xref: /linux/sound/core/pcm_misc.c (revision d2912cb15bdda8ba4a5dd73396ad62641af2f520)
1 /*
2  *  PCM Interface - misc routines
3  *  Copyright (c) 1998 by Jaroslav Kysela <perex@perex.cz>
4  *
5  *
6  *   This library is free software; you can redistribute it and/or modify
7  *   it under the terms of the GNU Library General Public License as
8  *   published by the Free Software Foundation; either version 2 of
9  *   the License, or (at your option) any later version.
10  *
11  *   This program is distributed in the hope that it will be useful,
12  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
13  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14  *   GNU Library General Public License for more details.
15  *
16  *   You should have received a copy of the GNU Library General Public
17  *   License along with this library; if not, write to the Free Software
18  *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
19  *
20  */
21 
22 #include <linux/time.h>
23 #include <linux/export.h>
24 #include <sound/core.h>
25 #include <sound/pcm.h>
26 
27 #include "pcm_local.h"
28 
29 #define SND_PCM_FORMAT_UNKNOWN (-1)
30 
31 /* NOTE: "signed" prefix must be given below since the default char is
32  *       unsigned on some architectures!
33  */
34 struct pcm_format_data {
35 	unsigned char width;	/* bit width */
36 	unsigned char phys;	/* physical bit width */
37 	signed char le;	/* 0 = big-endian, 1 = little-endian, -1 = others */
38 	signed char signd;	/* 0 = unsigned, 1 = signed, -1 = others */
39 	unsigned char silence[8];	/* silence data to fill */
40 };
41 
42 /* we do lots of calculations on snd_pcm_format_t; shut up sparse */
43 #define INT	__force int
44 
45 static struct pcm_format_data pcm_formats[(INT)SNDRV_PCM_FORMAT_LAST+1] = {
46 	[SNDRV_PCM_FORMAT_S8] = {
47 		.width = 8, .phys = 8, .le = -1, .signd = 1,
48 		.silence = {},
49 	},
50 	[SNDRV_PCM_FORMAT_U8] = {
51 		.width = 8, .phys = 8, .le = -1, .signd = 0,
52 		.silence = { 0x80 },
53 	},
54 	[SNDRV_PCM_FORMAT_S16_LE] = {
55 		.width = 16, .phys = 16, .le = 1, .signd = 1,
56 		.silence = {},
57 	},
58 	[SNDRV_PCM_FORMAT_S16_BE] = {
59 		.width = 16, .phys = 16, .le = 0, .signd = 1,
60 		.silence = {},
61 	},
62 	[SNDRV_PCM_FORMAT_U16_LE] = {
63 		.width = 16, .phys = 16, .le = 1, .signd = 0,
64 		.silence = { 0x00, 0x80 },
65 	},
66 	[SNDRV_PCM_FORMAT_U16_BE] = {
67 		.width = 16, .phys = 16, .le = 0, .signd = 0,
68 		.silence = { 0x80, 0x00 },
69 	},
70 	[SNDRV_PCM_FORMAT_S24_LE] = {
71 		.width = 24, .phys = 32, .le = 1, .signd = 1,
72 		.silence = {},
73 	},
74 	[SNDRV_PCM_FORMAT_S24_BE] = {
75 		.width = 24, .phys = 32, .le = 0, .signd = 1,
76 		.silence = {},
77 	},
78 	[SNDRV_PCM_FORMAT_U24_LE] = {
79 		.width = 24, .phys = 32, .le = 1, .signd = 0,
80 		.silence = { 0x00, 0x00, 0x80 },
81 	},
82 	[SNDRV_PCM_FORMAT_U24_BE] = {
83 		.width = 24, .phys = 32, .le = 0, .signd = 0,
84 		.silence = { 0x00, 0x80, 0x00, 0x00 },
85 	},
86 	[SNDRV_PCM_FORMAT_S32_LE] = {
