sound/usb/clock.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  *   Clock domain and sample rate management functions
   4  */
   5
   6 #include <linux/bitops.h>
   7 #include <linux/init.h>
   8 #include <linux/string.h>
   9 #include <linux/usb.h>
  10 #include <linux/usb/audio.h>
  11 #include <linux/usb/audio-v2.h>
  12 #include <linux/usb/audio-v3.h>
  13
  14 #include <sound/core.h>
  15 #include <sound/info.h>
  16 #include <sound/pcm.h>
  17
  18 #include "usbaudio.h"
  19 #include "card.h"
  20 #include "helper.h"
  21 #include "clock.h"
  22 #include "quirks.h"
  23
  24 static void *find_uac_clock_desc(struct usb_host_interface *iface, int id,
  25                                  bool (*validator)(void *, int), u8 type)
  26 {
  27         void *cs = NULL;
  28
  29         while ((cs = snd_usb_find_csint_desc(iface->extra, iface->extralen,
  30                                              cs, type))) {
  31                 if (validator(cs, id))
  32                         return cs;
  33         }
  34
  35         return NULL;
  36 }
  37
  38 static bool validate_clock_source_v2(void *p, int id)
  39 {
  40         struct uac_clock_source_descriptor *cs = p;
  41         return cs->bClockID == id;
  42 }
  43
  44 static bool validate_clock_source_v3(void *p, int id)
  45 {
  46         struct uac3_clock_source_descriptor *cs = p;
  47         return cs->bClockID == id;
  48 }
  49
  50 static bool validate_clock_selector_v2(void *p, int id)
  51 {
  52         struct uac_clock_selector_descriptor *cs = p;
  53         return cs->bClockID == id;
  54 }
  55
  56 static bool validate_clock_selector_v3(void *p, int id)
  57 {
  58         struct uac3_clock_selector_descriptor *cs = p;
  59         return cs->bClockID == id;
  60 }
  61
  62 static bool validate_clock_multiplier_v2(void *p, int id)
  63 {
  64         struct uac_clock_multiplier_descriptor *cs = p;
  65         return cs->bClockID == id;
  66 }
  67
  68 static bool validate_clock_multiplier_v3(void *p, int id)
  69 {
  70         struct uac3_clock_multiplier_descriptor *cs = p;
  71         return cs->bClockID == id;
  72 }
  73
  74 #define DEFINE_FIND_HELPER(name, obj, validator, type)          \
  75 static obj *name(struct usb_host_interface *iface, int id)      \
  76 {                                                               \
  77         return find_uac_clock_desc(iface, id, validator, type); \
  78 }
  79
  80 DEFINE_FIND_HELPER(snd_usb_find_clock_source,
  81                    struct uac_clock_source_descriptor,
  82                    validate_clock_source_v2, UAC2_CLOCK_SOURCE);
  83 DEFINE_FIND_HELPER(snd_usb_find_clock_source_v3,
  84                    struct uac3_clock_source_descriptor,
  85                    validate_clock_source_v3, UAC3_CLOCK_SOURCE);
  86
  87 DEFINE_FIND_HELPER(snd_usb_find_clock_selector,
  88                    struct uac_clock_selector_descriptor,
  89                    validate_clock_selector_v2, UAC2_CLOCK_SELECTOR);
  90 DEFINE_FIND_HELPER(snd_usb_find_clock_selector_v3,
  91                    struct uac3_clock_selector_descriptor,
  92                    validate_clock_selector_v3, UAC3_CLOCK_SELECTOR);
  93
  94 DEFINE_FIND_HELPER(snd_usb_find_clock_multiplier,
  95                    struct uac_clock_multiplier_descriptor,
  96                    validate_clock_multiplier_v2, UAC2_CLOCK_MULTIPLIER);
  97 DEFINE_FIND_HELPER(snd_usb_find_clock_multiplier_v3,
  98                    struct uac3_clock_multiplier_descriptor,
  99                    validate_clock_multiplier_v3, UAC3_CLOCK_MULTIPLIER);
 100
