ASoC: meson: aiu-encoder-i2s: fix bit clock polarity

[PATCH] ASoC: meson: aiu-encoder-i2s: fix bit clock polarity

Posted by Valerio Setti via B4 Relay 6 days, 23 hours ago

From: Valerio Setti <vsetti@baylibre.com>

According to I2S specs audio data is sampled on the rising edge of the
clock and it can change on the falling one. When operating in normal mode
this SoC behaves the opposite so a clock polarity inversion is required
in this case.

This was tested on an OdroidC2 (Amlogic S905 SoC) board.

Signed-off-by: Valerio Setti <vsetti@baylibre.com>
---
 sound/soc/meson/aiu-encoder-i2s.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/sound/soc/meson/aiu-encoder-i2s.c b/sound/soc/meson/aiu-encoder-i2s.c
index a0dd914c8ed13616fbcbc0828e36418cfd255391..3b4061508c18047fe8d6f3f98061720f8ce238f2 100644
--- a/sound/soc/meson/aiu-encoder-i2s.c
+++ b/sound/soc/meson/aiu-encoder-i2s.c
@@ -236,8 +236,12 @@ static int aiu_encoder_i2s_set_fmt(struct snd_soc_dai *dai, unsigned int fmt)
 	    inv == SND_SOC_DAIFMT_IB_IF)
 		val |= AIU_CLK_CTRL_LRCLK_INVERT;
 
-	if (inv == SND_SOC_DAIFMT_IB_NF ||
-	    inv == SND_SOC_DAIFMT_IB_IF)
+	/*
+	 * The SoC changes data on the rising edge of the bitclock
+	 * so an inversion of the bitclock is required in normal mode
+	 */
+	if (inv == SND_SOC_DAIFMT_NB_NF ||
+	    inv == SND_SOC_DAIFMT_NB_IF)
 		val |= AIU_CLK_CTRL_AOCLK_INVERT;
 
 	/* Signal skew */
@@ -328,4 +332,3 @@ const struct snd_soc_dai_ops aiu_encoder_i2s_dai_ops = {
 	.startup	= aiu_encoder_i2s_startup,
 	.shutdown	= aiu_encoder_i2s_shutdown,
 };
-

---
base-commit: 8f5ae30d69d7543eee0d70083daf4de8fe15d585
change-id: 20251006-fix-i2s-polarity-d744338fa223

Best regards,
-- 
Valerio Setti <vsetti@baylibre.com>

Re: [PATCH] ASoC: meson: aiu-encoder-i2s: fix bit clock polarity

Posted by Mark Brown 6 days, 4 hours ago

On Tue, 07 Oct 2025 00:12:19 +0200, Valerio Setti wrote:
> According to I2S specs audio data is sampled on the rising edge of the
> clock and it can change on the falling one. When operating in normal mode
> this SoC behaves the opposite so a clock polarity inversion is required
> in this case.
> 
> This was tested on an OdroidC2 (Amlogic S905 SoC) board.
> 
> [...]

Applied to

   https://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound.git for-next

Thanks!

[1/1] ASoC: meson: aiu-encoder-i2s: fix bit clock polarity
      commit: 4c4ed5e073a923fb3323022e1131cb51ad8df7a0

All being well this means that it will be integrated into the linux-next
tree (usually sometime in the next 24 hours) and sent to Linus during
the next merge window (or sooner if it is a bug fix), however if
problems are discovered then the patch may be dropped or reverted.

You may get further e-mails resulting from automated or manual testing
and review of the tree, please engage with people reporting problems and
send followup patches addressing any issues that are reported if needed.

If any updates are required or you are submitting further changes they
should be sent as incremental updates against current git, existing
patches will not be replaced.

Please add any relevant lists and maintainers to the CCs when replying
to this mail.

Thanks,
Mark

Re: [PATCH] ASoC: meson: aiu-encoder-i2s: fix bit clock polarity

Posted by Jerome Brunet 6 days, 12 hours ago

On Tue 07 Oct 2025 at 00:12, Valerio Setti via B4 Relay <devnull+vsetti.baylibre.com@kernel.org> wrote:

> From: Valerio Setti <vsetti@baylibre.com>
>
> According to I2S specs audio data is sampled on the rising edge of the
> clock and it can change on the falling one. When operating in normal mode
> this SoC behaves the opposite so a clock polarity inversion is required
> in this case.
>
> This was tested on an OdroidC2 (Amlogic S905 SoC) board.
>
> Signed-off-by: Valerio Setti <vsetti@baylibre.com>

Reviewed-by: Jerome Brunet <jbrunet@baylibre.com>

Tested on the libretech cc s905x (GXL)

Tested-by: Jerome Brunet <jbrunet@baylibre.com>

> ---
>  sound/soc/meson/aiu-encoder-i2s.c | 9 ++++++---
>  1 file changed, 6 insertions(+), 3 deletions(-)
>
> diff --git a/sound/soc/meson/aiu-encoder-i2s.c b/sound/soc/meson/aiu-encoder-i2s.c
> index a0dd914c8ed13616fbcbc0828e36418cfd255391..3b4061508c18047fe8d6f3f98061720f8ce238f2 100644
> --- a/sound/soc/meson/aiu-encoder-i2s.c
> +++ b/sound/soc/meson/aiu-encoder-i2s.c
> @@ -236,8 +236,12 @@ static int aiu_encoder_i2s_set_fmt(struct snd_soc_dai *dai, unsigned int fmt)
>  	    inv == SND_SOC_DAIFMT_IB_IF)
>  		val |= AIU_CLK_CTRL_LRCLK_INVERT;
>  
> -	if (inv == SND_SOC_DAIFMT_IB_NF ||
> -	    inv == SND_SOC_DAIFMT_IB_IF)
> +	/*
> +	 * The SoC changes data on the rising edge of the bitclock
> +	 * so an inversion of the bitclock is required in normal mode
> +	 */
> +	if (inv == SND_SOC_DAIFMT_NB_NF ||
> +	    inv == SND_SOC_DAIFMT_NB_IF)
>  		val |= AIU_CLK_CTRL_AOCLK_INVERT;
>  
>  	/* Signal skew */
> @@ -328,4 +332,3 @@ const struct snd_soc_dai_ops aiu_encoder_i2s_dai_ops = {
>  	.startup	= aiu_encoder_i2s_startup,
>  	.shutdown	= aiu_encoder_i2s_shutdown,
>  };
> -
>
> ---
> base-commit: 8f5ae30d69d7543eee0d70083daf4de8fe15d585
> change-id: 20251006-fix-i2s-polarity-d744338fa223
>
> Best regards,

-- 
Jerome