drivers/usb/gadget/f_hid.c

   1 /*
   2  * f_hid.c -- USB HID function driver
   3  *
   4  * Copyright (C) 2010 Fabien Chouteau <fabien.chouteau@barco.com>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  */
  11
  12 #include <linux/kernel.h>
  13 #include <linux/utsname.h>
  14 #include <linux/module.h>
  15 #include <linux/hid.h>
  16 #include <linux/cdev.h>
  17 #include <linux/mutex.h>
  18 #include <linux/poll.h>
  19 #include <linux/uaccess.h>
  20 #include <linux/wait.h>
  21 #include <linux/usb/g_hid.h>
  22
  23 static int major, minors;
  24 static struct class *hidg_class;
  25
  26 /*-------------------------------------------------------------------------*/
  27 /*                            HID gadget struct                            */
  28
  29 struct f_hidg {
  30         /* configuration */
  31         unsigned char                   bInterfaceSubClass;
  32         unsigned char                   bInterfaceProtocol;
  33         unsigned short                  report_desc_length;
  34         char                            *report_desc;
  35         unsigned short                  report_length;
  36
  37         /* recv report */
  38         char                            *set_report_buff;
  39         unsigned short                  set_report_length;
  40         spinlock_t                      read_spinlock;
  41         wait_queue_head_t               read_queue;
  42
  43         /* send report */
  44         spinlock_t                      write_spinlock;
  45         bool                            write_pending;
  46         wait_queue_head_t               write_queue;
  47         struct usb_request              *req;
  48
  49         int                             minor;
  50         struct cdev                     cdev;
  51         struct usb_function             func;
  52         struct usb_ep                   *in_ep;
  53 };
  54
  55 static inline struct f_hidg *func_to_hidg(struct usb_function *f)
  56 {
  57         return container_of(f, struct f_hidg, func);
  58 }
  59
  60 /*-------------------------------------------------------------------------*/
  61 /*                           Static descriptors                            */
  62
  63 static struct usb_interface_descriptor hidg_interface_desc = {
  64         .bLength                = sizeof hidg_interface_desc,
  65         .bDescriptorType        = USB_DT_INTERFACE,
  66         /* .bInterfaceNumber    = DYNAMIC */
  67         .bAlternateSetting      = 0,
  68         .bNumEndpoints          = 1,
  69         .bInterfaceClass        = USB_CLASS_HID,
  70         /* .bInterfaceSubClass  = DYNAMIC */
  71         /* .bInterfaceProtocol  = DYNAMIC */
  72         /* .iInterface          = DYNAMIC */
  73 };
  74
  75 static struct hid_descriptor hidg_desc = {
  76         .bLength                        = sizeof hidg_desc,
  77         .bDescriptorType                = HID_DT_HID,
  78         .bcdHID                         = 0x0101,
  79         .bCountryCode                   = 0x00,
  80         .bNumDescriptors                = 0x1,
  81         /*.desc[0].bDescriptorType      = DYNAMIC */
  82         /*.desc[0].wDescriptorLenght    = DYNAMIC */
  83 };
  84
  85 /* High-Speed Support */
  86
  87 static struct usb_endpoint_descriptor hidg_hs_in_ep_desc = {
  88         .bLength                = USB_DT_ENDPOINT_SIZE,
  89         .bDescriptorType        = USB_DT_ENDPOINT,
  90         .bEndpointAddress       = USB_DIR_IN,
  91         .bmAttributes           = USB_ENDPOINT_XFER_INT,
  92         /*.wMaxPacketSize       = DYNAMIC */
  93         .bInterval              = 4, /* FIXME: Add this field in the
  94                                       * HID gadget configuration?
  95                                       * (struct hidg_func_descriptor)
  96                                       */
  97 };
  98
  99 static struct usb_descriptor_header *hidg_hs_descriptors[] = {
 100         (struct usb_descriptor_header *)&hidg_interface_desc,
 101         (struct usb_descriptor_header *)&hidg_desc,
 102         (struct usb_descriptor_header *)&hidg_hs_in_ep_desc,
 103         NULL,
 104 };
 105
 106 /* Full-Speed Support */
 107
 108 static struct usb_endpoint_descriptor hidg_fs_in_ep_desc = {
 109         .bLength                = USB_DT_ENDPOINT_SIZE,
 110         .bDescriptorType        = USB_DT_ENDPOINT,
 111         .bEndpointAddress       = USB_DIR_IN,
 112         .bmAttributes           = USB_ENDPOINT_XFER_INT,
 113         /*.wMaxPacketSize       = DYNAMIC */
 114         .bInterval              = 10, /* FIXME: Add this field in the
 115                                        * HID gadget configuration?
