drivers/usb/serial/opticon.c - maze/linux - Git at Google

 /*
  * Opticon USB barcode to serial driver
  *
  * Copyright (C) 2011 Martin Jansen <martin.jansen@opticon.com>
  * Copyright (C) 2008 - 2009 Greg Kroah-Hartman <gregkh@suse.de>
  * Copyright (C) 2008 - 2009 Novell Inc.
  *
  *	This program is free software; you can redistribute it and/or
  *	modify it under the terms of the GNU General Public License version
  *	2 as published by the Free Software Foundation.
  */

 #include <linux/kernel.h>
 #include <linux/init.h>
 #include <linux/tty.h>
 #include <linux/tty_driver.h>
 #include <linux/slab.h>
 #include <linux/tty_flip.h>
 #include <linux/serial.h>
 #include <linux/module.h>
 #include <linux/usb.h>
 #include <linux/usb/serial.h>
 #include <linux/uaccess.h>

 #define CONTROL_RTS			0x02
 #define RESEND_CTS_STATE	0x03

 /* max number of write urbs in flight */
 #define URB_UPPER_LIMIT	8

 /* This driver works for the Opticon 1D barcode reader
  * an examples of 1D barcode types are EAN, UPC, Code39, IATA etc.. */
 #define DRIVER_DESC	"Opticon USB barcode to serial driver (1D)"

 static const struct usb_device_id id_table[] = {
 	{ USB_DEVICE(0x065a, 0x0009) },
 	{ },
 };
 MODULE_DEVICE_TABLE(usb, id_table);

 /* This structure holds all of the individual device information */
 struct opticon_private {
 	struct usb_device *udev;
 	struct usb_serial *serial;
 	struct usb_serial_port *port;
 	unsigned char *bulk_in_buffer;
 	struct urb *bulk_read_urb;
 	int buffer_size;
 	u8 bulk_address;
 	spinlock_t lock;	/* protects the following flags */
 	bool throttled;
 	bool actually_throttled;
 	bool rts;
 	bool cts;
 	int outstanding_urbs;
 };


 static void opticon_read_bulk_callback(struct urb *urb)
 {
 	struct opticon_private *priv = urb->context;
 	unsigned char *data = urb->transfer_buffer;
 	struct usb_serial_port *port = priv->port;
 	int status = urb->status;
 	struct tty_struct *tty;
 	int result;
 	int data_length;
 	unsigned long flags;

 	switch (status) {
 	case 0:
 		/* success */
 		break;
 	case -ECONNRESET:
 	case -ENOENT:
 	case -ESHUTDOWN:
 		/* this urb is terminated, clean up */
 		dev_dbg(&priv->udev->dev, "%s - urb shutting down with status: %d\n",
 			__func__, status);
 		return;
 	default:
 		dev_dbg(&priv->udev->dev, "%s - nonzero urb status received: %d\n",
 			__func__, status);
 		goto exit;
 	}

 	usb_serial_debug_data(&port->dev, __func__, urb->actual_length, data);

 	if (urb->actual_length > 2) {
 		data_length = urb->actual_length - 2;

 		/*
 		 * Data from the device comes with a 2 byte header:
 		 *
 		 * <0x00><0x00>data...
 		 *	This is real data to be sent to the tty layer
 		 * <0x00><0x01)level
 		 *	This is a CTS level change, the third byte is the CTS
 		 *	value (0 for low, 1 for high).
 		 */
 		if ((data[0] == 0x00) && (data[1] == 0x00)) {
 			/* real data, send it to the tty layer */
 			tty = tty_port_tty_get(&port->port);
 			if (tty) {
 				tty_insert_flip_string(tty, data + 2,
 						       data_length);
 				tty_flip_buffer_push(tty);
 				tty_kref_put(tty);
 			}
 		} else {
 			if ((data[0] == 0x00) && (data[1] == 0x01)) {
 				spin_lock_irqsave(&priv->lock, flags);
 				/* CTS status information package */
 				if (data[2] == 0x00)
 					priv->cts = false;
 				else
 					priv->cts = true;
 				spin_unlock_irqrestore(&priv->lock, flags);
 			} else {
 				dev_dbg(&priv->udev->dev,
 					"Unknown data packet received from the device:"
 					" %2x %2x\n",
 					data[0], data[1]);
 			}
 		}
 	} else {
 		dev_dbg(&priv->udev->dev,
 			"Improper amount of data received from the device, "
 			"%d bytes", urb->actual_length);
 	}

 exit:
 	spin_lock(&priv->lock);

