linux驱动学习——字符设备的注册

//分配
struct cdev *my_cdev = cdev_alloc();
//初始化
// cdev:  待初始化的cdev结构
// fops:  设备对应的操作函数集
void cdev_init(struct cdev *cdev, const struct file_operations *fops);
//注册， 告诉内核
// dev: 添加到内核的字符设备结构
// num: 设备号
// count: 关联到设备的设备号数目，通常为1
int cdev_add(struct cdev *dev, dev_t num, unsigned count);
//去除字符设备
void cdev_del(struct cedv *);

#include
#include
#include
#include
#include

MODULE_LICENSE("GPL");
MODULE_AUTHOR("ZZX");

static int major = 230;
static int minor = 0;
static dev_t devno;
static struct cdev cdev;
static int hello_open(struct inode *inode, struct file *ifilep)
{
	printk("hello openn");
	return 0;
}
static struct file_operations hello_ops =
{
	.open = hello_open,
};

static int hello_init(void)
{
	int result;
	int error;

	printk("hello_initn");

	devno = MKDEV(major, minor);
	result = register_chrdev_region(devno, 1, "dev_test");
	if(result < 0){
		printk("register_chrdev_region fauiln");
		return result;
	}
	cdev_init(&cdev, &hello_ops);
	error = cdev_add(&cdev, devno, 1);
	if(error < 0)
	{
		printk("cdev_add failn");
		unregister_chrdev_region(devno,1);
		return error;
	}


	return 0;
}

static void hello_exit(void)
{
	printk("hello_exitn");
	cdev_del(&cdev);
	unregister_chrdev_region(devno,1);
	return; 
}

module_init(hello_init);
module_exit(hello_exit);

mknode /dev/test c 230 0