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v3.1
  1/*
  2 *   Clock domain and sample rate management functions
  3 *
  4 *   This program is free software; you can redistribute it and/or modify
  5 *   it under the terms of the GNU General Public License as published by
  6 *   the Free Software Foundation; either version 2 of the License, or
  7 *   (at your option) any later version.
  8 *
  9 *   This program is distributed in the hope that it will be useful,
 10 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 11 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 12 *   GNU General Public License for more details.
 13 *
 14 *   You should have received a copy of the GNU General Public License
 15 *   along with this program; if not, write to the Free Software
 16 *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
 17 *
 18 */
 19
 20#include <linux/bitops.h>
 21#include <linux/init.h>
 22#include <linux/string.h>
 23#include <linux/usb.h>
 24#include <linux/usb/audio.h>
 25#include <linux/usb/audio-v2.h>
 26
 27#include <sound/core.h>
 28#include <sound/info.h>
 29#include <sound/pcm.h>
 30
 31#include "usbaudio.h"
 32#include "card.h"
 33#include "helper.h"
 34#include "clock.h"
 35
 36static struct uac_clock_source_descriptor *
 37	snd_usb_find_clock_source(struct usb_host_interface *ctrl_iface,
 38				  int clock_id)
 39{
 40	struct uac_clock_source_descriptor *cs = NULL;
 41
 42	while ((cs = snd_usb_find_csint_desc(ctrl_iface->extra,
 43					     ctrl_iface->extralen,
 44					     cs, UAC2_CLOCK_SOURCE))) {
 45		if (cs->bClockID == clock_id)
 46			return cs;
 47	}
 48
 49	return NULL;
 50}
 51
 52static struct uac_clock_selector_descriptor *
 53	snd_usb_find_clock_selector(struct usb_host_interface *ctrl_iface,
 54				    int clock_id)
 55{
 56	struct uac_clock_selector_descriptor *cs = NULL;
 57
 58	while ((cs = snd_usb_find_csint_desc(ctrl_iface->extra,
 59					     ctrl_iface->extralen,
 60					     cs, UAC2_CLOCK_SELECTOR))) {
 61		if (cs->bClockID == clock_id)
 62			return cs;
 63	}
 64
 65	return NULL;
 66}
 67
 68static struct uac_clock_multiplier_descriptor *
 69	snd_usb_find_clock_multiplier(struct usb_host_interface *ctrl_iface,
 70				      int clock_id)
 71{
 72	struct uac_clock_multiplier_descriptor *cs = NULL;
 73
 74	while ((cs = snd_usb_find_csint_desc(ctrl_iface->extra,
 75					     ctrl_iface->extralen,
 76					     cs, UAC2_CLOCK_MULTIPLIER))) {
 77		if (cs->bClockID == clock_id)
 78			return cs;
 79	}
 80
 81	return NULL;
 82}
 83
 84static int uac_clock_selector_get_val(struct snd_usb_audio *chip, int selector_id)
 85{
 86	unsigned char buf;
 87	int ret;
 88
 89	ret = snd_usb_ctl_msg(chip->dev, usb_rcvctrlpipe(chip->dev, 0),
 90			      UAC2_CS_CUR,
 91			      USB_RECIP_INTERFACE | USB_TYPE_CLASS | USB_DIR_IN,
 92			      UAC2_CX_CLOCK_SELECTOR << 8,
 93			      snd_usb_ctrl_intf(chip) | (selector_id << 8),
 94			      &buf, sizeof(buf), 1000);
 95
 96	if (ret < 0)
 97		return ret;
 98
 99	return buf;
100}
101
102static bool uac_clock_source_is_valid(struct snd_usb_audio *chip, int source_id)