 	/* Continue trying to always read if we should */
 	if (!priv->throttled) {
 		usb_fill_bulk_urb(priv->bulk_read_urb, priv->udev,
 				  usb_rcvbulkpipe(priv->udev,
 						  priv->bulk_address),
 				  priv->bulk_in_buffer, priv->buffer_size,
 				  opticon_read_bulk_callback, priv);
 		result = usb_submit_urb(priv->bulk_read_urb, GFP_ATOMIC);
 		if (result)
 			dev_err(&port->dev,
 			    "%s - failed resubmitting read urb, error %d\n",
 							__func__, result);
 	} else
 		priv->actually_throttled = true;
 	spin_unlock(&priv->lock);
 }

 static int send_control_msg(struct usb_serial_port *port, u8 requesttype,
 				u8 val)
 {
 	struct usb_serial *serial = port->serial;
 	int retval;
 	u8 *buffer;

 	buffer = kzalloc(1, GFP_KERNEL);
 	if (!buffer)
 		return -ENOMEM;

 	buffer[0] = val;
 	/* Send the message to the vendor control endpoint
 	 * of the connected device */
 	retval = usb_control_msg(serial->dev, usb_sndctrlpipe(serial->dev, 0),
 				requesttype,
 				USB_DIR_OUT|USB_TYPE_VENDOR|USB_RECIP_INTERFACE,
 				0, 0, buffer, 1, 0);
 	kfree(buffer);

 	return retval;
 }

 static int opticon_open(struct tty_struct *tty, struct usb_serial_port *port)
 {
 	struct opticon_private *priv = usb_get_serial_data(port->serial);
 	unsigned long flags;
 	int result = 0;

 	spin_lock_irqsave(&priv->lock, flags);
 	priv->throttled = false;
 	priv->actually_throttled = false;
 	priv->port = port;
 	priv->rts = false;
 	spin_unlock_irqrestore(&priv->lock, flags);

 	/* Clear RTS line */
 	send_control_msg(port, CONTROL_RTS, 0);

 	/* Setup the read URB and start reading from the device */
 	usb_fill_bulk_urb(priv->bulk_read_urb, priv->udev,
 			  usb_rcvbulkpipe(priv->udev,
 					  priv->bulk_address),
 			  priv->bulk_in_buffer, priv->buffer_size,
 			  opticon_read_bulk_callback, priv);

 	/* clear the halt status of the enpoint */
 	usb_clear_halt(priv->udev, priv->bulk_read_urb->pipe);

 	result = usb_submit_urb(priv->bulk_read_urb, GFP_KERNEL);
 	if (result)
 		dev_err(&port->dev,
 			"%s - failed resubmitting read urb, error %d\n",
 			__func__, result);
 	/* Request CTS line state, sometimes during opening the current
 	 * CTS state can be missed. */
 	send_control_msg(port, RESEND_CTS_STATE, 1);
 	return result;
 }

 static void opticon_close(struct usb_serial_port *port)
 {
 	struct opticon_private *priv = usb_get_serial_data(port->serial);

 	/* shutdown our urbs */
 	usb_kill_urb(priv->bulk_read_urb);
 }

 static void opticon_write_control_callback(struct urb *urb)
 {
 	struct opticon_private *priv = urb->context;
 	int status = urb->status;
 	unsigned long flags;

 	/* free up the transfer buffer, as usb_free_urb() does not do this */
 	kfree(urb->transfer_buffer);

 	/* setup packet may be set if we're using it for writing */
 	kfree(urb->setup_packet);

 	if (status)
 		dev_dbg(&priv->udev->dev, "%s - nonzero write bulk status received: %d\n",
 			__func__, status);

 	spin_lock_irqsave(&priv->lock, flags);
 	--priv->outstanding_urbs;
 	spin_unlock_irqrestore(&priv->lock, flags);

 	usb_serial_port_softint(priv->port);
 }

 static int opticon_write(struct tty_struct *tty, struct usb_serial_port *port,
 			 const unsigned char *buf, int count)
 {
 	struct opticon_private *priv = usb_get_serial_data(port->serial);
 	struct usb_serial *serial = port->serial;
 	struct urb *urb;
 	unsigned char *buffer;
 	unsigned long flags;
 	int status;
 	struct usb_ctrlrequest *dr;

 	spin_lock_irqsave(&priv->lock, flags);
 	if (priv->outstanding_urbs > URB_UPPER_LIMIT) {
 		spin_unlock_irqrestore(&priv->lock, flags);
 		dev_dbg(&port->dev, "%s - write limit hit\n", __func__);
 		return 0;
 	}
 	priv->outstanding_urbs++;
 	spin_unlock_irqrestore(&priv->lock, flags);

 	buffer = kmalloc(count, GFP_ATOMIC);
 	if (!buffer) {
 		dev_err(&port->dev, "out of memory\n");
 		count = -ENOMEM;

 		goto error_no_buffer;
 	}

 	urb = usb_alloc_urb(0, GFP_ATOMIC);
 	if (!urb) {
 		dev_err(&port->dev, "no more free urbs\n");
 		count = -ENOMEM;
 		goto error_no_urb;
 	}

 	memcpy(buffer, buf, count);

 	usb_serial_debug_data(&port->dev, __func__, count, buffer);

 	/* The conncected devices do not have a bulk write endpoint,
 	 * to transmit data to de barcode device the control endpoint is used */
 	dr = kmalloc(sizeof(struct usb_ctrlrequest), GFP_NOIO);
 	if (!dr) {
 		dev_err(&port->dev, "out of memory\n");
 		count = -ENOMEM;
 		goto error_no_dr;
 	}

 	dr->bRequestType = USB_TYPE_VENDOR | USB_RECIP_INTERFACE | USB_DIR_OUT;
 	dr->bRequest = 0x01;
 	dr->wValue = 0;
 	dr->wIndex = 0;
 	dr->wLength = cpu_to_le16(count);

 	usb_fill_control_urb(urb, serial->dev,
 		usb_sndctrlpipe(serial->dev, 0),
 		(unsigned char *)dr, buffer, count,
 		opticon_write_control_callback, priv);