87 		.width = 32, .phys = 32, .le = 1, .signd = 1,
88 		.silence = {},
89 	},
90 	[SNDRV_PCM_FORMAT_S32_BE] = {
91 		.width = 32, .phys = 32, .le = 0, .signd = 1,
92 		.silence = {},
93 	},
94 	[SNDRV_PCM_FORMAT_U32_LE] = {
95 		.width = 32, .phys = 32, .le = 1, .signd = 0,
96 		.silence = { 0x00, 0x00, 0x00, 0x80 },
97 	},
98 	[SNDRV_PCM_FORMAT_U32_BE] = {
99 		.width = 32, .phys = 32, .le = 0, .signd = 0,
100 		.silence = { 0x80, 0x00, 0x00, 0x00 },
101 	},
102 	[SNDRV_PCM_FORMAT_FLOAT_LE] = {
103 		.width = 32, .phys = 32, .le = 1, .signd = -1,
104 		.silence = {},
105 	},
106 	[SNDRV_PCM_FORMAT_FLOAT_BE] = {
107 		.width = 32, .phys = 32, .le = 0, .signd = -1,
108 		.silence = {},
109 	},
110 	[SNDRV_PCM_FORMAT_FLOAT64_LE] = {
111 		.width = 64, .phys = 64, .le = 1, .signd = -1,
112 		.silence = {},
113 	},
114 	[SNDRV_PCM_FORMAT_FLOAT64_BE] = {
115 		.width = 64, .phys = 64, .le = 0, .signd = -1,
116 		.silence = {},
117 	},
118 	[SNDRV_PCM_FORMAT_IEC958_SUBFRAME_LE] = {
119 		.width = 32, .phys = 32, .le = 1, .signd = -1,
120 		.silence = {},
121 	},
122 	[SNDRV_PCM_FORMAT_IEC958_SUBFRAME_BE] = {
123 		.width = 32, .phys = 32, .le = 0, .signd = -1,
124 		.silence = {},
125 	},
126 	[SNDRV_PCM_FORMAT_MU_LAW] = {
127 		.width = 8, .phys = 8, .le = -1, .signd = -1,
128 		.silence = { 0x7f },
129 	},
130 	[SNDRV_PCM_FORMAT_A_LAW] = {
131 		.width = 8, .phys = 8, .le = -1, .signd = -1,
132 		.silence = { 0x55 },
133 	},
134 	[SNDRV_PCM_FORMAT_IMA_ADPCM] = {
135 		.width = 4, .phys = 4, .le = -1, .signd = -1,
136 		.silence = {},
137 	},
138 	[SNDRV_PCM_FORMAT_G723_24] = {
139 		.width = 3, .phys = 3, .le = -1, .signd = -1,
140 		.silence = {},
141 	},
142 	[SNDRV_PCM_FORMAT_G723_40] = {
143 		.width = 5, .phys = 5, .le = -1, .signd = -1,
144 		.silence = {},
145 	},
146 	[SNDRV_PCM_FORMAT_DSD_U8] = {
147 		.width = 8, .phys = 8, .le = 1, .signd = 0,
148 		.silence = { 0x69 },
149 	},
150 	[SNDRV_PCM_FORMAT_DSD_U16_LE] = {
151 		.width = 16, .phys = 16, .le = 1, .signd = 0,
152 		.silence = { 0x69, 0x69 },
153 	},
154 	[SNDRV_PCM_FORMAT_DSD_U32_LE] = {
155 		.width = 32, .phys = 32, .le = 1, .signd = 0,
156 		.silence = { 0x69, 0x69, 0x69, 0x69 },
157 	},
158 	[SNDRV_PCM_FORMAT_DSD_U16_BE] = {
159 		.width = 16, .phys = 16, .le = 0, .signd = 0,
160 		.silence = { 0x69, 0x69 },
161 	},
162 	[SNDRV_PCM_FORMAT_DSD_U32_BE] = {
163 		.width = 32, .phys = 32, .le = 0, .signd = 0,
164 		.silence = { 0x69, 0x69, 0x69, 0x69 },
165 	},
166 	/* FIXME: the following two formats are not defined properly yet */
167 	[SNDRV_PCM_FORMAT_MPEG] = {
168 		.le = -1, .signd = -1,
169 	},
170 	[SNDRV_PCM_FORMAT_GSM] = {
171 		.le = -1, .signd = -1,
172 	},
173 	[SNDRV_PCM_FORMAT_S20_LE] = {
174 		.width = 20, .phys = 32, .le = 1, .signd = 1,
175 		.silence = {},
176 	},
177 	[SNDRV_PCM_FORMAT_S20_BE] = {
178 		.width = 20, .phys = 32, .le = 0, .signd = 1,
179 		.silence = {},
180 	},
181 	[SNDRV_PCM_FORMAT_U20_LE] = {
