最简单的点亮LED灯驱动程序

一，驱动程序：

#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 

#define GPBCONADDR 0x56000010  //GPBCON物理地址
#define GPBDATADDR 0x56000014

static struct class *firstdev_class;
static struct device *firstdev_class_dev;

volatile unsigned long *gpbcon;
volatile unsigned long *gpbdat;	


static int wzc_driver_open(struct inode *inode, struct file *file)
{
	printk("wzc open!\n");
	gpbcon = (volatile unsigned long *)ioremap(GPBCONADDR,16); //ioremap实现物理地址到虚拟地址的转换
	gpbdat = gpbcon+1;
	*gpbcon &= ~((3<<5*2) | (3<<6*2) | (3<<7*2) | (3<<8*2));//使IO口功能为输出
	*gpbcon |= ((1<<5*2) | (1<<6*2) | (1<<7*2) | (1<<8*2));
	return 0;
}

static int  wzc_driver_write(struct file *filp, char __user *buff, size_t count, loff_t *offp)
{
	int val;
	copy_from_user(&val, buff, 4);//copy_from_user实现从用户空间读取参数到内核空间
	printk("wzc write!\n");
	if(val ==1)
	{
		*gpbdat &= ~(0x0f<<5);
	}
	else if(val == 0)
	{
		*gpbdat |= (0x0f<<5);
	}
	return 0;
}

static struct file_operations wzc_fp = 
{
	.owner = THIS_MODULE,
	.open = wzc_driver_open,
	.write = wzc_driver_write
};


int major;
static int wzc_driver_init(void)
{
	printk("wzc init2212!\n");
	major = register_chrdev(0,"wzc_driver",&wzc_fp);	//注册字符驱动程序，0代表系统自动分配
	firstdev_class = class_create(THIS_MODULE, "firstdev");
	firstdev_class_dev = device_create(firstdev_class, NULL, MKDEV(major, 0), NULL, "firstdev");
	return 0;
}



static void wzc_driver_exit(void)
{
	unregister_chrdev(major,"wzc_driver");
	device_unregister(firstdev_class_dev);
	class_destroy(firstdev_class);
}


module_init(wzc_driver_init);
module_exit(wzc_driver_exit);
MODULE_LICENSE("GPL");

二，测试程序：

#include 
#include 
#include 
#include 

int main(int argc, char** argv)
{
	int fd;
	int val;
	if(argc != 2)
	{
		printf("usage:\n");
		printf("%s \n",argv[0]);
		return 0;
	}
	fd = open("/dev/firstdev",O_RDWR);
	if(fd<0)
	{
		printf("can't open file!\n");
		return 0;
	}
	if(strcmp(argv[1],"on") == 0)
	{
		val = 1;
		write(fd,&val,4);
	}
	else if(strcmp(argv[1],"off") == 0)
	{
		val = 0;
		write(fd,&val,4);
	}
	else
	{
		printf("usage:\n");
		printf("%s \n",argv[0]);
		return 0;
	}
	return 0;
}