 101 static int uac_clock_selector_get_val(struct snd_usb_audio *chip, int selector_id)
 102 {
 103         unsigned char buf;
 104         int ret;
 105
 106         ret = snd_usb_ctl_msg(chip->dev, usb_rcvctrlpipe(chip->dev, 0),
 107                               UAC2_CS_CUR,
 108                               USB_RECIP_INTERFACE | USB_TYPE_CLASS | USB_DIR_IN,
 109                               UAC2_CX_CLOCK_SELECTOR << 8,
 110                               snd_usb_ctrl_intf(chip) | (selector_id << 8),
 111                               &buf, sizeof(buf));
 112
 113         if (ret < 0)
 114                 return ret;
 115
 116         return buf;
 117 }
 118
 119 static int uac_clock_selector_set_val(struct snd_usb_audio *chip, int selector_id,
 120                                         unsigned char pin)
 121 {
 122         int ret;
 123
 124         ret = snd_usb_ctl_msg(chip->dev, usb_sndctrlpipe(chip->dev, 0),
 125                               UAC2_CS_CUR,
 126                               USB_RECIP_INTERFACE | USB_TYPE_CLASS | USB_DIR_OUT,
 127                               UAC2_CX_CLOCK_SELECTOR << 8,
 128                               snd_usb_ctrl_intf(chip) | (selector_id << 8),
 129                               &pin, sizeof(pin));
 130         if (ret < 0)
 131                 return ret;
 132
 133         if (ret != sizeof(pin)) {
 134                 usb_audio_err(chip,
 135                         "setting selector (id %d) unexpected length %d\n",
 136                         selector_id, ret);
 137                 return -EINVAL;
 138         }
 139
 140         ret = uac_clock_selector_get_val(chip, selector_id);
 141         if (ret < 0)
 142                 return ret;
 143
 144         if (ret != pin) {
 145                 usb_audio_err(chip,
 146                         "setting selector (id %d) to %x failed (current: %d)\n",
 147                         selector_id, pin, ret);
 148                 return -EINVAL;
 149         }
 150
 151         return ret;
 152 }
 153
 154 static bool uac_clock_source_is_valid_quirk(struct snd_usb_audio *chip,
 155                                             const struct audioformat *fmt,
 156                                             int source_id)
 157 {
 158         bool ret = false;
 159         int count;
 160         unsigned char data;
 161         struct usb_device *dev = chip->dev;
 162
 163         if (fmt->protocol == UAC_VERSION_2) {
 164                 struct uac_clock_source_descriptor *cs_desc =
 165                         snd_usb_find_clock_source(chip->ctrl_intf, source_id);
 166
 167                 if (!cs_desc)
 168                         return false;
 169
 170                 /*
 171                  * Assume the clock is valid if clock source supports only one
 172                  * single sample rate, the terminal is connected directly to it
 173                  * (there is no clock selector) and clock type is internal.
 174                  * This is to deal with some Denon DJ controllers that always
 175                  * reports that clock is invalid.
 176                  */
 177                 if (fmt->nr_rates == 1 &&
 178                     (fmt->clock & 0xff) == cs_desc->bClockID &&
 179                     (cs_desc->bmAttributes & 0x3) !=
 180                                 UAC_CLOCK_SOURCE_TYPE_EXT)
 181                         return true;
 182         }
 183
 184         /*
 185          * MOTU MicroBook IIc
 186          * Sample rate changes takes more than 2 seconds for this device. Clock
 187          * validity request returns false during that period.
