drivers/input/tablet/wacom_sys.c

   1 /*
   2  * drivers/input/tablet/wacom_sys.c
   3  *
   4  *  USB Wacom tablet support - system specific code
   5  */
   6
   7 /*
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License as published by
  10  * the Free Software Foundation; either version 2 of the License, or
  11  * (at your option) any later version.
  12  */
  13
  14 #include "wacom_wac.h"
  15 #include "wacom.h"
  16
  17 /* defines to get HID report descriptor */
  18 #define HID_DEVICET_HID         (USB_TYPE_CLASS | 0x01)
  19 #define HID_DEVICET_REPORT      (USB_TYPE_CLASS | 0x02)
  20 #define HID_USAGE_UNDEFINED             0x00
  21 #define HID_USAGE_PAGE                  0x05
  22 #define HID_USAGE_PAGE_DIGITIZER        0x0d
  23 #define HID_USAGE_PAGE_DESKTOP          0x01
  24 #define HID_USAGE                       0x09
  25 #define HID_USAGE_X                     0x30
  26 #define HID_USAGE_Y                     0x31
  27 #define HID_USAGE_X_TILT                0x3d
  28 #define HID_USAGE_Y_TILT                0x3e
  29 #define HID_USAGE_FINGER                0x22
  30 #define HID_USAGE_STYLUS                0x20
  31 #define HID_COLLECTION                  0xc0
  32
  33 enum {
  34         WCM_UNDEFINED = 0,
  35         WCM_DESKTOP,
  36         WCM_DIGITIZER,
  37 };
  38
  39 struct hid_descriptor {
  40         struct usb_descriptor_header header;
  41         __le16   bcdHID;
  42         u8       bCountryCode;
  43         u8       bNumDescriptors;
  44         u8       bDescriptorType;
  45         __le16   wDescriptorLength;
  46 } __attribute__ ((packed));
  47
  48 /* defines to get/set USB message */
  49 #define USB_REQ_GET_REPORT      0x01
  50 #define USB_REQ_SET_REPORT      0x09
  51 #define WAC_HID_FEATURE_REPORT  0x03
  52 #define WAC_MSG_RETRIES         5
  53
  54 static int usb_get_report(struct usb_interface *intf, unsigned char type,
  55                                 unsigned char id, void *buf, int size)
  56 {
  57         return usb_control_msg(interface_to_usbdev(intf),
  58                 usb_rcvctrlpipe(interface_to_usbdev(intf), 0),
  59                 USB_REQ_GET_REPORT, USB_TYPE_CLASS | USB_RECIP_INTERFACE,
  60                 (type << 8) + id, intf->altsetting[0].desc.bInterfaceNumber,
  61                 buf, size, 100);
  62 }
  63
  64 static int usb_set_report(struct usb_interface *intf, unsigned char type,
  65                                 unsigned char id, void *buf, int size)
  66 {
  67         return usb_control_msg(interface_to_usbdev(intf),
  68                 usb_sndctrlpipe(interface_to_usbdev(intf), 0),
  69                 USB_REQ_SET_REPORT, USB_TYPE_CLASS | USB_RECIP_INTERFACE,
  70                 (type << 8) + id, intf->altsetting[0].desc.bInterfaceNumber,
  71                 buf, size, 1000);
  72 }
  73
  74 static void wacom_sys_irq(struct urb *urb)
  75 {
  76         struct wacom *wacom = urb->context;
  77         int retval;
  78
  79         switch (urb->status) {
  80         case 0:
  81                 /* success */
  82                 break;
  83         case -ECONNRESET:
  84         case -ENOENT:
  85         case -ESHUTDOWN:
  86                 /* this urb is terminated, clean up */
  87                 dbg("%s - urb shutting down with status: %d", __func__, urb->status);
  88                 return;
  89         default:
  90                 dbg("%s - nonzero urb status received: %d", __func__, urb->status);
  91                 goto exit;
  92         }
  93
  94         wacom_wac_irq(&wacom->wacom_wac, urb->actual_length);
  95
  96  exit:
  97         usb_mark_last_busy(wacom->usbdev);
  98         retval = usb_submit_urb(urb, GFP_ATOMIC);
  99         if (retval)
 100                 err ("%s - usb_submit_urb failed with result %d",
 101                      __func__, retval);
 102 }
 103
 104 static int wacom_open(struct input_dev *dev)
 105 {
 106         struct wacom *wacom = input_get_drvdata(dev);
 107         int retval = 0;
 108
 109         if (usb_autopm_get_interface(wacom->intf) < 0)
 110                 return -EIO;
 111
 112         mutex_lock(&wacom->lock);
 113
 114         if (usb_submit_urb(wacom->irq, GFP_KERNEL)) {
 115                 retval = -EIO;
 116                 goto out;
 117         }
 118
 119         wacom->open = true;
 120         wacom->intf->needs_remote_wakeup = 1;
 121
 122 out:
 123         mutex_unlock(&wacom->lock);
 124         usb_autopm_put_interface(wacom->intf);
 125         return retval;
 126 }
 127
 128 static void wacom_close(struct input_dev *dev)
 129 {
 130         struct wacom *wacom = input_get_drvdata(dev);
 131         int autopm_error;
 132
 133         autopm_error = usb_autopm_get_interface(wacom->intf);
 134
