[PATCH] USB: Add Lego USB Infrared Tower driver

drivers/usb/misc/Kconfig

@@ -58,6 +58,18 @@ config USB_RIO500
 	  To compile this driver as a module, choose M here: the
 	  module will be called rio500.
 
+config USB_LEGOTOWER
+	tristate "USB Lego Infrared Tower support (EXPERIMENTAL)"
+	depends on USB && EXPERIMENTAL
+	help
+	  Say Y here if you want to connect a USB Lego Infrared Tower to your
+	  computer's USB port.
+
+	  This code is also available as a module ( = code which can be
+	  inserted in and removed from the running kernel whenever you want).
+	  The module will be called legousbtower. If you want to compile it as
+	  a module, say M here and read <file:Documentation/modules.txt>.
+
 config USB_BRLVGER
 	tristate "Tieman Voyager USB Braille display support (EXPERIMENTAL)"
 	depends on USB && EXPERIMENTAL

drivers/usb/misc/Makefile

@@ -12,3 +12,4 @@ obj-$(CONFIG_USB_SPEEDTOUCH)	+= speedtch.o
 obj-$(CONFIG_USB_TEST)		+= usbtest.o
 obj-$(CONFIG_USB_TIGL)		+= tiglusb.o
 obj-$(CONFIG_USB_USS720)	+= uss720.o
+obj-$(CONFIG_USB_LEGOTOWER)	+= legousbtower.o

drivers/usb/misc/legousbtower.c

+/*
+ * LEGO USB Tower driver
+ *
+ * Copyright (c) 2003 David Glance <davidgsf@sourceforge.net> 
+ *               2001 Juergen Stuber <stuber@loria.fr>
+ *
+ *	This program is free software; you can redistribute it and/or
+ *	modify it under the terms of the GNU General Public License as
+ *	published by the Free Software Foundation; either version 2 of
+ *	the License, or (at your option) any later version.
+ *
+ * derived from USB Skeleton driver - 0.5
+ * Copyright (c) 2001 Greg Kroah-Hartman (greg@kroah.com)
+ *
+ * History:
+ *
+ * 2001-10-13 - 0.1 js
+ *   - first version
+ * 2001-11-03 - 0.2 js
+ *   - simplified buffering, one-shot URBs for writing
+ * 2001-11-10 - 0.3 js
+ *   - removed IOCTL (setting power/mode is more complicated, postponed)
+ * 2001-11-28 - 0.4 js
+ *   - added vendor commands for mode of operation and power level in open
+ * 2001-12-04 - 0.5 js
+ *   - set IR mode by default (by oversight 0.4 set VLL mode)
+ * 2002-01-11 - 0.5? pcchan
+ *   - make read buffer reusable and work around bytes_to_write issue between
+ *     uhci and legusbtower
+ * 2002-09-23 - 0.52 david (david@csse.uwa.edu.au)
+ *   - imported into lejos project
+ *   - changed wake_up to wake_up_interruptible
+ *   - changed to use lego0 rather than tower0
+ *   - changed dbg() to use __func__ rather than deprecated __FUNCTION__
+ * 2003-01-12 - 0.53 david (david@csse.uwa.edu.au)
+ *   - changed read and write to write everything or timeout (from a patch by Chris Riesen and 
+ *     Brett Thaeler driver)
+ *   - added ioctl functionality to set timeouts
+ * 2003-07-18 - 0.54 davidgsf (david@csse.uwa.edu.au) 
+ *   - initial import into LegoUSB project
+ *   - merge of existing LegoUSB.c driver
+ * 2003-07-18 - 0.56 davidgsf (david@csse.uwa.edu.au) 
+ *   - port to 2.6 style driver
+ */
+
+#include <linux/config.h>
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+#include <linux/smp_lock.h>
+#include <linux/completion.h>
+#include <asm/uaccess.h>
+#include <linux/usb.h>
+
+
+#ifdef CONFIG_USB_DEBUG
+	static int debug = 4;
+#else
+	static int debug = 1;
+#endif
+
+/* Use our own dbg macro */
+#undef dbg
+#define dbg(lvl, format, arg...) do { if (debug >= lvl) printk(KERN_DEBUG  __FILE__ " : " format " \n", ## arg); } while (0)