182 		.width = 20, .phys = 32, .le = 1, .signd = 0,
183 		.silence = { 0x00, 0x00, 0x08, 0x00 },
184 	},
185 	[SNDRV_PCM_FORMAT_U20_BE] = {
186 		.width = 20, .phys = 32, .le = 0, .signd = 0,
187 		.silence = { 0x00, 0x08, 0x00, 0x00 },
188 	},
189 	/* FIXME: the following format is not defined properly yet */
190 	[SNDRV_PCM_FORMAT_SPECIAL] = {
191 		.le = -1, .signd = -1,
192 	},
193 	[SNDRV_PCM_FORMAT_S24_3LE] = {
194 		.width = 24, .phys = 24, .le = 1, .signd = 1,
195 		.silence = {},
196 	},
197 	[SNDRV_PCM_FORMAT_S24_3BE] = {
198 		.width = 24, .phys = 24, .le = 0, .signd = 1,
199 		.silence = {},
200 	},
201 	[SNDRV_PCM_FORMAT_U24_3LE] = {
202 		.width = 24, .phys = 24, .le = 1, .signd = 0,
203 		.silence = { 0x00, 0x00, 0x80 },
204 	},
205 	[SNDRV_PCM_FORMAT_U24_3BE] = {
206 		.width = 24, .phys = 24, .le = 0, .signd = 0,
207 		.silence = { 0x80, 0x00, 0x00 },
208 	},
209 	[SNDRV_PCM_FORMAT_S20_3LE] = {
210 		.width = 20, .phys = 24, .le = 1, .signd = 1,
211 		.silence = {},
212 	},
213 	[SNDRV_PCM_FORMAT_S20_3BE] = {
214 		.width = 20, .phys = 24, .le = 0, .signd = 1,
215 		.silence = {},
216 	},
217 	[SNDRV_PCM_FORMAT_U20_3LE] = {
218 		.width = 20, .phys = 24, .le = 1, .signd = 0,
219 		.silence = { 0x00, 0x00, 0x08 },
220 	},
221 	[SNDRV_PCM_FORMAT_U20_3BE] = {
222 		.width = 20, .phys = 24, .le = 0, .signd = 0,
223 		.silence = { 0x08, 0x00, 0x00 },
224 	},
225 	[SNDRV_PCM_FORMAT_S18_3LE] = {
226 		.width = 18, .phys = 24, .le = 1, .signd = 1,
227 		.silence = {},
228 	},
229 	[SNDRV_PCM_FORMAT_S18_3BE] = {
230 		.width = 18, .phys = 24, .le = 0, .signd = 1,
231 		.silence = {},
232 	},
233 	[SNDRV_PCM_FORMAT_U18_3LE] = {
234 		.width = 18, .phys = 24, .le = 1, .signd = 0,
235 		.silence = { 0x00, 0x00, 0x02 },
236 	},
237 	[SNDRV_PCM_FORMAT_U18_3BE] = {
238 		.width = 18, .phys = 24, .le = 0, .signd = 0,
239 		.silence = { 0x02, 0x00, 0x00 },
240 	},
241 	[SNDRV_PCM_FORMAT_G723_24_1B] = {
242 		.width = 3, .phys = 8, .le = -1, .signd = -1,
243 		.silence = {},
244 	},
245 	[SNDRV_PCM_FORMAT_G723_40_1B] = {
246 		.width = 5, .phys = 8, .le = -1, .signd = -1,
247 		.silence = {},
248 	},
249 };
250 
251 
252 /**
253  * snd_pcm_format_signed - Check the PCM format is signed linear
254  * @format: the format to check
255  *
256  * Return: 1 if the given PCM format is signed linear, 0 if unsigned
257  * linear, and a negative error code for non-linear formats.
258  */
259 int snd_pcm_format_signed(snd_pcm_format_t format)
260 {
261 	int val;
262 	if ((INT)format < 0 || (INT)format > (INT)SNDRV_PCM_FORMAT_LAST)
263 		return -EINVAL;
264 	if ((val = pcm_formats[(INT)format].signd) < 0)
265 		return -EINVAL;
266 	return val;
267 }
268 EXPORT_SYMBOL(snd_pcm_format_signed);
269 
270 /**
271  * snd_pcm_format_unsigned - Check the PCM format is unsigned linear
272  * @format: the format to check
273  *
274  * Return: 1 if the given PCM format is unsigned linear, 0 if signed
275  * linear, and a negative error code for non-linear formats.
