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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
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#include "quirks.h"
36
37static struct uac_clock_source_descriptor *
38 snd_usb_find_clock_source(struct usb_host_interface *ctrl_iface,
39 int clock_id)
40{
41 struct uac_clock_source_descriptor *cs = NULL;
42
43 while ((cs = snd_usb_find_csint_desc(ctrl_iface->extra,
44 ctrl_iface->extralen,
45 cs, UAC2_CLOCK_SOURCE))) {
46 if (cs->bClockID == clock_id)
47 return cs;
48 }
49
50 return NULL;
51}
52
53static struct uac_clock_selector_descriptor *
54 snd_usb_find_clock_selector(struct usb_host_interface *ctrl_iface,
55 int clock_id)
56{
57 struct uac_clock_selector_descriptor *cs = NULL;
58
59 while ((cs = snd_usb_find_csint_desc(ctrl_iface->extra,
60 ctrl_iface->extralen,
61 cs, UAC2_CLOCK_SELECTOR))) {
62 if (cs->bClockID == clock_id)
63 return cs;
64 }
65
66 return NULL;
67}
68
69static struct uac_clock_multiplier_descriptor *
70 snd_usb_find_clock_multiplier(struct usb_host_interface *ctrl_iface,
71 int clock_id)
72{
73 struct uac_clock_multiplier_descriptor *cs = NULL;
74
75 while ((cs = snd_usb_find_csint_desc(ctrl_iface->extra,
76 ctrl_iface->extralen,
77 cs, UAC2_CLOCK_MULTIPLIER))) {
78 if (cs->bClockID == clock_id)
79 return cs;
80 }
81
82 return NULL;
83}
84
85static int uac_clock_selector_get_val(struct snd_usb_audio *chip, int selector_id)
86{
87 unsigned char buf;
88 int ret;
89
90 ret = snd_usb_ctl_msg(chip->dev, usb_rcvctrlpipe(chip->dev, 0),
91 UAC2_CS_CUR,
92 USB_RECIP_INTERFACE | USB_TYPE_CLASS | USB_DIR_IN,
93 UAC2_CX_CLOCK_SELECTOR << 8,
94 snd_usb_ctrl_intf(chip) | (selector_id << 8),
95 &buf, sizeof(buf));
96
97 if (ret < 0)
98 return ret;
99
100 return buf;
101}
102
103static int uac_clock_selector_set_val(struct snd_usb_audio *chip, int selector_id,
104 unsigned char pin)
105{
106 int ret;
107
108 ret = snd_usb_ctl_msg(chip->dev, usb_sndctrlpipe(chip->dev, 0),
109 UAC2_CS_CUR,
110 USB_RECIP_INTERFACE | USB_TYPE_CLASS | USB_DIR_OUT,
111 UAC2_CX_CLOCK_SELECTOR << 8,
112 snd_usb_ctrl_intf(chip) | (selector_id << 8),
113 &pin, sizeof(pin));
114 if (ret < 0)
115 return ret;
116
117 if (ret != sizeof(pin)) {
118 usb_audio_err(chip,
119 "setting selector (id %d) unexpected length %d\n",
120 selector_id, ret);
121 return -EINVAL;
122 }
123
124 ret = uac_clock_selector_get_val(chip, selector_id);
125 if (ret < 0)
126 return ret;
127
128 if (ret != pin) {
129 usb_audio_err(chip,
130 "setting selector (id %d) to %x failed (current: %d)\n",
131 selector_id, pin, ret);
132 return -EINVAL;
133 }
134
135 return ret;
136}
137
138static bool uac_clock_source_is_valid(struct snd_usb_audio *chip, int source_id)
139{
140 int err;
141 unsigned char data;
142 struct usb_device *dev = chip->dev;
143 struct uac_clock_source_descriptor *cs_desc =
144 snd_usb_find_clock_source(chip->ctrl_intf, source_id);
145
146 if (!cs_desc)
147 return 0;
148
149 /* If a clock source can't tell us whether it's valid, we assume it is */
150 if (!uac2_control_is_readable(cs_desc->bmControls,
151 UAC2_CS_CONTROL_CLOCK_VALID - 1))
152 return 1;
153
154 err = snd_usb_ctl_msg(dev, usb_rcvctrlpipe(dev, 0), UAC2_CS_CUR,
155 USB_TYPE_CLASS | USB_RECIP_INTERFACE | USB_DIR_IN,
156 UAC2_CS_CONTROL_CLOCK_VALID << 8,
157 snd_usb_ctrl_intf(chip) | (source_id << 8),
158 &data, sizeof(data));
159
160 if (err < 0) {
161 dev_warn(&dev->dev,
162 "%s(): cannot get clock validity for id %d\n",
163 __func__, source_id);
164 return 0;
165 }
166
167 return !!data;
168}
169
170static int __uac_clock_find_source(struct snd_usb_audio *chip,
171 int entity_id, unsigned long *visited,
172 bool validate)
173{
174 struct uac_clock_source_descriptor *source;
175 struct uac_clock_selector_descriptor *selector;
176 struct uac_clock_multiplier_descriptor *multiplier;
177
178 entity_id &= 0xff;
179
180 if (test_and_set_bit(entity_id, visited)) {
181 usb_audio_warn(chip,
182 "%s(): recursive clock topology detected, id %d.\n",
183 __func__, entity_id);
184 return -EINVAL;
185 }
186
187 /* first, see if the ID we're looking for is a clock source already */
188 source = snd_usb_find_clock_source(chip->ctrl_intf, entity_id);
189 if (source) {
190 entity_id = source->bClockID;
191 if (validate && !uac_clock_source_is_valid(chip, entity_id)) {
192 usb_audio_err(chip,
193 "clock source %d is not valid, cannot use\n",
194 entity_id);
195 return -ENXIO;
196 }
197 return entity_id;
198 }
199
200 selector = snd_usb_find_clock_selector(chip->ctrl_intf, entity_id);
201 if (selector) {
202 int ret, i, cur;
203
204 /* the entity ID we are looking for is a selector.