+
+
+/* Version Information */
+#define DRIVER_VERSION "v0.56"
+#define DRIVER_AUTHOR "David Glance, davidgsf@sourceforge.net"
+#define DRIVER_DESC "LEGO USB Tower Driver"
+
+/* Module paramaters */
+MODULE_PARM(debug, "i");
+MODULE_PARM_DESC(debug, "Debug enabled or not");
+
+
+/* Define these values to match your device */
+#define LEGO_USB_TOWER_VENDOR_ID	0x0694
+#define LEGO_USB_TOWER_PRODUCT_ID	0x0001
+
+/* table of devices that work with this driver */
+static struct usb_device_id tower_table [] = {
+	{ USB_DEVICE(LEGO_USB_TOWER_VENDOR_ID, LEGO_USB_TOWER_PRODUCT_ID) },
+	{ }					/* Terminating entry */
+};
+
+MODULE_DEVICE_TABLE (usb, tower_table);
+
+/* FIXME: Get a minor range for your devices from the usb maintainer */
+#define LEGO_USB_TOWER_MINOR_BASE	0xB3
+
+/* we can have up to this number of device plugged in at once */
+#define MAX_DEVICES		16
+
+#define COMMAND_TIMEOUT    (2*HZ)  /* 60 second timeout for a command */
+
+/* Structure to hold all of our device specific stuff */
+struct lego_usb_tower {
+	struct semaphore	sem;		/* locks this structure */
+	struct usb_device* 	udev;		/* save off the usb device pointer */
+	struct usb_interface*   interface;
+	unsigned char		minor;		/* the starting minor number for this device */
+
+	int			open_count;	/* number of times this port has been opened */
+
+	char*			read_buffer;
+	int			read_buffer_length;
+
+	wait_queue_head_t	read_wait;
+	wait_queue_head_t	write_wait;
+
+	char*			interrupt_in_buffer;
+	struct usb_endpoint_descriptor* interrupt_in_endpoint;
+	struct urb*		interrupt_in_urb;
+
+	char*			interrupt_out_buffer;
+	struct usb_endpoint_descriptor* interrupt_out_endpoint;
+	struct urb*		interrupt_out_urb;
+
+};
+
+/* Note that no locking is needed:
+ * read_buffer is arbitrated by read_buffer_length == 0
+ * interrupt_out_buffer is arbitrated by interrupt_out_urb->status == -EINPROGRESS
+ * interrupt_in_buffer belongs to urb alone and is overwritten on overflow
+ */
+
+/* the global usb devfs handle */
+// extern devfs_handle_t usb_devfs_handle;
+
+
+/* local function prototypes */
+static ssize_t tower_read	(struct file *file, char *buffer, size_t count, loff_t *ppos);
+static ssize_t tower_write	(struct file *file, const char *buffer, size_t count, loff_t *ppos);
+static int tower_ioctl		(struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg);
+static inline void tower_delete (struct lego_usb_tower *dev);
+static int tower_open		(struct inode *inode, struct file *file);
+static int tower_release	(struct inode *inode, struct file *file);
+static int tower_release_internal (struct lego_usb_tower *dev);
+static void tower_abort_transfers (struct lego_usb_tower *dev);
+static void tower_interrupt_in_callback (struct urb *urb, struct pt_regs *regs);
+static void tower_interrupt_out_callback (struct urb *urb, struct pt_regs *regs);
+
+static int  tower_probe	(struct usb_interface *interface, const struct usb_device_id *id);
+static void tower_disconnect	(struct usb_interface *interface);
+
+
+/* prevent races between open() and disconnect */
+static DECLARE_MUTEX (disconnect_sem);
+
+/* file operations needed when we register this driver */
+static struct file_operations tower_fops = {
+	.owner = 	THIS_MODULE,
+	.read  = 	tower_read,
+	.write =	tower_write,
+	.ioctl =	tower_ioctl,
+	.open =		tower_open,
+	.release = 	tower_release,
+};
+
+/* 
