#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/fs.h>
#include <linux/module.h>
#include <linux/kdev_t.h>
#include <linux/cdev.h>#define MAJOR_NUM 255
#define MINOR_NUM 0
#define DEV_NAME "demo1"static int open(struct inode * node, struct file * file)
{printk("demo open...\n");return 0;
}static ssize_t read(struct file * file, char __user * buf, size_t len, loff_t * offset)
{printk("demo read...\n");return 0;
}static ssize_t write(struct file * file, const char __user * buf, size_t len, loff_t * offset)
{printk("demo write...\n");return 0;
}static int close(struct inode * node, struct file * file)
{printk("demo close...\n");return 0;
}static dev_t dev_num;
static struct file_operations fops = 
{.owner = THIS_MODULE,.open = open,.read = read,.write = write,.release = close
};
static struct cdev dev;static int __init demo_init(void)
{dev_num = MKDEV(MAJOR_NUM, MINOR_NUM);cdev_init(&dev, &fops);cdev_add(&dev, dev_num, 1);register_chrdev_region(dev_num, 1, DEV_NAME);printk("demo_init  ##########################\n");return 0;
}static void __exit demo_exit(void)
{unregister_chrdev_region(dev_num, 1);cdev_del(&dev);printk("demo_exit  ##########################\n");
}module_init(demo_init);
module_exit(demo_exit);