 116                                        * (struct hidg_func_descriptor)
 117                                        */
 118 };
 119
 120 static struct usb_descriptor_header *hidg_fs_descriptors[] = {
 121         (struct usb_descriptor_header *)&hidg_interface_desc,
 122         (struct usb_descriptor_header *)&hidg_desc,
 123         (struct usb_descriptor_header *)&hidg_fs_in_ep_desc,
 124         NULL,
 125 };
 126
 127 /*-------------------------------------------------------------------------*/
 128 /*                              Char Device                                */
 129
 130 static ssize_t f_hidg_read(struct file *file, char __user *buffer,
 131                         size_t count, loff_t *ptr)
 132 {
 133         struct f_hidg   *hidg     = file->private_data;
 134         char            *tmp_buff = NULL;
 135         unsigned long   flags;
 136
 137         if (!count)
 138                 return 0;
 139
 140         if (!access_ok(VERIFY_WRITE, buffer, count))
 141                 return -EFAULT;
 142
 143         spin_lock_irqsave(&hidg->read_spinlock, flags);
 144
 145 #define READ_COND (hidg->set_report_buff != NULL)
 146
 147         while (!READ_COND) {
 148                 spin_unlock_irqrestore(&hidg->read_spinlock, flags);
 149                 if (file->f_flags & O_NONBLOCK)
 150                         return -EAGAIN;
 151
 152                 if (wait_event_interruptible(hidg->read_queue, READ_COND))
 153                         return -ERESTARTSYS;
 154
 155                 spin_lock_irqsave(&hidg->read_spinlock, flags);
 156         }
 157
 158
 159         count = min_t(unsigned, count, hidg->set_report_length);
 160         tmp_buff = hidg->set_report_buff;
 161         hidg->set_report_buff = NULL;
 162
 163         spin_unlock_irqrestore(&hidg->read_spinlock, flags);
 164
 165         if (tmp_buff != NULL) {
 166                 /* copy to user outside spinlock */
 167                 count -= copy_to_user(buffer, tmp_buff, count);
 168                 kfree(tmp_buff);
 169         } else
 170                 count = -ENOMEM;
 171
 172         return count;
 173 }
 174
 175 static void f_hidg_req_complete(struct usb_ep *ep, struct usb_request *req)
 176 {
 177         struct f_hidg *hidg = (struct f_hidg *)ep->driver_data;
 178         unsigned long flags;
 179
 180         if (req->status != 0) {
 181                 ERROR(hidg->func.config->cdev,
 182                         "End Point Request ERROR: %d\n", req->status);
 183         }
 184
 185         spin_lock_irqsave(&hidg->write_spinlock, flags);
 186         hidg->write_pending = 0;
 187         spin_unlock_irqrestore(&hidg->write_spinlock, flags);
 188         wake_up(&hidg->write_queue);
 189 }
 190
 191 static ssize_t f_hidg_write(struct file *file, const char __user *buffer,
 192                             size_t count, loff_t *offp)
 193 {
 194         struct f_hidg *hidg  = file->private_data;
 195         unsigned long flags;
 196         ssize_t status = -ENOMEM;
 197
 198         if (!access_ok(VERIFY_READ, buffer, count))
 199                 return -EFAULT;
 200
 201         spin_lock_irqsave(&hidg->write_spinlock, flags);
 202
 203 #define WRITE_COND (!hidg->write_pending)
 204
 205         /* write queue */
 206         while (!WRITE_COND) {
 207                 spin_unlock_irqrestore(&hidg->write_spinlock, flags);
 208                 if (file->f_flags & O_NONBLOCK)
 209                         return -EAGAIN;
 210
 211                 if (wait_event_interruptible_exclusive(
 212                                 hidg->write_queue, WRITE_COND))
 213                         return -ERESTARTSYS;
 214
 215                 spin_lock_irqsave(&hidg->write_spinlock, flags);
 216         }
 217
 218         hidg->write_pending = 1;
 219         count  = min_t(unsigned, count, hidg->report_length);
 220
 221         spin_unlock_irqrestore(&hidg->write_spinlock, flags);
 222         status = copy_from_user(hidg->req->buf, buffer, count);
 223
 224         if (status != 0) {
 225                 ERROR(hidg->func.config->cdev,
 226                         "copy_from_user error\n");
