summaryrefslogtreecommitdiff
path: root/drivers/usb/gadget/f_hid.c
blob: 511e527178e23d0e3cb3787700b5f7cc4f3baa32 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
/*
 * f_hid.c -- USB HID function driver
 *
 * Copyright (C) 2010 Fabien Chouteau <fabien.chouteau@barco.com>
 *
 * 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.
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/hid.h>
#include <linux/cdev.h>
#include <linux/mutex.h>
#include <linux/poll.h>
#include <linux/uaccess.h>
#include <linux/wait.h>
#include <linux/sched.h>
#include <linux/usb/g_hid.h>

static int major, minors;
static struct class *hidg_class;

/*-------------------------------------------------------------------------*/
/*                            HID gadget struct                            */

struct f_hidg_req_list {
	struct usb_request	*req;
	unsigned int		pos;
	struct list_head 	list;
};

struct f_hidg {
	/* configuration */
	unsigned char			bInterfaceSubClass;
	unsigned char			bInterfaceProtocol;
	unsigned short			report_desc_length;
	char				*report_desc;
	unsigned short			report_length;

	/* recv report */
	struct list_head		completed_out_req;
	spinlock_t			spinlock;
	wait_queue_head_t		read_queue;
	unsigned int			qlen;

	/* send report */
	struct mutex			lock;
	bool				write_pending;
	wait_queue_head_t		write_queue;
	struct usb_request		*req;

	int				minor;
	struct cdev			cdev;
	struct usb_function		func;

	struct usb_ep			*in_ep;
	struct usb_ep			*out_ep;
};

static inline struct f_hidg *func_to_hidg(struct usb_function *f)
{
	return container_of(f, struct f_hidg, func);
}

/*-------------------------------------------------------------------------*/
/*                           Static descriptors                            */

static struct usb_interface_descriptor hidg_interface_desc = {
	.bLength		= sizeof hidg_interface_desc,
	.bDescriptorType	= USB_DT_INTERFACE,
	/* .bInterfaceNumber	= DYNAMIC */
	.bAlternateSetting	= 0,
	.bNumEndpoints		= 2,
	.bInterfaceClass	= USB_CLASS_HID,
	/* .bInterfaceSubClass	= DYNAMIC */
	/* .bInterfaceProtocol	= DYNAMIC */
	/* .iInterface		= DYNAMIC */
};

static struct hid_descriptor hidg_desc = {
	.bLength			= sizeof hidg_desc,
	.bDescriptorType		= HID_DT_HID,
	.bcdHID				= 0x0101,
	.bCountryCode			= 0x00,
	.bNumDescriptors		= 0x1,
	/*.desc[0].bDescriptorType	= DYNAMIC */
	/*.desc[0].wDescriptorLenght	= DYNAMIC */
};

/* High-Speed Support */

static struct usb_endpoint_descriptor hidg_hs_in_ep_desc = {
	.bLength		= USB_DT_ENDPOINT_SIZE,
	.bDescriptorType	= USB_DT_ENDPOINT,
	.bEndpointAddress	= USB_DIR_IN,
	.bmAttributes		= USB_ENDPOINT_XFER_INT,
	/*.wMaxPacketSize	= DYNAMIC */
	.bInterval		= 4, /* FIXME: Add this field in the
				      * HID gadget configuration?
				      * (struct hidg_func_descriptor)
				      */
};

static struct usb_endpoint_descriptor hidg_hs_out_ep_desc = {
	.bLength		= USB_DT_ENDPOINT_SIZE,
	.bDescriptorType	= USB_DT_ENDPOINT,
	.bEndpointAddress	= USB_DIR_OUT,
	.bmAttributes		= USB_ENDPOINT_XFER_INT,
	/*.wMaxPacketSize	= DYNAMIC */
	.bInterval		= 4, /* FIXME: Add this field in the
				      * HID gadget configuration?
				      * (struct hidg_func_descriptor)
				      */
};

static struct usb_descriptor_header *hidg_hs_descriptors[] = {
	(struct usb_descriptor_header *)&hidg_interface_desc,
	(struct usb_descriptor_header *)&hidg_desc,
	(struct usb_descriptor_header *)&hidg_hs_in_ep_desc,
	(struct usb_descriptor_header *)&hidg_hs_out_ep_desc,
	NULL,
};

