summaryrefslogtreecommitdiff
path: root/drivers/media/usb/em28xx/em28xx-audio.c
blob: 49a5f9532bd8d863e0b63d73b8216e532cae2b05 (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
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
/*
 *  Empiatech em28x1 audio extension
 *
 *  Copyright (C) 2006 Markus Rechberger <mrechberger@gmail.com>
 *
 *  Copyright (C) 2007-2014 Mauro Carvalho Chehab
 *	- Port to work with the in-kernel driver
 *	- Cleanups, fixes, alsa-controls, etc.
 *
 *  This driver is based on my previous au600 usb pstn audio driver
 *  and inherits all the copyrights
 *
 *  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.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#include <linux/kernel.h>
#include <linux/usb.h>
#include <linux/init.h>
#include <linux/sound.h>
#include <linux/spinlock.h>
#include <linux/soundcard.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>
#include <linux/proc_fs.h>
#include <linux/module.h>
#include <sound/core.h>
#include <sound/pcm.h>
#include <sound/pcm_params.h>
#include <sound/info.h>
#include <sound/initval.h>
#include <sound/control.h>
#include <sound/tlv.h>
#include <sound/ac97_codec.h>
#include <media/v4l2-common.h>
#include "em28xx.h"

static int debug;
module_param(debug, int, 0644);
MODULE_PARM_DESC(debug, "activates debug info");

#define EM28XX_MAX_AUDIO_BUFS		5
#define EM28XX_MIN_AUDIO_PACKETS	64

#define dprintk(fmt, arg...) do {					\
	    if (debug)							\
		printk(KERN_INFO "em28xx-audio %s: " fmt,		\
				  __func__, ##arg);		\
	} while (0)

static int index[SNDRV_CARDS] = SNDRV_DEFAULT_IDX;

static int em28xx_deinit_isoc_audio(struct em28xx *dev)
{
	int i;

	dprintk("Stopping isoc\n");
	for (i = 0; i < dev->adev.num_urb; i++) {
		struct urb *urb = dev->adev.urb[i];

		if (!irqs_disabled())
			usb_kill_urb(urb);
		else
			usb_unlink_urb(urb);
	}

	return 0;
}

static void em28xx_audio_isocirq(struct urb *urb)
{
	struct em28xx            *dev = urb->context;
	int                      i;
	unsigned int             oldptr;
	int                      period_elapsed = 0;
	int                      status;
	unsigned char            *cp;
	unsigned int             stride;
	struct snd_pcm_substream *substream;
	struct snd_pcm_runtime   *runtime;

	if (dev->disconnected) {
		dprintk("device disconnected while streaming. URB status=%d.\n", urb->status);
		atomic_set(&dev->adev.stream_started, 0);
		return;
	}

	switch (urb->status) {
	case 0:             /* success */
	case -ETIMEDOUT:    /* NAK */
		break;
	case -ECONNRESET:   /* kill */
	case -ENOENT:
	case -ESHUTDOWN:
		return;
	default:            /* error */
		dprintk("urb completition error %d.\n", urb->status);
		break;
	}

	if (atomic_read(&dev->adev.stream_started) == 0)
		return;

	if (dev->adev.capture_pcm_substream) {
		substream = dev->adev.capture_pcm_substream;
		runtime = substream->runtime;
		stride = runtime->frame_bits >> 3;

		for (i = 0; i < urb->number_of_packets; i++) {
			int length =
			    urb->iso_frame_desc[i].actual_length / stride;
			cp = (unsigned char *)urb->transfer_buffer +
			    urb->iso_frame_desc[i].offset;

			if (!length)
				continue;

			oldptr = dev->adev.hwptr_done_capture;
			if (oldptr + length >= runtime->buffer_size) {
				unsigned int cnt =
				    runtime->buffer_size - oldptr;
				memcpy(runtime->dma_area + oldptr * stride, cp,
				       cnt * stride);
				memcpy(runtime->dma_area, cp + cnt * stride,
				       length * stride - cnt * stride);
			} else {
				memcpy(runtime->dma_area + oldptr * stride, cp,
				       length * stride);
			}

			snd_pcm_stream_lock(substream);

			dev->adev.hwptr_done_capture += length;
			if (dev->adev.hwptr_done_capture >=
			    runtime->buffer_size)
				dev->adev.hwptr_done_capture -=
				    runtime->buffer_size;