 227                 status = -EINVAL;
 228                 goto release_write_pending;
 229         }
 230
 231         hidg->req->status   = 0;
 232         hidg->req->zero     = 0;
 233         hidg->req->length   = count;
 234         hidg->req->complete = f_hidg_req_complete;
 235         hidg->req->context  = hidg;
 236
 237         status = usb_ep_queue(hidg->in_ep, hidg->req, GFP_ATOMIC);
 238         if (status < 0) {
 239                 ERROR(hidg->func.config->cdev,
 240                         "usb_ep_queue error on int endpoint %zd\n", status);
 241                 goto release_write_pending;
 242         } else {
 243                 status = count;
 244         }
 245
 246         return status;
 247 release_write_pending:
 248         spin_lock_irqsave(&hidg->write_spinlock, flags);
 249         hidg->write_pending = 0;
 250         spin_unlock_irqrestore(&hidg->write_spinlock, flags);
 251
 252         wake_up(&hidg->write_queue);
 253
 254         return status;
 255 }
 256
 257 static unsigned int f_hidg_poll(struct file *file, poll_table *wait)
 258 {
 259         struct f_hidg   *hidg  = file->private_data;
 260         unsigned int    ret = 0;
 261
 262         poll_wait(file, &hidg->read_queue, wait);
 263         poll_wait(file, &hidg->write_queue, wait);
 264
 265         if (WRITE_COND)
 266                 ret |= POLLOUT | POLLWRNORM;
 267
 268         if (READ_COND)
 269                 ret |= POLLIN | POLLRDNORM;
 270
 271         return ret;
 272 }
 273
 274 #undef WRITE_COND
 275 #undef READ_COND
 276
 277 static int f_hidg_release(struct inode *inode, struct file *fd)
 278 {
 279         fd->private_data = NULL;
 280         return 0;
 281 }
 282
 283 static int f_hidg_open(struct inode *inode, struct file *fd)
 284 {
 285         struct f_hidg *hidg =
 286                 container_of(inode->i_cdev, struct f_hidg, cdev);
 287
 288         fd->private_data = hidg;
 289
 290         return 0;
 291 }
 292
 293 /*-------------------------------------------------------------------------*/
 294 /*                                usb_function                             */
 295
 296 static void hidg_set_report_complete(struct usb_ep *ep, struct usb_request *req)
 297 {
 298         struct f_hidg *hidg = (struct f_hidg *)req->context;
 299
 300         if (req->status != 0 || req->buf == NULL || req->actual == 0) {
 301                 ERROR(hidg->func.config->cdev, "%s FAILED\n", __func__);
 302                 return;
 303         }
 304
 305         spin_lock(&hidg->read_spinlock);
 306
 307         hidg->set_report_buff = krealloc(hidg->set_report_buff,
 308                                          req->actual, GFP_ATOMIC);
 309
 310         if (hidg->set_report_buff == NULL) {
 311                 spin_unlock(&hidg->read_spinlock);
 312                 return;
 313         }
 314         hidg->set_report_length = req->actual;
 315         memcpy(hidg->set_report_buff, req->buf, req->actual);
 316
 317         spin_unlock(&hidg->read_spinlock);
 318
 319         wake_up(&hidg->read_queue);
 320 }
 321
 322 static int hidg_setup(struct usb_function *f,
 323                 const struct usb_ctrlrequest *ctrl)
 324 {
 325         struct f_hidg                   *hidg = func_to_hidg(f);
 326         struct usb_composite_dev        *cdev = f->config->cdev;
 327         struct usb_request              *req  = cdev->req;
 328         int status = 0;
 329         __u16 value, length;
 330
 331         value   = __le16_to_cpu(ctrl->wValue);
 332         length  = __le16_to_cpu(ctrl->wLength);
 333
 334         VDBG(cdev, "hid_setup crtl_request : bRequestType:0x%x bRequest:0x%x "
 335                 "Value:0x%x\n", ctrl->bRequestType, ctrl->bRequest, value);
 336
 337         switch ((ctrl->bRequestType << 8) | ctrl->bRequest) {
 338         case ((USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE) << 8
 339                   | HID_REQ_GET_REPORT):
 340                 VDBG(cdev, "get_report\n");
 341
 342                 /* send an empty report */
 343                 length = min_t(unsigned, length, hidg->report_length);