 	/* send it down the pipe */
 	status = usb_submit_urb(urb, GFP_ATOMIC);
 	if (status) {
 		dev_err(&port->dev,
 		"%s - usb_submit_urb(write endpoint) failed status = %d\n",
 							__func__, status);
 		count = status;
 		goto error;
 	}

 	/* we are done with this urb, so let the host driver
 	 * really free it when it is finished with it */
 	usb_free_urb(urb);

 	return count;
 error:
 	kfree(dr);
 error_no_dr:
 	usb_free_urb(urb);
 error_no_urb:
 	kfree(buffer);
 error_no_buffer:
 	spin_lock_irqsave(&priv->lock, flags);
 	--priv->outstanding_urbs;
 	spin_unlock_irqrestore(&priv->lock, flags);
 	return count;
 }

 static int opticon_write_room(struct tty_struct *tty)
 {
 	struct usb_serial_port *port = tty->driver_data;
 	struct opticon_private *priv = usb_get_serial_data(port->serial);
 	unsigned long flags;

 	/*
 	 * We really can take almost anything the user throws at us
 	 * but let's pick a nice big number to tell the tty
 	 * layer that we have lots of free space, unless we don't.
 	 */
 	spin_lock_irqsave(&priv->lock, flags);
 	if (priv->outstanding_urbs > URB_UPPER_LIMIT * 2 / 3) {
 		spin_unlock_irqrestore(&priv->lock, flags);
 		dev_dbg(&port->dev, "%s - write limit hit\n", __func__);
 		return 0;
 	}
 	spin_unlock_irqrestore(&priv->lock, flags);

 	return 2048;
 }

 static void opticon_throttle(struct tty_struct *tty)
 {
 	struct usb_serial_port *port = tty->driver_data;
 	struct opticon_private *priv = usb_get_serial_data(port->serial);
 	unsigned long flags;

 	spin_lock_irqsave(&priv->lock, flags);
 	priv->throttled = true;
 	spin_unlock_irqrestore(&priv->lock, flags);
 }


 static void opticon_unthrottle(struct tty_struct *tty)
 {
 	struct usb_serial_port *port = tty->driver_data;
 	struct opticon_private *priv = usb_get_serial_data(port->serial);
 	unsigned long flags;
 	int result, was_throttled;

 	spin_lock_irqsave(&priv->lock, flags);
 	priv->throttled = false;
 	was_throttled = priv->actually_throttled;
 	priv->actually_throttled = false;
 	spin_unlock_irqrestore(&priv->lock, flags);

 	if (was_throttled) {
 		result = usb_submit_urb(priv->bulk_read_urb, GFP_ATOMIC);
 		if (result)
 			dev_err(&port->dev,
 				"%s - failed submitting read urb, error %d\n",
 							__func__, result);
 	}
 }

 static int opticon_tiocmget(struct tty_struct *tty)
 {
 	struct usb_serial_port *port = tty->driver_data;
 	struct opticon_private *priv = usb_get_serial_data(port->serial);
 	unsigned long flags;
 	int result = 0;

 	spin_lock_irqsave(&priv->lock, flags);
 	if (priv->rts)
 		result |= TIOCM_RTS;
 	if (priv->cts)
 		result |= TIOCM_CTS;
 	spin_unlock_irqrestore(&priv->lock, flags);

 	dev_dbg(&port->dev, "%s - %x\n", __func__, result);
 	return result;
 }

 static int opticon_tiocmset(struct tty_struct *tty,
 			   unsigned int set, unsigned int clear)
 {
 	struct usb_serial_port *port = tty->driver_data;
 	struct usb_serial *serial = port->serial;
 	struct opticon_private *priv = usb_get_serial_data(port->serial);
 	unsigned long flags;
 	bool rts;
 	bool changed = false;
 	int ret;

 	/* We only support RTS so we only handle that */
 	spin_lock_irqsave(&priv->lock, flags);

 	rts = priv->rts;
 	if (set & TIOCM_RTS)
 		priv->rts = true;
 	if (clear & TIOCM_RTS)
 		priv->rts = false;
 	changed = rts ^ priv->rts;
 	spin_unlock_irqrestore(&priv->lock, flags);

 	if (!changed)
 		return 0;

 	/* Send the new RTS state to the connected device */
 	mutex_lock(&serial->disc_mutex);
 	if (!serial->disconnected)
 		ret = send_control_msg(port, CONTROL_RTS, !rts);
 	else
 		ret = -ENODEV;
 	mutex_unlock(&serial->disc_mutex);

 	return ret;
 }

 static int get_serial_info(struct opticon_private *priv,
 			   struct serial_struct __user *serial)
 {
 	struct serial_struct tmp;

 	if (!serial)
 		return -EFAULT;

 	memset(&tmp, 0x00, sizeof(tmp));

