simple_device.c

fsmlabs的real time linux的内核

/*
 * Written by Der Herr Hofrat, [e-mail]
 * (C) 2002 FSMLabs
 * License: GPL Version 2
 */

#include <linux/module.h>
#include <linux/version.h>
#include <linux/init.h>
#include <asm/io.h>
#include <asm/uaccess.h>  
#include "device_common.h"

static int 
driver_open(struct inode *inode, 
	struct file *file )
{
    printk("driver open called\n");
    return 0;
}

static int 
driver_close(struct inode *inode, 
	struct file *file)
{
    printk("driver close called\n");
    return 0;
}

static ssize_t 
driver_read(struct file *File, 
	char *buf, 
	size_t count, 
	loff_t *offset)
{
    printk("driver read called\n");
    return 0;
}

static ssize_t 
driver_write(struct file *File, 
	const char *user, 
	size_t count,
	loff_t *offset)
{
    printk("driver write called\n");
    return 0;
}

static struct file_operations simple_fops={
	THIS_MODULE, /* need this only for 2.4.X kernels */
    NULL,  /* llseek */
    driver_read,  /* read */
    driver_write,  /* write */
    NULL,  /* readdir */
    NULL,  /* poll */
    NULL,  /* ioctl */
    NULL,  /* mmap */
    driver_open,  /* open */
    NULL,  /* flush */
    driver_close,  /* release */
    NULL,  /* fsync */
    NULL,  /* fasync */
    NULL,  /* lock */
};

static int __init simple_init(void)
{
    if(register_chrdev(SIMPLE_MAJOR,DEV_NAME, &simple_fops) == 0) {
        printk("driver for major %d registered successfully\n",SIMPLE_MAJOR);
        return 0;
    };
    printk("unable to get major %d\n",SIMPLE_MAJOR);
    return -EIO;
}

static void __exit simple_exit(void)
{
    unregister_chrdev(SIMPLE_MAJOR,DEV_NAME);
}

module_init(simple_init);
module_exit(simple_exit);