+ * usb class driver info in order to get a minor number from the usb core,
+ * and to have the device registered with devfs and the driver core
+ */
+static struct usb_class_driver tower_class = {
+	.name =		"usb/legousbtower%d",
+	.fops =		&tower_fops,
+	.mode =		S_IFCHR | S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | S_IROTH,
+	.minor_base =	LEGO_USB_TOWER_MINOR_BASE,
+};
+
+
+/* usb specific object needed to register this driver with the usb subsystem */
+static struct usb_driver tower_driver = {
+	.owner =        THIS_MODULE,
+	.name =	        "legousbtower",
+	.probe = 	tower_probe,
+	.disconnect = 	tower_disconnect,
+	.id_table = 	tower_table,
+};
+
+
+/**
+ *	lego_usb_tower_debug_data
+ */
+static inline void lego_usb_tower_debug_data (int level, const char *function, int size, const unsigned char *data)
+{
+	int i;
+
+	if (debug < level)
+		return; 
+	
+	printk (KERN_DEBUG __FILE__": %s - length = %d, data = ", function, size);
+	for (i = 0; i < size; ++i) {
+		printk ("%.2x ", data[i]);
+	}
+	printk ("\n");
+}
+
+
+/**
+ *	tower_delete
+ */
+static inline void tower_delete (struct lego_usb_tower *dev)
+{
+	dbg(2, "%s enter", __func__);
+
+	tower_abort_transfers (dev);
+
+	/* free data structures */
+	if (dev->interrupt_in_urb != NULL) {
+		usb_free_urb (dev->interrupt_in_urb);
+       }
+	if (dev->interrupt_out_urb != NULL) {
+		usb_free_urb (dev->interrupt_out_urb);
+	}
+	if (dev->read_buffer != NULL) {
+		kfree (dev->read_buffer);
+	}
+	if (dev->interrupt_in_buffer != NULL) {
+		kfree (dev->interrupt_in_buffer);
+	}
+	if (dev->interrupt_out_buffer != NULL) {
+		kfree (dev->interrupt_out_buffer);
+	}
+	kfree (dev);
+
+	dbg(2, "%s : leave", __func__);
+}
+
+
+/**
+ *	tower_open
+ */
+static int tower_open (struct inode *inode, struct file *file)
+{
+	struct lego_usb_tower *dev = NULL;
+	int subminor;
+	int retval = 0;
+	struct usb_interface *interface;
+	
+	dbg(2,"%s : enter", __func__);
+
+	subminor = iminor(inode);
+
+	down (&disconnect_sem);
+
+	interface = usb_find_interface (&tower_driver, subminor);
+
+	if (!interface) {
+		err ("%s - error, can't find device for minor %d",
+		     __FUNCTION__, subminor);
+		retval = -ENODEV;
+		goto exit_no_device;
+	}
+
+	dev = usb_get_intfdata(interface);
+
+	if (!dev) {
+		retval = -ENODEV;
+		goto exit_no_device;
+	}
+
+	/* lock this device */
+	down (&dev->sem);
+
+	
+	/* increment our usage count for the device */
+	++dev->open_count;
+
+	/* save device in the file's private structure */
+	file->private_data = dev;
+
+
+	/* initialize in direction */
+	dev->read_buffer_length = 0;
+
+	up (&dev->sem);
+
+ exit_no_device:
+
+	up (&disconnect_sem);
+
+	dbg(2,"%s : leave, return value %d ", __func__, retval);
+
+	return retval;
+}
+
+/**
+ *	tower_release
+ */
+static int tower_release (struct inode *inode, struct file *file)
+{
+	struct lego_usb_tower *dev;
+	int retval = 0;
+
+	dbg(2," %s : enter", __func__);
+
+	dev = (struct lego_usb_tower *)file->private_data;
+
+	if (dev == NULL) {
+	        dbg(1," %s : object is NULL", __func__);
+		retval = -ENODEV;
+		        goto exit;
+	}
+
+
+	/* lock our device */
+	down (&dev->sem);
+
+ 	if (dev->open_count <= 0) {
+		dbg(1," %s : device not opened", __func__);
+		retval = -ENODEV;
+		goto exit;
+	}
+
+	/* do the work */
+	retval = tower_release_internal (dev);
+
+ exit:
+	up (&dev->sem);
+	dbg(2," %s : leave, return value %d", __func__, retval);
