summaryrefslogtreecommitdiff
path: root/sound/usb/clock.c
blob: 17bbde73d4d159f37efa79491bd367117eb0bcef (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
// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *   Clock domain and sample rate management functions
 */

#include <linux/bitops.h>
#include <linux/init.h>
#include <linux/string.h>
#include <linux/usb.h>
#include <linux/usb/audio.h>
#include <linux/usb/audio-v2.h>
#include <linux/usb/audio-v3.h>

#include <sound/core.h>
#include <sound/info.h>
#include <sound/pcm.h>

#include "usbaudio.h"
#include "card.h"
#include "helper.h"
#include "clock.h"
#include "quirks.h"

static void *find_uac_clock_desc(struct usb_host_interface *iface, int id,
				 bool (*validator)(void *, int), u8 type)
{
	void *cs = NULL;

	while ((cs = snd_usb_find_csint_desc(iface->extra, iface->extralen,
					     cs, type))) {
		if (validator(cs, id))
			return cs;
	}

	return NULL;
}

static bool validate_clock_source_v2(void *p, int id)
{
	struct uac_clock_source_descriptor *cs = p;
	return cs->bClockID == id;
}

static bool validate_clock_source_v3(void *p, int id)
{
	struct uac3_clock_source_descriptor *cs = p;
	return cs->bClockID == id;
}

static bool validate_clock_selector_v2(void *p, int id)
{
	struct uac_clock_selector_descriptor *cs = p;
	return cs->bClockID == id;
}

static bool validate_clock_selector_v3(void *p, int id)
{
	struct uac3_clock_selector_descriptor *cs = p;
	return cs->bClockID == id;
}

static bool validate_clock_multiplier_v2(void *p, int id)
{
	struct uac_clock_multiplier_descriptor *cs = p;
	return cs->bClockID == id;
}

static bool validate_clock_multiplier_v3(void *p, int id)
{
	struct uac3_clock_multiplier_descriptor *cs = p;
	return cs->bClockID == id;
}

#define DEFINE_FIND_HELPER(name, obj, validator, type)		\
static obj *name(struct usb_host_interface *iface, int id)	\
{								\
	return find_uac_clock_desc(iface, id, validator, type);	\
}

DEFINE_FIND_HELPER(snd_usb_find_clock_source,
		   struct uac_clock_source_descriptor,
		   validate_clock_source_v2, UAC2_CLOCK_SOURCE);
DEFINE_FIND_HELPER(snd_usb_find_clock_source_v3,
		   struct uac3_clock_source_descriptor,
		   validate_clock_source_v3, UAC3_CLOCK_SOURCE);

DEFINE_FIND_HELPER(snd_usb_find_clock_selector,
		   struct uac_clock_selector_descriptor,
		   validate_clock_selector_v2, UAC2_CLOCK_SELECTOR);
DEFINE_FIND_HELPER(snd_usb_find_clock_selector_v3,
		   struct uac3_clock_selector_descriptor,
		   validate_clock_selector_v3, UAC3_CLOCK_SELECTOR);

DEFINE_FIND_HELPER(snd_usb_find_clock_multiplier,
		   struct uac_clock_multiplier_descriptor,
		   validate_clock_multiplier_v2, UAC2_CLOCK_MULTIPLIER);
DEFINE_FIND_HELPER(snd_usb_find_clock_multiplier_v3,
		   struct uac3_clock_multiplier_descriptor,
		   validate_clock_multiplier_v3, UAC3_CLOCK_MULTIPLIER);

static int uac_clock_selector_get_val(struct snd_usb_audio *chip, int selector_id)
{
	unsigned char buf;
	int ret;

	ret = snd_usb_ctl_msg(chip->dev, usb_rcvctrlpipe(chip->dev, 0),
			      UAC2_CS_CUR,
			      USB_RECIP_INTERFACE | USB_TYPE_CLASS | USB_DIR_IN,
			      UAC2_CX_CLOCK_SELECTOR << 8,
			      snd_usb_ctrl_intf(chip) | (selector_id << 8),
			      &buf, sizeof(buf));