 	/* fake emulate a 16550 uart to make userspace code happy */
 	tmp.type		= PORT_16550A;
 	tmp.line		= priv->serial->minor;
 	tmp.port		= 0;
 	tmp.irq			= 0;
 	tmp.flags		= ASYNC_SKIP_TEST | ASYNC_AUTO_IRQ;
 	tmp.xmit_fifo_size	= 1024;
 	tmp.baud_base		= 9600;
 	tmp.close_delay		= 5*HZ;
 	tmp.closing_wait	= 30*HZ;

 	if (copy_to_user(serial, &tmp, sizeof(*serial)))
 		return -EFAULT;
 	return 0;
 }

 static int opticon_ioctl(struct tty_struct *tty,
 			 unsigned int cmd, unsigned long arg)
 {
 	struct usb_serial_port *port = tty->driver_data;
 	struct opticon_private *priv = usb_get_serial_data(port->serial);

 	dev_dbg(&port->dev, "%s - port %d, cmd = 0x%x\n", __func__, port->number, cmd);

 	switch (cmd) {
 	case TIOCGSERIAL:
 		return get_serial_info(priv,
 				       (struct serial_struct __user *)arg);
 	}

 	return -ENOIOCTLCMD;
 }

 static int opticon_startup(struct usb_serial *serial)
 {
 	struct opticon_private *priv;
 	struct usb_host_interface *intf;
 	int i;
 	int retval = -ENOMEM;
 	bool bulk_in_found = false;

 	/* create our private serial structure */
 	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
 	if (priv == NULL) {
 		dev_err(&serial->dev->dev, "%s - Out of memory\n", __func__);
 		return -ENOMEM;
 	}
 	spin_lock_init(&priv->lock);
 	priv->serial = serial;
 	priv->port = serial->port[0];
 	priv->udev = serial->dev;
 	priv->outstanding_urbs = 0;	/* Init the outstanding urbs */

 	/* find our bulk endpoint */
 	intf = serial->interface->altsetting;
 	for (i = 0; i < intf->desc.bNumEndpoints; ++i) {
 		struct usb_endpoint_descriptor *endpoint;

 		endpoint = &intf->endpoint[i].desc;
 		if (!usb_endpoint_is_bulk_in(endpoint))
 			continue;

 		priv->bulk_read_urb = usb_alloc_urb(0, GFP_KERNEL);
 		if (!priv->bulk_read_urb) {
 			dev_err(&priv->udev->dev, "out of memory\n");
 			goto error;
 		}

 		priv->buffer_size = usb_endpoint_maxp(endpoint) * 2;
 		priv->bulk_in_buffer = kmalloc(priv->buffer_size, GFP_KERNEL);
 		if (!priv->bulk_in_buffer) {
 			dev_err(&priv->udev->dev, "out of memory\n");
 			goto error;
 		}

 		priv->bulk_address = endpoint->bEndpointAddress;

 		bulk_in_found = true;
 		break;
 		}

 	if (!bulk_in_found) {
 		dev_err(&priv->udev->dev,
 			"Error - the proper endpoints were not found!\n");
 		goto error;
 	}

 	usb_set_serial_data(serial, priv);
 	return 0;

 error:
 	usb_free_urb(priv->bulk_read_urb);
 	kfree(priv->bulk_in_buffer);
 	kfree(priv);
 	return retval;
 }

 static void opticon_disconnect(struct usb_serial *serial)
 {
 	struct opticon_private *priv = usb_get_serial_data(serial);

 	usb_kill_urb(priv->bulk_read_urb);
 	usb_free_urb(priv->bulk_read_urb);
 }

 static void opticon_release(struct usb_serial *serial)
 {
 	struct opticon_private *priv = usb_get_serial_data(serial);

 	kfree(priv->bulk_in_buffer);
 	kfree(priv);
 }

 static int opticon_suspend(struct usb_serial *serial, pm_message_t message)
 {
 	struct opticon_private *priv = usb_get_serial_data(serial);

 	usb_kill_urb(priv->bulk_read_urb);
 	return 0;
 }

 static int opticon_resume(struct usb_serial *serial)
 {
 	struct opticon_private *priv = usb_get_serial_data(serial);
 	struct usb_serial_port *port = serial->port[0];
 	int result;

 	mutex_lock(&port->port.mutex);
 	/* This is protected by the port mutex against close/open */
 	if (test_bit(ASYNCB_INITIALIZED, &port->port.flags))
 		result = usb_submit_urb(priv->bulk_read_urb, GFP_NOIO);
 	else
 		result = 0;
 	mutex_unlock(&port->port.mutex);
 	return result;
 }

 static struct usb_serial_driver opticon_device = {
 	.driver = {
 		.owner =	THIS_MODULE,
 		.name =		"opticon",
 	},
 	.id_table =		id_table,
 	.num_ports =		1,
 	.attach =		opticon_startup,
 	.open =			opticon_open,
 	.close =		opticon_close,
 	.write =		opticon_write,
 	.write_room = 		opticon_write_room,
 	.disconnect =		opticon_disconnect,
 	.release =		opticon_release,
 	.throttle = 		opticon_throttle,
 	.unthrottle =		opticon_unthrottle,
 	.ioctl =		opticon_ioctl,
 	.tiocmget =		opticon_tiocmget,
 	.tiocmset =		opticon_tiocmset,
 	.suspend = 		opticon_suspend,
 	.resume =		opticon_resume,
 };

 static struct usb_serial_driver * const serial_drivers[] = {
 	&opticon_device, NULL
 };

 module_usb_serial_driver(serial_drivers, id_table);