 188          */
 189         if (chip->usb_id == USB_ID(0x07fd, 0x0004)) {
 190                 count = 0;
 191
 192                 while ((!ret) && (count < 50)) {
 193                         int err;
 194
 195                         msleep(100);
 196
 197                         err = snd_usb_ctl_msg(dev, usb_rcvctrlpipe(dev, 0), UAC2_CS_CUR,
 198                                               USB_TYPE_CLASS | USB_RECIP_INTERFACE | USB_DIR_IN,
 199                                               UAC2_CS_CONTROL_CLOCK_VALID << 8,
 200                                               snd_usb_ctrl_intf(chip) | (source_id << 8),
 201                                               &data, sizeof(data));
 202                         if (err < 0) {
 203                                 dev_warn(&dev->dev,
 204                                          "%s(): cannot get clock validity for id %d\n",
 205                                            __func__, source_id);
 206                                 return false;
 207                         }
 208
 209                         ret = !!data;
 210                         count++;
 211                 }
 212         }
 213
 214         return ret;
 215 }
 216
 217 static bool uac_clock_source_is_valid(struct snd_usb_audio *chip,
 218                                       const struct audioformat *fmt,
 219                                       int source_id)
 220 {
 221         int err;
 222         unsigned char data;
 223         struct usb_device *dev = chip->dev;
 224         u32 bmControls;
 225
 226         if (fmt->protocol == UAC_VERSION_3) {
 227                 struct uac3_clock_source_descriptor *cs_desc =
 228                         snd_usb_find_clock_source_v3(chip->ctrl_intf, source_id);
 229
 230                 if (!cs_desc)
 231                         return false;
 232                 bmControls = le32_to_cpu(cs_desc->bmControls);
 233         } else { /* UAC_VERSION_1/2 */
 234                 struct uac_clock_source_descriptor *cs_desc =
 235                         snd_usb_find_clock_source(chip->ctrl_intf, source_id);
 236
 237                 if (!cs_desc)
 238                         return false;
 239                 bmControls = cs_desc->bmControls;
 240         }
 241
 242         /* If a clock source can't tell us whether it's valid, we assume it is */
 243         if (!uac_v2v3_control_is_readable(bmControls,
 244                                       UAC2_CS_CONTROL_CLOCK_VALID))
 245                 return true;
 246
 247         err = snd_usb_ctl_msg(dev, usb_rcvctrlpipe(dev, 0), UAC2_CS_CUR,
 248                               USB_TYPE_CLASS | USB_RECIP_INTERFACE | USB_DIR_IN,
 249                               UAC2_CS_CONTROL_CLOCK_VALID << 8,
 250                               snd_usb_ctrl_intf(chip) | (source_id << 8),
 251                               &data, sizeof(data));
 252
 253         if (err < 0) {
 254                 dev_warn(&dev->dev,
 255                          "%s(): cannot get clock validity for id %d\n",
 256                            __func__, source_id);
 257                 return false;
 258         }
 259
 260         if (data)
 261                 return true;
 262         else
 263                 return uac_clock_source_is_valid_quirk(chip, fmt, source_id);
 264 }
 265
 266 static int __uac_clock_find_source(struct snd_usb_audio *chip,
 267                                    const struct audioformat *fmt, int entity_id,
 268                                    unsigned long *visited, bool validate)
 269 {
 270         struct uac_clock_source_descriptor *source;
 271         struct uac_clock_selector_descriptor *selector;
 272         struct uac_clock_multiplier_descriptor *multiplier;
 273
 274         entity_id &= 0xff;
 275
 276         if (test_and_set_bit(entity_id, visited)) {
 277                 usb_audio_warn(chip,
 278                          "%s(): recursive clock topology detected, id %d.\n",
 279                          __func__, entity_id);
 280                 return -EINVAL;
 281         }
 282
 283         /* first, see if the ID we're looking for is a clock source already */
 284         source = snd_usb_find_clock_source(chip->ctrl_intf, entity_id);
 285         if (source) {
 286                 entity_id = source->bClockID;
 287                 if (validate && !uac_clock_source_is_valid(chip, fmt,
 288                                                                 entity_id)) {
 289                         usb_audio_err(chip,
 290                                 "clock source %d is not valid, cannot use\n",
 291                                 entity_id);
 292                         return -ENXIO;
 293                 }
 294                 return entity_id;
 295         }
 296
 297         selector = snd_usb_find_clock_selector(chip->ctrl_intf, entity_id);
 298         if (selector) {
 299                 int ret, i, cur;
 300
 301                 /* the entity ID we are looking for is a selector.