+	return retval;
+}
+
+
+/**
+ *	tower_release_internal
+ */
+static int tower_release_internal (struct lego_usb_tower *dev)
+{
+	int retval = 0;
+
+	dbg(2," %s : enter", __func__);
+
+	if (dev->udev == NULL) {
+		/* the device was unplugged before the file was released */
+		tower_delete (dev);
+		goto exit;
+	}
+
+	/* decrement our usage count for the device */
+	--dev->open_count;
+	if (dev->open_count <= 0) {
+	        tower_abort_transfers (dev);
+		dev->open_count = 0;
+	}
+
+ exit:
+	dbg(2," %s : leave", __func__);
+	return retval;
+}
+
+
+/**
+ *	tower_abort_transfers
+ *      aborts transfers and frees associated data structures
+ */
+static void tower_abort_transfers (struct lego_usb_tower *dev)
+{
+	dbg(2," %s : enter", __func__);
+
+	if (dev == NULL) {
+		dbg(1," %s : dev is null", __func__);
+	        goto exit;
+	}
+
+	/* shutdown transfer */
+	if (dev->interrupt_in_urb != NULL) {
+	        usb_unlink_urb (dev->interrupt_in_urb);
+	}
+	if (dev->interrupt_out_urb != NULL) {
+	        usb_unlink_urb (dev->interrupt_out_urb);
+	}
+
+ exit:
+	dbg(2," %s : leave", __func__);
+}
+
+
+/**
+ *	tower_read
+ */
+static ssize_t tower_read (struct file *file, char *buffer, size_t count, loff_t *ppos)
+{
+	struct lego_usb_tower *dev;
+	size_t bytes_read = 0;
+	size_t bytes_to_read;
+	int i;
+	int retval = 0;
+	int timeout = 0;
+
+	dbg(2," %s : enter, count = %d", __func__, count);
+
+	dev = (struct lego_usb_tower *)file->private_data;
+	
+	/* lock this object */
+	down (&dev->sem);
+
+	/* verify that the device wasn't unplugged */
+	if (dev->udev == NULL) {
+		retval = -ENODEV;
+		err("No device or device unplugged %d", retval);
+		goto exit;
+	}
+	
+	/* verify that we actually have some data to read */
+	if (count == 0) {
+	  	dbg(1," %s : read request of 0 bytes", __func__);
+		goto exit;
+	}
+
+
+	timeout = COMMAND_TIMEOUT;
+
+	while (1) {
+		if (dev->read_buffer_length == 0) {
+
+			/* start reading */
+			usb_fill_int_urb (dev->interrupt_in_urb,dev->udev,
+					  usb_rcvintpipe(dev->udev, dev->interrupt_in_endpoint->bEndpointAddress),
+					  dev->interrupt_in_buffer,
+					  dev->interrupt_in_endpoint->wMaxPacketSize,
+					  tower_interrupt_in_callback,
+					  dev,
+					  dev->interrupt_in_endpoint->bInterval);
+			
+			retval = usb_submit_urb (dev->interrupt_in_urb, GFP_KERNEL);
+			
+			if (retval < 0) {
+				err("Couldn't submit interrupt_in_urb");
+				goto exit;
+			}
+
+			if (timeout <= 0) {
+			        retval = -ETIMEDOUT;
+			        goto exit;
+			}
+
+			if (signal_pending(current)) {
+
+				retval = -EINTR;
+				goto exit;
+			}
+
+			up (&dev->sem);
+			timeout = interruptible_sleep_on_timeout (&dev->read_wait, timeout);
+			down (&dev->sem);
+
+	        } else {
+	                /* copy the data from read_buffer into userspace */
+                        bytes_to_read = count > dev->read_buffer_length ? dev->read_buffer_length : count;
+	                 if (copy_to_user (buffer, dev->read_buffer, bytes_to_read) != 0) {
+	                         retval = -EFAULT;
+	                         goto exit;
+	                 }
+	                 dev->read_buffer_length -= bytes_to_read;
+                        for (i=0; i<dev->read_buffer_length; i++) {
+                                dev->read_buffer[i] = dev->read_buffer[i+bytes_to_read];
+                        }
+
