test.c

周立功ARM7试验箱

#ifndef __KERNEL__
    #define __KERNEL__
#endif
#ifndef MODULE
    #define MODULE
#endif

#include <linux/module.h>
#include <linux/sched.h>
#include <linux/kernel.h>       /* printk() */
#include <linux/init.h>


static loff_t test_llseek(struct file *filp, loff_t off, int whence);
static ssize_t test_read(struct file *filp, char *buf, size_t count, loff_t *f_pos);
static ssize_t test_write(struct file *filp, const char *buf, size_t count,
                           loff_t *f_pos);
static int test_open(struct inode *inode, struct file *filp);
static int test_release(struct inode *inode, struct file *filp); 
static int test_ioctl(struct inode *inode, struct file *filp, unsigned int cmd,
		              unsigned long param);
int  test_init(void);
void test_cleanup(void);


#define MAJOR_NR 125
#define DEVICE_NAME "test"               /* name for messaging */

module_init(test_init);
module_exit(test_cleanup);

/********************************************************************************************************/


static struct file_operations test_fops =        /* driver info  */
{
    owner:      THIS_MODULE,
    llseek:     test_llseek,
    read:       test_read,
    write:      test_write,
    ioctl:      test_ioctl,
    open:       test_open,
    release:    test_release,
};

        static loff_t test_llseek(struct file *filp, loff_t off, int whence)
{
    return 0;
}

        static ssize_t test_read(struct file *filp, char *buf, size_t count,
                           loff_t *f_pos)
{
    return 0;
}

        static ssize_t test_write(struct file *filp, const char *buf, size_t count,
                            loff_t *f_pos)
{
    return 0;
}
                
        static int  test_open(struct inode *inode, struct file *filp)
{
    MOD_INC_USE_COUNT;
    return 0;          /* success */
} 

        static int  test_release(struct inode *inode, struct file *filp) 
{
    MOD_DEC_USE_COUNT;
    return(0); 
} 

        static int test_ioctl(struct inode *inode, struct file *filp, 
                    unsigned int cmd, unsigned long arg)
{
    return 0;
}

        int  test_init(void)
{
    int  result;

    result = register_chrdev(MAJOR_NR,  DEVICE_NAME,  &test_fops); 
    if (result < 0)
    {
        printk(KERN_ERR DEVICE_NAME ": Unable to get major %d\n", MAJOR_NR );
        return(result); 
    } 

    printk(KERN_ERR DEVICE_NAME ": init OK\n");
    return(0); 
}

        void test_cleanup(void)
{
    unregister_chrdev(MAJOR_NR, DEVICE_NAME);
}

/*********************************************************************************************************
**                            End Of File
********************************************************************************************************/