	if (ret < 0)
		return ret;

	return buf;
}

static int uac_clock_selector_set_val(struct snd_usb_audio *chip, int selector_id,
					unsigned char pin)
{
	int ret;

	ret = snd_usb_ctl_msg(chip->dev, usb_sndctrlpipe(chip->dev, 0),
			      UAC2_CS_CUR,
			      USB_RECIP_INTERFACE | USB_TYPE_CLASS | USB_DIR_OUT,
			      UAC2_CX_CLOCK_SELECTOR << 8,
			      snd_usb_ctrl_intf(chip) | (selector_id << 8),
			      &pin, sizeof(pin));
	if (ret < 0)
		return ret;

	if (ret != sizeof(pin)) {
		usb_audio_err(chip,
			"setting selector (id %d) unexpected length %d\n",
			selector_id, ret);
		return -EINVAL;
	}

	ret = uac_clock_selector_get_val(chip, selector_id);
	if (ret < 0)
		return ret;

	if (ret != pin) {
		usb_audio_err(chip,
			"setting selector (id %d) to %x failed (current: %d)\n",
			selector_id, pin, ret);
		return -EINVAL;
	}

	return ret;
}

static bool uac_clock_source_is_valid_quirk(struct snd_usb_audio *chip,
					    const struct audioformat *fmt,
					    int source_id)
{
	bool ret = false;
	int count;
	unsigned char data;
	struct usb_device *dev = chip->dev;

	if (fmt->protocol == UAC_VERSION_2) {
		struct uac_clock_source_descriptor *cs_desc =
			snd_usb_find_clock_source(chip->ctrl_intf, source_id);

		if (!cs_desc)
			return false;

		/*
		 * Assume the clock is valid if clock source supports only one
		 * single sample rate, the terminal is connected directly to it
		 * (there is no clock selector) and clock type is internal.
		 * This is to deal with some Denon DJ controllers that always
		 * reports that clock is invalid.
		 */
		if (fmt->nr_rates == 1 &&
		    (fmt->clock & 0xff) == cs_desc->bClockID &&
		    (cs_desc->bmAttributes & 0x3) !=
				UAC_CLOCK_SOURCE_TYPE_EXT)
			return true;
	}

	/*
	 * MOTU MicroBook IIc
	 * Sample rate changes takes more than 2 seconds for this device. Clock
	 * validity request returns false during that period.
	 */
	if (chip->usb_id == USB_ID(0x07fd, 0x0004)) {
		count = 0;

		while ((!ret) && (count < 50)) {
			int err;

			msleep(100);

			err = snd_usb_ctl_msg(dev, usb_rcvctrlpipe(dev, 0), UAC2_CS_CUR,
					      USB_TYPE_CLASS | USB_RECIP_INTERFACE | USB_DIR_IN,
					      UAC2_CS_CONTROL_CLOCK_VALID << 8,
					      snd_usb_ctrl_intf(chip) | (source_id << 8),
					      &data, sizeof(data));
			if (err < 0) {
				dev_warn(&dev->dev,
					 "%s(): cannot get clock validity for id %d\n",
					   __func__, source_id);
				return false;
			}

			ret = !!data;
			count++;
		}
	}

	return ret;
}

static bool uac_clock_source_is_valid(struct snd_usb_audio *chip,
				      const struct audioformat *fmt,
				      int source_id)
{
	int err;
	unsigned char data;
	struct usb_device *dev = chip->dev;
	u32 bmControls;

	if (fmt->protocol == UAC_VERSION_3) {
		struct uac3_clock_source_descriptor *cs_desc =
			snd_usb_find_clock_source_v3(chip->ctrl_intf, source_id);