 135         mutex_lock(&wacom->lock);
 136         usb_kill_urb(wacom->irq);
 137         wacom->open = false;
 138         wacom->intf->needs_remote_wakeup = 0;
 139         mutex_unlock(&wacom->lock);
 140
 141         if (!autopm_error)
 142                 usb_autopm_put_interface(wacom->intf);
 143 }
 144
 145 static int wacom_parse_hid(struct usb_interface *intf, struct hid_descriptor *hid_desc,
 146                            struct wacom_features *features)
 147 {
 148         struct usb_device *dev = interface_to_usbdev(intf);
 149         char limit = 0;
 150         /* result has to be defined as int for some devices */
 151         int result = 0;
 152         int i = 0, usage = WCM_UNDEFINED, finger = 0, pen = 0;
 153         unsigned char *report;
 154
 155         report = kzalloc(hid_desc->wDescriptorLength, GFP_KERNEL);
 156         if (!report)
 157                 return -ENOMEM;
 158
 159         /* retrive report descriptors */
 160         do {
 161                 result = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0),
 162                         USB_REQ_GET_DESCRIPTOR,
 163                         USB_RECIP_INTERFACE | USB_DIR_IN,
 164                         HID_DEVICET_REPORT << 8,
 165                         intf->altsetting[0].desc.bInterfaceNumber, /* interface */
 166                         report,
 167                         hid_desc->wDescriptorLength,
 168                         5000); /* 5 secs */
 169         } while (result < 0 && limit++ < WAC_MSG_RETRIES);
 170
 171         /* No need to parse the Descriptor. It isn't an error though */
 172         if (result < 0)
 173                 goto out;
 174
 175         for (i = 0; i < hid_desc->wDescriptorLength; i++) {
 176
 177                 switch (report[i]) {
 178                 case HID_USAGE_PAGE:
 179                         switch (report[i + 1]) {
 180                         case HID_USAGE_PAGE_DIGITIZER:
 181                                 usage = WCM_DIGITIZER;
 182                                 i++;
 183                                 break;
 184
 185                         case HID_USAGE_PAGE_DESKTOP:
 186                                 usage = WCM_DESKTOP;
 187                                 i++;
 188                                 break;
 189                         }
 190                         break;
 191
 192                 case HID_USAGE:
 193                         switch (report[i + 1]) {
 194                         case HID_USAGE_X:
 195                                 if (usage == WCM_DESKTOP) {
 196                                         if (finger) {
 197                                                 features->device_type = BTN_TOOL_FINGER;
 198                                                 if (features->type == TABLETPC2FG) {
 199                                                         /* need to reset back */
 200                                                         features->pktlen = WACOM_PKGLEN_TPC2FG;
 201                                                         features->device_type = BTN_TOOL_DOUBLETAP;
 202                                                 }
 203                                                 if (features->type == BAMBOO_PT) {
 204                                                         /* need to reset back */
 205                                                         features->pktlen = WACOM_PKGLEN_BBTOUCH;
 206                                                         features->device_type = BTN_TOOL_DOUBLETAP;
 207                                                         features->x_phy =
 208                                                                 get_unaligned_le16(&report[i + 5]);
 209                                                         features->x_max =
 210                                                                 get_unaligned_le16(&report[i + 8]);
 211                                                         i += 15;
 212                                                 } else {
 213                                                         features->x_max =
 214                                                                 get_unaligned_le16(&report[i + 3]);
 215                                                         features->x_phy =
 216                                                                 get_unaligned_le16(&report[i + 6]);
 217                                                         features->unit = report[i + 9];
 218                                                         features->unitExpo = report[i + 11];
 219                                                         i += 12;
 220                                                 }
 221                                         } else if (pen) {