 302                  * find out what it currently selects */
 303                 ret = uac_clock_selector_get_val(chip, selector->bClockID);
 304                 if (ret < 0)
 305                         return ret;
 306
 307                 /* Selector values are one-based */
 308
 309                 if (ret > selector->bNrInPins || ret < 1) {
 310                         usb_audio_err(chip,
 311                                 "%s(): selector reported illegal value, id %d, ret %d\n",
 312                                 __func__, selector->bClockID, ret);
 313
 314                         return -EINVAL;
 315                 }
 316
 317                 cur = ret;
 318                 ret = __uac_clock_find_source(chip, fmt,
 319                                               selector->baCSourceID[ret - 1],
 320                                               visited, validate);
 321                 if (!validate || ret > 0 || !chip->autoclock)
 322                         return ret;
 323
 324                 /* The current clock source is invalid, try others. */
 325                 for (i = 1; i <= selector->bNrInPins; i++) {
 326                         int err;
 327
 328                         if (i == cur)
 329                                 continue;
 330
 331                         ret = __uac_clock_find_source(chip, fmt,
 332                                                       selector->baCSourceID[i - 1],
 333                                                       visited, true);
 334                         if (ret < 0)
 335                                 continue;
 336
 337                         err = uac_clock_selector_set_val(chip, entity_id, i);
 338                         if (err < 0)
 339                                 continue;
 340
 341                         usb_audio_info(chip,
 342                                  "found and selected valid clock source %d\n",
 343                                  ret);
 344                         return ret;
 345                 }
 346
 347                 return -ENXIO;
 348         }
 349
 350         /* FIXME: multipliers only act as pass-thru element for now */
 351         multiplier = snd_usb_find_clock_multiplier(chip->ctrl_intf, entity_id);
 352         if (multiplier)
 353                 return __uac_clock_find_source(chip, fmt,
 354                                                multiplier->bCSourceID,
 355                                                visited, validate);
 356
 357         return -EINVAL;
 358 }
 359
 360 static int __uac3_clock_find_source(struct snd_usb_audio *chip,
 361                                     const struct audioformat *fmt, int entity_id,
 362                                     unsigned long *visited, bool validate)
 363 {
 364         struct uac3_clock_source_descriptor *source;
 365         struct uac3_clock_selector_descriptor *selector;
 366         struct uac3_clock_multiplier_descriptor *multiplier;
 367
 368         entity_id &= 0xff;
 369
 370         if (test_and_set_bit(entity_id, visited)) {
 371                 usb_audio_warn(chip,
 372                          "%s(): recursive clock topology detected, id %d.\n",
 373                          __func__, entity_id);
 374                 return -EINVAL;
 375         }
 376
 377         /* first, see if the ID we're looking for is a clock source already */
 378         source = snd_usb_find_clock_source_v3(chip->ctrl_intf, entity_id);
 379         if (source) {
 380                 entity_id = source->bClockID;
 381                 if (validate && !uac_clock_source_is_valid(chip, fmt,
 382                                                                 entity_id)) {
 383                         usb_audio_err(chip,
 384                                 "clock source %d is not valid, cannot use\n",
 385                                 entity_id);
 386                         return -ENXIO;
 387                 }
 388                 return entity_id;
 389         }
 390
 391         selector = snd_usb_find_clock_selector_v3(chip->ctrl_intf, entity_id);
 392         if (selector) {
 393                 int ret, i, cur;
 394
 395                 /* the entity ID we are looking for is a selector.