		if (!cs_desc)
			return false;
		bmControls = le32_to_cpu(cs_desc->bmControls);
	} else { /* UAC_VERSION_1/2 */
		struct uac_clock_source_descriptor *cs_desc =
			snd_usb_find_clock_source(chip->ctrl_intf, source_id);

		if (!cs_desc)
			return false;
		bmControls = cs_desc->bmControls;
	}

	/* If a clock source can't tell us whether it's valid, we assume it is */
	if (!uac_v2v3_control_is_readable(bmControls,
				      UAC2_CS_CONTROL_CLOCK_VALID))
		return true;

	err = snd_usb_ctl_msg(dev, usb_rcvctrlpipe(dev, 0), UAC2_CS_CUR,
			      USB_TYPE_CLASS | USB_RECIP_INTERFACE | USB_DIR_IN,
			      UAC2_CS_CONTROL_CLOCK_VALID << 8,
			      snd_usb_ctrl_intf(chip) | (source_id << 8),
			      &data, sizeof(data));

	if (err < 0) {
		dev_warn(&dev->dev,
			 "%s(): cannot get clock validity for id %d\n",
			   __func__, source_id);
		return false;
	}

	if (data)
		return true;
	else
		return uac_clock_source_is_valid_quirk(chip, fmt, source_id);
}

static int __uac_clock_find_source(struct snd_usb_audio *chip,
				   const struct audioformat *fmt, int entity_id,
				   unsigned long *visited, bool validate)
{
	struct uac_clock_source_descriptor *source;
	struct uac_clock_selector_descriptor *selector;
	struct uac_clock_multiplier_descriptor *multiplier;

	entity_id &= 0xff;

	if (test_and_set_bit(entity_id, visited)) {
		usb_audio_warn(chip,
			 "%s(): recursive clock topology detected, id %d.\n",
			 __func__, entity_id);
		return -EINVAL;
	}

	/* first, see if the ID we're looking for is a clock source already */
	source = snd_usb_find_clock_source(chip->ctrl_intf, entity_id);
	if (source) {
		entity_id = source->bClockID;
		if (validate && !uac_clock_source_is_valid(chip, fmt,
								entity_id)) {
			usb_audio_err(chip,
				"clock source %d is not valid, cannot use\n",
				entity_id);
			return -ENXIO;
		}
		return entity_id;
	}

	selector = snd_usb_find_clock_selector(chip->ctrl_intf, entity_id);
	if (selector) {
		int ret, i, cur, err;

		if (selector->bNrInPins == 1) {
			ret = 1;
			goto find_source;
		}

		/* the entity ID we are looking for is a selector.
		 * find out what it currently selects */
		ret = uac_clock_selector_get_val(chip, selector->bClockID);
		if (ret < 0)
			return ret;

		/* Selector values are one-based */

		if (ret > selector->bNrInPins || ret < 1) {
			usb_audio_err(chip,
				"%s(): selector reported illegal value, id %d, ret %d\n",
				__func__, selector->bClockID, ret);

			return -EINVAL;
		}

	find_source:
		cur = ret;
		ret = __uac_clock_find_source(chip, fmt,
					      selector->baCSourceID[ret - 1],
					      visited, validate);
		if (ret > 0) {
			err = uac_clock_selector_set_val(chip, entity_id, cur);
			if (err < 0)
				return err;
		}

		if (!validate || ret > 0 || !chip->autoclock)
			return ret;

