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ALSA: pcm: Add snd_pcm_rate_range_to_bits() 

This helper function can convert a given sample rate range to
SNDRV_PCM_RATE_xxx bits.

Signed-off-by: Mengdong Lin <mengdong.lin@linux.intel.com>
Acked-by: Takashi Iwai <tiwai@suse.de>
Acked-by: Liam Girdwood <liam.r.girdwood@linux.intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
This commit is contained in:
Mengdong Lin 2016-01-15 16:13:10 +08:00 committed by Mark Brown
parent 92e963f50f
commit 3bdff244a2
2 changed files with 32 additions and 0 deletions
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2
include/sound/pcm.h
View File

@ -1093,6 +1093,8 @@ unsigned int snd_pcm_rate_to_rate_bit(unsigned int rate);
unsigned int snd_pcm_rate_bit_to_rate(unsigned int rate_bit);
unsigned int snd_pcm_rate_mask_intersect(unsigned int rates_a,
unsigned int rates_b);
unsigned int snd_pcm_rate_range_to_bits(unsigned int rate_min,
unsigned int rate_max);
/**
* snd_pcm_set_runtime_buffer - Set the PCM runtime buffer

30
sound/core/pcm_misc.c
View File

@ -565,3 +565,33 @@ unsigned int snd_pcm_rate_mask_intersect(unsigned int rates_a,
return rates_a & rates_b;
}
EXPORT_SYMBOL_GPL(snd_pcm_rate_mask_intersect);
/**
* snd_pcm_rate_range_to_bits - converts rate range to SNDRV_PCM_RATE_xxx bit
* @rate_min: the minimum sample rate
* @rate_max: the maximum sample rate
*
* This function has an implicit assumption: the rates in the given range have
* only the pre-defined rates like 44100 or 16000.
*
* Return: The SNDRV_PCM_RATE_xxx flag that corresponds to the given rate range,
* or SNDRV_PCM_RATE_KNOT for an unknown range.
*/
unsigned int snd_pcm_rate_range_to_bits(unsigned int rate_min,
unsigned int rate_max)
{
unsigned int rates = 0;
int i;
for (i = 0; i < snd_pcm_known_rates.count; i++) {
if (snd_pcm_known_rates.list[i] >= rate_min
&& snd_pcm_known_rates.list[i] <= rate_max)
rates |= 1 << i;
}
if (!rates)
rates = SNDRV_PCM_RATE_KNOT;
return rates;
}
EXPORT_SYMBOL_GPL(snd_pcm_rate_range_to_bits);