 344                 memset(req->buf, 0x0, length);
 345
 346                 goto respond;
 347                 break;
 348
 349         case ((USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE) << 8
 350                   | HID_REQ_GET_PROTOCOL):
 351                 VDBG(cdev, "get_protocol\n");
 352                 goto stall;
 353                 break;
 354
 355         case ((USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_INTERFACE) << 8
 356                   | HID_REQ_SET_REPORT):
 357                 VDBG(cdev, "set_report | wLenght=%d\n", ctrl->wLength);
 358                 req->context  = hidg;
 359                 req->complete = hidg_set_report_complete;
 360                 goto respond;
 361                 break;
 362
 363         case ((USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_INTERFACE) << 8
 364                   | HID_REQ_SET_PROTOCOL):
 365                 VDBG(cdev, "set_protocol\n");
 366                 goto stall;
 367                 break;
 368
 369         case ((USB_DIR_IN | USB_TYPE_STANDARD | USB_RECIP_INTERFACE) << 8
 370                   | USB_REQ_GET_DESCRIPTOR):
 371                 switch (value >> 8) {
 372                 case HID_DT_HID:
 373                         VDBG(cdev, "USB_REQ_GET_DESCRIPTOR: HID\n");
 374                         length = min_t(unsigned short, length,
 375                                                    hidg_desc.bLength);
 376                         memcpy(req->buf, &hidg_desc, length);
 377                         goto respond;
 378                         break;
 379                 case HID_DT_REPORT:
 380                         VDBG(cdev, "USB_REQ_GET_DESCRIPTOR: REPORT\n");
 381                         length = min_t(unsigned short, length,
 382                                                    hidg->report_desc_length);
 383                         memcpy(req->buf, hidg->report_desc, length);
 384                         goto respond;
 385                         break;
 386
 387                 default:
 388                         VDBG(cdev, "Unknown decriptor request 0x%x\n",
 389                                  value >> 8);
 390                         goto stall;
 391                         break;
 392                 }
 393                 break;
 394
 395         default:
 396                 VDBG(cdev, "Unknown request 0x%x\n",
 397                          ctrl->bRequest);
 398                 goto stall;
 399                 break;
 400         }
 401
 402 stall:
 403         return -EOPNOTSUPP;
 404
 405 respond:
 406         req->zero = 0;
 407         req->length = length;
 408         status = usb_ep_queue(cdev->gadget->ep0, req, GFP_ATOMIC);
 409         if (status < 0)
 410                 ERROR(cdev, "usb_ep_queue error on ep0 %d\n", value);
 411         return status;
 412 }
 413
 414 static void hidg_disable(struct usb_function *f)
 415 {
 416         struct f_hidg *hidg = func_to_hidg(f);
 417
 418         usb_ep_disable(hidg->in_ep);
 419         hidg->in_ep->driver_data = NULL;
 420 }
 421
 422 static int hidg_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
 423 {
 424         struct usb_composite_dev                *cdev = f->config->cdev;
 425         struct f_hidg                           *hidg = func_to_hidg(f);
 426         int status = 0;
 427
 428         VDBG(cdev, "hidg_set_alt intf:%d alt:%d\n", intf, alt);
 429
 430         if (hidg->in_ep != NULL) {
 431                 /* restart endpoint */
 432                 if (hidg->in_ep->driver_data != NULL)
 433                         usb_ep_disable(hidg->in_ep);
 434
 435                 status = config_ep_by_speed(f->config->cdev->gadget, f,
 436                                             hidg->in_ep);
 437                 if (status) {
 438                         ERROR(cdev, "config_ep_by_speed FAILED!\n");
 439                         goto fail;
 440                 }
 441                 status = usb_ep_enable(hidg->in_ep);
 442                 if (status < 0) {
 443                         ERROR(cdev, "Enable endpoint FAILED!\n");