 222                                                 /* penabled only accepts exact bytes of data */
 223                                                 if (features->type == TABLETPC2FG)
 224                                                         features->pktlen = WACOM_PKGLEN_GRAPHIRE;
 225                                                 if (features->type == BAMBOO_PT)
 226                                                         features->pktlen = WACOM_PKGLEN_BBFUN;
 227                                                 features->device_type = BTN_TOOL_PEN;
 228                                                 features->x_max =
 229                                                         get_unaligned_le16(&report[i + 3]);
 230                                                 i += 4;
 231                                         }
 232                                 } else if (usage == WCM_DIGITIZER) {
 233                                         /* max pressure isn't reported
 234                                         features->pressure_max = (unsigned short)
 235                                                         (report[i+4] << 8  | report[i + 3]);
 236                                         */
 237                                         features->pressure_max = 255;
 238                                         i += 4;
 239                                 }
 240                                 break;
 241
 242                         case HID_USAGE_Y:
 243                                 if (usage == WCM_DESKTOP) {
 244                                         if (finger) {
 245                                                 features->device_type = BTN_TOOL_FINGER;
 246                                                 if (features->type == TABLETPC2FG) {
 247                                                         /* need to reset back */
 248                                                         features->pktlen = WACOM_PKGLEN_TPC2FG;
 249                                                         features->device_type = BTN_TOOL_DOUBLETAP;
 250                                                         features->y_max =
 251                                                                 get_unaligned_le16(&report[i + 3]);
 252                                                         features->y_phy =
 253                                                                 get_unaligned_le16(&report[i + 6]);
 254                                                         i += 7;
 255                                                 } else if (features->type == BAMBOO_PT) {
 256                                                         /* need to reset back */
 257                                                         features->pktlen = WACOM_PKGLEN_BBTOUCH;
 258                                                         features->device_type = BTN_TOOL_DOUBLETAP;
 259                                                         features->y_phy =
 260                                                                 get_unaligned_le16(&report[i + 3]);
 261                                                         features->y_max =
 262                                                                 get_unaligned_le16(&report[i + 6]);
 263                                                         i += 12;
 264                                                 } else {
 265                                                         features->y_max =
 266                                                                 features->x_max;
 267                                                         features->y_phy =
 268                                                                 get_unaligned_le16(&report[i + 3]);
 269                                                         i += 4;
 270                                                 }
 271                                         } else if (pen) {
 272                                                 /* penabled only accepts exact bytes of data */
 273                                                 if (features->type == TABLETPC2FG)
 274                                                         features->pktlen = WACOM_PKGLEN_GRAPHIRE;
 275                                                 if (features->type == BAMBOO_PT)
 276                                                         features->pktlen = WACOM_PKGLEN_BBFUN;
 277                                                 features->device_type = BTN_TOOL_PEN;
 278                                                 features->y_max =
 279                                                         get_unaligned_le16(&report[i + 3]);
 280                                                 i += 4;
