[alsa-devel] [PATCH v5 02/15] ASoC: sun4i-i2s: Add set_tdm_slot functionality

[Maxime Ripard]

Hi,

On Wed, Aug 14, 2019 at 08:08:41AM +0200, codekipper at gmail.com wrote:
> From: Marcus Cooper <codekipper at gmail.com>
>
> Codecs without a control connection such as i2s based HDMI audio and
> the Pine64 DAC require a different amount of bit clocks per frame than
> what is calculated by the sample width. Use the tdm slot bindings to
> provide this mechanism.
>
> Signed-off-by: Marcus Cooper <codekipper at gmail.com>
> ---
>  sound/soc/sunxi/sun4i-i2s.c | 23 +++++++++++++++++++++--
>  1 file changed, 21 insertions(+), 2 deletions(-)
>
> diff --git a/sound/soc/sunxi/sun4i-i2s.c b/sound/soc/sunxi/sun4i-i2s.c
> index 8201334a059b..7c37b6291df0 100644
> --- a/sound/soc/sunxi/sun4i-i2s.c
> +++ b/sound/soc/sunxi/sun4i-i2s.c
> @@ -195,6 +195,9 @@ struct sun4i_i2s {
>  	struct regmap_field	*field_rxchansel;
>
>  	const struct sun4i_i2s_quirks	*variant;
> +
> +	unsigned int	tdm_slots;
> +	unsigned int	slot_width;
>  };
>
>  struct sun4i_i2s_clk_div {
> @@ -346,7 +349,7 @@ static int sun4i_i2s_set_clk_rate(struct snd_soc_dai *dai,
>  	if (i2s->variant->has_fmt_set_lrck_period)
>  		regmap_update_bits(i2s->regmap, SUN4I_I2S_FMT0_REG,
>  				   SUN8I_I2S_FMT0_LRCK_PERIOD_MASK,
> -				   SUN8I_I2S_FMT0_LRCK_PERIOD(32));
> +				   SUN8I_I2S_FMT0_LRCK_PERIOD(word_size));
>
>
>  	/* Set sign extension to pad out LSB with 0 */
>  	regmap_field_write(i2s->field_fmt_sext, 0);
> @@ -450,7 +453,8 @@ static int sun4i_i2s_hw_params(struct snd_pcm_substream *substream,
>  	regmap_field_write(i2s->field_fmt_sr, sr);
>
>  	return sun4i_i2s_set_clk_rate(dai, params_rate(params),
> -				      params_width(params));
> +				      i2s->tdm_slots ?
> +				      i2s->slot_width : params_width(params));

This is slightly more complicated than that.

On the H3 (and all related ones), the CHAN_CFG_TX_SLOT_NUM and
_RX_SLOT_NUM fields in the CHAN_CFG register need to be set to the
number of slots as well.

Maxime

--
Maxime Ripard, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com
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