+                        buffer += bytes_to_read;
+                        count -= bytes_to_read;
+                        bytes_read += bytes_to_read;
+			if (count == 0) {
+				break;
+			}
+                }
+
+
+        }
+
+        retval = bytes_read;
+
+ exit:
+	/* unlock the device */
+	up (&dev->sem);
+
+	dbg(2," %s : leave, return value %d", __func__, retval);
+	return retval;
+}
+
+
+/**
+ *	tower_write
+ */
+static ssize_t tower_write (struct file *file, const char *buffer, size_t count, loff_t *ppos)
+{
+	struct lego_usb_tower *dev;
+	size_t bytes_written = 0;
+	size_t bytes_to_write;
+        size_t buffer_size;
+	int retval = 0;
+	int timeout = 0;
+
+	dbg(2," %s : enter, count = %d", __func__, count);
+
+	dev = (struct lego_usb_tower *)file->private_data;
+
+	/* lock this object */
+	down (&dev->sem);
+
+	/* verify that the device wasn't unplugged */
+	if (dev->udev == NULL) {
+		retval = -ENODEV;
+		err("No device or device unplugged %d", retval);
+		goto exit;
+	}
+
+	/* verify that we actually have some data to write */
+	if (count == 0) {
+        	dbg(1," %s : write request of 0 bytes", __func__);
+		goto exit;
+	}
+
+
+        while (count > 0) {
+                if (dev->interrupt_out_urb->status == -EINPROGRESS) {
+		        timeout = COMMAND_TIMEOUT;
+
+			while (timeout > 0) {
+				if (signal_pending(current)) {
+					dbg(1," %s : interrupted", __func__);
+					retval = -EINTR;
+					goto exit;
+				}
+				up (&dev->sem);
+				timeout = interruptible_sleep_on_timeout (&dev->write_wait, timeout);
+				down (&dev->sem);
+				if (timeout > 0) {
+					break;
+				}
+				dbg(1," %s : interrupted timeout: %d", __func__, timeout);
+			}
+
+
+			dbg(1," %s : final timeout: %d", __func__, timeout);
+
+			if (timeout == 0) {
+				dbg(1, "%s - command timed out.", __func__);
+				retval = -ETIMEDOUT;
+				goto exit;
+			}
+
+                	dbg(4," %s : in progress, count = %d", __func__, count);
+
+                } else {
+		        dbg(4," %s : sending, count = %d", __func__, count);
+
+                        /* write the data into interrupt_out_buffer from userspace */
+                        buffer_size = dev->interrupt_out_endpoint->wMaxPacketSize;
+                        bytes_to_write = count > buffer_size ? buffer_size : count;
+			dbg(4," %s : buffer_size = %d, count = %d, bytes_to_write = %d", __func__, buffer_size, count, bytes_to_write);
+
+                        if (copy_from_user (dev->interrupt_out_buffer, buffer, bytes_to_write) != 0) {
+                                retval = -EFAULT;
+                                goto exit;
+                        }
+
+                        /* send off the urb */
+                        usb_fill_int_urb(
+                                dev->interrupt_out_urb,
+                                dev->udev, 
+                                usb_sndintpipe(dev->udev, dev->interrupt_out_endpoint->bEndpointAddress),
+                                dev->interrupt_out_buffer,
+                                bytes_to_write,
+                                tower_interrupt_out_callback,
+                                dev,
+				dev->interrupt_in_endpoint->bInterval);
+
+                        dev->interrupt_out_urb->actual_length = bytes_to_write;
+                        retval = usb_submit_urb (dev->interrupt_out_urb, GFP_KERNEL);
+