		/* The current clock source is invalid, try others. */
		for (i = 1; i <= selector->bNrInPins; i++) {
			if (i == cur)
				continue;

			ret = __uac_clock_find_source(chip, fmt,
						      selector->baCSourceID[i - 1],
						      visited, true);
			if (ret < 0)
				continue;

			err = uac_clock_selector_set_val(chip, entity_id, i);
			if (err < 0)
				continue;

			usb_audio_info(chip,
				 "found and selected valid clock source %d\n",
				 ret);
			return ret;
		}

		return -ENXIO;
	}

	/* FIXME: multipliers only act as pass-thru element for now */
	multiplier = snd_usb_find_clock_multiplier(chip->ctrl_intf, entity_id);
	if (multiplier)
		return __uac_clock_find_source(chip, fmt,
					       multiplier->bCSourceID,
					       visited, validate);

	return -EINVAL;
}

static int __uac3_clock_find_source(struct snd_usb_audio *chip,
				    const struct audioformat *fmt, int entity_id,
				    unsigned long *visited, bool validate)
{
	struct uac3_clock_source_descriptor *source;
	struct uac3_clock_selector_descriptor *selector;
	struct uac3_clock_multiplier_descriptor *multiplier;

	entity_id &= 0xff;

	if (test_and_set_bit(entity_id, visited)) {
		usb_audio_warn(chip,
			 "%s(): recursive clock topology detected, id %d.\n",
			 __func__, entity_id);
		return -EINVAL;
	}

	/* first, see if the ID we're looking for is a clock source already */
	source = snd_usb_find_clock_source_v3(chip->ctrl_intf, entity_id);
	if (source) {
		entity_id = source->bClockID;
		if (validate && !uac_clock_source_is_valid(chip, fmt,
								entity_id)) {
			usb_audio_err(chip,
				"clock source %d is not valid, cannot use\n",
				entity_id);
			return -ENXIO;
		}
		return entity_id;
	}

	selector = snd_usb_find_clock_selector_v3(chip->ctrl_intf, entity_id);
	if (selector) {
		int ret, i, cur, err;

		/* the entity ID we are looking for is a selector.
		 * find out what it currently selects */
		ret = uac_clock_selector_get_val(chip, selector->bClockID);
		if (ret < 0)
			return ret;

		/* Selector values are one-based */

		if (ret > selector->bNrInPins || ret < 1) {
			usb_audio_err(chip,
				"%s(): selector reported illegal value, id %d, ret %d\n",
				__func__, selector->bClockID, ret);

			return -EINVAL;
		}

		cur = ret;
		ret = __uac3_clock_find_source(chip, fmt,
					       selector->baCSourceID[ret - 1],
					       visited, validate);
		if (ret > 0) {
			err = uac_clock_selector_set_val(chip, entity_id, cur);
			if (err < 0)
				return err;
		}

		if (!validate || ret > 0 || !chip->autoclock)
			return ret;

		/* The current clock source is invalid, try others. */
		for (i = 1; i <= selector->bNrInPins; i++) {
			int err;

			if (i == cur)
				continue;

			ret = __uac3_clock_find_source(chip, fmt,
						       selector->baCSourceID[i - 1],
						       visited, true);
			if (ret < 0)
				continue;

			err = uac_clock_selector_set_val(chip, entity_id, i);
			if (err < 0)
				continue;

			usb_audio_info(chip,
				 "found and selected valid clock source %d\n",
				 ret);
			return ret;
		}

		return -ENXIO;
	}

	/* FIXME: multipliers only act as pass-thru element for now */
	multiplier = snd_usb_find_clock_multiplier_v3(chip->ctrl_intf,
						      entity_id);
	if (multiplier)
		return __uac3_clock_find_source(chip, fmt,
						multiplier->bCSourceID,
						visited, validate);

	return -EINVAL;
}

/*
 * For all kinds of sample rate settings and other device queries,
 * the clock source (end-leaf) must be used. However, clock selectors,
 * clock multipliers and sample rate converters may be specified as
 * clock source input to terminal. This functions walks the clock path
 * to its end and tries to find the source.
 *
 * The 'visited' bitfield is used internally to detect recursive loops.
 *
 * Returns the clock source UnitID (>=0) on success, or an error.
 */
int snd_usb_clock_find_source(struct snd_usb_audio *chip,
			      const struct audioformat *fmt, bool validate)
{
	DECLARE_BITMAP(visited, 256);
	memset(visited, 0, sizeof(visited));

	switch (fmt->protocol) {
	case UAC_VERSION_2:
		return __uac_clock_find_source(chip, fmt, fmt->clock, visited,
					       validate);
	case UAC_VERSION_3:
		return __uac3_clock_find_source(chip, fmt, fmt->clock, visited,
					       validate);
	default:
		return -EINVAL;
	}
}

static int set_sample_rate_v1(struct snd_usb_audio *chip,
			      const struct audioformat *fmt, int rate)
{
	struct usb_device *dev = chip->dev;
	unsigned char data[3];
	int err, crate;