 281                                         }
 282                                 }
 283                                 break;
 284
 285                         case HID_USAGE_FINGER:
 286                                 finger = 1;
 287                                 i++;
 288                                 break;
 289
 290                         case HID_USAGE_STYLUS:
 291                                 pen = 1;
 292                                 i++;
 293                                 break;
 294
 295                         case HID_USAGE_UNDEFINED:
 296                                 if (usage == WCM_DESKTOP && finger) /* capacity */
 297                                         features->pressure_max =
 298                                                 get_unaligned_le16(&report[i + 3]);
 299                                 i += 4;
 300                                 break;
 301                         }
 302                         break;
 303
 304                 case HID_COLLECTION:
 305                         /* reset UsagePage and Finger */
 306                         finger = usage = 0;
 307                         break;
 308                 }
 309         }
 310
 311  out:
 312         result = 0;
 313         kfree(report);
 314         return result;
 315 }
 316
 317 static int wacom_query_tablet_data(struct usb_interface *intf, struct wacom_features *features)
 318 {
 319         unsigned char *rep_data;
 320         int limit = 0, report_id = 2;
 321         int error = -ENOMEM;
 322
 323         rep_data = kmalloc(4, GFP_KERNEL);
 324         if (!rep_data)
 325                 return error;
 326
 327         /* ask to report tablet data if it is MT Tablet PC or
 328          * not a Tablet PC */
 329         if (features->type == TABLETPC2FG) {
 330                 do {
 331                         rep_data[0] = 3;
 332                         rep_data[1] = 4;
 333                         rep_data[2] = 0;
 334                         rep_data[3] = 0;
 335                         report_id = 3;
 336                         error = usb_set_report(intf, WAC_HID_FEATURE_REPORT,
 337                                 report_id, rep_data, 4);
 338                         if (error >= 0)
 339                                 error = usb_get_report(intf,
 340                                         WAC_HID_FEATURE_REPORT, report_id,
 341                                         rep_data, 4);
 342                 } while ((error < 0 || rep_data[1] != 4) && limit++ < WAC_MSG_RETRIES);
 343         } else if (features->type != TABLETPC) {
 344                 do {
 345                         rep_data[0] = 2;
 346                         rep_data[1] = 2;
 347                         error = usb_set_report(intf, WAC_HID_FEATURE_REPORT,
 348                                 report_id, rep_data, 2);
 349                         if (error >= 0)
 350                                 error = usb_get_report(intf,
 351                                         WAC_HID_FEATURE_REPORT, report_id,
 352                                         rep_data, 2);
 353                 } while ((error < 0 || rep_data[1] != 2) && limit++ < WAC_MSG_RETRIES);
 354         }
 355
 356         kfree(rep_data);
 357
 358         return error < 0 ? error : 0;
 359 }
 360
 361 static int wacom_retrieve_hid_descriptor(struct usb_interface *intf,
 362                 struct wacom_features *features)
 363 {
 364         int error = 0;
 365         struct usb_host_interface *interface = intf->cur_altsetting;
 366         struct hid_descriptor *hid_desc;
 367
 368         /* default features */
 369         features->device_type = BTN_TOOL_PEN;
 370         features->x_fuzz = 4;
 371         features->y_fuzz = 4;
 372         features->pressure_fuzz = 0;
 373         features->distance_fuzz = 0;
 374
 375         /* only Tablet PCs and Bamboo P&T need to retrieve the info */
 376         if ((features->type != TABLETPC) && (features->type != TABLETPC2FG) &&
 377             (features->type != BAMBOO_PT))
 378                 goto out;
 379
 380         if (usb_get_extra_descriptor(interface, HID_DEVICET_HID, &hid_desc)) {
 381                 if (usb_get_extra_descriptor(&interface->endpoint[0],
 382                                 HID_DEVICET_REPORT, &hid_desc)) {
 383                         printk("wacom: can not retrieve extra class descriptor\n");
 384                         error = 1;
 385                         goto out;
 386                 }
 387         }
 388         error = wacom_parse_hid(intf, hid_desc, features);
 389         if (error)
 390                 goto out;
 391
 392  out:
 393         return error;
 394 }
 395
 396 struct wacom_usbdev_data {