 396                  * find out what it currently selects */
 397                 ret = uac_clock_selector_get_val(chip, selector->bClockID);
 398                 if (ret < 0)
 399                         return ret;
 400
 401                 /* Selector values are one-based */
 402
 403                 if (ret > selector->bNrInPins || ret < 1) {
 404                         usb_audio_err(chip,
 405                                 "%s(): selector reported illegal value, id %d, ret %d\n",
 406                                 __func__, selector->bClockID, ret);
 407
 408                         return -EINVAL;
 409                 }
 410
 411                 cur = ret;
 412                 ret = __uac3_clock_find_source(chip, fmt,
 413                                                selector->baCSourceID[ret - 1],
 414                                                visited, validate);
 415                 if (!validate || ret > 0 || !chip->autoclock)
 416                         return ret;
 417
 418                 /* The current clock source is invalid, try others. */
 419                 for (i = 1; i <= selector->bNrInPins; i++) {
 420                         int err;
 421
 422                         if (i == cur)
 423                                 continue;
 424
 425                         ret = __uac3_clock_find_source(chip, fmt,
 426                                                        selector->baCSourceID[i - 1],
 427                                                        visited, true);
 428                         if (ret < 0)
 429                                 continue;
 430
 431                         err = uac_clock_selector_set_val(chip, entity_id, i);
 432                         if (err < 0)
 433                                 continue;
 434
 435                         usb_audio_info(chip,
 436                                  "found and selected valid clock source %d\n",
 437                                  ret);
 438                         return ret;
 439                 }
 440
 441                 return -ENXIO;
 442         }
 443
 444         /* FIXME: multipliers only act as pass-thru element for now */
 445         multiplier = snd_usb_find_clock_multiplier_v3(chip->ctrl_intf,
 446                                                       entity_id);
 447         if (multiplier)
 448                 return __uac3_clock_find_source(chip, fmt,
 449                                                 multiplier->bCSourceID,
 450                                                 visited, validate);
 451
 452         return -EINVAL;
 453 }
 454
 455 /*
 456  * For all kinds of sample rate settings and other device queries,
 457  * the clock source (end-leaf) must be used. However, clock selectors,
 458  * clock multipliers and sample rate converters may be specified as
 459  * clock source input to terminal. This functions walks the clock path
 460  * to its end and tries to find the source.
 461  *
 462  * The 'visited' bitfield is used internally to detect recursive loops.
 463  *
 464  * Returns the clock source UnitID (>=0) on success, or an error.
 465  */
 466 int snd_usb_clock_find_source(struct snd_usb_audio *chip,
 467                               const struct audioformat *fmt, bool validate)
 468 {
 469         DECLARE_BITMAP(visited, 256);
 470         memset(visited, 0, sizeof(visited));
 471
 472         switch (fmt->protocol) {
 473         case UAC_VERSION_2:
 474                 return __uac_clock_find_source(chip, fmt, fmt->clock, visited,
 475                                                validate);
 476         case UAC_VERSION_3:
 477                 return __uac3_clock_find_source(chip, fmt, fmt->clock, visited,
 478                                                validate);
 479         default:
 480                 return -EINVAL;
