static int cypress_open(struct tty_struct *tty, struct usb_serial_port *port)
{
	struct cypress_private *priv = usb_get_serial_port_data(port);
	struct usb_serial *serial = port->serial;
	unsigned long flags;
	int result = 0;

	if (!priv->comm_is_ok)
		return -EIO;

	/* clear halts before open */
	usb_clear_halt(serial->dev, 0x81);
	usb_clear_halt(serial->dev, 0x02);

	spin_lock_irqsave(&priv->lock, flags);
	/* reset read/write statistics */
	priv->bytes_in = 0;
	priv->bytes_out = 0;
	priv->cmd_count = 0;
	priv->rx_flags = 0;
	spin_unlock_irqrestore(&priv->lock, flags);

	/* Set termios */
	cypress_send(port);

	if (tty)
 		cypress_set_termios(tty, port, &priv->tmp_termios);
 
 	/* setup the port and start reading from the device */
 	usb_fill_int_urb(port->interrupt_in_urb, serial->dev,
 		usb_rcvintpipe(serial->dev, port->interrupt_in_endpointAddress),
 		port->interrupt_in_urb->transfer_buffer,
		port->interrupt_in_urb->transfer_buffer_length,
		cypress_read_int_callback, port, priv->read_urb_interval);
	result = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);

	if (result) {
		dev_err(&port->dev,
			"%s - failed submitting read urb, error %d\n",
							__func__, result);
		cypress_set_dead(port);
	}

	return result;
} /* cypress_open */

Unknown