+                        if (retval < 0) {
+                                err("Couldn't submit interrupt_out_urb %d", retval);
+                                goto exit;
+                        }
+
+                        buffer += bytes_to_write;
+                        count -= bytes_to_write;
+
+                        bytes_written += bytes_to_write;
+                }
+        }
+
+        retval = bytes_written;
+
+ exit:
+	/* unlock the device */
+	up (&dev->sem);
+
+	dbg(2," %s : leave, return value %d", __func__, retval);
+
+	return retval;
+}
+
+
+/**
+ *	Number of reasons why this isn't supported - GKH doesn't like them
+ *      since they are non-portable and also most of this is derived from
+ *      proprietary information
+ */
+
+static int tower_ioctl (struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg)
+{
+        int retval =  -ENOTTY;  /* default: we don't understand ioctl */
+
+	return retval;
+}
+
+
+/**
+ *	tower_interrupt_in_callback
+ */
+static void tower_interrupt_in_callback (struct urb *urb, struct pt_regs *regs)
+{
+	struct lego_usb_tower *dev = (struct lego_usb_tower *)urb->context;
+
+	dbg(4," %s : enter, status %d", __func__, urb->status);
+
+        lego_usb_tower_debug_data(5,__func__, urb->actual_length, urb->transfer_buffer);
+
+        if (urb->status != 0) {
+                if ((urb->status != -ENOENT) && (urb->status != -ECONNRESET)) {
+		        dbg(1," %s : nonzero status received: %d", __func__, urb->status);
+                }
+                goto exit;
+        }
+
+        down (&dev->sem);
+
+        if (urb->actual_length > 0) {
+                if (dev->read_buffer_length < (4 * dev->interrupt_in_endpoint->wMaxPacketSize) - (urb->actual_length)) {
+
+                        memcpy (dev->read_buffer+dev->read_buffer_length, dev->interrupt_in_buffer, urb->actual_length);
+
+                        dev->read_buffer_length += urb->actual_length;
+		        dbg(1," %s reading  %d ", __func__, urb->actual_length);
+                        wake_up_interruptible (&dev->read_wait);
+
+                } else {
+		        dbg(1," %s : read_buffer overflow", __func__);
+                }
+        }
+
+        up (&dev->sem);
+
+ exit:
+        lego_usb_tower_debug_data(5,__func__, urb->actual_length, urb->transfer_buffer);
+	dbg(4," %s : leave, status %d", __func__, urb->status);
+}
+
+
+/**
+ *	tower_interrupt_out_callback
+ */
+static void tower_interrupt_out_callback (struct urb *urb, struct pt_regs *regs)
+{
+	struct lego_usb_tower *dev = (struct lego_usb_tower *)urb->context;
+
+	dbg(4," %s : enter, status %d", __func__, urb->status);
+        lego_usb_tower_debug_data(5,__func__, urb->actual_length, urb->transfer_buffer);
+
+        if (urb->status != 0) {
+                if ((urb->status != -ENOENT) && 
+                    (urb->status != -ECONNRESET)) {
+                        dbg(1, " %s :nonzero status received: %d", __func__, urb->status);
+                }
+                goto exit;
+        }                        
+
+        wake_up_interruptible(&dev->write_wait);
+ exit:
+
+        lego_usb_tower_debug_data(5,__func__, urb->actual_length, urb->transfer_buffer);
+	dbg(4," %s : leave, status %d", __func__, urb->status);
+}
+
+
+/**
+ *	tower_probe
+ *
+ *	Called by the usb core when a new device is connected that it thinks
+ *	this driver might be interested in.
