[alsa-devel] [PATCH] ALSA: Add snd_pcm_rate_bit_to_rate()

[Takashi Iwai]

At Fri, 15 Jun 2012 16:35:28 +0100,
Dimitris Papastamos wrote:
> 
> This is essentially the reverse of snd_pcm_rate_to_rate_bit().
> 
> This is generally useful as the Compress API uses the rate bit
> directly and it helps to be able to map back to the actual sample
> rate.
> 
> Signed-off-by: Dimitris Papastamos <dp at opensource.wolfsonmicro.com>

Applied to topic/misc branch of sound git tree.
If this change is necessary, simply pull that branch.


thanks,

Takashi

> ---
>  include/sound/pcm.h   |    1 +
>  sound/core/pcm_misc.c |   18 ++++++++++++++++++
>  2 files changed, 19 insertions(+)
> 
> diff --git a/include/sound/pcm.h b/include/sound/pcm.h
> index 1d58d79..18ad1f1 100644
> --- a/include/sound/pcm.h
> +++ b/include/sound/pcm.h
> @@ -892,6 +892,7 @@ extern const struct snd_pcm_hw_constraint_list snd_pcm_known_rates;
>  
>  int snd_pcm_limit_hw_rates(struct snd_pcm_runtime *runtime);
>  unsigned int snd_pcm_rate_to_rate_bit(unsigned int rate);
> +unsigned int snd_pcm_rate_bit_to_rate(unsigned int rate_bit);
>  
>  static inline void snd_pcm_set_runtime_buffer(struct snd_pcm_substream *substream,
>  					      struct snd_dma_buffer *bufp)
> diff --git a/sound/core/pcm_misc.c b/sound/core/pcm_misc.c
> index 9c9eff9..d4fc1bf 100644
> --- a/sound/core/pcm_misc.c
> +++ b/sound/core/pcm_misc.c
> @@ -488,3 +488,21 @@ unsigned int snd_pcm_rate_to_rate_bit(unsigned int rate)
>  	return SNDRV_PCM_RATE_KNOT;
>  }
>  EXPORT_SYMBOL(snd_pcm_rate_to_rate_bit);
> +
> +/**
> + * snd_pcm_rate_bit_to_rate - converts SNDRV_PCM_RATE_xxx bit to sample rate
> + * @rate_bit: the rate bit to convert
> + *
> + * Returns the sample rate that corresponds to the given SNDRV_PCM_RATE_xxx flag
> + * or 0 for an unknown rate bit
> + */
> +unsigned int snd_pcm_rate_bit_to_rate(unsigned int rate_bit)
> +{
> +	unsigned int i;
> +
> +	for (i = 0; i < snd_pcm_known_rates.count; i++)
> +		if ((1u << i) == rate_bit)
> +			return snd_pcm_known_rates.list[i];
> +	return 0;
> +}
> +EXPORT_SYMBOL(snd_pcm_rate_bit_to_rate);
> -- 
> 1.7.10.4
> 
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