 MODULE_DESCRIPTION(DRIVER_DESC);
 MODULE_LICENSE("GPL");
	/*
	* Opticon USB barcode to serial driver
	*
	* Copyright (C) 2011 Martin Jansen <martin.jansen@opticon.com>
	* Copyright (C) 2008 - 2009 Greg Kroah-Hartman <gregkh@suse.de>
	* Copyright (C) 2008 - 2009 Novell Inc.
	*
	* This program is free software; you can redistribute it and/or
	* modify it under the terms of the GNU General Public License version
	* 2 as published by the Free Software Foundation.
	*/

	#include <linux/kernel.h>
	#include <linux/init.h>
	#include <linux/tty.h>
	#include <linux/tty_driver.h>
	#include <linux/slab.h>
	#include <linux/tty_flip.h>
	#include <linux/serial.h>
	#include <linux/module.h>
	#include <linux/usb.h>
	#include <linux/usb/serial.h>
	#include <linux/uaccess.h>

	#define CONTROL_RTS 0x02
	#define RESEND_CTS_STATE 0x03

	/* max number of write urbs in flight */
	#define URB_UPPER_LIMIT 8

	/* This driver works for the Opticon 1D barcode reader
	* an examples of 1D barcode types are EAN, UPC, Code39, IATA etc.. */
	#define DRIVER_DESC "Opticon USB barcode to serial driver (1D)"

	static const struct usb_device_id id_table[] = {
	{ USB_DEVICE(0x065a, 0x0009) },
	{ },
	};
	MODULE_DEVICE_TABLE(usb, id_table);

	/* This structure holds all of the individual device information */
	struct opticon_private {
	struct usb_device *udev;
	struct usb_serial *serial;
	struct usb_serial_port *port;
	unsigned char *bulk_in_buffer;
	struct urb *bulk_read_urb;
	int buffer_size;
	u8 bulk_address;
	spinlock_t lock; /* protects the following flags */
	bool throttled;
	bool actually_throttled;
	bool rts;
	bool cts;
	int outstanding_urbs;
	};



	static void opticon_read_bulk_callback(struct urb *urb)
	{
	struct opticon_private *priv = urb->context;
	unsigned char *data = urb->transfer_buffer;
	struct usb_serial_port *port = priv->port;
	int status = urb->status;
	struct tty_struct *tty;
	int result;
	int data_length;
	unsigned long flags;

	switch (status) {
	case 0:
	/* success */
	break;
	case -ECONNRESET:
	case -ENOENT:
	case -ESHUTDOWN:
	/* this urb is terminated, clean up */
	dev_dbg(&priv->udev->dev, "%s - urb shutting down with status: %d\n",
	__func__, status);
	return;
	default:
	dev_dbg(&priv->udev->dev, "%s - nonzero urb status received: %d\n",
	__func__, status);
	goto exit;
	}

	usb_serial_debug_data(&port->dev, __func__, urb->actual_length, data);

	if (urb->actual_length > 2) {
	data_length = urb->actual_length - 2;

	/*
	* Data from the device comes with a 2 byte header:
	*
	* <0x00><0x00>data...
	* This is real data to be sent to the tty layer
	* <0x00><0x01)level
	* This is a CTS level change, the third byte is the CTS
	* value (0 for low, 1 for high).
	*/
	if ((data[0] == 0x00) && (data[1] == 0x00)) {
	/* real data, send it to the tty layer */
	tty = tty_port_tty_get(&port->port);
	if (tty) {
	tty_insert_flip_string(tty, data + 2,
	data_length);
	tty_flip_buffer_push(tty);
	tty_kref_put(tty);
	}
	} else {
	if ((data[0] == 0x00) && (data[1] == 0x01)) {
	spin_lock_irqsave(&priv->lock, flags);
	/* CTS status information package */
	if (data[2] == 0x00)
	priv->cts = false;
	else
	priv->cts = true;
	spin_unlock_irqrestore(&priv->lock, flags);
	} else {
	dev_dbg(&priv->udev->dev,
	"Unknown data packet received from the device:"
	" %2x %2x\n",
	data[0], data[1]);
	}
	}
	} else {
	dev_dbg(&priv->udev->dev,
	"Improper amount of data received from the device, "
	"%d bytes", urb->actual_length);
	}

	exit:
	spin_lock(&priv->lock);