			dev->adev.capture_transfer_done += length;
			if (dev->adev.capture_transfer_done >=
			    runtime->period_size) {
				dev->adev.capture_transfer_done -=
				    runtime->period_size;
				period_elapsed = 1;
			}

			snd_pcm_stream_unlock(substream);
		}
		if (period_elapsed)
			snd_pcm_period_elapsed(substream);
	}
	urb->status = 0;

	status = usb_submit_urb(urb, GFP_ATOMIC);
	if (status < 0)
		em28xx_errdev("resubmit of audio urb failed (error=%i)\n",
			      status);
	return;
}

static int em28xx_init_audio_isoc(struct em28xx *dev)
{
	int       i, errCode;

	dprintk("Starting isoc transfers\n");

	/* Start streaming */
	for (i = 0; i < dev->adev.num_urb; i++) {
		memset(dev->adev.transfer_buffer[i], 0x80,
		       dev->adev.urb[i]->transfer_buffer_length);

		errCode = usb_submit_urb(dev->adev.urb[i], GFP_ATOMIC);
		if (errCode) {
			em28xx_errdev("submit of audio urb failed (error=%i)\n",
				      errCode);
			em28xx_deinit_isoc_audio(dev);
			atomic_set(&dev->adev.stream_started, 0);
			return errCode;
		}

	}

	return 0;
}

static int snd_pcm_alloc_vmalloc_buffer(struct snd_pcm_substream *subs,
					size_t size)
{
	struct snd_pcm_runtime *runtime = subs->runtime;

	dprintk("Allocating vbuffer\n");
	if (runtime->dma_area) {
		if (runtime->dma_bytes > size)
			return 0;

		vfree(runtime->dma_area);
	}
	runtime->dma_area = vmalloc(size);
	if (!runtime->dma_area)
		return -ENOMEM;

	runtime->dma_bytes = size;

	return 0;
}

static struct snd_pcm_hardware snd_em28xx_hw_capture = {
	.info = SNDRV_PCM_INFO_BLOCK_TRANSFER |
		SNDRV_PCM_INFO_MMAP           |
		SNDRV_PCM_INFO_INTERLEAVED    |
		SNDRV_PCM_INFO_BATCH	      |
		SNDRV_PCM_INFO_MMAP_VALID,

	.formats = SNDRV_PCM_FMTBIT_S16_LE,

	.rates = SNDRV_PCM_RATE_48000,

	.rate_min = 48000,
	.rate_max = 48000,
	.channels_min = 2,
	.channels_max = 2,
	.buffer_bytes_max = 62720 * 8,	/* just about the value in usbaudio.c */

	/*
	 * The period is 12.288 bytes. Allow a 10% of variation along its
	 * value, in order to avoid overruns/underruns due to some clock
	 * drift.
	 *
	 * FIXME: This period assumes 64 packets, and a 48000 PCM rate.
	 * Calculate it dynamically.
	 */
	.period_bytes_min = 11059,
	.period_bytes_max = 13516,

	.periods_min = 2,
	.periods_max = 98,		/* 12544, */
};

static int snd_em28xx_capture_open(struct snd_pcm_substream *substream)
{
	struct em28xx *dev = snd_pcm_substream_chip(substream);
	struct snd_pcm_runtime *runtime = substream->runtime;
	int nonblock, ret = 0;

	if (!dev) {
		em28xx_err("BUG: em28xx can't find device struct."
				" Can't proceed with open\n");
		return -ENODEV;
	}

	if (dev->disconnected)
		return -ENODEV;

	dprintk("opening device and trying to acquire exclusive lock\n");

	nonblock = !!(substream->f_flags & O_NONBLOCK);
	if (nonblock) {
		if (!mutex_trylock(&dev->lock))
			return -EAGAIN;
	} else
		mutex_lock(&dev->lock);

	runtime->hw = snd_em28xx_hw_capture;

	if (dev->adev.users == 0) {
		if (dev->alt == 0 || dev->is_audio_only) {
			if (dev->is_audio_only)
				/* audio is on a separate interface */
				dev->alt = 1;
			else
				/* audio is on the same interface as video */
				dev->alt = 7;
				/*
				 * FIXME: The intention seems to be to select
				 * the alt setting with the largest
				 * wMaxPacketSize for the video endpoint.
				 * At least dev->alt should be used instead, but
				 * we should probably not touch it at all if it
				 * is already >0, because wMaxPacketSize of the
				 * audio endpoints seems to be the same for all.
				 */
			dprintk("changing alternate number on interface %d to %d\n",
				dev->ifnum, dev->alt);
			usb_set_interface(dev->udev, dev->ifnum, dev->alt);
		}