+ */
+static int tower_probe (struct usb_interface *interface, const struct usb_device_id *id)
+{
+	struct usb_device *udev = interface_to_usbdev(interface);
+	struct lego_usb_tower *dev = NULL;
+	struct usb_host_interface *iface_desc;
+	struct usb_endpoint_descriptor* endpoint;
+	int i;
+	int retval = -ENOMEM;
+
+	dbg(2," %s : enter", __func__);
+
+	if (udev == NULL) {
+		info ("udev is NULL.");
+	}
+	
+	/* See if the device offered us matches what we can accept */
+	if ((udev->descriptor.idVendor != LEGO_USB_TOWER_VENDOR_ID) ||
+	    (udev->descriptor.idProduct != LEGO_USB_TOWER_PRODUCT_ID)) {
+		return -ENODEV;
+	}
+
+
+	/* allocate memory for our device state and intialize it */
+
+	dev = kmalloc (sizeof(struct lego_usb_tower), GFP_KERNEL);
+
+	if (dev == NULL) {
+		err ("Out of memory");
+		goto exit;
+	}
+
+	init_MUTEX (&dev->sem);
+
+	dev->udev = udev;
+	dev->open_count = 0;
+
+	dev->read_buffer = NULL;
+	dev->read_buffer_length = 0;
+
+	init_waitqueue_head (&dev->read_wait);
+	init_waitqueue_head (&dev->write_wait);
+
+	dev->interrupt_in_buffer = NULL;
+	dev->interrupt_in_endpoint = NULL;
+	dev->interrupt_in_urb = NULL;
+
+	dev->interrupt_out_buffer = NULL;
+	dev->interrupt_out_endpoint = NULL;
+	dev->interrupt_out_urb = NULL;
+
+
+	iface_desc = &interface->altsetting[0];
+
+	/* set up the endpoint information */
+	for (i = 0; i < iface_desc->desc.bNumEndpoints; ++i) {
+		endpoint = &iface_desc->endpoint[i].desc;
+
+		if (((endpoint->bEndpointAddress & USB_ENDPOINT_DIR_MASK) == USB_DIR_IN) &&
+		    ((endpoint->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK) == USB_ENDPOINT_XFER_INT)) {
+	                dev->interrupt_in_endpoint = endpoint;
+		}
+		
+		if (((endpoint->bEndpointAddress & USB_ENDPOINT_DIR_MASK) == USB_DIR_OUT) &&
+		    ((endpoint->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK) == USB_ENDPOINT_XFER_INT)) {
+	                dev->interrupt_out_endpoint = endpoint;
+		}
+	}
+	if(dev->interrupt_in_endpoint == NULL) {
+	        err("interrupt in endpoint not found");
+	        goto error;
+	}
+	if (dev->interrupt_out_endpoint == NULL) {
+	        err("interrupt out endpoint not found");
+	        goto error;
+	}
+
+	dev->read_buffer = kmalloc ((4*dev->interrupt_in_endpoint->wMaxPacketSize), GFP_KERNEL);
+	if (!dev->read_buffer) {
+	        err("Couldn't allocate read_buffer");
+	        goto error;
+	}
+	dev->interrupt_in_buffer = kmalloc (dev->interrupt_in_endpoint->wMaxPacketSize, GFP_KERNEL);
+	if (!dev->interrupt_in_buffer) {
+	        err("Couldn't allocate interrupt_in_buffer");
+	        goto error;
+	}
+	dev->interrupt_in_urb = usb_alloc_urb(0, GFP_KERNEL);
+	if (!dev->interrupt_in_urb) {
+	        err("Couldn't allocate interrupt_in_urb");
+	        goto error;
+	}
+	dev->interrupt_out_buffer = kmalloc (dev->interrupt_out_endpoint->wMaxPacketSize, GFP_KERNEL);