103{
104	int err;
105	unsigned char data;
106	struct usb_device *dev = chip->dev;
107	struct uac_clock_source_descriptor *cs_desc =
108		snd_usb_find_clock_source(chip->ctrl_intf, source_id);
109
110	if (!cs_desc)
111		return 0;
112
113	/* If a clock source can't tell us whether it's valid, we assume it is */
114	if (!uac2_control_is_readable(cs_desc->bmControls, UAC2_CS_CONTROL_CLOCK_VALID))
115		return 1;
116
117	err = snd_usb_ctl_msg(dev, usb_rcvctrlpipe(dev, 0), UAC2_CS_CUR,
118			      USB_TYPE_CLASS | USB_RECIP_INTERFACE | USB_DIR_IN,
119			      UAC2_CS_CONTROL_CLOCK_VALID << 8,
120			      snd_usb_ctrl_intf(chip) | (source_id << 8),
121			      &data, sizeof(data), 1000);
122
123	if (err < 0) {
124		snd_printk(KERN_WARNING "%s(): cannot get clock validity for id %d\n",
125			   __func__, source_id);
126		return 0;
127	}
128
129	return !!data;
130}
131
132static int __uac_clock_find_source(struct snd_usb_audio *chip,
133				   int entity_id, unsigned long *visited)
134{
135	struct uac_clock_source_descriptor *source;
136	struct uac_clock_selector_descriptor *selector;
137	struct uac_clock_multiplier_descriptor *multiplier;
138
139	entity_id &= 0xff;
140
141	if (test_and_set_bit(entity_id, visited)) {
142		snd_printk(KERN_WARNING
143			"%s(): recursive clock topology detected, id %d.\n",
144			__func__, entity_id);
145		return -EINVAL;
146	}
147
148	/* first, see if the ID we're looking for is a clock source already */
149	source = snd_usb_find_clock_source(chip->ctrl_intf, entity_id);
150	if (source)
151		return source->bClockID;
152
153	selector = snd_usb_find_clock_selector(chip->ctrl_intf, entity_id);
154	if (selector) {
155		int ret;
156
157		/* the entity ID we are looking for is a selector.
158		 * find out what it currently selects */
159		ret = uac_clock_selector_get_val(chip, selector->bClockID);
160		if (ret < 0)
161			return ret;
162
163		/* Selector values are one-based */
164
165		if (ret > selector->bNrInPins || ret < 1) {
166			printk(KERN_ERR
167				"%s(): selector reported illegal value, id %d, ret %d\n",
168				__func__, selector->bClockID, ret);
169
170			return -EINVAL;
171		}
172
173		return __uac_clock_find_source(chip, selector->baCSourceID[ret-1],
174					       visited);
175	}
176
177	/* FIXME: multipliers only act as pass-thru element for now */
178	multiplier = snd_usb_find_clock_multiplier(chip->ctrl_intf, entity_id);
179	if (multiplier)
180		return __uac_clock_find_source(chip, multiplier->bCSourceID,
181						visited);
182
183	return -EINVAL;
184}
185
186/*
187 * For all kinds of sample rate settings and other device queries,
188 * the clock source (end-leaf) must be used. However, clock selectors,
189 * clock multipliers and sample rate converters may be specified as
190 * clock source input to terminal. This functions walks the clock path
191 * to its end and tries to find the source.
192 *
193 * The 'visited' bitfield is used internally to detect recursive loops.
194 *
195 * Returns the clock source UnitID (>=0) on success, or an error.