		/* Sets volume, mute, etc */
		dev->mute = 0;
		ret = em28xx_audio_analog_set(dev);
		if (ret < 0)
			goto err;
	}

	kref_get(&dev->ref);
	dev->adev.users++;
	mutex_unlock(&dev->lock);

	/* Dynamically adjust the period size */
	snd_pcm_hw_constraint_integer(runtime, SNDRV_PCM_HW_PARAM_PERIODS);
	snd_pcm_hw_constraint_minmax(runtime, SNDRV_PCM_HW_PARAM_PERIOD_BYTES,
				     dev->adev.period * 95 / 100,
				     dev->adev.period * 105 / 100);

	dev->adev.capture_pcm_substream = substream;

	return 0;
err:
	mutex_unlock(&dev->lock);

	em28xx_err("Error while configuring em28xx mixer\n");
	return ret;
}

static int snd_em28xx_pcm_close(struct snd_pcm_substream *substream)
{
	struct em28xx *dev = snd_pcm_substream_chip(substream);

	dprintk("closing device\n");

	dev->mute = 1;
	mutex_lock(&dev->lock);
	dev->adev.users--;
	if (atomic_read(&dev->adev.stream_started) > 0) {
		atomic_set(&dev->adev.stream_started, 0);
		schedule_work(&dev->adev.wq_trigger);
	}

	em28xx_audio_analog_set(dev);
	if (substream->runtime->dma_area) {
		dprintk("freeing\n");
		vfree(substream->runtime->dma_area);
		substream->runtime->dma_area = NULL;
	}
	mutex_unlock(&dev->lock);
	kref_put(&dev->ref, em28xx_free_device);

	return 0;
}

static int snd_em28xx_hw_capture_params(struct snd_pcm_substream *substream,
					struct snd_pcm_hw_params *hw_params)
{
	int ret;
	struct em28xx *dev = snd_pcm_substream_chip(substream);

	if (dev->disconnected)
		return -ENODEV;

	dprintk("Setting capture parameters\n");

	ret = snd_pcm_alloc_vmalloc_buffer(substream,
					   params_buffer_bytes(hw_params));
	if (ret < 0)
		return ret;
#if 0
	/* TODO: set up em28xx audio chip to deliver the correct audio format,
	   current default is 48000hz multiplexed => 96000hz mono
	   which shouldn't matter since analogue TV only supports mono */
	unsigned int channels, rate, format;

	format = params_format(hw_params);
	rate = params_rate(hw_params);
	channels = params_channels(hw_params);
#endif

	return 0;
}

static int snd_em28xx_hw_capture_free(struct snd_pcm_substream *substream)
{
	struct em28xx *dev = snd_pcm_substream_chip(substream);
	struct em28xx_audio *adev = &dev->adev;

	dprintk("Stop capture, if needed\n");

	if (atomic_read(&adev->stream_started) > 0) {
		atomic_set(&adev->stream_started, 0);
		schedule_work(&adev->wq_trigger);
	}

	return 0;
}

static int snd_em28xx_prepare(struct snd_pcm_substream *substream)
{
	struct em28xx *dev = snd_pcm_substream_chip(substream);

	if (dev->disconnected)
		return -ENODEV;

	dev->adev.hwptr_done_capture = 0;
	dev->adev.capture_transfer_done = 0;

	return 0;
}

static void audio_trigger(struct work_struct *work)
{
	struct em28xx_audio *adev =
			    container_of(work, struct em28xx_audio, wq_trigger);
	struct em28xx *dev = container_of(adev, struct em28xx, adev);

	if (atomic_read(&adev->stream_started)) {
		dprintk("starting capture");
		em28xx_init_audio_isoc(dev);
	} else {
		dprintk("stopping capture");
		em28xx_deinit_isoc_audio(dev);
	}
}

static int snd_em28xx_capture_trigger(struct snd_pcm_substream *substream,
				      int cmd)
{
	struct em28xx *dev = snd_pcm_substream_chip(substream);
	int retval = 0;