	/* if endpoint doesn't have sampling rate control, bail out */
	if (!(fmt->attributes & UAC_EP_CS_ATTR_SAMPLE_RATE))
		return 0;

	data[0] = rate;
	data[1] = rate >> 8;
	data[2] = rate >> 16;
	err = snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0), UAC_SET_CUR,
			      USB_TYPE_CLASS | USB_RECIP_ENDPOINT | USB_DIR_OUT,
			      UAC_EP_CS_ATTR_SAMPLE_RATE << 8,
			      fmt->endpoint, data, sizeof(data));
	if (err < 0) {
		dev_err(&dev->dev, "%d:%d: cannot set freq %d to ep %#x\n",
			fmt->iface, fmt->altsetting, rate, fmt->endpoint);
		return err;
	}

	/* Don't check the sample rate for devices which we know don't
	 * support reading */
	if (snd_usb_get_sample_rate_quirk(chip))
		return 0;
	/* the firmware is likely buggy, don't repeat to fail too many times */
	if (chip->sample_rate_read_error > 2)
		return 0;

	err = snd_usb_ctl_msg(dev, usb_rcvctrlpipe(dev, 0), UAC_GET_CUR,
			      USB_TYPE_CLASS | USB_RECIP_ENDPOINT | USB_DIR_IN,
			      UAC_EP_CS_ATTR_SAMPLE_RATE << 8,
			      fmt->endpoint, data, sizeof(data));
	if (err < 0) {
		dev_err(&dev->dev, "%d:%d: cannot get freq at ep %#x\n",
			fmt->iface, fmt->altsetting, fmt->endpoint);
		chip->sample_rate_read_error++;
		return 0; /* some devices don't support reading */
	}

	crate = data[0] | (data[1] << 8) | (data[2] << 16);
	if (!crate) {
		dev_info(&dev->dev, "failed to read current rate; disabling the check\n");
		chip->sample_rate_read_error = 3; /* three strikes, see above */
		return 0;
	}

	if (crate != rate) {
		dev_warn(&dev->dev, "current rate %d is different from the runtime rate %d\n", crate, rate);
		// runtime->rate = crate;
	}

	return 0;
}

static int get_sample_rate_v2v3(struct snd_usb_audio *chip, int iface,
			      int altsetting, int clock)
{
	struct usb_device *dev = chip->dev;
	__le32 data;
	int err;

	err = snd_usb_ctl_msg(dev, usb_rcvctrlpipe(dev, 0), UAC2_CS_CUR,
			      USB_TYPE_CLASS | USB_RECIP_INTERFACE | USB_DIR_IN,
			      UAC2_CS_CONTROL_SAM_FREQ << 8,
			      snd_usb_ctrl_intf(chip) | (clock << 8),
			      &data, sizeof(data));
	if (err < 0) {
		dev_warn(&dev->dev, "%d:%d: cannot get freq (v2/v3): err %d\n",
			 iface, altsetting, err);
		return 0;
	}

	return le32_to_cpu(data);
}

/*
 * Try to set the given sample rate:
 *
 * Return 0 if the clock source is read-only, the actual rate on success,
 * or a negative error code.
 *
 * This function gets called from format.c to validate each sample rate, too.
 * Hence no message is shown upon error
 */
int snd_usb_set_sample_rate_v2v3(struct snd_usb_audio *chip,
				 const struct audioformat *fmt,
				 int clock, int rate)
{
	bool writeable;
	u32 bmControls;
	__le32 data;
	int err;