196 */
197int snd_usb_clock_find_source(struct snd_usb_audio *chip, int entity_id)
198{
199	DECLARE_BITMAP(visited, 256);
200	memset(visited, 0, sizeof(visited));
201	return __uac_clock_find_source(chip, entity_id, visited);
202}
203
204static int set_sample_rate_v1(struct snd_usb_audio *chip, int iface,
205			      struct usb_host_interface *alts,
206			      struct audioformat *fmt, int rate)
207{
208	struct usb_device *dev = chip->dev;
209	unsigned int ep;
210	unsigned char data[3];
211	int err, crate;
212
213	ep = get_endpoint(alts, 0)->bEndpointAddress;
214
215	/* if endpoint doesn't have sampling rate control, bail out */
216	if (!(fmt->attributes & UAC_EP_CS_ATTR_SAMPLE_RATE))
217		return 0;
218
219	data[0] = rate;
220	data[1] = rate >> 8;
221	data[2] = rate >> 16;
222	if ((err = snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0), UAC_SET_CUR,
223				   USB_TYPE_CLASS | USB_RECIP_ENDPOINT | USB_DIR_OUT,
224				   UAC_EP_CS_ATTR_SAMPLE_RATE << 8, ep,
225				   data, sizeof(data), 1000)) < 0) {
226		snd_printk(KERN_ERR "%d:%d:%d: cannot set freq %d to ep %#x\n",
227			   dev->devnum, iface, fmt->altsetting, rate, ep);
228		return err;
229	}
230
231	if ((err = snd_usb_ctl_msg(dev, usb_rcvctrlpipe(dev, 0), UAC_GET_CUR,
232				   USB_TYPE_CLASS | USB_RECIP_ENDPOINT | USB_DIR_IN,
233				   UAC_EP_CS_ATTR_SAMPLE_RATE << 8, ep,
234				   data, sizeof(data), 1000)) < 0) {
235		snd_printk(KERN_WARNING "%d:%d:%d: cannot get freq at ep %#x\n",
236			   dev->devnum, iface, fmt->altsetting, ep);
237		return 0; /* some devices don't support reading */
238	}
239
240	crate = data[0] | (data[1] << 8) | (data[2] << 16);
241	if (crate != rate) {
242		snd_printd(KERN_WARNING "current rate %d is different from the runtime rate %d\n", crate, rate);
243		// runtime->rate = crate;
244	}
245
246	return 0;
247}
248
249static int set_sample_rate_v2(struct snd_usb_audio *chip, int iface,
250			      struct usb_host_interface *alts,
251			      struct audioformat *fmt, int rate)
252{
253	struct usb_device *dev = chip->dev;
254	unsigned char data[4];
255	int err, crate;
256	int clock = snd_usb_clock_find_source(chip, fmt->clock);
257
258	if (clock < 0)
259		return clock;
260
261	if (!uac_clock_source_is_valid(chip, clock)) {
262		/* TODO: should we try to find valid clock setups by ourself? */
263		snd_printk(KERN_ERR "%d:%d:%d: clock source %d is not valid, cannot use\n",
264			   dev->devnum, iface, fmt->altsetting, clock);
265		return -ENXIO;
266	}
267
268	data[0] = rate;
269	data[1] = rate >> 8;
270	data[2] = rate >> 16;
271	data[3] = rate >> 24;
272	if ((err = snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0), UAC2_CS_CUR,
273				   USB_TYPE_CLASS | USB_RECIP_INTERFACE | USB_DIR_OUT,
274				   UAC2_CS_CONTROL_SAM_FREQ << 8,
275				   snd_usb_ctrl_intf(chip) | (clock << 8),
276				   data, sizeof(data), 1000)) < 0) {
277		snd_printk(KERN_ERR "%d:%d:%d: cannot set freq %d (v2)\n",
278			   dev->devnum, iface, fmt->altsetting, rate);
279		return err;
280	}
281
282	if ((err = snd_usb_ctl_msg(dev, usb_rcvctrlpipe(dev, 0), UAC2_CS_CUR,
283				   USB_TYPE_CLASS | USB_RECIP_INTERFACE | USB_DIR_IN,
284				   UAC2_CS_CONTROL_SAM_FREQ << 8,
285				   snd_usb_ctrl_intf(chip) | (clock << 8),
286				   data, sizeof(data), 1000)) < 0) {
287		snd_printk(KERN_WARNING "%d:%d:%d: cannot get freq (v2)\n",
288			   dev->devnum, iface, fmt->altsetting);
289		return err;
290	}
291
292	crate = data[0] | (data[1] << 8) | (data[2] << 16) | (data[3] << 24);
293	if (crate != rate)
294		snd_printd(KERN_WARNING "current rate %d is different from the runtime rate %d\n", crate, rate);
295
296	return 0;
297}
298
299int snd_usb_init_sample_rate(struct snd_usb_audio *chip, int iface,
300			     struct usb_host_interface *alts,
301			     struct audioformat *fmt, int rate)
302{
303	struct usb_interface_descriptor *altsd = get_iface_desc(alts);
304
305	switch (altsd->bInterfaceProtocol) {
306	case UAC_VERSION_1:
307	default:
308		return set_sample_rate_v1(chip, iface, alts, fmt, rate);
309
310	case UAC_VERSION_2:
311		return set_sample_rate_v2(chip, iface, alts, fmt, rate);
312	}
313}
314
v3.1
  1/*
  2 *   Clock domain and sample rate management functions
  3 *
  4 *   This program is free software; you can redistribute it and/or modify
  5 *   it under the terms of the GNU General Public License as published by
  6 *   the Free Software Foundation; either version 2 of the License, or
  7 *   (at your option) any later version.