	/* Continue trying to always read if we should */
	if (!priv->throttled) {
	usb_fill_bulk_urb(priv->bulk_read_urb, priv->udev,
	usb_rcvbulkpipe(priv->udev,
	priv->bulk_address),
	priv->bulk_in_buffer, priv->buffer_size,
	opticon_read_bulk_callback, priv);
	result = usb_submit_urb(priv->bulk_read_urb, GFP_ATOMIC);
	if (result)
	dev_err(&port->dev,
	"%s - failed resubmitting read urb, error %d\n",
	__func__, result);
	} else
	priv->actually_throttled = true;
	spin_unlock(&priv->lock);
	}

	static int send_control_msg(struct usb_serial_port *port, u8 requesttype,
	u8 val)
	{
	struct usb_serial *serial = port->serial;
	int retval;
	u8 *buffer;

	buffer = kzalloc(1, GFP_KERNEL);
	if (!buffer)
	return -ENOMEM;

	buffer[0] = val;
	/* Send the message to the vendor control endpoint
	* of the connected device */
	retval = usb_control_msg(serial->dev, usb_sndctrlpipe(serial->dev, 0),
	requesttype,
	USB_DIR_OUT\|USB_TYPE_VENDOR\|USB_RECIP_INTERFACE,
	0, 0, buffer, 1, 0);
	kfree(buffer);

	return retval;
	}

	static int opticon_open(struct tty_struct tty, struct usb_serial_port port)
	{
	struct opticon_private *priv = usb_get_serial_data(port->serial);
	unsigned long flags;
	int result = 0;

	spin_lock_irqsave(&priv->lock, flags);
	priv->throttled = false;
	priv->actually_throttled = false;
	priv->port = port;
	priv->rts = false;
	spin_unlock_irqrestore(&priv->lock, flags);

	/* Clear RTS line */
	send_control_msg(port, CONTROL_RTS, 0);

	/* Setup the read URB and start reading from the device */
	usb_fill_bulk_urb(priv->bulk_read_urb, priv->udev,
	usb_rcvbulkpipe(priv->udev,
	priv->bulk_address),
	priv->bulk_in_buffer, priv->buffer_size,
	opticon_read_bulk_callback, priv);

	/* clear the halt status of the enpoint */
	usb_clear_halt(priv->udev, priv->bulk_read_urb->pipe);

	result = usb_submit_urb(priv->bulk_read_urb, GFP_KERNEL);
	if (result)
	dev_err(&port->dev,
	"%s - failed resubmitting read urb, error %d\n",
	__func__, result);
	/* Request CTS line state, sometimes during opening the current
	* CTS state can be missed. */
	send_control_msg(port, RESEND_CTS_STATE, 1);
	return result;
	}

	static void opticon_close(struct usb_serial_port *port)
	{
	struct opticon_private *priv = usb_get_serial_data(port->serial);

	/* shutdown our urbs */
	usb_kill_urb(priv->bulk_read_urb);
	}

	static void opticon_write_control_callback(struct urb *urb)
	{
	struct opticon_private *priv = urb->context;
	int status = urb->status;
	unsigned long flags;

	/* free up the transfer buffer, as usb_free_urb() does not do this */
	kfree(urb->transfer_buffer);

	/* setup packet may be set if we're using it for writing */
	kfree(urb->setup_packet);

	if (status)
	dev_dbg(&priv->udev->dev, "%s - nonzero write bulk status received: %d\n",
	__func__, status);

	spin_lock_irqsave(&priv->lock, flags);
	--priv->outstanding_urbs;
	spin_unlock_irqrestore(&priv->lock, flags);

	usb_serial_port_softint(priv->port);
	}

	static int opticon_write(struct tty_struct tty, struct usb_serial_port port,
	const unsigned char *buf, int count)
	{
	struct opticon_private *priv = usb_get_serial_data(port->serial);
	struct usb_serial *serial = port->serial;
	struct urb *urb;
	unsigned char *buffer;
	unsigned long flags;
	int status;
	struct usb_ctrlrequest *dr;

	spin_lock_irqsave(&priv->lock, flags);
	if (priv->outstanding_urbs > URB_UPPER_LIMIT) {
	spin_unlock_irqrestore(&priv->lock, flags);
	dev_dbg(&port->dev, "%s - write limit hit\n", __func__);
	return 0;
	}
	priv->outstanding_urbs++;
	spin_unlock_irqrestore(&priv->lock, flags);

	buffer = kmalloc(count, GFP_ATOMIC);
	if (!buffer) {
	dev_err(&port->dev, "out of memory\n");
	count = -ENOMEM;

	goto error_no_buffer;
	}

	urb = usb_alloc_urb(0, GFP_ATOMIC);
	if (!urb) {
	dev_err(&port->dev, "no more free urbs\n");
	count = -ENOMEM;
	goto error_no_urb;
	}

	memcpy(buffer, buf, count);

	usb_serial_debug_data(&port->dev, __func__, count, buffer);

	/* The conncected devices do not have a bulk write endpoint,
	* to transmit data to de barcode device the control endpoint is used */
	dr = kmalloc(sizeof(struct usb_ctrlrequest), GFP_NOIO);
	if (!dr) {
	dev_err(&port->dev, "out of memory\n");
	count = -ENOMEM;
	goto error_no_dr;
	}

	dr->bRequestType = USB_TYPE_VENDOR \| USB_RECIP_INTERFACE \| USB_DIR_OUT;
	dr->bRequest = 0x01;
	dr->wValue = 0;
	dr->wIndex = 0;
	dr->wLength = cpu_to_le16(count);

	usb_fill_control_urb(urb, serial->dev,
	usb_sndctrlpipe(serial->dev, 0),
	(unsigned char *)dr, buffer, count,
	opticon_write_control_callback, priv);

