From e7b8a6d3efa8316dfe786e9cd559c62e9152337c Mon Sep 17 00:00:00 2001 From: Maxime Ripard Date: Thu, 9 Nov 2017 10:40:46 +0100 Subject: ASoC: sun8i-codec: Add a comment on the LRCK inversion The current code might be a bit intriguing without having experienced the issue before, and might come up as a mistake. Make explicit what's going on by adding a comment. Signed-off-by: Maxime Ripard Signed-off-by: Mark Brown --- sound/soc/sunxi/sun8i-codec.c | 11 +++++++++++ 1 file changed, 11 insertions(+) (limited to 'sound') diff --git a/sound/soc/sunxi/sun8i-codec.c b/sound/soc/sunxi/sun8i-codec.c index c2ceca485d6a..b3329692e3dc 100644 --- a/sound/soc/sunxi/sun8i-codec.c +++ b/sound/soc/sunxi/sun8i-codec.c @@ -197,6 +197,17 @@ static int sun8i_set_fmt(struct snd_soc_dai *dai, unsigned int fmt) regmap_update_bits(scodec->regmap, SUN8I_AIF1CLK_CTRL, BIT(SUN8I_AIF1CLK_CTRL_AIF1_BCLK_INV), value << SUN8I_AIF1CLK_CTRL_AIF1_BCLK_INV); + + /* + * It appears that the DAI and the codec don't share the same + * polarity for the LRCK signal when they mean 'normal' and + * 'inverted' in the datasheet. + * + * Since the DAI here is our regular i2s driver that have been + * tested with way more codecs than just this one, it means + * that the codec probably gets it backward, and we have to + * invert the value here. + */ regmap_update_bits(scodec->regmap, SUN8I_AIF1CLK_CTRL, BIT(SUN8I_AIF1CLK_CTRL_AIF1_LRCK_INV), !value << SUN8I_AIF1CLK_CTRL_AIF1_LRCK_INV); -- cgit