	if (fmt->protocol == UAC_VERSION_3) {
		struct uac3_clock_source_descriptor *cs_desc;

		cs_desc = snd_usb_find_clock_source_v3(chip->ctrl_intf, clock);
		bmControls = le32_to_cpu(cs_desc->bmControls);
	} else {
		struct uac_clock_source_descriptor *cs_desc;

		cs_desc = snd_usb_find_clock_source(chip->ctrl_intf, clock);
		bmControls = cs_desc->bmControls;
	}

	writeable = uac_v2v3_control_is_writeable(bmControls,
						  UAC2_CS_CONTROL_SAM_FREQ);
	if (!writeable)
		return 0;

	data = cpu_to_le32(rate);
	err = snd_usb_ctl_msg(chip->dev, usb_sndctrlpipe(chip->dev, 0), UAC2_CS_CUR,
			      USB_TYPE_CLASS | USB_RECIP_INTERFACE | USB_DIR_OUT,
			      UAC2_CS_CONTROL_SAM_FREQ << 8,
			      snd_usb_ctrl_intf(chip) | (clock << 8),
			      &data, sizeof(data));
	if (err < 0)
		return err;

	return get_sample_rate_v2v3(chip, fmt->iface, fmt->altsetting, clock);
}

static int set_sample_rate_v2v3(struct snd_usb_audio *chip,
				const struct audioformat *fmt, int rate)
{
	int cur_rate, prev_rate;
	int clock;

	/* First, try to find a valid clock. This may trigger
	 * automatic clock selection if the current clock is not
	 * valid.
	 */
	clock = snd_usb_clock_find_source(chip, fmt, true);
	if (clock < 0) {
		/* We did not find a valid clock, but that might be
		 * because the current sample rate does not match an
		 * external clock source. Try again without validation
		 * and we will do another validation after setting the
		 * rate.
		 */
		clock = snd_usb_clock_find_source(chip, fmt, false);
		if (clock < 0)
			return clock;
	}

	prev_rate = get_sample_rate_v2v3(chip, fmt->iface, fmt->altsetting, clock);
	if (prev_rate == rate)
		goto validation;

	cur_rate = snd_usb_set_sample_rate_v2v3(chip, fmt, clock, rate);
	if (cur_rate < 0) {
		usb_audio_err(chip,
			      "%d:%d: cannot set freq %d (v2/v3): err %d\n",
			      fmt->iface, fmt->altsetting, rate, cur_rate);
		return cur_rate;
	}

	if (!cur_rate)
		cur_rate = prev_rate;

	if (cur_rate != rate) {
		usb_audio_dbg(chip,
			      "%d:%d: freq mismatch: req %d, clock runs @%d\n",
			      fmt->iface, fmt->altsetting, rate, cur_rate);
		/* continue processing */
	}

validation:
	/* validate clock after rate change */
	if (!uac_clock_source_is_valid(chip, fmt, clock))
		return -ENXIO;
	return 0;
}

int snd_usb_init_sample_rate(struct snd_usb_audio *chip,
			     const struct audioformat *fmt, int rate)
{
	usb_audio_dbg(chip, "%d:%d Set sample rate %d, clock %d\n",
		      fmt->iface, fmt->altsetting, rate, fmt->clock);

	switch (fmt->protocol) {
	case UAC_VERSION_1:
	default:
		return set_sample_rate_v1(chip, fmt, rate);

	case UAC_VERSION_3:
		if (chip->badd_profile >= UAC3_FUNCTION_SUBCLASS_GENERIC_IO) {
			if (rate != UAC3_BADD_SAMPLING_RATE)
				return -ENXIO;
			else
				return 0;
		}
		fallthrough;
	case UAC_VERSION_2:
		return set_sample_rate_v2v3(chip, fmt, rate);
	}
}