Re: [PATCH v3 3/9] ASoc: sun4i-i2s: Add 20, 24 and 32 bit support

[Chen-Yu Tsai]

On Fri, Dec 21, 2018 at 11:21 PM <codekipper@xxxxxxxxx> wrote:
>
> From: Marcus Cooper <codekipper@xxxxxxxxx>
>
> Extend the functionality of the driver to include support of 20 and
> 24 bits per sample for the earlier SoCs.
>
> Newer SoCs can also handle 32bit samples.
>
> Signed-off-by: Marcus Cooper <codekipper@xxxxxxxxx>
> ---
>  sound/soc/sunxi/sun4i-i2s.c | 41 ++++++++++++++++++++++++++++++++++---
>  1 file changed, 38 insertions(+), 3 deletions(-)
>
> diff --git a/sound/soc/sunxi/sun4i-i2s.c b/sound/soc/sunxi/sun4i-i2s.c
> index 80bf29e0cc86..adb988ae9ac5 100644
> --- a/sound/soc/sunxi/sun4i-i2s.c
> +++ b/sound/soc/sunxi/sun4i-i2s.c
> @@ -399,6 +399,11 @@ static int sun4i_i2s_hw_params(struct snd_pcm_substream *substream,
>         case 16:
>                 width = DMA_SLAVE_BUSWIDTH_2_BYTES;
>                 break;
> +       case 20:
> +       case 24:
> +       case 32:
> +               width = DMA_SLAVE_BUSWIDTH_4_BYTES;
> +               break;
>         default:
>                 dev_err(dai->dev, "Unsupported physical sample width: %d\n",
>                         params_physical_width(params));
> @@ -411,7 +416,18 @@ static int sun4i_i2s_hw_params(struct snd_pcm_substream *substream,
>                 sr = 0;
>                 wss = 0;
>                 break;
> -
> +       case 20:
> +               sr = 1;
> +               wss = 1;
> +               break;
> +       case 24:
> +               sr = 2;
> +               wss = 2;
> +               break;
> +       case 32:
> +               sr = 4;
> +               wss = 4;
> +               break;
>         default:
>                 dev_err(dai->dev, "Unsupported sample width: %d\n",
>                         params_width(params));
> @@ -687,6 +703,13 @@ static int sun4i_i2s_dai_probe(struct snd_soc_dai *dai)
>         return 0;
>  }
>
> +#define SUN4I_FORMATS  (SNDRV_PCM_FMTBIT_S16_LE | \
> +                        SNDRV_PCM_FMTBIT_S20_3LE | \
> +                        SNDRV_PCM_FMTBIT_S24_LE)

IIRC SNDRV_PCM_FMTBIT_S24_LE and SNDRV_PCM_FMTBIT_S32_LE with .sig_bits = 24
are different things, in regards to how the sample is aligned in a 4 byte
space. Have you checked that things actually work as expected? This was
something that did not work using SNDRV_PCM_FMTBIT_S24_LE on sun4i-codec.

> +
> +#define SUN8I_FORMATS  (SUN4I_FORMATS | \
> +                        SNDRV_PCM_FMTBIT_S32_LE)
> +
>  static struct snd_soc_dai_driver sun4i_i2s_dai = {
>         .probe = sun4i_i2s_dai_probe,
>         .capture = {
> @@ -694,14 +717,14 @@ static struct snd_soc_dai_driver sun4i_i2s_dai = {
>                 .channels_min = 2,
>                 .channels_max = 2,
>                 .rates = SNDRV_PCM_RATE_8000_192000,
> -               .formats = SNDRV_PCM_FMTBIT_S16_LE,
> +               .formats = SUN4I_FORMATS,
>         },
>         .playback = {
>                 .stream_name = "Playback",
>                 .channels_min = 2,
>                 .channels_max = 2,
>                 .rates = SNDRV_PCM_RATE_8000_192000,
> -               .formats = SNDRV_PCM_FMTBIT_S16_LE,
> +               .formats = SUN4I_FORMATS,
>         },
>         .ops = &sun4i_i2s_dai_ops,
>         .symmetric_rates = 1,
> @@ -1106,6 +1129,18 @@ static int sun4i_i2s_probe(struct platform_device *pdev)
>         i2s->capture_dma_data.addr = res->start + SUN4I_I2S_FIFO_RX_REG;
>         i2s->capture_dma_data.maxburst = 8;
>
> +       soc_dai = devm_kmemdup(&pdev->dev, &sun4i_i2s_dai,
> +                              sizeof(*soc_dai), GFP_KERNEL);
> +       if (!soc_dai) {
> +               ret = -ENOMEM;
> +               goto err_pm_disable;
> +       }
> +
> +       if (i2s->variant->has_fmt_set_lrck_period) {

This condition deserves a comment, particularly as to why you use it
in place of having a separate quirk field to represent 32 bit support.

Regards
ChenYu

> +               soc_dai->playback.formats = SUN8I_FORMATS;
> +               soc_dai->capture.formats = SUN8I_FORMATS;
> +       }
> +
>         pm_runtime_enable(&pdev->dev);
>         if (!pm_runtime_enabled(&pdev->dev)) {
>                 ret = sun4i_i2s_runtime_resume(&pdev->dev);
> --
> 2.20.1
>