2 * Frontier Designs Alphatrack driver
4 * Copyright (C) 2007 Michael Taht (m@taht.net)
6 * Based on the usbled driver and ldusb drivers by
8 * Copyright (C) 2004 Greg Kroah-Hartman (greg@kroah.com)
9 * Copyright (C) 2005 Michael Hund <mhund@ld-didactic.de>
11 * The ldusb driver was, in turn, derived from Lego USB Tower driver
12 * Copyright (C) 2003 David Glance <advidgsf@sourceforge.net>
13 * 2001-2004 Juergen Stuber <starblue@users.sourceforge.net>
15 * This program is free software; you can redistribute it and/or
16 * modify it under the terms of the GNU General Public License as
17 * published by the Free Software Foundation, version 2.
22 * This driver uses a ring buffer for time critical reading of
23 * interrupt in reports and provides read and write methods for
24 * raw interrupt reports.
28 * Note: this currently uses a dumb ringbuffer for reads and writes.
29 * A more optimal driver would cache and kill off outstanding urbs that are
30 * now invalid, and ignore ones that already were in the queue but valid
31 * as we only have 30 commands for the alphatrack. In particular this is
32 * key for getting lights to flash in time as otherwise many commands
33 * can be buffered up before the light change makes it to the interface.
36 #include <linux/kernel.h>
37 #include <linux/errno.h>
38 #include <linux/init.h>
39 #include <linux/slab.h>
40 #include <linux/module.h>
41 #include <linux/kobject.h>
42 #include <linux/mutex.h>
44 #include <linux/uaccess.h>
45 #include <linux/input.h>
46 #include <linux/usb.h>
47 #include <linux/poll.h>
49 #include "alphatrack.h"
51 #define VENDOR_ID 0x165b
52 #define PRODUCT_ID 0xfad1
54 #ifdef CONFIG_USB_DYNAMIC_MINORS
55 #define USB_ALPHATRACK_MINOR_BASE 0
57 /* FIXME 176 - is another driver's minor - apply for that */
58 #define USB_ALPHATRACK_MINOR_BASE 176
61 /* table of devices that work with this driver */
62 static const struct usb_device_id usb_alphatrack_table[] = {
63 {USB_DEVICE(VENDOR_ID, PRODUCT_ID)},
64 {} /* Terminating entry */
67 MODULE_DEVICE_TABLE(usb, usb_alphatrack_table);
68 MODULE_VERSION("0.41");
69 MODULE_AUTHOR("Mike Taht <m@taht.net>");
70 MODULE_DESCRIPTION("Alphatrack USB Driver");
71 MODULE_LICENSE("GPL");
72 MODULE_SUPPORTED_DEVICE("Frontier Designs Alphatrack Control Surface");
74 /* These aren't done yet */
76 #define SUPPRESS_EXTRA_ONLINE_EVENTS 0
77 #define BUFFERED_WRITES 0
78 #define SUPPRESS_EXTRA_OFFLINE_EVENTS 0
79 #define COMPRESS_FADER_EVENTS 0
81 #define BUFFERED_READS 1
82 #define RING_BUFFER_SIZE 512
83 #define WRITE_BUFFER_SIZE 34
84 #define ALPHATRACK_USB_TIMEOUT 10
85 #define OUTPUT_CMD_SIZE 8
86 #define INPUT_CMD_SIZE 12
87 #define ALPHATRACK_DEBUG 0
89 static int debug = ALPHATRACK_DEBUG;
91 /* Use our own dbg macro */
92 #define dbg_info(dev, format, arg...) do \
93 { if (debug) dev_info(dev , format , ## arg); } while (0)
95 #define alphatrack_ocmd_info(dev, cmd, format, arg...)
97 #define alphatrack_icmd_info(dev, cmd, format, arg...)
99 /* Module parameters */
101 module_param(debug, int, S_IRUGO | S_IWUSR);
102 MODULE_PARM_DESC(debug, "Debug enabled or not");
105 * All interrupt in transfers are collected in a ring buffer to
106 * avoid racing conditions and get better performance of the driver.