	if (dev->disconnected)
		return -ENODEV;

	switch (cmd) {
	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE: /* fall through */
	case SNDRV_PCM_TRIGGER_RESUME: /* fall through */
	case SNDRV_PCM_TRIGGER_START:
		atomic_set(&dev->adev.stream_started, 1);
		break;
	case SNDRV_PCM_TRIGGER_PAUSE_PUSH: /* fall through */
	case SNDRV_PCM_TRIGGER_SUSPEND: /* fall through */
	case SNDRV_PCM_TRIGGER_STOP:
		atomic_set(&dev->adev.stream_started, 0);
		break;
	default:
		retval = -EINVAL;
	}
	schedule_work(&dev->adev.wq_trigger);
	return retval;
}

static snd_pcm_uframes_t snd_em28xx_capture_pointer(struct snd_pcm_substream
						    *substream)
{
	unsigned long flags;
	struct em28xx *dev;
	snd_pcm_uframes_t hwptr_done;

	dev = snd_pcm_substream_chip(substream);
	if (dev->disconnected)
		return SNDRV_PCM_POS_XRUN;

	spin_lock_irqsave(&dev->adev.slock, flags);
	hwptr_done = dev->adev.hwptr_done_capture;
	spin_unlock_irqrestore(&dev->adev.slock, flags);

	return hwptr_done;
}

static struct page *snd_pcm_get_vmalloc_page(struct snd_pcm_substream *subs,
					     unsigned long offset)
{
	void *pageptr = subs->runtime->dma_area + offset;

	return vmalloc_to_page(pageptr);
}

/*
 * AC97 volume control support
 */
static int em28xx_vol_info(struct snd_kcontrol *kcontrol,
			   struct snd_ctl_elem_info *info)
{
	struct em28xx *dev = snd_kcontrol_chip(kcontrol);

	if (dev->disconnected)
		return -ENODEV;

	info->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
	info->count = 2;
	info->value.integer.min = 0;
	info->value.integer.max = 0x1f;

	return 0;
}

static int em28xx_vol_put(struct snd_kcontrol *kcontrol,
			  struct snd_ctl_elem_value *value)
{
	struct em28xx *dev = snd_kcontrol_chip(kcontrol);
	struct snd_pcm_substream *substream = dev->adev.capture_pcm_substream;
	u16 val = (0x1f - (value->value.integer.value[0] & 0x1f)) |
		  (0x1f - (value->value.integer.value[1] & 0x1f)) << 8;
	int nonblock = 0;
	int rc;

	if (dev->disconnected)
		return -ENODEV;

	if (substream)
		nonblock = !!(substream->f_flags & O_NONBLOCK);
	if (nonblock) {
		if (!mutex_trylock(&dev->lock))
			return -EAGAIN;
	} else
		mutex_lock(&dev->lock);
	rc = em28xx_read_ac97(dev, kcontrol->private_value);
	if (rc < 0)
		goto err;

	val |= rc & 0x8000;	/* Preserve the mute flag */

	rc = em28xx_write_ac97(dev, kcontrol->private_value, val);
	if (rc < 0)
		goto err;

	dprintk("%sleft vol %d, right vol %d (0x%04x) to ac97 volume control 0x%04x\n",
		(val & 0x8000) ? "muted " : "",
		0x1f - ((val >> 8) & 0x1f), 0x1f - (val & 0x1f),
		val, (int)kcontrol->private_value);

err:
	mutex_unlock(&dev->lock);
	return rc;
}

static int em28xx_vol_get(struct snd_kcontrol *kcontrol,
			  struct snd_ctl_elem_value *value)
{
	struct em28xx *dev = snd_kcontrol_chip(kcontrol);
	struct snd_pcm_substream *substream = dev->adev.capture_pcm_substream;
	int nonblock = 0;
	int val;

	if (dev->disconnected)
		return -ENODEV;

	if (substream)
		nonblock = !!(substream->f_flags & O_NONBLOCK);
	if (nonblock) {
		if (!mutex_trylock(&dev->lock))
			return -EAGAIN;
	} else
		mutex_lock(&dev->lock);
	val = em28xx_read_ac97(dev, kcontrol->private_value);
	mutex_unlock(&dev->lock);
	if (val < 0)
		return val;