/* Full-Speed Support */

static struct usb_endpoint_descriptor hidg_fs_in_ep_desc = {
	.bLength		= USB_DT_ENDPOINT_SIZE,
	.bDescriptorType	= USB_DT_ENDPOINT,
	.bEndpointAddress	= USB_DIR_IN,
	.bmAttributes		= USB_ENDPOINT_XFER_INT,
	/*.wMaxPacketSize	= DYNAMIC */
	.bInterval		= 10, /* FIXME: Add this field in the
				       * HID gadget configuration?
				       * (struct hidg_func_descriptor)
				       */
};

static struct usb_endpoint_descriptor hidg_fs_out_ep_desc = {
	.bLength		= USB_DT_ENDPOINT_SIZE,
	.bDescriptorType	= USB_DT_ENDPOINT,
	.bEndpointAddress	= USB_DIR_OUT,
	.bmAttributes		= USB_ENDPOINT_XFER_INT,
	/*.wMaxPacketSize	= DYNAMIC */
	.bInterval		= 10, /* FIXME: Add this field in the
				       * HID gadget configuration?
				       * (struct hidg_func_descriptor)
				       */
};

static struct usb_descriptor_header *hidg_fs_descriptors[] = {
	(struct usb_descriptor_header *)&hidg_interface_desc,
	(struct usb_descriptor_header *)&hidg_desc,
	(struct usb_descriptor_header *)&hidg_fs_in_ep_desc,
	(struct usb_descriptor_header *)&hidg_fs_out_ep_desc,
	NULL,
};

/*-------------------------------------------------------------------------*/
/*                              Char Device                                */

static ssize_t f_hidg_read(struct file *file, char __user *buffer,
			size_t count, loff_t *ptr)
{
	struct f_hidg *hidg = file->private_data;
	struct f_hidg_req_list *list;
	struct usb_request *req;
	unsigned long flags;
	int ret;

	if (!count)
		return 0;

	if (!access_ok(VERIFY_WRITE, buffer, count))
		return -EFAULT;

	spin_lock_irqsave(&hidg->spinlock, flags);

#define READ_COND (!list_empty(&hidg->completed_out_req))

	/* wait for at least one buffer to complete */
	while (!READ_COND) {
		spin_unlock_irqrestore(&hidg->spinlock, flags);
		if (file->f_flags & O_NONBLOCK)
			return -EAGAIN;

		if (wait_event_interruptible(hidg->read_queue, READ_COND))
			return -ERESTARTSYS;

		spin_lock_irqsave(&hidg->spinlock, flags);
	}

	/* pick the first one */
	list = list_first_entry(&hidg->completed_out_req,
				struct f_hidg_req_list, list);
	req = list->req;
	count = min_t(unsigned int, count, req->actual - list->pos);
	spin_unlock_irqrestore(&hidg->spinlock, flags);

	/* copy to user outside spinlock */
	count -= copy_to_user(buffer, req->buf + list->pos, count);
	list->pos += count;

	/*
	 * if this request is completely handled and transfered to
	 * userspace, remove its entry from the list and requeue it
	 * again. Otherwise, we will revisit it again upon the next
	 * call, taking into account its current read position.
	 */
	if (list->pos == req->actual) {
		spin_lock_irqsave(&hidg->spinlock, flags);
		list_del(&list->list);
		kfree(list);
		spin_unlock_irqrestore(&hidg->spinlock, flags);

		req->length = hidg->report_length;
		ret = usb_ep_queue(hidg->out_ep, req, GFP_KERNEL);
		if (ret < 0)
			return ret;
	}

	return count;
}

static void f_hidg_req_complete(struct usb_ep *ep, struct usb_request *req)
{
	struct f_hidg *hidg = (struct f_hidg *)ep->driver_data;

	if (req->status != 0) {
		ERROR(hidg->func.config->cdev,
			"End Point Request ERROR: %d\n", req->status);
	}

	hidg->write_pending = 0;
	wake_up(&hidg->write_queue);
}

static ssize_t f_hidg_write(struct file *file, const char __user *buffer,
			    size_t count, loff_t *offp)
{
	struct f_hidg *hidg  = file->private_data;
	ssize_t status = -ENOMEM;

	if (!access_ok(VERIFY_READ, buffer, count))
		return -EFAULT;

	mutex_lock(&hidg->lock);

