Mouse driver

Hi all...
I'm developing a serial mouse driver and I would like to know how can I do to associate a driver with the device.
To do this driver code I followed a tutorial by Alan Cox. I used the register_chrdev function to associate the driver with the device, however when I issue "cat /dev/mymouse" (the mymouse device was created using the "mknod" command with the same major number of the driver and the module is already loaded), I got a error message. Is there any way of to do this?
When are the open_mouse and ourmouse_interrupt functions called?

Thanks!!

#define MODULE

#include<linux/ioport.h>
#include <linux/config.h>

#include <linux/module.h>

#include<linux/sched.h>
#include<linux/poll.h>
#include<linux/interrupt.h>
#include<linux/miscdevice.h>
#include<linux/init.h>

#include <linux/kernel.h> // printk()
#include <linux/malloc.h> // kmalloc()
#include<linux/slab.h> //
#include <linux/fs.h> // everything...
#include <linux/errno.h> // error codes
#include <linux/types.h> // size_t
#include <linux/proc_fs.h>
#include <linux/fcntl.h> // O_ACCMODE
#include <linux/devfs_fs_kernel.h>
#include <linux/devfs_fs.h>

#include <asm/system.h>
#include<asm/segment.h>
#include<asm/io.h>

#ifdef CONFIG_DEVFS_FS
#include <linux/devfs_fs_kernel.h>
#else
typedef void * devfs_handle_t;
#endif

/**/

#define OURMOUSE_BASE 0x300
//#define OURMOUSE_BASE 0x23c
//#define OURMOUSE_BASE 0x064
#define OURMOUSE_MINOR 0
#define OURMOUSE_MAJOR 250
//#define MOUSE_IRQ 5
#define MOUSE_IRQ 12

static int mouse_users = 0; // User count
static int mouse_dx = 0; // Position changes
static int mouse_dy = 0;
static int mouse_event = 0; // Mouse has moved
static int mouse_buttons = 0;
static int mouse_intr = MOUSE_IRQ;

static struct wait_queue *mouse_wait; static spinlock_t mouse_lock = SPIN_LOCK_UNLOCKED;

//Listing 1: File Operations
static ssize_t mouse_read(struct file *f, char *buffer,size_t count, loff_t *pos);
static ssize_t write_mouse(struct file *file, const char *buffer, size_t count, loff_t *ppos);
static unsigned int mouse_poll(struct file *file, poll_table *wait); static int open_mouse(struct inode *inode, struct file *file); static int close_mouse(struct inode *inode,struct file *file);

//static devfs_handle_t mydev;

struct file_operations our_mouse_fops = {
NULL, // Mice don't seek
mouse_read, // You can read a mouse write_mouse, // This won't do a lot
NULL, // No readdir - not a directory mouse_poll, // Poll
NULL, // No ioctl calls
NULL, // No mmap
open_mouse, // Called on open
NULL, // Flush - 2.2 only
close_mouse, // Called on close
NULL, // No media change on a mouse
NULL, // Asynchronous I/O - we will add this later NULL
};

static struct miscdevice our_mouse = { OURMOUSE_MINOR, "ourmouse",&our_mouse_fops, &our_mouse_fops };

static int ourmouse_init(void)
{
printk("estou no ourmouse_init \n");
if(check_region(OURMOUSE_BASE, 3))

        return -ENODEV;

printk("ourmouse: depois do check_region(OURMOUSE_BASE,3) \n"); request_region(OURMOUSE_BASE, 3,"ourmouse"); register_chrdev(OURMOUSE_MAJOR,"ourmouse",&our_mouse_fops);
/*
devfs_register(NULL,

                  "ourmouse",
                 0,
                 OURMOUSE_MAJOR,
                 OURMOUSE_MINOR,
                 S_IFCHR | S_IRUGO | S_IWUGO,
                 &our_mouse_fops,
                 0);