	dprintk("%sleft vol %d, right vol %d (0x%04x) from ac97 volume control 0x%04x\n",
		(val & 0x8000) ? "muted " : "",
		0x1f - ((val >> 8) & 0x1f), 0x1f - (val & 0x1f),
		val, (int)kcontrol->private_value);

	value->value.integer.value[0] = 0x1f - (val & 0x1f);
	value->value.integer.value[1] = 0x1f - ((val << 8) & 0x1f);

	return 0;
}

static int em28xx_vol_put_mute(struct snd_kcontrol *kcontrol,
			       struct snd_ctl_elem_value *value)
{
	struct em28xx *dev = snd_kcontrol_chip(kcontrol);
	u16 val = value->value.integer.value[0];
	struct snd_pcm_substream *substream = dev->adev.capture_pcm_substream;
	int nonblock = 0;
	int rc;

	if (dev->disconnected)
		return -ENODEV;

	if (substream)
		nonblock = !!(substream->f_flags & O_NONBLOCK);
	if (nonblock) {
		if (!mutex_trylock(&dev->lock))
			return -EAGAIN;
	} else
		mutex_lock(&dev->lock);
	rc = em28xx_read_ac97(dev, kcontrol->private_value);
	if (rc < 0)
		goto err;

	if (val)
		rc &= 0x1f1f;
	else
		rc |= 0x8000;

	rc = em28xx_write_ac97(dev, kcontrol->private_value, rc);
	if (rc < 0)
		goto err;

	dprintk("%sleft vol %d, right vol %d (0x%04x) to ac97 volume control 0x%04x\n",
		(val & 0x8000) ? "muted " : "",
		0x1f - ((val >> 8) & 0x1f), 0x1f - (val & 0x1f),
		val, (int)kcontrol->private_value);

err:
	mutex_unlock(&dev->lock);
	return rc;
}

static int em28xx_vol_get_mute(struct snd_kcontrol *kcontrol,
			       struct snd_ctl_elem_value *value)
{
	struct em28xx *dev = snd_kcontrol_chip(kcontrol);
	struct snd_pcm_substream *substream = dev->adev.capture_pcm_substream;
	int nonblock = 0;
	int val;

	if (dev->disconnected)
		return -ENODEV;

	if (substream)
		nonblock = !!(substream->f_flags & O_NONBLOCK);
	if (nonblock) {
		if (!mutex_trylock(&dev->lock))
			return -EAGAIN;
	} else
		mutex_lock(&dev->lock);
	val = em28xx_read_ac97(dev, kcontrol->private_value);
	mutex_unlock(&dev->lock);
	if (val < 0)
		return val;

	if (val & 0x8000)
		value->value.integer.value[0] = 0;
	else
		value->value.integer.value[0] = 1;

	dprintk("%sleft vol %d, right vol %d (0x%04x) from ac97 volume control 0x%04x\n",
		(val & 0x8000) ? "muted " : "",
		0x1f - ((val >> 8) & 0x1f), 0x1f - (val & 0x1f),
		val, (int)kcontrol->private_value);

	return 0;
}

static const DECLARE_TLV_DB_SCALE(em28xx_db_scale, -3450, 150, 0);

static int em28xx_cvol_new(struct snd_card *card, struct em28xx *dev,
			   char *name, int id)
{
	int err;
	char ctl_name[44];
	struct snd_kcontrol *kctl;
	struct snd_kcontrol_new tmp;

	memset(&tmp, 0, sizeof(tmp));
	tmp.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
	tmp.private_value = id,
	tmp.name  = ctl_name,

	/* Add Mute Control */
	sprintf(ctl_name, "%s Switch", name);
	tmp.get  = em28xx_vol_get_mute;
	tmp.put  = em28xx_vol_put_mute;
	tmp.info = snd_ctl_boolean_mono_info;
	kctl = snd_ctl_new1(&tmp, dev);
	err = snd_ctl_add(card, kctl);
	if (err < 0)
		return err;
	dprintk("Added control %s for ac97 volume control 0x%04x\n",
		ctl_name, id);

	memset(&tmp, 0, sizeof(tmp));
	tmp.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
	tmp.private_value = id,
	tmp.name  = ctl_name,

