[alsa-devel] [PATCH] ASoC: max98090: support 20-bit and 24-bit audio format

[Pierre-Louis Bossart]

On 1/28/19 3:15 AM, Tzung-Bi Shih wrote:
>  From datasheet of max98090:
> If RJ = 1,
>    WS = 00, 16 bits
>    WS = 01, 20 bits
>    WS = 10, 24 bits

Yes, but there is a if (Right Justified)

DAI Input Data Word Size (TDM = 0)

If RJ = 1: 00: 16 bits 01: 20 bits 10: 24 bits 11: Reserved

If RJ = 0: 00: 16 bits 01, 10, 11: 20 bits

You can't arbitrarily set the RJ bit without having the SOC know about 
it - this should be conditional on the DAI format already used elsewhere:

case SND_SOC_DAIFMT_RIGHT_J:
             regval |= M98090_RJ_MASK;
             break;

I also vaguely recall there were limitations on capture with an odd 
format being used?

>
> Signed-off-by: Tzung-Bi Shih <tzungbi at google.com>
> ---
>   sound/soc/codecs/max98090.c | 16 +++++++++++++++-
>   sound/soc/codecs/max98090.h |  3 +++
>   2 files changed, 18 insertions(+), 1 deletion(-)
>
> diff --git a/sound/soc/codecs/max98090.c b/sound/soc/codecs/max98090.c
> index c97f21836c66..0ecc2f1accb5 100644
> --- a/sound/soc/codecs/max98090.c
> +++ b/sound/soc/codecs/max98090.c
> @@ -1942,7 +1942,21 @@ static int max98090_dai_hw_params(struct snd_pcm_substream *substream,
>   	switch (params_width(params)) {
>   	case 16:
>   		snd_soc_component_update_bits(component, M98090_REG_INTERFACE_FORMAT,
> -			M98090_WS_MASK, 0);
> +			M98090_RJ_MASK, M98090_RJ_MASK);
> +		snd_soc_component_update_bits(component, M98090_REG_INTERFACE_FORMAT,
> +			M98090_WS_MASK, M98090_FORMAT_S16_LE);
> +		break;
> +	case 20:
> +		snd_soc_component_update_bits(component, M98090_REG_INTERFACE_FORMAT,
> +			M98090_RJ_MASK, M98090_RJ_MASK);
> +		snd_soc_component_update_bits(component, M98090_REG_INTERFACE_FORMAT,
> +			M98090_WS_MASK, M98090_FORMAT_S20_LE;
> +		break;
> +	case 24:
> +		snd_soc_component_update_bits(component, M98090_REG_INTERFACE_FORMAT,
> +			M98090_RJ_MASK, M98090_RJ_MASK);
> +		snd_soc_component_update_bits(component, M98090_REG_INTERFACE_FORMAT,
> +			M98090_WS_MASK, M98090_FORMAT_S24_LE);
>   		break;
>   	default:
>   		return -EINVAL;
> diff --git a/sound/soc/codecs/max98090.h b/sound/soc/codecs/max98090.h
> index b1572a2d19da..9088f9d64ff2 100644
> --- a/sound/soc/codecs/max98090.h
> +++ b/sound/soc/codecs/max98090.h
> @@ -706,6 +706,9 @@
>   #define M98090_WS_SHIFT			0
>   #define M98090_WS_WIDTH			2
>   #define M98090_WS_NUM			(1<<M98090_WS_WIDTH)
> +#define M98090_FORMAT_S16_LE		(0<<0)
> +#define M98090_FORMAT_S20_LE		(1<<0)
> +#define M98090_FORMAT_S24_LE		(2<<0)
>   
>   /*
>    * M98090_REG_TDM_CONTROL