109 static int ring_buffer_size = RING_BUFFER_SIZE;
111 module_param(ring_buffer_size, int, S_IRUGO);
112 MODULE_PARM_DESC(ring_buffer_size, "Read ring buffer size");
114 /* The write_buffer can one day contain more than one interrupt out transfer.*/
116 static int write_buffer_size = WRITE_BUFFER_SIZE;
117 module_param(write_buffer_size, int, S_IRUGO);
118 MODULE_PARM_DESC(write_buffer_size, "Write buffer size");
121 * Increase the interval for debugging purposes.
122 * or set to 1 to use the standard interval from the endpoint descriptors.
125 static int min_interrupt_in_interval = ALPHATRACK_USB_TIMEOUT;
126 module_param(min_interrupt_in_interval, int, 0);
127 MODULE_PARM_DESC(min_interrupt_in_interval,
128 "Minimum interrupt in interval in ms");
130 static int min_interrupt_out_interval = ALPHATRACK_USB_TIMEOUT;
131 module_param(min_interrupt_out_interval, int, 0);
132 MODULE_PARM_DESC(min_interrupt_out_interval,
133 "Minimum interrupt out interval in ms");
135 /* Structure to hold all of our device specific stuff */
137 struct usb_alphatrack {
138 struct mutex mtx; /* locks this structure */
139 struct usb_interface *intf; /* save off the usb interface pointer */
140 int open_count; /* number of times this port has been opened */
143 struct alphatrack_icmd (*ring_buffer)[RING_BUFFER_SIZE];
144 struct alphatrack_ocmd (*write_buffer)[WRITE_BUFFER_SIZE];
145 unsigned int ring_head;
146 unsigned int ring_tail;
148 wait_queue_head_t read_wait;
149 wait_queue_head_t write_wait;
151 unsigned char *interrupt_in_buffer;
152 unsigned char *oldi_buffer;
153 struct usb_endpoint_descriptor *interrupt_in_endpoint;
154 struct urb *interrupt_in_urb;
155 int interrupt_in_interval;
156 size_t interrupt_in_endpoint_size;
157 int interrupt_in_running;
158 int interrupt_in_done;
160 char *interrupt_out_buffer;
161 struct usb_endpoint_descriptor *interrupt_out_endpoint;
162 struct urb *interrupt_out_urb;
163 int interrupt_out_interval;
164 size_t interrupt_out_endpoint_size;
165 int interrupt_out_busy;
167 atomic_t writes_pending;
168 int event; /* alternate interface to events */
169 int fader; /* 10 bits */
170 int lights; /* 23 bits */
171 unsigned char dump_state; /* 0 if disabled 1 if enabled */
172 unsigned char enable; /* 0 if disabled 1 if enabled */
173 unsigned char offline; /* if the device is out of range or asleep */
174 unsigned char verbose; /* be verbose in error reporting */
175 unsigned char last_cmd[OUTPUT_CMD_SIZE];
176 unsigned char screen[32];
179 /* prevent races between open() and disconnect() */
180 static DEFINE_MUTEX(disconnect_mutex);
182 /* forward declaration */
184 static struct usb_driver usb_alphatrack_driver;
187 * usb_alphatrack_abort_transfers
188 * aborts transfers and frees associated data structures
190 static void usb_alphatrack_abort_transfers(struct usb_alphatrack *dev)
192 /* shutdown transfer */
193 if (dev->interrupt_in_running) {
194 dev->interrupt_in_running = 0;
196 usb_kill_urb(dev->interrupt_in_urb);
198 if (dev->interrupt_out_busy)
200 usb_kill_urb(dev->interrupt_out_urb);
203 /** usb_alphatrack_delete */
204 static void usb_alphatrack_delete(struct usb_alphatrack *dev)
206 usb_alphatrack_abort_transfers(dev);
207 usb_free_urb(dev->interrupt_in_urb);
208 usb_free_urb(dev->interrupt_out_urb);
209 kfree(dev->ring_buffer);
210 kfree(dev->interrupt_in_buffer);
211 kfree(dev->interrupt_out_buffer);
212 kfree(dev); /* fixme oldi_buffer */
215 /** usb_alphatrack_interrupt_in_callback */
217 static void usb_alphatrack_interrupt_in_callback(struct urb *urb)
219 struct usb_alphatrack *dev = urb->context;
220 unsigned int next_ring_head;
224 if (urb->status == -ENOENT ||
225 urb->status == -ECONNRESET || urb->status == -ESHUTDOWN) {
228 dbg_info(&dev->intf->dev,
229 "%s: nonzero status received: %d\n", __func__,
231 goto resubmit; /* maybe we can recover */
235 if (urb->actual_length != INPUT_CMD_SIZE) {
236 dev_warn(&dev->intf->dev,
237 "Urb length was %d bytes!!"