	/* Add Volume Control */
	sprintf(ctl_name, "%s Volume", name);
	tmp.get   = em28xx_vol_get;
	tmp.put   = em28xx_vol_put;
	tmp.info  = em28xx_vol_info;
	tmp.tlv.p = em28xx_db_scale,
	kctl = snd_ctl_new1(&tmp, dev);
	err = snd_ctl_add(card, kctl);
	if (err < 0)
		return err;
	dprintk("Added control %s for ac97 volume control 0x%04x\n",
		ctl_name, id);

	return 0;
}

/*
 * register/unregister code and data
 */
static struct snd_pcm_ops snd_em28xx_pcm_capture = {
	.open      = snd_em28xx_capture_open,
	.close     = snd_em28xx_pcm_close,
	.ioctl     = snd_pcm_lib_ioctl,
	.hw_params = snd_em28xx_hw_capture_params,
	.hw_free   = snd_em28xx_hw_capture_free,
	.prepare   = snd_em28xx_prepare,
	.trigger   = snd_em28xx_capture_trigger,
	.pointer   = snd_em28xx_capture_pointer,
	.page      = snd_pcm_get_vmalloc_page,
};

static void em28xx_audio_free_urb(struct em28xx *dev)
{
	int i;

	for (i = 0; i < dev->adev.num_urb; i++) {
		struct urb *urb = dev->adev.urb[i];

		if (!urb)
			continue;

		usb_free_coherent(dev->udev, urb->transfer_buffer_length,
				  dev->adev.transfer_buffer[i],
				  urb->transfer_dma);

		usb_free_urb(urb);
	}
	kfree(dev->adev.urb);
	kfree(dev->adev.transfer_buffer);
	dev->adev.num_urb = 0;
}

/* high bandwidth multiplier, as encoded in highspeed endpoint descriptors */
static int em28xx_audio_ep_packet_size(struct usb_device *udev,
				       struct usb_endpoint_descriptor *e)
{
	int size = le16_to_cpu(e->wMaxPacketSize);

	if (udev->speed == USB_SPEED_HIGH)
		return (size & 0x7ff) *  (1 + (((size) >> 11) & 0x03));

	return size & 0x7ff;
}

static int em28xx_audio_urb_init(struct em28xx *dev)
{
	struct usb_interface *intf;
	struct usb_endpoint_descriptor *e, *ep = NULL;
	int                 i, ep_size, interval, num_urb, npackets;
	int		    urb_size, bytes_per_transfer;
	u8 alt;

	if (dev->ifnum)
		alt = 1;
	else
		alt = 7;

	intf = usb_ifnum_to_if(dev->udev, dev->ifnum);

	if (intf->num_altsetting <= alt) {
		em28xx_errdev("alt %d doesn't exist on interface %d\n",
			      dev->ifnum, alt);
		return -ENODEV;
	}

	for (i = 0; i < intf->altsetting[alt].desc.bNumEndpoints; i++) {
		e = &intf->altsetting[alt].endpoint[i].desc;
		if (!usb_endpoint_dir_in(e))
			continue;
		if (e->bEndpointAddress == EM28XX_EP_AUDIO) {
			ep = e;
			break;
		}
	}

	if (!ep) {
		em28xx_errdev("Couldn't find an audio endpoint");
		return -ENODEV;
	}

	ep_size = em28xx_audio_ep_packet_size(dev->udev, ep);
	interval = 1 << (ep->bInterval - 1);

	em28xx_info("Endpoint 0x%02x %s on intf %d alt %d interval = %d, size %d\n",
		    EM28XX_EP_AUDIO, usb_speed_string(dev->udev->speed),
		     dev->ifnum, alt,
		     interval,
		     ep_size);

	/* Calculate the number and size of URBs to better fit the audio samples */

	/*
	 * Estimate the number of bytes per DMA transfer.
	 *
	 * This is given by the bit rate (for now, only 48000 Hz) multiplied
	 * by 2 channels and 2 bytes/sample divided by the number of microframe
	 * intervals and by the microframe rate (125 us)
	 */
	bytes_per_transfer = DIV_ROUND_UP(48000 * 2 * 2, 125 * interval);

	/*
	 * Estimate the number of transfer URBs. Don't let it go past the
	 * maximum number of URBs that is known to be supported by the device.
	 */
	num_urb = DIV_ROUND_UP(bytes_per_transfer, ep_size);
	if (num_urb > EM28XX_MAX_AUDIO_BUFS)
		num_urb = EM28XX_MAX_AUDIO_BUFS;