205 * find out what it currently selects */
206 ret = uac_clock_selector_get_val(chip, selector->bClockID);
207 if (ret < 0)
208 return ret;
209
210 /* Selector values are one-based */
211
212 if (ret > selector->bNrInPins || ret < 1) {
213 usb_audio_err(chip,
214 "%s(): selector reported illegal value, id %d, ret %d\n",
215 __func__, selector->bClockID, ret);
216
217 return -EINVAL;
218 }
219
220 cur = ret;
221 ret = __uac_clock_find_source(chip, selector->baCSourceID[ret - 1],
222 visited, validate);
223 if (!validate || ret > 0 || !chip->autoclock)
224 return ret;
225
226 /* The current clock source is invalid, try others. */
227 for (i = 1; i <= selector->bNrInPins; i++) {
228 int err;
229
230 if (i == cur)
231 continue;
232
233 ret = __uac_clock_find_source(chip, selector->baCSourceID[i - 1],
234 visited, true);
235 if (ret < 0)
236 continue;
237
238 err = uac_clock_selector_set_val(chip, entity_id, i);
239 if (err < 0)
240 continue;
241
242 usb_audio_info(chip,
243 "found and selected valid clock source %d\n",
244 ret);
245 return ret;
246 }
247
248 return -ENXIO;
249 }
250
251 /* FIXME: multipliers only act as pass-thru element for now */
252 multiplier = snd_usb_find_clock_multiplier(chip->ctrl_intf, entity_id);
253 if (multiplier)
254 return __uac_clock_find_source(chip, multiplier->bCSourceID,
255 visited, validate);
256
257 return -EINVAL;
258}
259
260/*
261 * For all kinds of sample rate settings and other device queries,
262 * the clock source (end-leaf) must be used. However, clock selectors,
263 * clock multipliers and sample rate converters may be specified as
264 * clock source input to terminal. This functions walks the clock path
265 * to its end and tries to find the source.
266 *
267 * The 'visited' bitfield is used internally to detect recursive loops.
268 *
269 * Returns the clock source UnitID (>=0) on success, or an error.
270 */
271int snd_usb_clock_find_source(struct snd_usb_audio *chip, int entity_id,
272 bool validate)
273{
274 DECLARE_BITMAP(visited, 256);
275 memset(visited, 0, sizeof(visited));
276 return __uac_clock_find_source(chip, entity_id, visited, validate);
277}
278
279static int set_sample_rate_v1(struct snd_usb_audio *chip, int iface,
280 struct usb_host_interface *alts,
281 struct audioformat *fmt, int rate)
282{
283 struct usb_device *dev = chip->dev;
284 unsigned int ep;
285 unsigned char data[3];
286 int err, crate;
287
288 if (get_iface_desc(alts)->bNumEndpoints < 1)
289 return -EINVAL;
290 ep = get_endpoint(alts, 0)->bEndpointAddress;
291
292 /* if endpoint doesn't have sampling rate control, bail out */
293 if (!(fmt->attributes & UAC_EP_CS_ATTR_SAMPLE_RATE))
294 return 0;
295
296 data[0] = rate;
297 data[1] = rate >> 8;
298 data[2] = rate >> 16;
299 if ((err = snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0), UAC_SET_CUR,
300 USB_TYPE_CLASS | USB_RECIP_ENDPOINT | USB_DIR_OUT,
301 UAC_EP_CS_ATTR_SAMPLE_RATE << 8, ep,
302 data, sizeof(data))) < 0) {
303 dev_err(&dev->dev, "%d:%d: cannot set freq %d to ep %#x\n",
304 iface, fmt->altsetting, rate, ep);
305 return err;
306 }
307
308 /* Don't check the sample rate for devices which we know don't
309 * support reading */
310 if (snd_usb_get_sample_rate_quirk(chip))
311 return 0;
312
313 if ((err = snd_usb_ctl_msg(dev, usb_rcvctrlpipe(dev, 0), UAC_GET_CUR,
314 USB_TYPE_CLASS | USB_RECIP_ENDPOINT | USB_DIR_IN,