	/* send it down the pipe */
	status = usb_submit_urb(urb, GFP_ATOMIC);
	if (status) {
	dev_err(&port->dev,
	"%s - usb_submit_urb(write endpoint) failed status = %d\n",
	__func__, status);
	count = status;
	goto error;
	}

	/* we are done with this urb, so let the host driver
	* really free it when it is finished with it */
	usb_free_urb(urb);

	return count;
	error:
	kfree(dr);
	error_no_dr:
	usb_free_urb(urb);
	error_no_urb:
	kfree(buffer);
	error_no_buffer:
	spin_lock_irqsave(&priv->lock, flags);
	--priv->outstanding_urbs;
	spin_unlock_irqrestore(&priv->lock, flags);
	return count;
	}

	static int opticon_write_room(struct tty_struct *tty)
	{
	struct usb_serial_port *port = tty->driver_data;
	struct opticon_private *priv = usb_get_serial_data(port->serial);
	unsigned long flags;

	/*
	* We really can take almost anything the user throws at us
	* but let's pick a nice big number to tell the tty
	* layer that we have lots of free space, unless we don't.
	*/
	spin_lock_irqsave(&priv->lock, flags);
	if (priv->outstanding_urbs > URB_UPPER_LIMIT * 2 / 3) {
	spin_unlock_irqrestore(&priv->lock, flags);
	dev_dbg(&port->dev, "%s - write limit hit\n", __func__);
	return 0;
	}
	spin_unlock_irqrestore(&priv->lock, flags);

	return 2048;
	}

	static void opticon_throttle(struct tty_struct *tty)
	{
	struct usb_serial_port *port = tty->driver_data;
	struct opticon_private *priv = usb_get_serial_data(port->serial);
	unsigned long flags;

	spin_lock_irqsave(&priv->lock, flags);
	priv->throttled = true;
	spin_unlock_irqrestore(&priv->lock, flags);
	}


	static void opticon_unthrottle(struct tty_struct *tty)
	{
	struct usb_serial_port *port = tty->driver_data;
	struct opticon_private *priv = usb_get_serial_data(port->serial);
	unsigned long flags;
	int result, was_throttled;

	spin_lock_irqsave(&priv->lock, flags);
	priv->throttled = false;
	was_throttled = priv->actually_throttled;
	priv->actually_throttled = false;
	spin_unlock_irqrestore(&priv->lock, flags);

	if (was_throttled) {
	result = usb_submit_urb(priv->bulk_read_urb, GFP_ATOMIC);
	if (result)
	dev_err(&port->dev,
	"%s - failed submitting read urb, error %d\n",
	__func__, result);
	}
	}

	static int opticon_tiocmget(struct tty_struct *tty)
	{
	struct usb_serial_port *port = tty->driver_data;
	struct opticon_private *priv = usb_get_serial_data(port->serial);
	unsigned long flags;
	int result = 0;

	spin_lock_irqsave(&priv->lock, flags);
	if (priv->rts)
	result \|= TIOCM_RTS;
	if (priv->cts)
	result \|= TIOCM_CTS;
	spin_unlock_irqrestore(&priv->lock, flags);

	dev_dbg(&port->dev, "%s - %x\n", __func__, result);
	return result;
	}

	static int opticon_tiocmset(struct tty_struct *tty,
	unsigned int set, unsigned int clear)
	{
	struct usb_serial_port *port = tty->driver_data;
	struct usb_serial *serial = port->serial;
	struct opticon_private *priv = usb_get_serial_data(port->serial);
	unsigned long flags;
	bool rts;
	bool changed = false;
	int ret;

	/* We only support RTS so we only handle that */
	spin_lock_irqsave(&priv->lock, flags);

	rts = priv->rts;
	if (set & TIOCM_RTS)
	priv->rts = true;
	if (clear & TIOCM_RTS)
	priv->rts = false;
	changed = rts ^ priv->rts;
	spin_unlock_irqrestore(&priv->lock, flags);

	if (!changed)
	return 0;

	/* Send the new RTS state to the connected device */
	mutex_lock(&serial->disc_mutex);
	if (!serial->disconnected)
	ret = send_control_msg(port, CONTROL_RTS, !rts);
	else
	ret = -ENODEV;
	mutex_unlock(&serial->disc_mutex);

	return ret;
	}

	static int get_serial_info(struct opticon_private *priv,
	struct serial_struct __user *serial)
	{
	struct serial_struct tmp;

	if (!serial)
	return -EFAULT;

	memset(&tmp, 0x00, sizeof(tmp));