276  */
277 int snd_pcm_format_unsigned(snd_pcm_format_t format)
278 {
279 	int val;
280 
281 	val = snd_pcm_format_signed(format);
282 	if (val < 0)
283 		return val;
284 	return !val;
285 }
286 EXPORT_SYMBOL(snd_pcm_format_unsigned);
287 
288 /**
289  * snd_pcm_format_linear - Check the PCM format is linear
290  * @format: the format to check
291  *
292  * Return: 1 if the given PCM format is linear, 0 if not.
293  */
294 int snd_pcm_format_linear(snd_pcm_format_t format)
295 {
296 	return snd_pcm_format_signed(format) >= 0;
297 }
298 EXPORT_SYMBOL(snd_pcm_format_linear);
299 
300 /**
301  * snd_pcm_format_little_endian - Check the PCM format is little-endian
302  * @format: the format to check
303  *
304  * Return: 1 if the given PCM format is little-endian, 0 if
305  * big-endian, or a negative error code if endian not specified.
306  */
307 int snd_pcm_format_little_endian(snd_pcm_format_t format)
308 {
309 	int val;
310 	if ((INT)format < 0 || (INT)format > (INT)SNDRV_PCM_FORMAT_LAST)
311 		return -EINVAL;
312 	if ((val = pcm_formats[(INT)format].le) < 0)
313 		return -EINVAL;
314 	return val;
315 }
316 EXPORT_SYMBOL(snd_pcm_format_little_endian);
317 
318 /**
319  * snd_pcm_format_big_endian - Check the PCM format is big-endian
320  * @format: the format to check
321  *
322  * Return: 1 if the given PCM format is big-endian, 0 if
323  * little-endian, or a negative error code if endian not specified.
324  */
325 int snd_pcm_format_big_endian(snd_pcm_format_t format)
326 {
327 	int val;
328 
329 	val = snd_pcm_format_little_endian(format);
330 	if (val < 0)
331 		return val;
332 	return !val;
333 }
334 EXPORT_SYMBOL(snd_pcm_format_big_endian);
335 
336 /**
337  * snd_pcm_format_width - return the bit-width of the format
338  * @format: the format to check
339  *
340  * Return: The bit-width of the format, or a negative error code
341  * if unknown format.
342  */
343 int snd_pcm_format_width(snd_pcm_format_t format)
344 {
345 	int val;
346 	if ((INT)format < 0 || (INT)format > (INT)SNDRV_PCM_FORMAT_LAST)
347 		return -EINVAL;
348 	if ((val = pcm_formats[(INT)format].width) == 0)
349 		return -EINVAL;
350 	return val;
351 }
352 EXPORT_SYMBOL(snd_pcm_format_width);
353 
354 /**
355  * snd_pcm_format_physical_width - return the physical bit-width of the format
356  * @format: the format to check
357  *
358  * Return: The physical bit-width of the format, or a negative error code
359  * if unknown format.
360  */
361 int snd_pcm_format_physical_width(snd_pcm_format_t format)
362 {
363 	int val;
364 	if ((INT)format < 0 || (INT)format > (INT)SNDRV_PCM_FORMAT_LAST)
365 		return -EINVAL;
366 	if ((val = pcm_formats[(INT)format].phys) == 0)
367 		return -EINVAL;
368 	return val;
369 }
370 EXPORT_SYMBOL(snd_pcm_format_physical_width);
371 
372 /**
373  * snd_pcm_format_size - return the byte size of samples on the given format
374  * @format: the format to check
375  * @samples: sampling rate
376  *
377  * Return: The byte size of the given samples for the format, or a
378  * negative error code if unknown format.
379  */
380 ssize_t snd_pcm_format_size(snd_pcm_format_t format, size_t samples)
381 {
382 	int phys_width = snd_pcm_format_physical_width(format);
383 	if (phys_width < 0)
384 		return -EINVAL;
385 	return samples * phys_width / 8;
386 }
387 EXPORT_SYMBOL(snd_pcm_format_size);
388 
389 /**
390  * snd_pcm_format_silence_64 - return the silent data in 8 bytes array
391  * @format: the format to check
392  *
393  * Return: The format pattern to fill or %NULL if error.
