Re: [PATCH v4 8/9] ASoc: sun4i-i2s: Add 20, 24 and 32 bit support

From: Maxime Ripard
Date: Tue Jun 04 2019 - 04:23:39 EST


On Mon, Jun 03, 2019 at 07:47:34PM +0200, 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 | 34 +++++++++++++++++++++++++++++++---
> 1 file changed, 31 insertions(+), 3 deletions(-)
>
> diff --git a/sound/soc/sunxi/sun4i-i2s.c b/sound/soc/sunxi/sun4i-i2s.c
> index 3549a87ed9e9..351b8021173b 100644
> --- a/sound/soc/sunxi/sun4i-i2s.c
> +++ b/sound/soc/sunxi/sun4i-i2s.c
> @@ -428,6 +428,11 @@ 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;

Doesn't this test the physical width? If so, then I'm not sure that 20
even exists, and that we can support 24.

> default:
> dev_err(dai->dev, "Unsupported physical sample width: %d\n",
> params_physical_width(params));
> @@ -440,7 +445,18 @@ 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;

This doesn't really works, wss being the slot size, and you can have a
different slot size and sample size. I have a patch that reworks this,
I'll send it.

Maxime

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

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