 397         struct list_head list;
 398         struct kref kref;
 399         struct usb_device *dev;
 400         struct wacom_shared shared;
 401 };
 402
 403 static LIST_HEAD(wacom_udev_list);
 404 static DEFINE_MUTEX(wacom_udev_list_lock);
 405
 406 static struct wacom_usbdev_data *wacom_get_usbdev_data(struct usb_device *dev)
 407 {
 408         struct wacom_usbdev_data *data;
 409
 410         list_for_each_entry(data, &wacom_udev_list, list) {
 411                 if (data->dev == dev) {
 412                         kref_get(&data->kref);
 413                         return data;
 414                 }
 415         }
 416
 417         return NULL;
 418 }
 419
 420 static int wacom_add_shared_data(struct wacom_wac *wacom,
 421                                  struct usb_device *dev)
 422 {
 423         struct wacom_usbdev_data *data;
 424         int retval = 0;
 425
 426         mutex_lock(&wacom_udev_list_lock);
 427
 428         data = wacom_get_usbdev_data(dev);
 429         if (!data) {
 430                 data = kzalloc(sizeof(struct wacom_usbdev_data), GFP_KERNEL);
 431                 if (!data) {
 432                         retval = -ENOMEM;
 433                         goto out;
 434                 }
 435
 436                 kref_init(&data->kref);
 437                 data->dev = dev;
 438                 list_add_tail(&data->list, &wacom_udev_list);
 439         }
 440
 441         wacom->shared = &data->shared;
 442
 443 out:
 444         mutex_unlock(&wacom_udev_list_lock);
 445         return retval;
 446 }
 447
 448 static void wacom_release_shared_data(struct kref *kref)
 449 {
 450         struct wacom_usbdev_data *data =
 451                 container_of(kref, struct wacom_usbdev_data, kref);
 452
 453         mutex_lock(&wacom_udev_list_lock);
 454         list_del(&data->list);
 455         mutex_unlock(&wacom_udev_list_lock);
 456
 457         kfree(data);
 458 }
 459
 460 static void wacom_remove_shared_data(struct wacom_wac *wacom)
 461 {
 462         struct wacom_usbdev_data *data;
 463
 464         if (wacom->shared) {
 465                 data = container_of(wacom->shared, struct wacom_usbdev_data, shared);
 466                 kref_put(&data->kref, wacom_release_shared_data);
 467                 wacom->shared = NULL;
 468         }
 469 }
 470
 471 static int wacom_probe(struct usb_interface *intf, const struct usb_device_id *id)
 472 {
 473         struct usb_device *dev = interface_to_usbdev(intf);
 474         struct usb_endpoint_descriptor *endpoint;
 475         struct wacom *wacom;
 476         struct wacom_wac *wacom_wac;
 477         struct wacom_features *features;
 478         struct input_dev *input_dev;
 479         int error;
 480
 481         if (!id->driver_info)
 482                 return -EINVAL;
 483
 484         wacom = kzalloc(sizeof(struct wacom), GFP_KERNEL);
 485         input_dev = input_allocate_device();
 486         if (!wacom || !input_dev) {
 487                 error = -ENOMEM;
 488                 goto fail1;
 489         }
 490
 491         wacom_wac = &wacom->wacom_wac;
 492         wacom_wac->features = *((struct wacom_features *)id->driver_info);
 493         features = &wacom_wac->features;
 494         if (features->pktlen > WACOM_PKGLEN_MAX) {
 495                 error = -EINVAL;
 496                 goto fail1;
 497         }
 498
 499         wacom_wac->data = usb_alloc_coherent(dev, WACOM_PKGLEN_MAX,
 500                                              GFP_KERNEL, &wacom->data_dma);
 501         if (!wacom_wac->data) {
 502                 error = -ENOMEM;
 503                 goto fail1;
 504         }
 505
 506         wacom->irq = usb_alloc_urb(0, GFP_KERNEL);
 507         if (!wacom->irq) {
 508                 error = -ENOMEM;
 509                 goto fail2;
 510         }
 511
 512         wacom->usbdev = dev;
 513         wacom->intf = intf;
 514         mutex_init(&wacom->lock);
 515         usb_make_path(dev, wacom->phys, sizeof(wacom->phys));
 516         strlcat(wacom->phys, "/input0", sizeof(wacom->phys));
 517
 518         wacom_wac->input = input_dev;
 519
 520         endpoint = &intf->cur_altsetting->endpoint[0].desc;
 521
 522         /* Retrieve the physical and logical size for OEM devices */
 523         error = wacom_retrieve_hid_descriptor(intf, features);
 524         if (error)
 525                 goto fail3;
 526
 527         wacom_setup_device_quirks(features);
 528
 529         strlcpy(wacom_wac->name, features->name, sizeof(wacom_wac->name));
 530
 531         if (features->quirks & WACOM_QUIRK_MULTI_INPUT) {
 532                 /* Append the device type to the name */
 533                 strlcat(wacom_wac->name,
 534                         features->device_type == BTN_TOOL_PEN ?