315 UAC_EP_CS_ATTR_SAMPLE_RATE << 8, ep,
316 data, sizeof(data))) < 0) {
317 dev_err(&dev->dev, "%d:%d: cannot get freq at ep %#x\n",
318 iface, fmt->altsetting, ep);
319 return 0; /* some devices don't support reading */
320 }
321
322 crate = data[0] | (data[1] << 8) | (data[2] << 16);
323 if (crate != rate) {
324 dev_warn(&dev->dev, "current rate %d is different from the runtime rate %d\n", crate, rate);
325 // runtime->rate = crate;
326 }
327
328 return 0;
329}
330
331static int get_sample_rate_v2(struct snd_usb_audio *chip, int iface,
332 int altsetting, int clock)
333{
334 struct usb_device *dev = chip->dev;
335 __le32 data;
336 int err;
337
338 err = snd_usb_ctl_msg(dev, usb_rcvctrlpipe(dev, 0), UAC2_CS_CUR,
339 USB_TYPE_CLASS | USB_RECIP_INTERFACE | USB_DIR_IN,
340 UAC2_CS_CONTROL_SAM_FREQ << 8,
341 snd_usb_ctrl_intf(chip) | (clock << 8),
342 &data, sizeof(data));
343 if (err < 0) {
344 dev_warn(&dev->dev, "%d:%d: cannot get freq (v2): err %d\n",
345 iface, altsetting, err);
346 return 0;
347 }
348
349 return le32_to_cpu(data);
350}
351
352static int set_sample_rate_v2(struct snd_usb_audio *chip, int iface,
353 struct usb_host_interface *alts,
354 struct audioformat *fmt, int rate)
355{
356 struct usb_device *dev = chip->dev;
357 __le32 data;
358 int err, cur_rate, prev_rate;
359 int clock;
360 bool writeable;
361 struct uac_clock_source_descriptor *cs_desc;
362
363 clock = snd_usb_clock_find_source(chip, fmt->clock, true);
364 if (clock < 0)
365 return clock;
366
367 prev_rate = get_sample_rate_v2(chip, iface, fmt->altsetting, clock);
368 if (prev_rate == rate)
369 return 0;
370
371 cs_desc = snd_usb_find_clock_source(chip->ctrl_intf, clock);
372 writeable = uac2_control_is_writeable(cs_desc->bmControls, UAC2_CS_CONTROL_SAM_FREQ - 1);
373 if (writeable) {
374 data = cpu_to_le32(rate);
375 err = snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0), UAC2_CS_CUR,
376 USB_TYPE_CLASS | USB_RECIP_INTERFACE | USB_DIR_OUT,
377 UAC2_CS_CONTROL_SAM_FREQ << 8,
378 snd_usb_ctrl_intf(chip) | (clock << 8),
379 &data, sizeof(data));
380 if (err < 0) {
381 usb_audio_err(chip,
382 "%d:%d: cannot set freq %d (v2): err %d\n",
383 iface, fmt->altsetting, rate, err);
384 return err;
385 }
386
387 cur_rate = get_sample_rate_v2(chip, iface, fmt->altsetting, clock);
388 } else {
389 cur_rate = prev_rate;
390 }
391
392 if (cur_rate != rate) {
393 if (!writeable) {
394 usb_audio_warn(chip,
395 "%d:%d: freq mismatch (RO clock): req %d, clock runs @%d\n",
396 iface, fmt->altsetting, rate, cur_rate);
397 return -ENXIO;
398 }
399 usb_audio_dbg(chip,
400 "current rate %d is different from the runtime rate %d\n",
401 cur_rate, rate);
402 }
403
404 /* Some devices doesn't respond to sample rate changes while the
405 * interface is active. */
406 if (rate != prev_rate) {
407 usb_set_interface(dev, iface, 0);
408 snd_usb_set_interface_quirk(dev);
409 usb_set_interface(dev, iface, fmt->altsetting);
410 snd_usb_set_interface_quirk(dev);
411 }
412
413 return 0;
414}
415
416int snd_usb_init_sample_rate(struct snd_usb_audio *chip, int iface,
417 struct usb_host_interface *alts,
418 struct audioformat *fmt, int rate)
419{
420 switch (fmt->protocol) {
421 case UAC_VERSION_1:
422 default:
423 return set_sample_rate_v1(chip, iface, alts, fmt, rate);
424
425 case UAC_VERSION_2:
426 return set_sample_rate_v2(chip, iface, alts, fmt, rate);
427 }
428}
429