	/*
	 * Now that we know the number of bytes per transfer and the number of
	 * URBs, estimate the typical size of an URB, in order to adjust the
	 * minimal number of packets.
	 */
	urb_size = bytes_per_transfer / num_urb;

	/*
	 * Now, calculate the amount of audio packets to be filled on each
	 * URB. In order to preserve the old behaviour, use a minimal
	 * threshold for this value.
	 */
	npackets = EM28XX_MIN_AUDIO_PACKETS;
	if (urb_size > ep_size * npackets)
		npackets = DIV_ROUND_UP(urb_size, ep_size);

	em28xx_info("Number of URBs: %d, with %d packets and %d size\n",
		    num_urb, npackets, urb_size);

	/* Estimate the bytes per period */
	dev->adev.period = urb_size * npackets;

	/* Allocate space to store the number of URBs to be used */

	dev->adev.transfer_buffer = kcalloc(num_urb,
					    sizeof(*dev->adev.transfer_buffer),
					    GFP_ATOMIC);
	if (!dev->adev.transfer_buffer) {
		return -ENOMEM;
	}

	dev->adev.urb = kcalloc(num_urb, sizeof(*dev->adev.urb), GFP_ATOMIC);
	if (!dev->adev.urb) {
		kfree(dev->adev.transfer_buffer);
		return -ENOMEM;
	}

	/* Alloc memory for each URB and for each transfer buffer */
	dev->adev.num_urb = num_urb;
	for (i = 0; i < num_urb; i++) {
		struct urb *urb;
		int j, k;
		void *buf;

		urb = usb_alloc_urb(npackets, GFP_ATOMIC);
		if (!urb) {
			em28xx_errdev("usb_alloc_urb failed!\n");
			em28xx_audio_free_urb(dev);
			return -ENOMEM;
		}
		dev->adev.urb[i] = urb;

		buf = usb_alloc_coherent(dev->udev, npackets * ep_size, GFP_ATOMIC,
					 &urb->transfer_dma);
		if (!buf) {
			em28xx_errdev("usb_alloc_coherent failed!\n");
			em28xx_audio_free_urb(dev);
			return -ENOMEM;
		}
		dev->adev.transfer_buffer[i] = buf;

		urb->dev = dev->udev;
		urb->context = dev;
		urb->pipe = usb_rcvisocpipe(dev->udev, EM28XX_EP_AUDIO);
		urb->transfer_flags = URB_ISO_ASAP | URB_NO_TRANSFER_DMA_MAP;
		urb->transfer_buffer = buf;
		urb->interval = interval;
		urb->complete = em28xx_audio_isocirq;
		urb->number_of_packets = npackets;
		urb->transfer_buffer_length = ep_size * npackets;

		for (j = k = 0; j < npackets; j++, k += ep_size) {
			urb->iso_frame_desc[j].offset = k;
			urb->iso_frame_desc[j].length = ep_size;
		}
	}

	return 0;
}

static int em28xx_audio_init(struct em28xx *dev)
{
	struct em28xx_audio *adev = &dev->adev;
	struct snd_pcm      *pcm;
	struct snd_card     *card;
	static int          devnr;
	int		    err;

	if (dev->usb_audio_type != EM28XX_USB_AUDIO_VENDOR) {
		/* This device does not support the extension (in this case
		   the device is expecting the snd-usb-audio module or
		   doesn't have analog audio support at all) */
		return 0;
	}

	em28xx_info("Binding audio extension\n");

	kref_get(&dev->ref);

	printk(KERN_INFO "em28xx-audio.c: Copyright (C) 2006 Markus "
			 "Rechberger\n");
	printk(KERN_INFO
	       "em28xx-audio.c: Copyright (C) 2007-2014 Mauro Carvalho Chehab\n");

	err = snd_card_new(&dev->udev->dev, index[devnr], "Em28xx Audio",
			   THIS_MODULE, 0, &card);
	if (err < 0)
		return err;

	spin_lock_init(&adev->slock);
	adev->sndcard = card;
	adev->udev = dev->udev;

	err = snd_pcm_new(card, "Em28xx Audio", 0, 0, 1, &pcm);
	if (err < 0)
		goto card_free;

	snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_CAPTURE, &snd_em28xx_pcm_capture);
	pcm->info_flags = 0;
	pcm->private_data = dev;
	strcpy(pcm->name, "Empia 28xx Capture");

	strcpy(card->driver, "Em28xx-Audio");
	strcpy(card->shortname, "Em28xx Audio");
	strcpy(card->longname, "Empia Em28xx Audio");