 481         }
 482 }
 483
 484 static int set_sample_rate_v1(struct snd_usb_audio *chip,
 485                               const struct audioformat *fmt, int rate)
 486 {
 487         struct usb_device *dev = chip->dev;
 488         unsigned char data[3];
 489         int err, crate;
 490
 491         /* if endpoint doesn't have sampling rate control, bail out */
 492         if (!(fmt->attributes & UAC_EP_CS_ATTR_SAMPLE_RATE))
 493                 return 0;
 494
 495         data[0] = rate;
 496         data[1] = rate >> 8;
 497         data[2] = rate >> 16;
 498         err = snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0), UAC_SET_CUR,
 499                               USB_TYPE_CLASS | USB_RECIP_ENDPOINT | USB_DIR_OUT,
 500                               UAC_EP_CS_ATTR_SAMPLE_RATE << 8,
 501                               fmt->endpoint, data, sizeof(data));
 502         if (err < 0) {
 503                 dev_err(&dev->dev, "%d:%d: cannot set freq %d to ep %#x\n",
 504                         fmt->iface, fmt->altsetting, rate, fmt->endpoint);
 505                 return err;
 506         }
 507
 508         /* Don't check the sample rate for devices which we know don't
 509          * support reading */
 510         if (snd_usb_get_sample_rate_quirk(chip))
 511                 return 0;
 512         /* the firmware is likely buggy, don't repeat to fail too many times */
 513         if (chip->sample_rate_read_error > 2)
 514                 return 0;
 515
 516         err = snd_usb_ctl_msg(dev, usb_rcvctrlpipe(dev, 0), UAC_GET_CUR,
 517                               USB_TYPE_CLASS | USB_RECIP_ENDPOINT | USB_DIR_IN,
 518                               UAC_EP_CS_ATTR_SAMPLE_RATE << 8,
 519                               fmt->endpoint, data, sizeof(data));
 520         if (err < 0) {
 521                 dev_err(&dev->dev, "%d:%d: cannot get freq at ep %#x\n",
 522                         fmt->iface, fmt->altsetting, fmt->endpoint);
 523                 chip->sample_rate_read_error++;
 524                 return 0; /* some devices don't support reading */
 525         }
 526
 527         crate = data[0] | (data[1] << 8) | (data[2] << 16);
 528         if (!crate) {
 529                 dev_info(&dev->dev, "failed to read current rate; disabling the check\n");
 530                 chip->sample_rate_read_error = 3; /* three strikes, see above */
 531                 return 0;
 532         }
 533
 534         if (crate != rate) {
 535                 dev_warn(&dev->dev, "current rate %d is different from the runtime rate %d\n", crate, rate);
 536                 // runtime->rate = crate;
 537         }
 538
 539         return 0;
 540 }
 541
 542 static int get_sample_rate_v2v3(struct snd_usb_audio *chip, int iface,
 543                               int altsetting, int clock)
 544 {
 545         struct usb_device *dev = chip->dev;
 546         __le32 data;
 547         int err;
 548
 549         err = snd_usb_ctl_msg(dev, usb_rcvctrlpipe(dev, 0), UAC2_CS_CUR,
 550                               USB_TYPE_CLASS | USB_RECIP_INTERFACE | USB_DIR_IN,
 551                               UAC2_CS_CONTROL_SAM_FREQ << 8,
 552                               snd_usb_ctrl_intf(chip) | (clock << 8),
 553                               &data, sizeof(data));
 554         if (err < 0) {
 555                 dev_warn(&dev->dev, "%d:%d: cannot get freq (v2/v3): err %d\n",
 556                          iface, altsetting, err);
 557                 return 0;
 558         }
 559
 560         return le32_to_cpu(data);
 561 }
 562
 563 /*
 564  * Try to set the given sample rate:
 565  *
 566  * Return 0 if the clock source is read-only, the actual rate on success,
 567  * or a negative error code.
 568  *
 569  * This function gets called from format.c to validate each sample rate, too.