  8 *
  9 *   This program is distributed in the hope that it will be useful,
 10 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 11 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 12 *   GNU General Public License for more details.
 13 *
 14 *   You should have received a copy of the GNU General Public License
 15 *   along with this program; if not, write to the Free Software
 16 *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
 17 *
 18 */
 19
 20#include <linux/bitops.h>
 21#include <linux/init.h>
 22#include <linux/string.h>
 23#include <linux/usb.h>
 24#include <linux/usb/audio.h>
 25#include <linux/usb/audio-v2.h>
 26
 27#include <sound/core.h>
 28#include <sound/info.h>
 29#include <sound/pcm.h>
 30
 31#include "usbaudio.h"
 32#include "card.h"
 33#include "helper.h"
 34#include "clock.h"
 35
 36static struct uac_clock_source_descriptor *
 37	snd_usb_find_clock_source(struct usb_host_interface *ctrl_iface,
 38				  int clock_id)
 39{
 40	struct uac_clock_source_descriptor *cs = NULL;
 41
 42	while ((cs = snd_usb_find_csint_desc(ctrl_iface->extra,
 43					     ctrl_iface->extralen,
 44					     cs, UAC2_CLOCK_SOURCE))) {
 45		if (cs->bClockID == clock_id)
 46			return cs;
 47	}
 48
 49	return NULL;
 50}
 51
 52static struct uac_clock_selector_descriptor *
 53	snd_usb_find_clock_selector(struct usb_host_interface *ctrl_iface,
 54				    int clock_id)
 55{
 56	struct uac_clock_selector_descriptor *cs = NULL;
 57
 58	while ((cs = snd_usb_find_csint_desc(ctrl_iface->extra,
 59					     ctrl_iface->extralen,
 60					     cs, UAC2_CLOCK_SELECTOR))) {
 61		if (cs->bClockID == clock_id)
 62			return cs;
 63	}
 64
 65	return NULL;
 66}
 67
 68static struct uac_clock_multiplier_descriptor *
 69	snd_usb_find_clock_multiplier(struct usb_host_interface *ctrl_iface,
 70				      int clock_id)
 71{
 72	struct uac_clock_multiplier_descriptor *cs = NULL;
 73
 74	while ((cs = snd_usb_find_csint_desc(ctrl_iface->extra,
 75					     ctrl_iface->extralen,
 76					     cs, UAC2_CLOCK_MULTIPLIER))) {
 77		if (cs->bClockID == clock_id)
 78			return cs;
 79	}
 80
 81	return NULL;
 82}
 83
 84static int uac_clock_selector_get_val(struct snd_usb_audio *chip, int selector_id)
 85{
 86	unsigned char buf;
 87	int ret;
 88
 89	ret = snd_usb_ctl_msg(chip->dev, usb_rcvctrlpipe(chip->dev, 0),
 90			      UAC2_CS_CUR,
 91			      USB_RECIP_INTERFACE | USB_TYPE_CLASS | USB_DIR_IN,
 92			      UAC2_CX_CLOCK_SELECTOR << 8,
 93			      snd_usb_ctrl_intf(chip) | (selector_id << 8),
 94			      &buf, sizeof(buf), 1000);
 95
 96	if (ret < 0)
 97		return ret;
 98
 99	return buf;
100}
101
102static bool uac_clock_source_is_valid(struct snd_usb_audio *chip, int source_id)
103{
104	int err;
105	unsigned char data;
106	struct usb_device *dev = chip->dev;
107	struct uac_clock_source_descriptor *cs_desc =
108		snd_usb_find_clock_source(chip->ctrl_intf, source_id);