#define WRITE_COND (!hidg->write_pending)

	/* write queue */
	while (!WRITE_COND) {
		mutex_unlock(&hidg->lock);
		if (file->f_flags & O_NONBLOCK)
			return -EAGAIN;

		if (wait_event_interruptible_exclusive(
				hidg->write_queue, WRITE_COND))
			return -ERESTARTSYS;

		mutex_lock(&hidg->lock);
	}

	count  = min_t(unsigned, count, hidg->report_length);
	status = copy_from_user(hidg->req->buf, buffer, count);

	if (status != 0) {
		ERROR(hidg->func.config->cdev,
			"copy_from_user error\n");
		mutex_unlock(&hidg->lock);
		return -EINVAL;
	}

	hidg->req->status   = 0;
	hidg->req->zero     = 0;
	hidg->req->length   = count;
	hidg->req->complete = f_hidg_req_complete;
	hidg->req->context  = hidg;
	hidg->write_pending = 1;

	status = usb_ep_queue(hidg->in_ep, hidg->req, GFP_ATOMIC);
	if (status < 0) {
		ERROR(hidg->func.config->cdev,
			"usb_ep_queue error on int endpoint %zd\n", status);
		hidg->write_pending = 0;
		wake_up(&hidg->write_queue);
	} else {
		status = count;
	}

	mutex_unlock(&hidg->lock);

	return status;
}

static unsigned int f_hidg_poll(struct file *file, poll_table *wait)
{
	struct f_hidg	*hidg  = file->private_data;
	unsigned int	ret = 0;

	poll_wait(file, &hidg->read_queue, wait);
	poll_wait(file, &hidg->write_queue, wait);

	if (WRITE_COND)
		ret |= POLLOUT | POLLWRNORM;

	if (READ_COND)
		ret |= POLLIN | POLLRDNORM;

	return ret;
}

#undef WRITE_COND
#undef READ_COND

static int f_hidg_release(struct inode *inode, struct file *fd)
{
	fd->private_data = NULL;
	return 0;
}

static int f_hidg_open(struct inode *inode, struct file *fd)
{
	struct f_hidg *hidg =
		container_of(inode->i_cdev, struct f_hidg, cdev);

	fd->private_data = hidg;

	return 0;
}

/*-------------------------------------------------------------------------*/
/*                                usb_function                             */

static struct usb_request *hidg_alloc_ep_req(struct usb_ep *ep, unsigned length)
{
	struct usb_request *req;

	req = usb_ep_alloc_request(ep, GFP_ATOMIC);
	if (req) {
		req->length = length;
		req->buf = kmalloc(length, GFP_ATOMIC);
		if (!req->buf) {
			usb_ep_free_request(ep, req);
			req = NULL;
		}
	}
	return req;
}

static void hidg_set_report_complete(struct usb_ep *ep, struct usb_request *req)
{
	struct f_hidg *hidg = (struct f_hidg *) req->context;
	struct f_hidg_req_list *req_list;
	unsigned long flags;

	req_list = kzalloc(sizeof(*req_list), GFP_ATOMIC);
	if (!req_list)
		return;

	req_list->req = req;

	spin_lock_irqsave(&hidg->spinlock, flags);
	list_add_tail(&req_list->list, &hidg->completed_out_req);
	spin_unlock_irqrestore(&hidg->spinlock, flags);

	wake_up(&hidg->read_queue);
}

static int hidg_setup(struct usb_function *f,
		const struct usb_ctrlrequest *ctrl)
{
	struct f_hidg			*hidg = func_to_hidg(f);
	struct usb_composite_dev	*cdev = f->config->cdev;
	struct usb_request		*req  = cdev->req;
	int status = 0;
	__u16 value, length;

	value	= __le16_to_cpu(ctrl->wValue);
	length	= __le16_to_cpu(ctrl->wLength);

	VDBG(cdev, "hid_setup crtl_request : bRequestType:0x%x bRequest:0x%x "
		"Value:0x%x\n", ctrl->bRequestType, ctrl->bRequest, value);

	switch ((ctrl->bRequestType << 8) | ctrl->bRequest) {
	case ((USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE) << 8
		  | HID_REQ_GET_REPORT):
		VDBG(cdev, "get_report\n");