394  */
395 const unsigned char *snd_pcm_format_silence_64(snd_pcm_format_t format)
396 {
397 	if ((INT)format < 0 || (INT)format > (INT)SNDRV_PCM_FORMAT_LAST)
398 		return NULL;
399 	if (! pcm_formats[(INT)format].phys)
400 		return NULL;
401 	return pcm_formats[(INT)format].silence;
402 }
403 EXPORT_SYMBOL(snd_pcm_format_silence_64);
404 
405 /**
406  * snd_pcm_format_set_silence - set the silence data on the buffer
407  * @format: the PCM format
408  * @data: the buffer pointer
409  * @samples: the number of samples to set silence
410  *
411  * Sets the silence data on the buffer for the given samples.
412  *
413  * Return: Zero if successful, or a negative error code on failure.
414  */
415 int snd_pcm_format_set_silence(snd_pcm_format_t format, void *data, unsigned int samples)
416 {
417 	int width;
418 	unsigned char *dst, *pat;
419 
420 	if ((INT)format < 0 || (INT)format > (INT)SNDRV_PCM_FORMAT_LAST)
421 		return -EINVAL;
422 	if (samples == 0)
423 		return 0;
424 	width = pcm_formats[(INT)format].phys; /* physical width */
425 	pat = pcm_formats[(INT)format].silence;
426 	if (! width)
427 		return -EINVAL;
428 	/* signed or 1 byte data */
429 	if (pcm_formats[(INT)format].signd == 1 || width <= 8) {
430 		unsigned int bytes = samples * width / 8;
431 		memset(data, *pat, bytes);
432 		return 0;
433 	}
434 	/* non-zero samples, fill using a loop */
435 	width /= 8;
436 	dst = data;
437 #if 0
438 	while (samples--) {
439 		memcpy(dst, pat, width);
440 		dst += width;
441 	}
442 #else
443 	/* a bit optimization for constant width */
444 	switch (width) {
445 	case 2:
446 		while (samples--) {
447 			memcpy(dst, pat, 2);
448 			dst += 2;
449 		}
450 		break;
451 	case 3:
452 		while (samples--) {
453 			memcpy(dst, pat, 3);
454 			dst += 3;
455 		}
456 		break;
457 	case 4:
458 		while (samples--) {
459 			memcpy(dst, pat, 4);
460 			dst += 4;
461 		}
462 		break;
463 	case 8:
464 		while (samples--) {
465 			memcpy(dst, pat, 8);
466 			dst += 8;
467 		}
468 		break;
469 	}
470 #endif
471 	return 0;
472 }
473 EXPORT_SYMBOL(snd_pcm_format_set_silence);
474 
475 /**
476  * snd_pcm_limit_hw_rates - determine rate_min/rate_max fields
477  * @runtime: the runtime instance
478  *
479  * Determines the rate_min and rate_max fields from the rates bits of
480  * the given runtime->hw.
481  *
482  * Return: Zero if successful.
483  */
484 int snd_pcm_limit_hw_rates(struct snd_pcm_runtime *runtime)
485 {
486 	int i;
487 	for (i = 0; i < (int)snd_pcm_known_rates.count; i++) {
488 		if (runtime->hw.rates & (1 << i)) {
489 			runtime->hw.rate_min = snd_pcm_known_rates.list[i];
490 			break;
491 		}
492 	}
493 	for (i = (int)snd_pcm_known_rates.count - 1; i >= 0; i--) {
494 		if (runtime->hw.rates & (1 << i)) {
495 			runtime->hw.rate_max = snd_pcm_known_rates.list[i];
496 			break;
497 		}
498 	}
499 	return 0;
500 }
501 EXPORT_SYMBOL(snd_pcm_limit_hw_rates);
502 
503 /**
504  * snd_pcm_rate_to_rate_bit - converts sample rate to SNDRV_PCM_RATE_xxx bit
505  * @rate: the sample rate to convert
506  *
507  * Return: The SNDRV_PCM_RATE_xxx flag that corresponds to the given rate, or
508  * SNDRV_PCM_RATE_KNOT for an unknown rate.