109
110	if (!cs_desc)
111		return 0;
112
113	/* If a clock source can't tell us whether it's valid, we assume it is */
114	if (!uac2_control_is_readable(cs_desc->bmControls, UAC2_CS_CONTROL_CLOCK_VALID))
115		return 1;
116
117	err = snd_usb_ctl_msg(dev, usb_rcvctrlpipe(dev, 0), UAC2_CS_CUR,
118			      USB_TYPE_CLASS | USB_RECIP_INTERFACE | USB_DIR_IN,
119			      UAC2_CS_CONTROL_CLOCK_VALID << 8,
120			      snd_usb_ctrl_intf(chip) | (source_id << 8),
121			      &data, sizeof(data), 1000);
122
123	if (err < 0) {
124		snd_printk(KERN_WARNING "%s(): cannot get clock validity for id %d\n",
125			   __func__, source_id);
126		return 0;
127	}
128
129	return !!data;
130}
131
132static int __uac_clock_find_source(struct snd_usb_audio *chip,
133				   int entity_id, unsigned long *visited)
134{
135	struct uac_clock_source_descriptor *source;
136	struct uac_clock_selector_descriptor *selector;
137	struct uac_clock_multiplier_descriptor *multiplier;
138
139	entity_id &= 0xff;
140
141	if (test_and_set_bit(entity_id, visited)) {
142		snd_printk(KERN_WARNING
143			"%s(): recursive clock topology detected, id %d.\n",
144			__func__, entity_id);
145		return -EINVAL;
146	}
147
148	/* first, see if the ID we're looking for is a clock source already */
149	source = snd_usb_find_clock_source(chip->ctrl_intf, entity_id);
150	if (source)
151		return source->bClockID;
152
153	selector = snd_usb_find_clock_selector(chip->ctrl_intf, entity_id);
154	if (selector) {
155		int ret;
156
157		/* the entity ID we are looking for is a selector.
158		 * find out what it currently selects */
159		ret = uac_clock_selector_get_val(chip, selector->bClockID);
160		if (ret < 0)
161			return ret;
162
163		/* Selector values are one-based */
164
165		if (ret > selector->bNrInPins || ret < 1) {
166			printk(KERN_ERR
167				"%s(): selector reported illegal value, id %d, ret %d\n",
168				__func__, selector->bClockID, ret);
169
170			return -EINVAL;
171		}
172
173		return __uac_clock_find_source(chip, selector->baCSourceID[ret-1],
174					       visited);
175	}
176
177	/* FIXME: multipliers only act as pass-thru element for now */
178	multiplier = snd_usb_find_clock_multiplier(chip->ctrl_intf, entity_id);
179	if (multiplier)
180		return __uac_clock_find_source(chip, multiplier->bCSourceID,
181						visited);
182
183	return -EINVAL;
184}
185
186/*
187 * For all kinds of sample rate settings and other device queries,
188 * the clock source (end-leaf) must be used. However, clock selectors,
189 * clock multipliers and sample rate converters may be specified as
190 * clock source input to terminal. This functions walks the clock path
191 * to its end and tries to find the source.
192 *
193 * The 'visited' bitfield is used internally to detect recursive loops.
194 *
195 * Returns the clock source UnitID (>=0) on success, or an error.