		/* send an empty report */
		length = min_t(unsigned, length, hidg->report_length);
		memset(req->buf, 0x0, length);

		goto respond;
		break;

	case ((USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE) << 8
		  | HID_REQ_GET_PROTOCOL):
		VDBG(cdev, "get_protocol\n");
		goto stall;
		break;

	case ((USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_INTERFACE) << 8
		  | HID_REQ_SET_REPORT):
		VDBG(cdev, "set_report | wLenght=%d\n", ctrl->wLength);
		goto stall;
		break;

	case ((USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_INTERFACE) << 8
		  | HID_REQ_SET_PROTOCOL):
		VDBG(cdev, "set_protocol\n");
		goto stall;
		break;

	case ((USB_DIR_IN | USB_TYPE_STANDARD | USB_RECIP_INTERFACE) << 8
		  | USB_REQ_GET_DESCRIPTOR):
		switch (value >> 8) {
		case HID_DT_HID:
			VDBG(cdev, "USB_REQ_GET_DESCRIPTOR: HID\n");
			length = min_t(unsigned short, length,
						   hidg_desc.bLength);
			memcpy(req->buf, &hidg_desc, length);
			goto respond;
			break;
		case HID_DT_REPORT:
			VDBG(cdev, "USB_REQ_GET_DESCRIPTOR: REPORT\n");
			length = min_t(unsigned short, length,
						   hidg->report_desc_length);
			memcpy(req->buf, hidg->report_desc, length);
			goto respond;
			break;

		default:
			VDBG(cdev, "Unknown descriptor request 0x%x\n",
				 value >> 8);
			goto stall;
			break;
		}
		break;

	default:
		VDBG(cdev, "Unknown request 0x%x\n",
			 ctrl->bRequest);
		goto stall;
		break;
	}

stall:
	return -EOPNOTSUPP;

respond:
	req->zero = 0;
	req->length = length;
	status = usb_ep_queue(cdev->gadget->ep0, req, GFP_ATOMIC);
	if (status < 0)
		ERROR(cdev, "usb_ep_queue error on ep0 %d\n", value);
	return status;
}

static void hidg_disable(struct usb_function *f)
{
	struct f_hidg *hidg = func_to_hidg(f);
	struct f_hidg_req_list *list, *next;

	usb_ep_disable(hidg->in_ep);
	hidg->in_ep->driver_data = NULL;

	usb_ep_disable(hidg->out_ep);
	hidg->out_ep->driver_data = NULL;

	list_for_each_entry_safe(list, next, &hidg->completed_out_req, list) {
		list_del(&list->list);
		kfree(list);
	}
}

static int hidg_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
{
	struct usb_composite_dev		*cdev = f->config->cdev;
	struct f_hidg				*hidg = func_to_hidg(f);
	int i, status = 0;

	VDBG(cdev, "hidg_set_alt intf:%d alt:%d\n", intf, alt);

	if (hidg->in_ep != NULL) {
		/* restart endpoint */
		if (hidg->in_ep->driver_data != NULL)
			usb_ep_disable(hidg->in_ep);

		status = config_ep_by_speed(f->config->cdev->gadget, f,
					    hidg->in_ep);
		if (status) {
			ERROR(cdev, "config_ep_by_speed FAILED!\n");
			goto fail;
		}
		status = usb_ep_enable(hidg->in_ep);
		if (status < 0) {
			ERROR(cdev, "Enable IN endpoint FAILED!\n");
			goto fail;
		}
		hidg->in_ep->driver_data = hidg;
	}


	if (hidg->out_ep != NULL) {
		/* restart endpoint */
		if (hidg->out_ep->driver_data != NULL)
			usb_ep_disable(hidg->out_ep);

		status = config_ep_by_speed(f->config->cdev->gadget, f,
					    hidg->out_ep);
		if (status) {
			ERROR(cdev, "config_ep_by_speed FAILED!\n");
			goto fail;
		}
		status = usb_ep_enable(hidg->out_ep);
		if (status < 0) {
			ERROR(cdev, "Enable IN endpoint FAILED!\n");
			goto fail;
		}
		hidg->out_ep->driver_data = hidg;