238 "Do something intelligent\n", urb->actual_length);
240 alphatrack_ocmd_info(&dev->intf->dev,
241 &(*dev->ring_buffer)[dev->ring_tail].cmd,
244 (dev->interrupt_in_buffer, dev->oldi_buffer,
245 INPUT_CMD_SIZE) == 0) {
248 memcpy(dev->oldi_buffer, dev->interrupt_in_buffer,
251 #if SUPPRESS_EXTRA_OFFLINE_EVENTS
252 if (dev->offline == 2 && dev->interrupt_in_buffer[1] == 0xff)
254 if (dev->offline == 1 && dev->interrupt_in_buffer[1] == 0xff) {
258 /* Always pass one offline event up the stack */
259 if (dev->offline > 0 && dev->interrupt_in_buffer[1] != 0xff)
261 if (dev->offline == 0 && dev->interrupt_in_buffer[1] == 0xff)
264 dbg_info(&dev->intf->dev, "%s: head, tail are %x, %x\n",
265 __func__, dev->ring_head, dev->ring_tail);
266 next_ring_head = (dev->ring_head + 1) % ring_buffer_size;
268 if (next_ring_head != dev->ring_tail) {
269 memcpy(&((*dev->ring_buffer)[dev->ring_head]),
270 dev->interrupt_in_buffer, urb->actual_length);
271 dev->ring_head = next_ring_head;
273 memset(dev->interrupt_in_buffer, 0, urb->actual_length);
275 dev_warn(&dev->intf->dev,
276 "Ring buffer overflow, %d bytes dropped\n",
278 memset(dev->interrupt_in_buffer, 0, urb->actual_length);
283 /* resubmit if we're still running */
284 if (dev->interrupt_in_running && dev->intf) {
285 retval = usb_submit_urb(dev->interrupt_in_urb, GFP_ATOMIC);
287 dev_err(&dev->intf->dev,
288 "usb_submit_urb failed (%d)\n", retval);
292 dev->interrupt_in_done = 1;
293 wake_up_interruptible(&dev->read_wait);
296 /** usb_alphatrack_interrupt_out_callback */
297 static void usb_alphatrack_interrupt_out_callback(struct urb *urb)
299 struct usb_alphatrack *dev = urb->context;
301 /* sync/async unlink faults aren't errors */
302 if (urb->status && !(urb->status == -ENOENT ||
303 urb->status == -ECONNRESET ||
304 urb->status == -ESHUTDOWN))
305 dbg_info(&dev->intf->dev,
306 "%s - nonzero write interrupt status received: %d\n",
307 __func__, urb->status);
308 atomic_dec(&dev->writes_pending);
309 dev->interrupt_out_busy = 0;
310 wake_up_interruptible(&dev->write_wait);
313 /** usb_alphatrack_open */
314 static int usb_alphatrack_open(struct inode *inode, struct file *file)
316 struct usb_alphatrack *dev;
319 struct usb_interface *interface;
321 nonseekable_open(inode, file);
322 subminor = iminor(inode);
324 mutex_lock(&disconnect_mutex);
326 interface = usb_find_interface(&usb_alphatrack_driver, subminor);
329 pr_err("%s - error, can't find device for minor %d\n",
332 goto unlock_disconnect_exit;
335 dev = usb_get_intfdata(interface);
339 goto unlock_disconnect_exit;
342 /* lock this device */
343 if (mutex_lock_interruptible(&dev->mtx)) {
344 retval = -ERESTARTSYS;
345 goto unlock_disconnect_exit;
348 /* allow opening only once */
349 if (dev->open_count) {
355 /* initialize in direction */
358 usb_fill_int_urb(dev->interrupt_in_urb,
359 interface_to_usbdev(interface),
360 usb_rcvintpipe(interface_to_usbdev(interface),
361 dev->interrupt_in_endpoint->
363 dev->interrupt_in_buffer,
364 dev->interrupt_in_endpoint_size,
365 usb_alphatrack_interrupt_in_callback, dev,
366 dev->interrupt_in_interval);
368 dev->interrupt_in_running = 1;
369 dev->interrupt_in_done = 0;
373 retval = usb_submit_urb(dev->interrupt_in_urb, GFP_KERNEL);
375 dev_err(&interface->dev,
376 "Couldn't submit interrupt_in_urb %d\n", retval);
377 dev->interrupt_in_running = 0;
382 /* save device in the file's private structure */