 570  * Hence no message is shown upon error
 571  */
 572 int snd_usb_set_sample_rate_v2v3(struct snd_usb_audio *chip,
 573                                  const struct audioformat *fmt,
 574                                  int clock, int rate)
 575 {
 576         bool writeable;
 577         u32 bmControls;
 578         __le32 data;
 579         int err;
 580
 581         if (fmt->protocol == UAC_VERSION_3) {
 582                 struct uac3_clock_source_descriptor *cs_desc;
 583
 584                 cs_desc = snd_usb_find_clock_source_v3(chip->ctrl_intf, clock);
 585                 bmControls = le32_to_cpu(cs_desc->bmControls);
 586         } else {
 587                 struct uac_clock_source_descriptor *cs_desc;
 588
 589                 cs_desc = snd_usb_find_clock_source(chip->ctrl_intf, clock);
 590                 bmControls = cs_desc->bmControls;
 591         }
 592
 593         writeable = uac_v2v3_control_is_writeable(bmControls,
 594                                                   UAC2_CS_CONTROL_SAM_FREQ);
 595         if (!writeable)
 596                 return 0;
 597
 598         data = cpu_to_le32(rate);
 599         err = snd_usb_ctl_msg(chip->dev, usb_sndctrlpipe(chip->dev, 0), UAC2_CS_CUR,
 600                               USB_TYPE_CLASS | USB_RECIP_INTERFACE | USB_DIR_OUT,
 601                               UAC2_CS_CONTROL_SAM_FREQ << 8,
 602                               snd_usb_ctrl_intf(chip) | (clock << 8),
 603                               &data, sizeof(data));
 604         if (err < 0)
 605                 return err;
 606
 607         return get_sample_rate_v2v3(chip, fmt->iface, fmt->altsetting, clock);
 608 }
 609
 610 static int set_sample_rate_v2v3(struct snd_usb_audio *chip,
 611                                 const struct audioformat *fmt, int rate)
 612 {
 613         int cur_rate, prev_rate;
 614         int clock;
 615
 616         /* First, try to find a valid clock. This may trigger
 617          * automatic clock selection if the current clock is not
 618          * valid.
 619          */
 620         clock = snd_usb_clock_find_source(chip, fmt, true);
 621         if (clock < 0) {
 622                 /* We did not find a valid clock, but that might be
 623                  * because the current sample rate does not match an
 624                  * external clock source. Try again without validation
 625                  * and we will do another validation after setting the
 626                  * rate.
 627                  */
 628                 clock = snd_usb_clock_find_source(chip, fmt, false);
 629                 if (clock < 0)
 630                         return clock;
 631         }
 632
 633         prev_rate = get_sample_rate_v2v3(chip, fmt->iface, fmt->altsetting, clock);
 634         if (prev_rate == rate)
 635                 goto validation;
 636
 637         cur_rate = snd_usb_set_sample_rate_v2v3(chip, fmt, clock, rate);
 638         if (cur_rate < 0) {
 639                 usb_audio_err(chip,
 640                               "%d:%d: cannot set freq %d (v2/v3): err %d\n",
 641                               fmt->iface, fmt->altsetting, rate, cur_rate);
 642                 return cur_rate;
 643         }
 644
 645         if (!cur_rate)
 646                 cur_rate = prev_rate;
 647
 648         if (cur_rate != rate) {
 649                 usb_audio_warn(chip,
 650                                "%d:%d: freq mismatch (RO clock): req %d, clock runs @%d\n",
 651                                fmt->iface, fmt->altsetting, rate, cur_rate);
 652                 return -ENXIO;
 653         }
 654
 655 validation:
 656         /* validate clock after rate change */
 657         if (!uac_clock_source_is_valid(chip, fmt, clock))
 658                 return -ENXIO;
 659         return 0;
 660 }
 661
 662 int snd_usb_init_sample_rate(struct snd_usb_audio *chip,
 663                              const struct audioformat *fmt, int rate)
 664 {
 665         usb_audio_dbg(chip, "%d:%d Set sample rate %d, clock %d\n",
 666                       fmt->iface, fmt->altsetting, rate, fmt->clock);
 667
 668         switch (fmt->protocol) {
 669         case UAC_VERSION_1:
 670         default:
 671                 return set_sample_rate_v1(chip, fmt, rate);
 672
 673         case UAC_VERSION_3:
 674                 if (chip->badd_profile >= UAC3_FUNCTION_SUBCLASS_GENERIC_IO) {
 675                         if (rate != UAC3_BADD_SAMPLING_RATE)
 676                                 return -ENXIO;
 677                         else
 678                                 return 0;
 679                 }
 680                 fallthrough;
 681         case UAC_VERSION_2:
 682                 return set_sample_rate_v2v3(chip, fmt, rate);
 683         }
 684 }
 685