原创 tty(1)

 // resubmit the timer again
 tiny->timer->expires = jiffies + DELAY_TIME;
 add_timer(tiny->timer);
 
/* //test timer
 static int i;
 struct tiny_serial *tiny = (struct tiny_serial *)timer_data;

 ++i;
 printk ("tiny timer i=%d\n",i);
 // resubmit the timer again
 tiny->timer->expires = jiffies + DELAY_TIME;
 add_timer(tiny->timer);
*/
}

static int tiny_open(struct tty_struct *tty, struct file *file)
{
 struct tiny_serial *tiny;
 struct timer_list *timer;
 int index;
 if (NULL == tty)
 {
  printk ("tty == NULL \n");
  return -1;
 }

 /* initialize the pointer in case something fails */
 tty->driver_data = NULL;

 /* get the serial object associated with this tty pointer */
 index = 0;
 tiny = tiny_table[index];
 if (tiny == NULL) {
  /* first time accessing this device, let's create it */
  tiny = kmalloc(sizeof(*tiny), GFP_KERNEL);
  if (!tiny)
   return -ENOMEM;

  init_MUTEX(&tiny->sem);
  tiny->open_count = 0;
  tiny->timer = NULL;

  tiny_table[index] = tiny;
 }

 down(&tiny->sem);

 /* save our structure within the tty structure */
 tty->driver_data = tiny;
 tiny->tty = tty;

 ++tiny->open_count;
 if (tiny->open_count == 1) {
  /* this is the first time this port is opened */
  /* do any hardware initialization needed here */

  /* create our timer and submit it */
  printk ("open 3 \n");
  if (NULL == tiny->timer) {
   timer = kmalloc(sizeof(*timer), GFP_KERNEL);
   if (NULL == timer) {
    up(&tiny->sem);
    return -ENOMEM;
   }
   tiny->timer = timer;
  }
  init_timer(tiny->timer);  //擦，需要添加这个才行。
  tiny->timer->data = (unsigned long )tiny;
  tiny->timer->expires = jiffies + DELAY_TIME;
  tiny->timer->function = tiny_timer;
  printk ("open 4 \n");
  add_timer(tiny->timer);
  printk ("open 5 \n");

 }

 up(&tiny->sem);
 return 0;
}

static void do_close(struct tiny_serial *tiny)
{
 down(&tiny->sem);

 if (!tiny->open_count) {
  /* port was never opened */
  goto exit;
 }

 --tiny->open_count;
 if (tiny->open_count <= 0) {
  /* The port is being closed by the last user. */
  /* Do any hardware specific stuff here */

  /* shut down our timer */
  del_timer(tiny->timer);
 }
exit:
 up(&tiny->sem);
}

static void tiny_close(struct tty_struct *tty, struct file *file)
{
 struct tiny_serial *tiny = tty->driver_data;

 if (tiny)
  do_close(tiny);
} 

static int tiny_write(struct tty_struct *tty,
        const unsigned char *buffer, int count)
{
 struct tiny_serial *tiny = tty->driver_data;
 int i;
 int retval = -EINVAL;

 if (!tiny)
  return -ENODEV;

 down(&tiny->sem);

 if (!tiny->open_count)
  /* port was not opened */
  goto exit;

 /* fake sending the data out a hardware port by
  * writing it to the kernel debug log.
  */
 printk(KERN_DEBUG "%s - ", __FUNCTION__);
 for (i = 0; i < count; ++i)
  printk("%02x ", buffer);
 printk("\n");
  
exit:
 up(&tiny->sem);
 return retval;
}