383 file->private_data = dev;
386 mutex_unlock(&dev->mtx);
388 unlock_disconnect_exit:
389 mutex_unlock(&disconnect_mutex);
394 /** usb_alphatrack_release */
395 static int usb_alphatrack_release(struct inode *inode, struct file *file)
397 struct usb_alphatrack *dev;
400 dev = file->private_data;
407 if (mutex_lock_interruptible(&dev->mtx)) {
408 retval = -ERESTARTSYS;
412 if (dev->open_count != 1) {
417 if (dev->intf == NULL) {
418 /* the device was unplugged before the file was released */
419 mutex_unlock(&dev->mtx);
420 /* unlock here as usb_alphatrack_delete frees dev */
421 usb_alphatrack_delete(dev);
426 /* wait until write transfer is finished */
427 if (dev->interrupt_out_busy)
428 wait_event_interruptible_timeout(dev->write_wait,
429 !dev->interrupt_out_busy,
431 usb_alphatrack_abort_transfers(dev);
435 mutex_unlock(&dev->mtx);
441 /** usb_alphatrack_poll */
442 static unsigned int usb_alphatrack_poll(struct file *file, poll_table *wait)
444 struct usb_alphatrack *dev;
445 unsigned int mask = 0;
447 dev = file->private_data;
449 poll_wait(file, &dev->read_wait, wait);
450 poll_wait(file, &dev->write_wait, wait);
452 if (dev->ring_head != dev->ring_tail)
453 mask |= POLLIN | POLLRDNORM;
454 if (!dev->interrupt_out_busy)
455 mask |= POLLOUT | POLLWRNORM;
460 /** usb_alphatrack_read */
461 static ssize_t usb_alphatrack_read(struct file *file, char __user *buffer,
462 size_t count, loff_t *ppos)
464 struct usb_alphatrack *dev;
469 dev = file->private_data;
471 /* verify that we actually have some data to read */
475 /* lock this object */
476 if (mutex_lock_interruptible(&dev->mtx)) {
477 retval = -ERESTARTSYS;
481 /* verify that the device wasn't unplugged */
482 if (dev->intf == NULL) {
484 pr_err("%s: No device or device unplugged %d\n",
489 while (dev->ring_head == dev->ring_tail) {
490 if (file->f_flags & O_NONBLOCK) {
494 dev->interrupt_in_done = 0;
496 wait_event_interruptible(dev->read_wait,
497 dev->interrupt_in_done);
502 alphatrack_ocmd_info(&dev->intf->dev,
503 &(*dev->ring_buffer)[dev->ring_tail].cmd, "%s",
504 ": copying to userspace");
507 while ((c < count) && (dev->ring_tail != dev->ring_head)) {
509 (&buffer[c], &(*dev->ring_buffer)[dev->ring_tail],
514 dev->ring_tail = (dev->ring_tail + 1) % ring_buffer_size;
516 dbg_info(&dev->intf->dev, "%s: head, tail are %x, %x\n",
517 __func__, dev->ring_head, dev->ring_tail);
522 /* unlock the device */
523 mutex_unlock(&dev->mtx);
529 /** usb_alphatrack_write */
530 static ssize_t usb_alphatrack_write(struct file *file,
531 const char __user *buffer, size_t count,
534 struct usb_alphatrack *dev;
535 size_t bytes_to_write;
538 dev = file->private_data;
540 /* verify that we actually have some data to write */
544 /* lock this object */
545 if (mutex_lock_interruptible(&dev->mtx)) {
546 retval = -ERESTARTSYS;
550 /* verify that the device wasn't unplugged */
551 if (dev->intf == NULL) {
553 pr_err("%s: No device or device unplugged %d\n",
558 /* wait until previous transfer is finished */
559 if (dev->interrupt_out_busy) {
560 if (file->f_flags & O_NONBLOCK) {
565 wait_event_interruptible(dev->write_wait,
566 !dev->interrupt_out_busy);
571 /* write the data into interrupt_out_buffer from userspace */
572 /* FIXME - if you write more than 12 bytes this breaks */
574 min(count, write_buffer_size * dev->interrupt_out_endpoint_size);
575 if (bytes_to_write < count)
576 dev_warn(&dev->intf->dev,