509  */
510 unsigned int snd_pcm_rate_to_rate_bit(unsigned int rate)
511 {
512 	unsigned int i;
513 
514 	for (i = 0; i < snd_pcm_known_rates.count; i++)
515 		if (snd_pcm_known_rates.list[i] == rate)
516 			return 1u << i;
517 	return SNDRV_PCM_RATE_KNOT;
518 }
519 EXPORT_SYMBOL(snd_pcm_rate_to_rate_bit);
520 
521 /**
522  * snd_pcm_rate_bit_to_rate - converts SNDRV_PCM_RATE_xxx bit to sample rate
523  * @rate_bit: the rate bit to convert
524  *
525  * Return: The sample rate that corresponds to the given SNDRV_PCM_RATE_xxx flag
526  * or 0 for an unknown rate bit.
527  */
528 unsigned int snd_pcm_rate_bit_to_rate(unsigned int rate_bit)
529 {
530 	unsigned int i;
531 
532 	for (i = 0; i < snd_pcm_known_rates.count; i++)
533 		if ((1u << i) == rate_bit)
534 			return snd_pcm_known_rates.list[i];
535 	return 0;
536 }
537 EXPORT_SYMBOL(snd_pcm_rate_bit_to_rate);
538 
539 static unsigned int snd_pcm_rate_mask_sanitize(unsigned int rates)
540 {
541 	if (rates & SNDRV_PCM_RATE_CONTINUOUS)
542 		return SNDRV_PCM_RATE_CONTINUOUS;
543 	else if (rates & SNDRV_PCM_RATE_KNOT)
544 		return SNDRV_PCM_RATE_KNOT;
545 	return rates;
546 }
547 
548 /**
549  * snd_pcm_rate_mask_intersect - computes the intersection between two rate masks
550  * @rates_a: The first rate mask
551  * @rates_b: The second rate mask
552  *
553  * This function computes the rates that are supported by both rate masks passed
554  * to the function. It will take care of the special handling of
555  * SNDRV_PCM_RATE_CONTINUOUS and SNDRV_PCM_RATE_KNOT.
556  *
557  * Return: A rate mask containing the rates that are supported by both rates_a
558  * and rates_b.
559  */
560 unsigned int snd_pcm_rate_mask_intersect(unsigned int rates_a,
561 	unsigned int rates_b)
562 {
563 	rates_a = snd_pcm_rate_mask_sanitize(rates_a);
564 	rates_b = snd_pcm_rate_mask_sanitize(rates_b);
565 
566 	if (rates_a & SNDRV_PCM_RATE_CONTINUOUS)
567 		return rates_b;
568 	else if (rates_b & SNDRV_PCM_RATE_CONTINUOUS)
569 		return rates_a;
570 	else if (rates_a & SNDRV_PCM_RATE_KNOT)
571 		return rates_b;
572 	else if (rates_b & SNDRV_PCM_RATE_KNOT)
573 		return rates_a;
574 	return rates_a & rates_b;
575 }
576 EXPORT_SYMBOL_GPL(snd_pcm_rate_mask_intersect);
577 
578 /**
579  * snd_pcm_rate_range_to_bits - converts rate range to SNDRV_PCM_RATE_xxx bit
580  * @rate_min: the minimum sample rate
581  * @rate_max: the maximum sample rate
582  *
583  * This function has an implicit assumption: the rates in the given range have
584  * only the pre-defined rates like 44100 or 16000.
585  *
586  * Return: The SNDRV_PCM_RATE_xxx flag that corresponds to the given rate range,
587  * or SNDRV_PCM_RATE_KNOT for an unknown range.
588  */
589 unsigned int snd_pcm_rate_range_to_bits(unsigned int rate_min,
590 	unsigned int rate_max)
591 {
592 	unsigned int rates = 0;
593 	int i;
594 
595 	for (i = 0; i < snd_pcm_known_rates.count; i++) {
596 		if (snd_pcm_known_rates.list[i] >= rate_min
597 			&& snd_pcm_known_rates.list[i] <= rate_max)
598 			rates |= 1 << i;
599 	}
600 
601 	if (!rates)
602 		rates = SNDRV_PCM_RATE_KNOT;
603 
604 	return rates;
605 }
606 EXPORT_SYMBOL_GPL(snd_pcm_rate_range_to_bits);
607