 444                         goto fail;
 445                 }
 446                 hidg->in_ep->driver_data = hidg;
 447         }
 448 fail:
 449         return status;
 450 }
 451
 452 const struct file_operations f_hidg_fops = {
 453         .owner          = THIS_MODULE,
 454         .open           = f_hidg_open,
 455         .release        = f_hidg_release,
 456         .write          = f_hidg_write,
 457         .read           = f_hidg_read,
 458         .poll           = f_hidg_poll,
 459         .llseek         = noop_llseek,
 460 };
 461
 462 static int __init hidg_bind(struct usb_configuration *c, struct usb_function *f)
 463 {
 464         struct usb_ep           *ep;
 465         struct f_hidg           *hidg = func_to_hidg(f);
 466         int                     status;
 467         dev_t                   dev;
 468
 469         /* allocate instance-specific interface IDs, and patch descriptors */
 470         status = usb_interface_id(c, f);
 471         if (status < 0)
 472                 goto fail;
 473         hidg_interface_desc.bInterfaceNumber = status;
 474
 475
 476         /* allocate instance-specific endpoints */
 477         status = -ENODEV;
 478         ep = usb_ep_autoconfig(c->cdev->gadget, &hidg_fs_in_ep_desc);
 479         if (!ep)
 480                 goto fail;
 481         ep->driver_data = c->cdev;      /* claim */
 482         hidg->in_ep = ep;
 483
 484         /* preallocate request and buffer */
 485         status = -ENOMEM;
 486         hidg->req = usb_ep_alloc_request(hidg->in_ep, GFP_KERNEL);
 487         if (!hidg->req)
 488                 goto fail;
 489
 490
 491         hidg->req->buf = kmalloc(hidg->report_length, GFP_KERNEL);
 492         if (!hidg->req->buf)
 493                 goto fail;
 494
 495         /* set descriptor dynamic values */
 496         hidg_interface_desc.bInterfaceSubClass = hidg->bInterfaceSubClass;
 497         hidg_interface_desc.bInterfaceProtocol = hidg->bInterfaceProtocol;
 498         hidg_hs_in_ep_desc.wMaxPacketSize = cpu_to_le16(hidg->report_length);
 499         hidg_fs_in_ep_desc.wMaxPacketSize = cpu_to_le16(hidg->report_length);
 500         hidg_desc.desc[0].bDescriptorType = HID_DT_REPORT;
 501         hidg_desc.desc[0].wDescriptorLength =
 502                 cpu_to_le16(hidg->report_desc_length);
 503
 504         hidg->set_report_buff = NULL;
 505
 506         /* copy descriptors */
 507         f->descriptors = usb_copy_descriptors(hidg_fs_descriptors);
 508         if (!f->descriptors)
 509                 goto fail;
 510
 511         if (gadget_is_dualspeed(c->cdev->gadget)) {
 512                 hidg_hs_in_ep_desc.bEndpointAddress =
 513                         hidg_fs_in_ep_desc.bEndpointAddress;
 514                 f->hs_descriptors = usb_copy_descriptors(hidg_hs_descriptors);
 515                 if (!f->hs_descriptors)
 516                         goto fail;
 517         }
 518
 519         spin_lock_init(&hidg->write_spinlock);
 520         spin_lock_init(&hidg->read_spinlock);
 521         init_waitqueue_head(&hidg->write_queue);
 522         init_waitqueue_head(&hidg->read_queue);
 523
 524         /* create char device */
 525         cdev_init(&hidg->cdev, &f_hidg_fops);
 526         dev = MKDEV(major, hidg->minor);
 527         status = cdev_add(&hidg->cdev, dev, 1);
 528         if (status)
 529                 goto fail;
 530
 531         device_create(hidg_class, NULL, dev, NULL, "%s%d", "hidg", hidg->minor);
 532
 533         return 0;
 534
 535 fail:
 536         ERROR(f->config->cdev, "hidg_bind FAILED\n");
 537         if (hidg->req != NULL) {
 538                 kfree(hidg->req->buf);
 539                 if (hidg->in_ep != NULL)
 540                         usb_ep_free_request(hidg->in_ep, hidg->req);
 541         }
 542
 543         usb_free_descriptors(f->hs_descriptors);
 544         usb_free_descriptors(f->descriptors);
 545
 546         return status;
 547 }
 548
 549 static void hidg_unbind(struct usb_configuration *c, struct usb_function *f)
 550 {
 551         struct f_hidg *hidg = func_to_hidg(f);
 552
 553         device_destroy(hidg_class, MKDEV(major, hidg->minor));