+	if (!dev->interrupt_out_buffer) {
+	        err("Couldn't allocate interrupt_out_buffer");
+	        goto error;
+	}
+	dev->interrupt_out_urb = usb_alloc_urb(0, GFP_KERNEL);
+	if (!dev->interrupt_out_urb) {
+	        err("Couldn't allocate interrupt_out_urb");
+	        goto error;
+	}                
+
+	/* initialize the devfs node for this device and register it */
+
+	/* we can register the device now, as it is ready */
+	usb_set_intfdata (interface, dev);
+
+	retval = usb_register_dev (interface, &tower_class);
+
+	if (retval) {
+		/* something prevented us from registering this driver */
+		err ("Not able to get a minor for this device.");
+		usb_set_intfdata (interface, NULL);
+		goto error;
+	}
+
+	dev->minor = interface->minor;
+
+	/* let the user know what node this device is now attached to */
+	info ("LEGO USB Tower device now attached to /dev/usb/lego%d", (dev->minor - LEGO_USB_TOWER_MINOR_BASE));
+
+
+
+ exit:
+	dbg(2," %s : leave, return value 0x%.8lx (dev)", __func__, (long) dev);
+
+	return retval;
+
+ error:
+	tower_delete(dev);
+	return retval;
+}
+
+
+/**
+ *	tower_disconnect
+ *
+ *	Called by the usb core when the device is removed from the system.
+ */
+static void tower_disconnect (struct usb_interface *interface)
+{
+	struct lego_usb_tower *dev;
+	int minor;
+
+	dbg(2," %s : enter", __func__);
+
+	down (&disconnect_sem);
+
+	dev = usb_get_intfdata (interface);
+	usb_set_intfdata (interface, NULL);
+
+
+	down (&dev->sem);
+
+	minor = dev->minor;
+
+	/* give back our minor */
+	usb_deregister_dev (interface, &tower_class);
+
+	/* if the device is not opened, then we clean up right now */
+	if (!dev->open_count) {
+		up (&dev->sem);
+		tower_delete (dev);
+	} else {
+		dev->udev = NULL;
+		up (&dev->sem);
+	}
+
+	up (&disconnect_sem);
+
+	info("LEGO USB Tower #%d now disconnected", (minor - LEGO_USB_TOWER_MINOR_BASE));
+
+	dbg(2," %s : leave", __func__);
+}
+
+
+
+/**
+ *	lego_usb_tower_init
+ */
+static int __init lego_usb_tower_init(void)
+{
+	int result;
+	int retval = 0;
+
+	dbg(2," %s : enter", __func__);
+
+	/* register this driver with the USB subsystem */
+	result = usb_register(&tower_driver);
+	if (result < 0) {
+		err("usb_register failed for the "__FILE__" driver. Error number %d", result);
+		retval = -1;
+	        goto exit;
+	}
+
+	info(DRIVER_DESC " " DRIVER_VERSION);
+
+ exit:
+	dbg(2," %s : leave, return value %d", __func__, retval);
+
+	return retval;
+}
+
+
+/**
+ *	lego_usb_tower_exit
+ */
+static void __exit lego_usb_tower_exit(void)
+{
+	dbg(2," %s : enter", __func__);
+
+	/* deregister this driver with the USB subsystem */
+	usb_deregister (&tower_driver);
+
+	dbg(2," %s : leave", __func__);
+}
+
+module_init (lego_usb_tower_init);
+module_exit (lego_usb_tower_exit);
+
+MODULE_AUTHOR(DRIVER_AUTHOR);
+MODULE_DESCRIPTION(DRIVER_DESC);
+#ifdef MODULE_LICENSE
+MODULE_LICENSE("GPL");
+#endif