字符设备模板3：misc_register

#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/types.h>
#include <linux/spinlock.h>
#include <linux/blkdev.h>
#include <linux/module.h>  
#include <linux/fs.h>  
#include <linux/errno.h>  
#include <linux/mm.h>  
#include <linux/cdev.h>  
#include <linux/miscdevice.h>

#define MISC_NAME   "miscdriver"

static int misc_open(struct inode *inode, struct file *file)
{
    printk("misc_open\n");
    return 0;
}

int temp_data = 0;

static int misc_ioctl( struct file *file, unsigned int cmd, unsigned long arg)
{    
    switch(cmd)
    {
        case 0x100:
            if(copy_from_user(&temp_data,  (int *)arg, sizeof(int))) 
                return -EFAULT;
            break;
        
        case 0x101:
            if(copy_to_user( (int *)arg, &temp_data, sizeof(int))) 
                return -EFAULT;
            break;
    }
    
    //printk(KERN_NOTICE"ioctl CMD%d done!\n",temp);    
    return 0;
}


static const struct file_operations misc_fops =
{
    .owner   =   THIS_MODULE,
    .open    =   misc_open,
    .unlocked_ioctl = misc_ioctl,
};

static struct miscdevice misc_dev =
{
    .minor = MISC_DYNAMIC_MINOR,
    .name = MISC_NAME,
    .fops = &misc_fops,
};


static int __init misc_init(void)
{
    int ret;
    
    ret = misc_register(&misc_dev);
    if (ret)
    {
        printk("misc_register error\n");
        return ret;
    }

    return 0;
}

static void __exit misc_exit(void)
{
    misc_deregister(&misc_dev);
}

module_init(misc_init);
module_exit(misc_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Decly");

#if 1

#include <stdio.h>  
#include <fcntl.h>  
#include <stdlib.h>  
#include <string.h>  
#include <sys/types.h>  
#include <sys/stat.h>
#include <unistd.h>
#include <sys/ioctl.h>

int main()
{
    int fd;
    int ret;
    int wdata, rdata;

    fd = open("/dev/miscdriver", O_RDWR);
    if( fd < 0 ) {
        printf("open miscdriver WRONG！\n");
        return 0;
    }

    ret = ioctl(fd, 0x101, &rdata);
    printf("ioctl: ret=%d rdata=%d\n", ret, rdata);

    wdata = 42;
    ret = ioctl(fd, 0x100, &wdata);

    ret = ioctl(fd, 0x101, &rdata);
    printf("ioctl: ret=%d rdata=%d\n", ret, rdata);
    
    close(fd);
    return 0;
}

#endif