		/*
		 * allocate a bunch of read buffers and queue them all at once.
		 */
		for (i = 0; i < hidg->qlen && status == 0; i++) {
			struct usb_request *req =
					hidg_alloc_ep_req(hidg->out_ep,
							  hidg->report_length);
			if (req) {
				req->complete = hidg_set_report_complete;
				req->context  = hidg;
				status = usb_ep_queue(hidg->out_ep, req,
						      GFP_ATOMIC);
				if (status)
					ERROR(cdev, "%s queue req --> %d\n",
						hidg->out_ep->name, status);
			} else {
				usb_ep_disable(hidg->out_ep);
				hidg->out_ep->driver_data = NULL;
				status = -ENOMEM;
				goto fail;
			}
		}
	}

fail:
	return status;
}

const struct file_operations f_hidg_fops = {
	.owner		= THIS_MODULE,
	.open		= f_hidg_open,
	.release	= f_hidg_release,
	.write		= f_hidg_write,
	.read		= f_hidg_read,
	.poll		= f_hidg_poll,
	.llseek		= noop_llseek,
};

static int __init hidg_bind(struct usb_configuration *c, struct usb_function *f)
{
	struct usb_ep		*ep;
	struct f_hidg		*hidg = func_to_hidg(f);
	int			status;
	dev_t			dev;

	/* allocate instance-specific interface IDs, and patch descriptors */
	status = usb_interface_id(c, f);
	if (status < 0)
		goto fail;
	hidg_interface_desc.bInterfaceNumber = status;


	/* allocate instance-specific endpoints */
	status = -ENODEV;
	ep = usb_ep_autoconfig(c->cdev->gadget, &hidg_fs_in_ep_desc);
	if (!ep)
		goto fail;
	ep->driver_data = c->cdev;	/* claim */
	hidg->in_ep = ep;

	ep = usb_ep_autoconfig(c->cdev->gadget, &hidg_fs_out_ep_desc);
	if (!ep)
		goto fail;
	ep->driver_data = c->cdev;	/* claim */
	hidg->out_ep = ep;

	/* preallocate request and buffer */
	status = -ENOMEM;
	hidg->req = usb_ep_alloc_request(hidg->in_ep, GFP_KERNEL);
	if (!hidg->req)
		goto fail;

	hidg->req->buf = kmalloc(hidg->report_length, GFP_KERNEL);
	if (!hidg->req->buf)
		goto fail;

	/* set descriptor dynamic values */
	hidg_interface_desc.bInterfaceSubClass = hidg->bInterfaceSubClass;
	hidg_interface_desc.bInterfaceProtocol = hidg->bInterfaceProtocol;
	hidg_hs_in_ep_desc.wMaxPacketSize = cpu_to_le16(hidg->report_length);
	hidg_fs_in_ep_desc.wMaxPacketSize = cpu_to_le16(hidg->report_length);
	hidg_hs_out_ep_desc.wMaxPacketSize = cpu_to_le16(hidg->report_length);
	hidg_fs_out_ep_desc.wMaxPacketSize = cpu_to_le16(hidg->report_length);
	hidg_desc.desc[0].bDescriptorType = HID_DT_REPORT;
	hidg_desc.desc[0].wDescriptorLength =
		cpu_to_le16(hidg->report_desc_length);

	/* copy descriptors */
	f->descriptors = usb_copy_descriptors(hidg_fs_descriptors);
	if (!f->descriptors)
		goto fail;

	if (gadget_is_dualspeed(c->cdev->gadget)) {
		hidg_hs_in_ep_desc.bEndpointAddress =
			hidg_fs_in_ep_desc.bEndpointAddress;
		hidg_hs_out_ep_desc.bEndpointAddress =
			hidg_fs_out_ep_desc.bEndpointAddress;
		f->hs_descriptors = usb_copy_descriptors(hidg_hs_descriptors);
		if (!f->hs_descriptors)
			goto fail;
	}

	mutex_init(&hidg->lock);
	spin_lock_init(&hidg->spinlock);
	init_waitqueue_head(&hidg->write_queue);
	init_waitqueue_head(&hidg->read_queue);
	INIT_LIST_HEAD(&hidg->completed_out_req);