	INIT_WORK(&adev->wq_trigger, audio_trigger);

	if (dev->audio_mode.ac97 != EM28XX_NO_AC97) {
		em28xx_cvol_new(card, dev, "Video", AC97_VIDEO);
		em28xx_cvol_new(card, dev, "Line In", AC97_LINE);
		em28xx_cvol_new(card, dev, "Phone", AC97_PHONE);
		em28xx_cvol_new(card, dev, "Microphone", AC97_MIC);
		em28xx_cvol_new(card, dev, "CD", AC97_CD);
		em28xx_cvol_new(card, dev, "AUX", AC97_AUX);
		em28xx_cvol_new(card, dev, "PCM", AC97_PCM);

		em28xx_cvol_new(card, dev, "Master", AC97_MASTER);
		em28xx_cvol_new(card, dev, "Line", AC97_HEADPHONE);
		em28xx_cvol_new(card, dev, "Mono", AC97_MASTER_MONO);
		em28xx_cvol_new(card, dev, "LFE", AC97_CENTER_LFE_MASTER);
		em28xx_cvol_new(card, dev, "Surround", AC97_SURROUND_MASTER);
	}

	err = em28xx_audio_urb_init(dev);
	if (err)
		goto card_free;

	err = snd_card_register(card);
	if (err < 0)
		goto urb_free;

	em28xx_info("Audio extension successfully initialized\n");
	return 0;

urb_free:
	em28xx_audio_free_urb(dev);

card_free:
	snd_card_free(card);
	adev->sndcard = NULL;

	return err;
}

static int em28xx_audio_fini(struct em28xx *dev)
{
	if (dev == NULL)
		return 0;

	if (dev->usb_audio_type != EM28XX_USB_AUDIO_VENDOR) {
		/* This device does not support the extension (in this case
		   the device is expecting the snd-usb-audio module or
		   doesn't have analog audio support at all) */
		return 0;
	}

	em28xx_info("Closing audio extension\n");

	if (dev->adev.sndcard) {
		snd_card_disconnect(dev->adev.sndcard);
		flush_work(&dev->adev.wq_trigger);

		em28xx_audio_free_urb(dev);

		snd_card_free(dev->adev.sndcard);
		dev->adev.sndcard = NULL;
	}

	kref_put(&dev->ref, em28xx_free_device);
	return 0;
}

static int em28xx_audio_suspend(struct em28xx *dev)
{
	if (dev == NULL)
		return 0;

	if (dev->usb_audio_type != EM28XX_USB_AUDIO_VENDOR)
		return 0;

	em28xx_info("Suspending audio extension\n");
	em28xx_deinit_isoc_audio(dev);
	atomic_set(&dev->adev.stream_started, 0);
	return 0;
}

static int em28xx_audio_resume(struct em28xx *dev)
{
	if (dev == NULL)
		return 0;

	if (dev->usb_audio_type != EM28XX_USB_AUDIO_VENDOR)
		return 0;

	em28xx_info("Resuming audio extension\n");
	/* Nothing to do other than schedule_work() ?? */
	schedule_work(&dev->adev.wq_trigger);
	return 0;
}

static struct em28xx_ops audio_ops = {
	.id   = EM28XX_AUDIO,
	.name = "Em28xx Audio Extension",
	.init = em28xx_audio_init,
	.fini = em28xx_audio_fini,
	.suspend = em28xx_audio_suspend,
	.resume = em28xx_audio_resume,
};

static int __init em28xx_alsa_register(void)
{
	return em28xx_register_extension(&audio_ops);
}

static void __exit em28xx_alsa_unregister(void)
{
	em28xx_unregister_extension(&audio_ops);
}

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Markus Rechberger <mrechberger@gmail.com>");
MODULE_AUTHOR("Mauro Carvalho Chehab");
MODULE_DESCRIPTION(DRIVER_DESC " - audio interface");
MODULE_VERSION(EM28XX_VERSION);

module_init(em28xx_alsa_register);
module_exit(em28xx_alsa_unregister);