USB: serial: add symbol serial driver

This is for the Symbol 6608 barcode scanner in a fake "HID" mode.

Thanks to Dalibor Grgec for working with me to get this to start to work
properly.

Cc: Dalibor Grgec <dalibor.grgec@zemris.fer.hr>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/usb/serial/Kconfig

@@ -515,6 +515,15 @@ config USB_SERIAL_SIERRAWIRELESS
 	  To compile this driver as a module, choose M here: the
 	  module will be called sierra.
 
+config USB_SERIAL_SYMBOL
+	tristate "USB Symbol Barcode driver (serial mode)"
+	help
+	  Say Y here if you want to use a Symbol USB Barcode device
+	  in serial emulation mode.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called symbolserial.
+
 config USB_SERIAL_TI
 	tristate "USB TI 3410/5052 Serial Driver"
 	help

drivers/usb/serial/Makefile

@@ -49,6 +49,7 @@ obj-$(CONFIG_USB_SERIAL_SAFE)			+= safe_serial.o
 obj-$(CONFIG_USB_SERIAL_SIEMENS_MPI)		+= siemens_mpi.o
 obj-$(CONFIG_USB_SERIAL_SIERRAWIRELESS)		+= sierra.o
 obj-$(CONFIG_USB_SERIAL_SPCP8X5)		+= spcp8x5.o
+obj-$(CONFIG_USB_SERIAL_SYMBOL)			+= symbolserial.o
 obj-$(CONFIG_USB_SERIAL_TI)			+= ti_usb_3410_5052.o
 obj-$(CONFIG_USB_SERIAL_VISOR)			+= visor.o
 obj-$(CONFIG_USB_SERIAL_WHITEHEAT)		+= whiteheat.o