	/* create char device */
	cdev_init(&hidg->cdev, &f_hidg_fops);
	dev = MKDEV(major, hidg->minor);
	status = cdev_add(&hidg->cdev, dev, 1);
	if (status)
		goto fail;

	device_create(hidg_class, NULL, dev, NULL, "%s%d", "hidg", hidg->minor);

	return 0;

fail:
	ERROR(f->config->cdev, "hidg_bind FAILED\n");
	if (hidg->req != NULL) {
		kfree(hidg->req->buf);
		if (hidg->in_ep != NULL)
			usb_ep_free_request(hidg->in_ep, hidg->req);
	}

	usb_free_descriptors(f->hs_descriptors);
	usb_free_descriptors(f->descriptors);

	return status;
}

static void hidg_unbind(struct usb_configuration *c, struct usb_function *f)
{
	struct f_hidg *hidg = func_to_hidg(f);

	device_destroy(hidg_class, MKDEV(major, hidg->minor));
	cdev_del(&hidg->cdev);

	/* disable/free request and end point */
	usb_ep_disable(hidg->in_ep);
	usb_ep_dequeue(hidg->in_ep, hidg->req);
	kfree(hidg->req->buf);
	usb_ep_free_request(hidg->in_ep, hidg->req);

	/* free descriptors copies */
	usb_free_descriptors(f->hs_descriptors);
	usb_free_descriptors(f->descriptors);

	kfree(hidg->report_desc);
	kfree(hidg);
}

/*-------------------------------------------------------------------------*/
/*                                 Strings                                 */

#define CT_FUNC_HID_IDX	0

static struct usb_string ct_func_string_defs[] = {
	[CT_FUNC_HID_IDX].s	= "HID Interface",
	{},			/* end of list */
};

static struct usb_gadget_strings ct_func_string_table = {
	.language	= 0x0409,	/* en-US */
	.strings	= ct_func_string_defs,
};

static struct usb_gadget_strings *ct_func_strings[] = {
	&ct_func_string_table,
	NULL,
};

/*-------------------------------------------------------------------------*/
/*                             usb_configuration                           */

int __init hidg_bind_config(struct usb_configuration *c,
			    struct hidg_func_descriptor *fdesc, int index)
{
	struct f_hidg *hidg;
	int status;

	if (index >= minors)
		return -ENOENT;

	/* maybe allocate device-global string IDs, and patch descriptors */
	if (ct_func_string_defs[CT_FUNC_HID_IDX].id == 0) {
		status = usb_string_id(c->cdev);
		if (status < 0)
			return status;
		ct_func_string_defs[CT_FUNC_HID_IDX].id = status;
		hidg_interface_desc.iInterface = status;
	}

	/* allocate and initialize one new instance */
	hidg = kzalloc(sizeof *hidg, GFP_KERNEL);
	if (!hidg)
		return -ENOMEM;

	hidg->minor = index;
	hidg->bInterfaceSubClass = fdesc->subclass;
	hidg->bInterfaceProtocol = fdesc->protocol;
	hidg->report_length = fdesc->report_length;
	hidg->report_desc_length = fdesc->report_desc_length;
	hidg->report_desc = kmemdup(fdesc->report_desc,
				    fdesc->report_desc_length,
				    GFP_KERNEL);
	if (!hidg->report_desc) {
		kfree(hidg);
		return -ENOMEM;
	}

	hidg->func.name    = "hid";
	hidg->func.strings = ct_func_strings;
	hidg->func.bind    = hidg_bind;
	hidg->func.unbind  = hidg_unbind;
	hidg->func.set_alt = hidg_set_alt;
	hidg->func.disable = hidg_disable;
	hidg->func.setup   = hidg_setup;

	/* this could me made configurable at some point */
	hidg->qlen	   = 4;

	status = usb_add_function(c, &hidg->func);
	if (status)
		kfree(hidg);

	return status;
}

int __init ghid_setup(struct usb_gadget *g, int count)
{
	int status;
	dev_t dev;

	hidg_class = class_create(THIS_MODULE, "hidg");

	status = alloc_chrdev_region(&dev, 0, count, "hidg");
	if (!status) {
		major = MAJOR(dev);
		minors = count;
	}

	return status;
}

void ghid_cleanup(void)
{
	if (major) {
		unregister_chrdev_region(MKDEV(major, 0), minors);
		major = minors = 0;
	}

	class_destroy(hidg_class);
	hidg_class = NULL;
}