196 */
197int snd_usb_clock_find_source(struct snd_usb_audio *chip, int entity_id)
198{
199	DECLARE_BITMAP(visited, 256);
200	memset(visited, 0, sizeof(visited));
201	return __uac_clock_find_source(chip, entity_id, visited);
202}
203
204static int set_sample_rate_v1(struct snd_usb_audio *chip, int iface,
205			      struct usb_host_interface *alts,
206			      struct audioformat *fmt, int rate)
207{
208	struct usb_device *dev = chip->dev;
209	unsigned int ep;
210	unsigned char data[3];
211	int err, crate;
212
213	ep = get_endpoint(alts, 0)->bEndpointAddress;
214
215	/* if endpoint doesn't have sampling rate control, bail out */
216	if (!(fmt->attributes & UAC_EP_CS_ATTR_SAMPLE_RATE))
217		return 0;
218
219	data[0] = rate;
220	data[1] = rate >> 8;
221	data[2] = rate >> 16;
222	if ((err = snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0), UAC_SET_CUR,
223				   USB_TYPE_CLASS | USB_RECIP_ENDPOINT | USB_DIR_OUT,
224				   UAC_EP_CS_ATTR_SAMPLE_RATE << 8, ep,
225				   data, sizeof(data), 1000)) < 0) {
226		snd_printk(KERN_ERR "%d:%d:%d: cannot set freq %d to ep %#x\n",
227			   dev->devnum, iface, fmt->altsetting, rate, ep);
228		return err;
229	}
230
231	if ((err = snd_usb_ctl_msg(dev, usb_rcvctrlpipe(dev, 0), UAC_GET_CUR,
232				   USB_TYPE_CLASS | USB_RECIP_ENDPOINT | USB_DIR_IN,
233				   UAC_EP_CS_ATTR_SAMPLE_RATE << 8, ep,
234				   data, sizeof(data), 1000)) < 0) {
235		snd_printk(KERN_WARNING "%d:%d:%d: cannot get freq at ep %#x\n",
236			   dev->devnum, iface, fmt->altsetting, ep);
237		return 0; /* some devices don't support reading */
238	}
239
240	crate = data[0] | (data[1] << 8) | (data[2] << 16);
241	if (crate != rate) {
242		snd_printd(KERN_WARNING "current rate %d is different from the runtime rate %d\n", crate, rate);
243		// runtime->rate = crate;
244	}
245
246	return 0;
247}
248
249static int set_sample_rate_v2(struct snd_usb_audio *chip, int iface,
250			      struct usb_host_interface *alts,
251			      struct audioformat *fmt, int rate)
252{
253	struct usb_device *dev = chip->dev;
254	unsigned char data[4];
255	int err, crate;
256	int clock = snd_usb_clock_find_source(chip, fmt->clock);
257
258	if (clock < 0)
259		return clock;
260
261	if (!uac_clock_source_is_valid(chip, clock)) {
262		/* TODO: should we try to find valid clock setups by ourself? */
263		snd_printk(KERN_ERR "%d:%d:%d: clock source %d is not valid, cannot use\n",
264			   dev->devnum, iface, fmt->altsetting, clock);
265		return -ENXIO;
266	}
267
268	data[0] = rate;
269	data[1] = rate >> 8;
270	data[2] = rate >> 16;
271	data[3] = rate >> 24;
272	if ((err = snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0), UAC2_CS_CUR,
273				   USB_TYPE_CLASS | USB_RECIP_INTERFACE | USB_DIR_OUT,
274				   UAC2_CS_CONTROL_SAM_FREQ << 8,
275				   snd_usb_ctrl_intf(chip) | (clock << 8),
276				   data, sizeof(data), 1000)) < 0) {
277		snd_printk(KERN_ERR "%d:%d:%d: cannot set freq %d (v2)\n",
278			   dev->devnum, iface, fmt->altsetting, rate);
279		return err;
280	}
281
282	if ((err = snd_usb_ctl_msg(dev, usb_rcvctrlpipe(dev, 0), UAC2_CS_CUR,
283				   USB_TYPE_CLASS | USB_RECIP_INTERFACE | USB_DIR_IN,
284				   UAC2_CS_CONTROL_SAM_FREQ << 8,
285				   snd_usb_ctrl_intf(chip) | (clock << 8),
286				   data, sizeof(data), 1000)) < 0) {
287		snd_printk(KERN_WARNING "%d:%d:%d: cannot get freq (v2)\n",
288			   dev->devnum, iface, fmt->altsetting);
289		return err;
290	}
291
292	crate = data[0] | (data[1] << 8) | (data[2] << 16) | (data[3] << 24);
293	if (crate != rate)
294		snd_printd(KERN_WARNING "current rate %d is different from the runtime rate %d\n", crate, rate);
295
296	return 0;
297}
298
299int snd_usb_init_sample_rate(struct snd_usb_audio *chip, int iface,
300			     struct usb_host_interface *alts,
301			     struct audioformat *fmt, int rate)
302{
303	struct usb_interface_descriptor *altsd = get_iface_desc(alts);
304
305	switch (altsd->bInterfaceProtocol) {
306	case UAC_VERSION_1:
307	default:
308		return set_sample_rate_v1(chip, iface, alts, fmt, rate);
309
310	case UAC_VERSION_2:
311		return set_sample_rate_v2(chip, iface, alts, fmt, rate);
312	}
313}
314