 554         cdev_del(&hidg->cdev);
 555
 556         /* disable/free request and end point */
 557         usb_ep_disable(hidg->in_ep);
 558         usb_ep_dequeue(hidg->in_ep, hidg->req);
 559         kfree(hidg->req->buf);
 560         usb_ep_free_request(hidg->in_ep, hidg->req);
 561
 562         /* free descriptors copies */
 563         usb_free_descriptors(f->hs_descriptors);
 564         usb_free_descriptors(f->descriptors);
 565
 566         kfree(hidg->report_desc);
 567         kfree(hidg->set_report_buff);
 568         kfree(hidg);
 569 }
 570
 571 /*-------------------------------------------------------------------------*/
 572 /*                                 Strings                                 */
 573
 574 #define CT_FUNC_HID_IDX 0
 575
 576 static struct usb_string ct_func_string_defs[] = {
 577         [CT_FUNC_HID_IDX].s     = "HID Interface",
 578         {},                     /* end of list */
 579 };
 580
 581 static struct usb_gadget_strings ct_func_string_table = {
 582         .language       = 0x0409,       /* en-US */
 583         .strings        = ct_func_string_defs,
 584 };
 585
 586 static struct usb_gadget_strings *ct_func_strings[] = {
 587         &ct_func_string_table,
 588         NULL,
 589 };
 590
 591 /*-------------------------------------------------------------------------*/
 592 /*                             usb_configuration                           */
 593
 594 int __init hidg_bind_config(struct usb_configuration *c,
 595                             struct hidg_func_descriptor *fdesc, int index)
 596 {
 597         struct f_hidg *hidg;
 598         int status;
 599
 600         if (index >= minors)
 601                 return -ENOENT;
 602
 603         /* maybe allocate device-global string IDs, and patch descriptors */
 604         if (ct_func_string_defs[CT_FUNC_HID_IDX].id == 0) {
 605                 status = usb_string_id(c->cdev);
 606                 if (status < 0)
 607                         return status;
 608                 ct_func_string_defs[CT_FUNC_HID_IDX].id = status;
 609                 hidg_interface_desc.iInterface = status;
 610         }
 611
 612         /* allocate and initialize one new instance */
 613         hidg = kzalloc(sizeof *hidg, GFP_KERNEL);
 614         if (!hidg)
 615                 return -ENOMEM;
 616
 617         hidg->minor = index;
 618         hidg->bInterfaceSubClass = fdesc->subclass;
 619         hidg->bInterfaceProtocol = fdesc->protocol;
 620         hidg->report_length = fdesc->report_length;
 621         hidg->report_desc_length = fdesc->report_desc_length;
 622         hidg->report_desc = kmemdup(fdesc->report_desc,
 623                                     fdesc->report_desc_length,
 624                                     GFP_KERNEL);
 625         if (!hidg->report_desc) {
 626                 kfree(hidg);
 627                 return -ENOMEM;
 628         }
 629
 630         hidg->func.name    = "hid";
 631         hidg->func.strings = ct_func_strings;
 632         hidg->func.bind    = hidg_bind;
 633         hidg->func.unbind  = hidg_unbind;
 634         hidg->func.set_alt = hidg_set_alt;
 635         hidg->func.disable = hidg_disable;
 636         hidg->func.setup   = hidg_setup;
 637
 638         status = usb_add_function(c, &hidg->func);
 639         if (status)
 640                 kfree(hidg);
 641
 642         return status;
 643 }
 644
 645 int __init ghid_setup(struct usb_gadget *g, int count)
 646 {
 647         int status;
 648         dev_t dev;
 649
 650         hidg_class = class_create(THIS_MODULE, "hidg");
 651
 652         status = alloc_chrdev_region(&dev, 0, count, "hidg");
 653         if (!status) {
 654                 major = MAJOR(dev);
 655                 minors = count;
 656         }
 657
 658         return status;
 659 }
 660
 661 void ghid_cleanup(void)
 662 {
 663         if (major) {
 664                 unregister_chrdev_region(MKDEV(major, 0), minors);
 665                 major = minors = 0;
 666         }
 667
 668         class_destroy(hidg_class);
 669         hidg_class = NULL;
 670 }