对初学者有帮助

#include <linux/config.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/fs.h>
#include <linux/cdev.h>
#include <linux/ioctl.h>
#include <asm/uaccess.h>
#include <asm/hardware.h>
#include <asm/arch/regs-gpio.h>

MODULE_LICENSE("GPL");

#define HELLO_MAGIC 'k'
#define LED_GPF4 _IO(HELLO_MAGIC,1)
#define LED_GPF5 _IO(HELLO_MAGIC,2)
#define LED_GPF6 _IO(HELLO_MAGIC,3)
#define LED_GPF7 _IO(HELLO_MAGIC,4)
#define LED_GPF8 _IO(HELLO_MAGIC,5)
#define LED_GPF9 _IO(HELLO_MAGIC,6)
#define LED_GPF10 _IO(HELLO_MAGIC,7)
#define LED_GPF11 _IO(HELLO_MAGIC,8)

#define GPFCON *(volatile unsigned int *)S3C2410_GPFCON
#define GPFDAT *(volatile unsigned int *)S3C2410_GPFDAT

static int led_major=0;

static int led_open(struct inode *inode ,struct file *file)
{	
	GPFCON &=(~(3<<14)+(1<<14)+~(3<<12)+(1<<12)+~(3<<10)+(1<<10)+~(3<<8)+(1<<8));
	return 0;
}

static int led_ioctl(struct inode *inode,struct file *file,unsigned int cmd,unsigned long arg)

{	
	int ret=0;
	switch(cmd)
		{
		case LED_GPF4:
			GPFDAT &=(~(1<<4));
			break;
		case LED_GPF5:
			GPFDAT &=(~(1<<5));
			break;
		case LED_GPF6:
			GPFDAT &=(~(1<<6));
			break;
		case LED_GPF7:
			GPFDAT &=(~(1<<7));
			break;
		case LED_GPF8:
			GPFDAT |=1<<4;
			break;
		case LED_GPF9:
			GPFDAT |=1<<5;
			break;
		case LED_GPF10:
			GPFDAT |=1<<6;
			break;
		case LED_GPF11:
			GPFDAT |=1<<7;
			break;
		}
	return 0;
}

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

static void led_setup_cdev(struct cdev *dev,int minor,struct file_operations *fops)
{
	int err;
	int devno=MKDEV(led_major,minor);
	cdev_init(dev,fops);
	dev->owner=THIS_MODULE;
	dev->ops=fops;
	err=cdev_add(dev,devno,1);
	if(err)
	printk(KERN_INFO"Error %d adding led %d\n",err,minor);
}

static struct file_operations led_remap_ops={
	.owner=THIS_MODULE,
	.open=led_open,
	.release=led_release,
	.ioctl=led_ioctl,
};

static struct cdev SimpleDevs;

static int led_init(void)
{
	int result;
	dev_t dev=MKDEV(led_major,0);
	if(led_major)
	 result=register_chrdev_region(dev,1,"led");
	else
	 {
		result=alloc_chrdev_region(&dev,0,1,"led");
		led_major=MAJOR(dev);
	 }
	if(result<0)
	 {
	  printk(KERN_WARNING"led:unable to get major %d\n",led_major);		
	  return result;
	 }
	if(led_major==0)
	led_major=result;
	printk(KERN_INFO"led register ok!!!!!!!!!!\n");
	
	led_setup_cdev(&SimpleDevs,0,&led_remap_ops);
	return 0;
}
static void led_exit(void)
{
	cdev_del(&SimpleDevs);
	unregister_chrdev_region(MKDEV(led_major,0),2);
	printk("led device uninstalled\n");
}
module_init(led_init);
module_exit(led_exit);