577 "Write buffer overflow, %zd bytes dropped\n",
578 count - bytes_to_write);
580 dbg_info(&dev->intf->dev, "%s: count = %zd, bytes_to_write = %zd\n",
581 __func__, count, bytes_to_write);
583 if (copy_from_user(dev->interrupt_out_buffer, buffer, bytes_to_write)) {
588 if (dev->interrupt_out_endpoint == NULL) {
589 dev_err(&dev->intf->dev, "Endpoint should not be null!\n");
593 /* send off the urb */
594 usb_fill_int_urb(dev->interrupt_out_urb,
595 interface_to_usbdev(dev->intf),
596 usb_sndintpipe(interface_to_usbdev(dev->intf),
597 dev->interrupt_out_endpoint->
599 dev->interrupt_out_buffer, bytes_to_write,
600 usb_alphatrack_interrupt_out_callback, dev,
601 dev->interrupt_out_interval);
602 dev->interrupt_out_busy = 1;
603 atomic_inc(&dev->writes_pending);
606 retval = usb_submit_urb(dev->interrupt_out_urb, GFP_KERNEL);
608 dev->interrupt_out_busy = 0;
609 dev_err(&dev->intf->dev,
610 "Couldn't submit interrupt_out_urb %d\n", retval);
611 atomic_dec(&dev->writes_pending);
614 retval = bytes_to_write;
617 /* unlock the device */
618 mutex_unlock(&dev->mtx);
624 /* file operations needed when we register this driver */
625 static const struct file_operations usb_alphatrack_fops = {
626 .owner = THIS_MODULE,
627 .read = usb_alphatrack_read,
628 .write = usb_alphatrack_write,
629 .open = usb_alphatrack_open,
630 .release = usb_alphatrack_release,
631 .poll = usb_alphatrack_poll,
636 * usb class driver info in order to get a minor number from the usb core,
637 * and to have the device registered with the driver core
640 static struct usb_class_driver usb_alphatrack_class = {
641 .name = "alphatrack%d",
642 .fops = &usb_alphatrack_fops,
643 .minor_base = USB_ALPHATRACK_MINOR_BASE,
647 * usb_alphatrack_probe
649 * Called by the usb core when a new device is connected that it thinks
650 * this driver might be interested in.
652 static int usb_alphatrack_probe(struct usb_interface *intf,
653 const struct usb_device_id *id)
655 struct usb_device *udev = interface_to_usbdev(intf);
656 struct usb_alphatrack *dev = NULL;
657 struct usb_host_interface *iface_desc;
658 struct usb_endpoint_descriptor *endpoint;
661 int retval = -ENOMEM;
663 /* allocate memory for our device state and initialize it */
665 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
669 mutex_init(&dev->mtx);
671 init_waitqueue_head(&dev->read_wait);
672 init_waitqueue_head(&dev->write_wait);
674 iface_desc = intf->cur_altsetting;
676 /* set up the endpoint information */
677 for (i = 0; i < iface_desc->desc.bNumEndpoints; ++i) {
678 endpoint = &iface_desc->endpoint[i].desc;
680 if (usb_endpoint_is_int_in(endpoint))
681 dev->interrupt_in_endpoint = endpoint;
683 if (usb_endpoint_is_int_out(endpoint))
684 dev->interrupt_out_endpoint = endpoint;
686 if (dev->interrupt_in_endpoint == NULL) {
687 dev_err(&intf->dev, "Interrupt in endpoint not found\n");
690 if (dev->interrupt_out_endpoint == NULL)
692 "Interrupt out endpoint not found"
693 "(using control endpoint instead)\n");
695 dev->interrupt_in_endpoint_size =
696 le16_to_cpu(dev->interrupt_in_endpoint->wMaxPacketSize);
698 if (dev->interrupt_in_endpoint_size != 64)
699 dev_warn(&intf->dev, "Interrupt in endpoint size is not 64!\n");
701 if (ring_buffer_size == 0)
702 ring_buffer_size = RING_BUFFER_SIZE;
704 true_size = min(ring_buffer_size, RING_BUFFER_SIZE);
707 * FIXME - there are more usb_alloc routines for dma correctness.