	/* fake emulate a 16550 uart to make userspace code happy */
	tmp.type = PORT_16550A;
	tmp.line = priv->serial->minor;
	tmp.port = 0;
	tmp.irq = 0;
	tmp.flags = ASYNC_SKIP_TEST \| ASYNC_AUTO_IRQ;
	tmp.xmit_fifo_size = 1024;
	tmp.baud_base = 9600;
	tmp.close_delay = 5*HZ;
	tmp.closing_wait = 30*HZ;

	if (copy_to_user(serial, &tmp, sizeof(*serial)))
	return -EFAULT;
	return 0;
	}

	static int opticon_ioctl(struct tty_struct *tty,
	unsigned int cmd, unsigned long arg)
	{
	struct usb_serial_port *port = tty->driver_data;
	struct opticon_private *priv = usb_get_serial_data(port->serial);

	dev_dbg(&port->dev, "%s - port %d, cmd = 0x%x\n", __func__, port->number, cmd);

	switch (cmd) {
	case TIOCGSERIAL:
	return get_serial_info(priv,
	(struct serial_struct __user *)arg);
	}

	return -ENOIOCTLCMD;
	}

	static int opticon_startup(struct usb_serial *serial)
	{
	struct opticon_private *priv;
	struct usb_host_interface *intf;
	int i;
	int retval = -ENOMEM;
	bool bulk_in_found = false;

	/* create our private serial structure */
	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
	if (priv == NULL) {
	dev_err(&serial->dev->dev, "%s - Out of memory\n", __func__);
	return -ENOMEM;
	}
	spin_lock_init(&priv->lock);
	priv->serial = serial;
	priv->port = serial->port[0];
	priv->udev = serial->dev;
	priv->outstanding_urbs = 0; /* Init the outstanding urbs */

	/* find our bulk endpoint */
	intf = serial->interface->altsetting;
	for (i = 0; i < intf->desc.bNumEndpoints; ++i) {
	struct usb_endpoint_descriptor *endpoint;

	endpoint = &intf->endpoint[i].desc;
	if (!usb_endpoint_is_bulk_in(endpoint))
	continue;

	priv->bulk_read_urb = usb_alloc_urb(0, GFP_KERNEL);
	if (!priv->bulk_read_urb) {
	dev_err(&priv->udev->dev, "out of memory\n");
	goto error;
	}

	priv->buffer_size = usb_endpoint_maxp(endpoint) * 2;
	priv->bulk_in_buffer = kmalloc(priv->buffer_size, GFP_KERNEL);
	if (!priv->bulk_in_buffer) {
	dev_err(&priv->udev->dev, "out of memory\n");
	goto error;
	}

	priv->bulk_address = endpoint->bEndpointAddress;

	bulk_in_found = true;
	break;
	}

	if (!bulk_in_found) {
	dev_err(&priv->udev->dev,
	"Error - the proper endpoints were not found!\n");
	goto error;
	}

	usb_set_serial_data(serial, priv);
	return 0;

	error:
	usb_free_urb(priv->bulk_read_urb);
	kfree(priv->bulk_in_buffer);
	kfree(priv);
	return retval;
	}

	static void opticon_disconnect(struct usb_serial *serial)
	{
	struct opticon_private *priv = usb_get_serial_data(serial);

	usb_kill_urb(priv->bulk_read_urb);
	usb_free_urb(priv->bulk_read_urb);
	}

	static void opticon_release(struct usb_serial *serial)
	{
	struct opticon_private *priv = usb_get_serial_data(serial);

	kfree(priv->bulk_in_buffer);
	kfree(priv);
	}

	static int opticon_suspend(struct usb_serial *serial, pm_message_t message)
	{
	struct opticon_private *priv = usb_get_serial_data(serial);

	usb_kill_urb(priv->bulk_read_urb);
	return 0;
	}

	static int opticon_resume(struct usb_serial *serial)
	{
	struct opticon_private *priv = usb_get_serial_data(serial);
	struct usb_serial_port *port = serial->port[0];
	int result;

	mutex_lock(&port->port.mutex);
	/* This is protected by the port mutex against close/open */
	if (test_bit(ASYNCB_INITIALIZED, &port->port.flags))
	result = usb_submit_urb(priv->bulk_read_urb, GFP_NOIO);
	else
	result = 0;
	mutex_unlock(&port->port.mutex);
	return result;
	}

	static struct usb_serial_driver opticon_device = {
	.driver = {
	.owner = THIS_MODULE,
	.name = "opticon",
	},
	.id_table = id_table,
	.num_ports = 1,
	.attach = opticon_startup,
	.open = opticon_open,
	.close = opticon_close,
	.write = opticon_write,
	.write_room = opticon_write_room,
	.disconnect = opticon_disconnect,
	.release = opticon_release,
	.throttle = opticon_throttle,
	.unthrottle = opticon_unthrottle,
	.ioctl = opticon_ioctl,
	.tiocmget = opticon_tiocmget,
	.tiocmset = opticon_tiocmset,
	.suspend = opticon_suspend,
	.resume = opticon_resume,
	};

	static struct usb_serial_driver * const serial_drivers[] = {
	&opticon_device, NULL
	};

	module_usb_serial_driver(serial_drivers, id_table);

	MODULE_DESCRIPTION(DRIVER_DESC);
	MODULE_LICENSE("GPL");