 535                                 " Pen" : " Finger",
 536                         sizeof(wacom_wac->name));
 537
 538                 error = wacom_add_shared_data(wacom_wac, dev);
 539                 if (error)
 540                         goto fail3;
 541         }
 542
 543         input_dev->name = wacom_wac->name;
 544         input_dev->dev.parent = &intf->dev;
 545         input_dev->open = wacom_open;
 546         input_dev->close = wacom_close;
 547         usb_to_input_id(dev, &input_dev->id);
 548         input_set_drvdata(input_dev, wacom);
 549
 550         wacom_setup_input_capabilities(input_dev, wacom_wac);
 551
 552         usb_fill_int_urb(wacom->irq, dev,
 553                          usb_rcvintpipe(dev, endpoint->bEndpointAddress),
 554                          wacom_wac->data, features->pktlen,
 555                          wacom_sys_irq, wacom, endpoint->bInterval);
 556         wacom->irq->transfer_dma = wacom->data_dma;
 557         wacom->irq->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
 558
 559         error = input_register_device(input_dev);
 560         if (error)
 561                 goto fail4;
 562
 563         /* Note that if query fails it is not a hard failure */
 564         wacom_query_tablet_data(intf, features);
 565
 566         usb_set_intfdata(intf, wacom);
 567         return 0;
 568
 569  fail4: wacom_remove_shared_data(wacom_wac);
 570  fail3: usb_free_urb(wacom->irq);
 571  fail2: usb_free_coherent(dev, WACOM_PKGLEN_MAX, wacom_wac->data, wacom->data_dma);
 572  fail1: input_free_device(input_dev);
 573         kfree(wacom);
 574         return error;
 575 }
 576
 577 static void wacom_disconnect(struct usb_interface *intf)
 578 {
 579         struct wacom *wacom = usb_get_intfdata(intf);
 580
 581         usb_set_intfdata(intf, NULL);
 582
 583         usb_kill_urb(wacom->irq);
 584         input_unregister_device(wacom->wacom_wac.input);
 585         usb_free_urb(wacom->irq);
 586         usb_free_coherent(interface_to_usbdev(intf), WACOM_PKGLEN_MAX,
 587                         wacom->wacom_wac.data, wacom->data_dma);
 588         wacom_remove_shared_data(&wacom->wacom_wac);
 589         kfree(wacom);
 590 }
 591
 592 static int wacom_suspend(struct usb_interface *intf, pm_message_t message)
 593 {
 594         struct wacom *wacom = usb_get_intfdata(intf);
 595
 596         mutex_lock(&wacom->lock);
 597         usb_kill_urb(wacom->irq);
 598         mutex_unlock(&wacom->lock);
 599
 600         return 0;
 601 }
 602
 603 static int wacom_resume(struct usb_interface *intf)
 604 {
 605         struct wacom *wacom = usb_get_intfdata(intf);
 606         struct wacom_features *features = &wacom->wacom_wac.features;
 607         int rv;
 608
 609         mutex_lock(&wacom->lock);
 610
 611         /* switch to wacom mode first */
 612         wacom_query_tablet_data(intf, features);
 613
 614         if (wacom->open)
 615                 rv = usb_submit_urb(wacom->irq, GFP_NOIO);
 616         else
 617                 rv = 0;
 618
 619         mutex_unlock(&wacom->lock);
 620
 621         return rv;
 622 }
 623
 624 static int wacom_reset_resume(struct usb_interface *intf)
 625 {
 626         return wacom_resume(intf);
 627 }
 628
 629 static struct usb_driver wacom_driver = {
 630         .name =         "wacom",
 631         .id_table =     wacom_ids,
 632         .probe =        wacom_probe,
 633         .disconnect =   wacom_disconnect,
 634         .suspend =      wacom_suspend,
 635         .resume =       wacom_resume,
 636         .reset_resume = wacom_reset_resume,
 637         .supports_autosuspend = 1,
 638 };
 639
 640 static int __init wacom_init(void)
 641 {
 642         int result;
 643
 644         result = usb_register(&wacom_driver);
 645         if (result == 0)
 646                 printk(KERN_INFO KBUILD_MODNAME ": " DRIVER_VERSION ":"
 647                        DRIVER_DESC "\n");
 648         return result;
 649 }
 650
 651 static void __exit wacom_exit(void)
 652 {
 653         usb_deregister(&wacom_driver);
 654 }
 655
 656 module_init(wacom_init);
 657 module_exit(wacom_exit);