710 dev->ring_buffer = kmalloc_array(true_size,
711 sizeof(struct alphatrack_icmd),
713 if (!dev->ring_buffer)
716 dev->interrupt_in_buffer = kmalloc(dev->interrupt_in_endpoint_size,
718 if (!dev->interrupt_in_buffer)
721 dev->oldi_buffer = kmalloc(dev->interrupt_in_endpoint_size, GFP_KERNEL);
722 if (!dev->oldi_buffer)
725 dev->interrupt_in_urb = usb_alloc_urb(0, GFP_KERNEL);
726 if (!dev->interrupt_in_urb) {
727 dev_err(&intf->dev, "Couldn't allocate interrupt_in_urb\n");
731 dev->interrupt_out_endpoint_size =
732 dev->interrupt_out_endpoint ? le16_to_cpu(dev->
733 interrupt_out_endpoint->
734 wMaxPacketSize) : udev->
735 descriptor.bMaxPacketSize0;
737 if (dev->interrupt_out_endpoint_size != 64)
739 "Interrupt out endpoint size is not 64!)\n");
741 if (write_buffer_size == 0)
742 write_buffer_size = WRITE_BUFFER_SIZE;
743 true_size = min(write_buffer_size, WRITE_BUFFER_SIZE);
745 dev->interrupt_out_buffer =
746 kmalloc_array(true_size,
747 dev->interrupt_out_endpoint_size,
749 if (!dev->interrupt_out_buffer)
752 dev->write_buffer = kmalloc_array(true_size,
753 sizeof(struct alphatrack_ocmd),
755 if (!dev->write_buffer)
758 dev->interrupt_out_urb = usb_alloc_urb(0, GFP_KERNEL);
759 if (!dev->interrupt_out_urb) {
760 dev_err(&intf->dev, "Couldn't allocate interrupt_out_urb\n");
763 dev->interrupt_in_interval =
764 min_interrupt_in_interval >
765 dev->interrupt_in_endpoint->
766 bInterval ? min_interrupt_in_interval : dev->interrupt_in_endpoint->
768 if (dev->interrupt_out_endpoint)
769 dev->interrupt_out_interval =
770 min_interrupt_out_interval >
771 dev->interrupt_out_endpoint->
772 bInterval ? min_interrupt_out_interval : dev->
773 interrupt_out_endpoint->bInterval;
775 /* we can register the device now, as it is ready */
776 usb_set_intfdata(intf, dev);
778 atomic_set(&dev->writes_pending, 0);
779 retval = usb_register_dev(intf, &usb_alphatrack_class);
781 /* something prevented us from registering this driver */
783 "Not able to get a minor for this device.\n");
784 usb_set_intfdata(intf, NULL);
788 /* let the user know what node this device is now attached to */
790 "Alphatrack Device #%d now attached to major %d minor %d\n",
791 (intf->minor - USB_ALPHATRACK_MINOR_BASE), USB_MAJOR,
798 usb_alphatrack_delete(dev);
804 * usb_alphatrack_disconnect
806 * Called by the usb core when the device is removed from the system.
808 static void usb_alphatrack_disconnect(struct usb_interface *intf)
810 struct usb_alphatrack *dev;
813 mutex_lock(&disconnect_mutex);
815 dev = usb_get_intfdata(intf);
816 usb_set_intfdata(intf, NULL);
818 mutex_lock(&dev->mtx);
822 /* give back our minor */
823 usb_deregister_dev(intf, &usb_alphatrack_class);
825 /* if the device is not opened, then we clean up right now */
826 if (!dev->open_count) {
827 mutex_unlock(&dev->mtx);
828 usb_alphatrack_delete(dev);
830 atomic_set(&dev->writes_pending, 0);
832 mutex_unlock(&dev->mtx);
835 mutex_unlock(&disconnect_mutex);
837 dev_info(&intf->dev, "Alphatrack Surface #%d now disconnected\n",
838 (minor - USB_ALPHATRACK_MINOR_BASE));
841 /* usb specific object needed to register this driver with the usb subsystem */
842 static struct usb_driver usb_alphatrack_driver = {
843 .name = "alphatrack",
844 .probe = usb_alphatrack_probe,
845 .disconnect = usb_alphatrack_disconnect,
846 .id_table = usb_alphatrack_table,
849 module_usb_driver(usb_alphatrack_driver);