drivers/usb/serial/symbolserial.c

+/*
+ * Symbol USB barcode to serial driver
+ *
+ * Copyright (C) 2009 Greg Kroah-Hartman <gregkh@suse.de>
+ * Copyright (C) 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/tty_flip.h>
+#include <linux/module.h>
+#include <linux/usb.h>
+#include <linux/usb/serial.h>
+#include <linux/uaccess.h>
+
+static int debug;
+
+static struct usb_device_id id_table[] = {
+	{ USB_DEVICE(0x05e0, 0x0600) },
+	{ },
+};
+MODULE_DEVICE_TABLE(usb, id_table);
+
+/* This structure holds all of the individual device information */
+struct symbol_private {
+	struct usb_device *udev;
+	struct usb_serial *serial;
+	struct usb_serial_port *port;
+	unsigned char *int_buffer;
+	struct urb *int_urb;
+	int buffer_size;
+	u8 bInterval;
+	u8 int_address;
+	spinlock_t lock;	/* protects the following flags */
+	bool throttled;
+	bool actually_throttled;
+	bool rts;
+};
+
+static void symbol_int_callback(struct urb *urb)
+{
+	struct symbol_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 available_room = 0;
+	int data_length;
+
+	dbg("%s - port %d", __func__, port->number);
+
+	switch (status) {
+	case 0:
+		/* success */
+		break;
+	case -ECONNRESET:
+	case -ENOENT:
+	case -ESHUTDOWN:
+		/* this urb is terminated, clean up */
+		dbg("%s - urb shutting down with status: %d",
+		    __func__, status);
+		return;
+	default:
+		dbg("%s - nonzero urb status received: %d",
+		    __func__, status);
+		goto exit;
+	}
+
+	usb_serial_debug_data(debug, &port->dev, __func__, urb->actual_length,
+			      data);
+
+	if (urb->actual_length > 1) {
+		data_length = urb->actual_length - 1;
+
+		/*
+		 * Data from the device comes with a 1 byte header:
+		 *
+		 * <size of data>data...
+		 * 	This is real data to be sent to the tty layer
+		 * we pretty much just ignore the size and send everything
+		 * else to the tty layer.
+		 */
+		tty = tty_port_tty_get(&port->port);
+		if (tty) {
+			available_room = tty_buffer_request_room(tty,
+							data_length);
+			if (available_room) {
+				tty_insert_flip_string(tty, &data[1],
+						       available_room);
+				tty_flip_buffer_push(tty);
+			}
+			tty_kref_put(tty);
+		}
+	} else {
+		dev_dbg(&priv->udev->dev,
+			"Improper ammount 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_int_urb(priv->int_urb, priv->udev,
+				 usb_rcvintpipe(priv->udev,
+				 		priv->int_address),
+				 priv->int_buffer, priv->buffer_size,
+				 symbol_int_callback, priv, priv->bInterval);
+		result = usb_submit_urb(priv->int_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 symbol_open(struct tty_struct *tty, struct usb_serial_port *port,
+			struct file *filp)
+{
+	struct symbol_private *priv = usb_get_serial_data(port->serial);
+	unsigned long flags;
+	int result = 0;
+
+	dbg("%s - port %d", __func__, port->number);
+
+	spin_lock_irqsave(&priv->lock, flags);
+	priv->throttled = false;
+	priv->actually_throttled = false;
+	priv->port = port;
+	spin_unlock_irqrestore(&priv->lock, flags);
+
+	/*
+	 * Force low_latency on so that our tty_push actually forces the data
+	 * through, otherwise it is scheduled, and with high data rates (like
+	 * with OHCI) data can get lost.
+	 */
+	if (tty)
+		tty->low_latency = 1;
+
+	/* Start reading from the device */
+	usb_fill_int_urb(priv->int_urb, priv->udev,
+			 usb_rcvintpipe(priv->udev, priv->int_address),
+			 priv->int_buffer, priv->buffer_size,
+			 symbol_int_callback, priv, priv->bInterval);
+	result = usb_submit_urb(priv->int_urb, GFP_KERNEL);
+	if (result)
+		dev_err(&port->dev,
+			"%s - failed resubmitting read urb, error %d\n",
+			__func__, result);
+	return result;
+}
+
+static void symbol_close(struct tty_struct *tty, struct usb_serial_port *port,
+			  struct file *filp)
+{
+	struct symbol_private *priv = usb_get_serial_data(port->serial);
+
+	dbg("%s - port %d", __func__, port->number);
+
+	/* shutdown our urbs */
+	usb_kill_urb(priv->int_urb);
+}
+
+static void symbol_throttle(struct tty_struct *tty)
+{
+	struct usb_serial_port *port = tty->driver_data;
+	struct symbol_private *priv = usb_get_serial_data(port->serial);
+	unsigned long flags;
+
+	dbg("%s - port %d", __func__, port->number);
+	spin_lock_irqsave(&priv->lock, flags);
+	priv->throttled = true;
+	spin_unlock_irqrestore(&priv->lock, flags);
+}
+
+static void symbol_unthrottle(struct tty_struct *tty)
+{
+	struct usb_serial_port *port = tty->driver_data;
+	struct symbol_private *priv = usb_get_serial_data(port->serial);
+	unsigned long flags;
+	int result;
+
+	dbg("%s - port %d", __func__, port->number);
+
+	spin_lock_irqsave(&priv->lock, flags);
+	priv->throttled = false;
+	priv->actually_throttled = false;
+	spin_unlock_irqrestore(&priv->lock, flags);
+
+	priv->int_urb->dev = port->serial->dev;
+	result = usb_submit_urb(priv->int_urb, GFP_ATOMIC);
+	if (result)
+		dev_err(&port->dev,
+			"%s - failed submitting read urb, error %d\n",
+							__func__, result);
+}
+
+static int symbol_startup(struct usb_serial *serial)
+{
+	struct symbol_private *priv;
+	struct usb_host_interface *intf;
+	int i;
+	int retval = -ENOMEM;
+	bool int_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;
+
+	/* find our interrupt 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_int_in(endpoint))
+			continue;
+
+		priv->int_urb = usb_alloc_urb(0, GFP_KERNEL);
+		if (!priv->int_urb) {
+			dev_err(&priv->udev->dev, "out of memory\n");
+			goto error;
+		}
+
+		priv->buffer_size = le16_to_cpu(endpoint->wMaxPacketSize) * 2;
+		priv->int_buffer = kmalloc(priv->buffer_size, GFP_KERNEL);
+		if (!priv->int_buffer) {
+			dev_err(&priv->udev->dev, "out of memory\n");
+			goto error;
+		}
+
+		priv->int_address = endpoint->bEndpointAddress;
+		priv->bInterval = endpoint->bInterval;
+
+		/* set up our int urb */
+		usb_fill_int_urb(priv->int_urb, priv->udev,
+				 usb_rcvintpipe(priv->udev,
+				 		endpoint->bEndpointAddress),
+				 priv->int_buffer, priv->buffer_size,
+				 symbol_int_callback, priv, priv->bInterval);
+
+		int_in_found = true;
+		break;
+		}
+
+	if (!int_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->int_urb);
+	kfree(priv->int_buffer);
+	kfree(priv);
+	return retval;
+}
+
+static void symbol_shutdown(struct usb_serial *serial)
+{
+	struct symbol_private *priv = usb_get_serial_data(serial);
+
+	dbg("%s", __func__);
+
+	usb_kill_urb(priv->int_urb);
+	usb_free_urb(priv->int_urb);
+	kfree(priv->int_buffer);
+	kfree(priv);
+	usb_set_serial_data(serial, NULL);
+}
+
+static struct usb_driver symbol_driver = {
+	.name =			"symbol",
+	.probe =		usb_serial_probe,
+	.disconnect =		usb_serial_disconnect,
+	.id_table =		id_table,
+	.no_dynamic_id = 	1,
+};
+
+static struct usb_serial_driver symbol_device = {
+	.driver = {
+		.owner =	THIS_MODULE,
+		.name =		"symbol",
+	},
+	.id_table =		id_table,
+	.usb_driver = 		&symbol_driver,
+	.num_ports =		1,
+	.attach =		symbol_startup,
+	.open =			symbol_open,
+	.close =		symbol_close,
+	.shutdown =		symbol_shutdown,
+	.throttle = 		symbol_throttle,
+	.unthrottle =		symbol_unthrottle,
+};
+
+static int __init symbol_init(void)
+{
+	int retval;
+
+	retval = usb_serial_register(&symbol_device);
+	if (retval)
+		return retval;
+	retval = usb_register(&symbol_driver);
+	if (retval)
+		usb_serial_deregister(&symbol_device);
+	return retval;
+}
+
+static void __exit symbol_exit(void)
+{
+	usb_deregister(&symbol_driver);
+	usb_serial_deregister(&symbol_device);
+}
+
+module_init(symbol_init);
+module_exit(symbol_exit);
+MODULE_LICENSE("GPL");
+
+module_param(debug, bool, S_IRUGO | S_IWUSR);
+MODULE_PARM_DESC(debug, "Debug enabled or not");