*/
//misc_register(&our_mouse);
return 0;
}

int init_module(void)
{
printk("estou no init_module \n");
if(ourmouse_init()<0)

         return -ENODEV;

printk("init_module: depois de ourmouse_init() \n"); return 0;
}

void cleanup_module(void)
{
//misc_deregister(&our_mouse);
//deffs_unregister(mydev);
unregister_chrdev(OURMOUSE_MAJOR,"ourmouse");
release_region(OURMOUSE_BASE, 3);
}

static void ourmouse_interrupt(int irq, void *dev_id, struct pt_regs *regs) {
char delta_x;
char delta_y;
unsigned char new_buttons;

   printk("uma interrupcao foi chamada \n");

   delta_x = inb(OURMOUSE_BASE);
   delta_y = inb(OURMOUSE_BASE+1);
   new_buttons = inb(OURMOUSE_BASE+2);

   if(delta_x || delta_y || new_buttons != mouse_buttons)
   {
           // Something happened
           spin_lock(&mouse_lock);
           mouse_event = 1;
           mouse_dx += delta_x;
           mouse_dy += delta_y;
           mouse_buttons = new_buttons;
           spin_unlock(&mouse_lock);

           wake_up_interruptible(&mouse_wait);

}
}

static int open_mouse(struct inode *inode, struct file *file) {
printk("estou no open_mouse \n");

if(mouse_users++)

       return 0;
   if(request_irq(mouse_intr, ourmouse_interrupt, 0,
      "ourmouse", NULL))
   {
       printk("request_irq: dentro do IF... algo deu errado \n");
       mouse_users--;
       return -EBUSY;

}
mouse_dx = 0;
mouse_dy = 0;
mouse_buttons = 0;
mouse_event = 0;
MOD_INC_USE_COUNT;
return 0;
}

static int close_mouse(struct inode *inode,struct file *file) {
if(--mouse_users)

           return 0;

free_irq(mouse_intr, NULL);
MOD_DEC_USE_COUNT;
return 0;
}

static ssize_t write_mouse(struct file *file, const char *buffer, size_t count, loff_t *ppos)
{
return -EINVAL;
}

static unsigned int mouse_poll(struct file *file, poll_table *wait) {
poll_wait(file, &mouse_wait, wait);
if(mouse_event)

           return POLLIN | POLLRDNORM;

return 0;
}

static ssize_t mouse_read(struct file *f, char *buffer,size_t count, loff_t *pos)
{
int dx, dy;
unsigned char button;
unsigned long flags;
int n;

if(count < 3)

       return -EINVAL;

//Wait for an event
//struct task_struct *current;
while(!mouse_event)
{
if(f->f_flags&O_NDELAY)
return -EAGAIN;
interruptible_sleep_on(&mouse_wait);
if(signal_pending(current))
return -ERESTARTSYS;
}

//Reading the Event
// mouse_read continued
// Grab the event
spin_lock_irqsave(&mouse_lock, flags);

dx = mouse_dx;
dy = mouse_dy;
button = mouse_buttons;

if(dx<=-127)

       dx=-127;
if(dx>=127)
       dx=127;
if(dy<=-127)
       dy=-127;
if(dy>=127)
       dy=127;

mouse_dx -= dx;
mouse_dy -= dy;

if (mouse_dx == 0 && mouse_dy == 0)

       mouse_event = 0;

spin_unlock_irqrestore(&mouse_lock, flags);

//================================================= //Copying Results to the Buffer
// mouse_read continued

if(put_user(button|0x80, buffer))

       return -EFAULT;
if(put_user((char)dx, buffer+1))
       return -EFAULT;
if(put_user((char)dy, buffer+2))
       return -EFAULT;

for(n=3; n < count; n++)

       if(put_user(0x00, buffer+n))
               return -EFAULT;

return count;
}
/**/

I think you should take a look at

Documentation/input/input-programming.txt

Vojtech Pavlik
SuSE Labs, SuSE CR