linux-kernel - Re: [PATCH v2 02/20] ASoC: sun4i-i2s: Add support for H6 I2S

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Date:   Thu, 3 Sep 2020 22:16:50 -0500
From:   Samuel Holland <samuel@...lland.org>
To:     Clément Péron <peron.clem@...il.com>,
        Maxime Ripard <mripard@...nel.org>,
        Chen-Yu Tsai <wens@...e.org>, Rob Herring <robh+dt@...nel.org>,
        Mark Brown <broonie@...nel.org>,
        Liam Girdwood <lgirdwood@...il.com>
Cc:     devicetree@...r.kernel.org,
        Jernej Skrabec <jernej.skrabec@...l.net>,
        alsa-devel@...a-project.org, linux-kernel@...r.kernel.org,
        Takashi Iwai <tiwai@...e.com>,
        Marcus Cooper <codekipper@...il.com>,
        linux-sunxi@...glegroups.com, linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH v2 02/20] ASoC: sun4i-i2s: Add support for H6 I2S

Clément,

On 9/3/20 3:30 PM, Clément Péron wrote:
> From: Jernej Skrabec <jernej.skrabec@...l.net>
> 
> H6 I2S is very similar to that in H3, except it supports up to 16
> channels.
> 
> Signed-off-by: Jernej Skrabec <jernej.skrabec@...l.net>
> Signed-off-by: Marcus Cooper <codekipper@...il.com>
> Signed-off-by: Clément Péron <peron.clem@...il.com>
> ---
>  sound/soc/sunxi/sun4i-i2s.c | 221 ++++++++++++++++++++++++++++++++++++
>  1 file changed, 221 insertions(+)
> 
> diff --git a/sound/soc/sunxi/sun4i-i2s.c b/sound/soc/sunxi/sun4i-i2s.c
> index fabff7bcccbc..acf24f512f2c 100644
> --- a/sound/soc/sunxi/sun4i-i2s.c
> +++ b/sound/soc/sunxi/sun4i-i2s.c

[snip]

> @@ -474,6 +489,65 @@ static int sun8i_i2s_set_chan_cfg(const struct sun4i_i2s *i2s,
>  	return 0;
>  }
>  
> +static int sun50i_h6_i2s_set_chan_cfg(const struct sun4i_i2s *i2s,
> +				      const struct snd_pcm_hw_params *params)
> +{
> +	unsigned int channels = params_channels(params);
> +	unsigned int slots = channels;
> +	unsigned int lrck_period;
> +
> +	if (i2s->slots)
> +		slots = i2s->slots;
> +
> +	/* Map the channels for playback and capture */
> +	regmap_write(i2s->regmap, SUN50I_H6_I2S_TX_CHAN_MAP1_REG, 0x76543210);
> +	regmap_write(i2s->regmap, SUN50I_H6_I2S_RX_CHAN_MAP1_REG, 0x76543210);
> +
> +	/* Configure the channels */
> +	regmap_update_bits(i2s->regmap, SUN8I_I2S_TX_CHAN_SEL_REG,
> +			   SUN50I_H6_I2S_TX_CHAN_SEL_MASK,
> +			   SUN50I_H6_I2S_TX_CHAN_SEL(channels));
> +	regmap_update_bits(i2s->regmap, SUN50I_H6_I2S_RX_CHAN_SEL_REG,
> +			   SUN50I_H6_I2S_TX_CHAN_SEL_MASK,
> +			   SUN50I_H6_I2S_TX_CHAN_SEL(channels));
> +
> +	regmap_update_bits(i2s->regmap, SUN8I_I2S_CHAN_CFG_REG,
> +			   SUN8I_I2S_CHAN_CFG_TX_SLOT_NUM_MASK,
> +			   SUN8I_I2S_CHAN_CFG_TX_SLOT_NUM(channels));
> +	regmap_update_bits(i2s->regmap, SUN8I_I2S_CHAN_CFG_REG,
> +			   SUN8I_I2S_CHAN_CFG_RX_SLOT_NUM_MASK,
> +			   SUN8I_I2S_CHAN_CFG_RX_SLOT_NUM(channels));
> +
> +	switch (i2s->format & SND_SOC_DAIFMT_FORMAT_MASK) {
> +	case SND_SOC_DAIFMT_DSP_A:
> +	case SND_SOC_DAIFMT_DSP_B:
> +	case SND_SOC_DAIFMT_LEFT_J:
> +	case SND_SOC_DAIFMT_RIGHT_J:

These cases don't match the documentation: LEFT_J and RIGHT_J are documented to
behave like I2S (lrck_period == slot_width), not like DSP_A/B (lrck_period ==
slot_width * slots).

> +		lrck_period = params_physical_width(params) * slots;
> +		break;
> +
> +	case SND_SOC_DAIFMT_I2S:
> +		lrck_period = params_physical_width(params);
> +		break;
> +
> +	default:
> +		return -EINVAL;
> +	}
> +
> +	if (i2s->slot_width)
> +		lrck_period = i2s->slot_width;

Here, i2s->slot_width is the number of bits for each slot, but in PCM mode, you
need to multiply by the number of slots, like above.

Also, there is already logic in sun4i_i2s_hw_params to use i2s->slot_width and
i2s->slots. You could avoid the duplication by passing slot_width/slots as
parameters to set_chan_cfg.

Regards,
Samuel

> +
> +	regmap_update_bits(i2s->regmap, SUN4I_I2S_FMT0_REG,
> +			   SUN8I_I2S_FMT0_LRCK_PERIOD_MASK,
> +			   SUN8I_I2S_FMT0_LRCK_PERIOD(lrck_period));
> +
> +	regmap_update_bits(i2s->regmap, SUN8I_I2S_TX_CHAN_SEL_REG,
> +			   SUN50I_H6_I2S_TX_CHAN_EN_MASK,
> +			   SUN50I_H6_I2S_TX_CHAN_EN(channels));
> +
> +	return 0;
> +}
> +
>  static int sun4i_i2s_hw_params(struct snd_pcm_substream *substream,
>  			       struct snd_pcm_hw_params *params,
>  			       struct snd_soc_dai *dai)

[snip]