[alsa-devel] [PATCH] ASoC: fsl_sai: Implement set_bclk_ratio

[Nicolin Chen]

On Sat, Aug 31, 2019 at 12:59:10AM +0300, Daniel Baluta wrote:
> From: Viorel Suman <viorel.suman at nxp.com>
> 
> This is to allow machine drivers to set a certain bitclk rate
> which might not be exactly rate * frame size.

Just a quick thought of mine: slot_width and slots could be
set via set_dai_tdm_slot() actually, while set_bclk_ratio()
would override that one with your change. I'm not sure which
one could be more important...so would you mind elaborating
your use case?

Thanks
Nicolin


> 
> Cc: NXP Linux Team <linux-imx at nxp.com>
> Signed-off-by: Viorel Suman <viorel.suman at nxp.com>
> Signed-off-by: Daniel Baluta <daniel.baluta at nxp.com>
> ---
>  sound/soc/fsl/fsl_sai.c | 21 +++++++++++++++++++--
>  sound/soc/fsl/fsl_sai.h |  1 +
>  2 files changed, 20 insertions(+), 2 deletions(-)
> 
> diff --git a/sound/soc/fsl/fsl_sai.c b/sound/soc/fsl/fsl_sai.c
> index fe126029f4e3..e896b577b1f7 100644
> --- a/sound/soc/fsl/fsl_sai.c
> +++ b/sound/soc/fsl/fsl_sai.c
> @@ -137,6 +137,16 @@ static int fsl_sai_set_dai_tdm_slot(struct snd_soc_dai *cpu_dai, u32 tx_mask,
>  	return 0;
>  }
>  
> +static int fsl_sai_set_dai_bclk_ratio(struct snd_soc_dai *dai,
> +				      unsigned int ratio)
> +{
> +	struct fsl_sai *sai = snd_soc_dai_get_drvdata(dai);
> +
> +	sai->bclk_ratio = ratio;
> +
> +	return 0;
> +}
> +
>  static int fsl_sai_set_dai_sysclk_tr(struct snd_soc_dai *cpu_dai,
>  		int clk_id, unsigned int freq, int fsl_dir)
>  {
> @@ -423,8 +433,14 @@ static int fsl_sai_hw_params(struct snd_pcm_substream *substream,
>  		slot_width = sai->slot_width;
>  
>  	if (!sai->is_slave_mode) {
> -		ret = fsl_sai_set_bclk(cpu_dai, tx,
> -				slots * slot_width * params_rate(params));
> +		if (sai->bclk_ratio)
> +			ret = fsl_sai_set_bclk(cpu_dai, tx,
> +					       sai->bclk_ratio *
> +					       params_rate(params));
> +		else
> +			ret = fsl_sai_set_bclk(cpu_dai, tx,
> +					       slots * slot_width *
> +					       params_rate(params));
>  		if (ret)
>  			return ret;
>  
> @@ -640,6 +656,7 @@ static void fsl_sai_shutdown(struct snd_pcm_substream *substream,
>  }
>  
>  static const struct snd_soc_dai_ops fsl_sai_pcm_dai_ops = {
> +	.set_bclk_ratio	= fsl_sai_set_dai_bclk_ratio,
>  	.set_sysclk	= fsl_sai_set_dai_sysclk,
>  	.set_fmt	= fsl_sai_set_dai_fmt,
>  	.set_tdm_slot	= fsl_sai_set_dai_tdm_slot,
> diff --git a/sound/soc/fsl/fsl_sai.h b/sound/soc/fsl/fsl_sai.h
> index 3a3f6f8e5595..f96f8d97489d 100644
> --- a/sound/soc/fsl/fsl_sai.h
> +++ b/sound/soc/fsl/fsl_sai.h
> @@ -177,6 +177,7 @@ struct fsl_sai {
>  	unsigned int mclk_streams;
>  	unsigned int slots;
>  	unsigned int slot_width;
> +	unsigned int bclk_ratio;
>  
>  	const struct fsl_sai_soc_data *soc_data;
>  	struct snd_dmaengine_dai_dma_data dma_params_rx;
> -- 
> 2.17.1
>