static int __init dev_init(void)
{
	int ret;

	ret = misc_register(&misc);

	printk (DEVICE_NAME"\tinitialized\n");

	s3c2410_gpio_cfgpin(S3C2410_GPG(4), S3C2410_GPIO_OUTPUT);
	set_bl(1);
	return ret;
}
static ssize_t dev_write(struct file *file, const char *buffer, size_t count, loff_t * ppos)
{
	unsigned char ch;
	int ret;
	if (count == 0) {
		return count;
	}
	ret = copy_from_user(&ch, buffer, sizeof ch) ? -EFAULT : 0;
	if (ret) {
		return ret;
	}

	ch &= 0x01;
	set_bl(ch);
		
	return count;
}
static int __init bl_dev_init(void)
{
	int ret;

	ret = gpio_request(GPIO_BL, "backlight");
	if (ret) {
		printk("%s: request GPIO %d for backlight failed, ret = %d\n",
				DEVICE_NAME, GPIO_BL, ret);
		return ret;
	}

	s3c_gpio_cfgpin(GPIO_BL, S3C_GPIO_OUTPUT);
	set_bl(1);

	gpio_free(GPIO_BL);

	ret = misc_register(&misc);

	printk(DEVICE_NAME"\tinitialized\n");

	return ret;
}