[alsa-devel] [PATCH 3/5] ASoC: codecs: ad193x: Fix frame polarity for DSP_A format

[Codrin.Ciubotariu at microchip.com]

From: Codrin Ciubotariu <codrin.ciubotariu at microchip.com>

By default, the codec starts to interpret the left (first) channel on
the falling edge (low polarity) of LRCLK. However, for DSP_A, the left
channel needs to start on the rising edge of LRCLK. This patch fixes
this channel swap by toggling the bit which selects the LRCLK polarity.

Signed-off-by: Codrin Ciubotariu <codrin.ciubotariu at microchip.com>
---
 sound/soc/codecs/ad193x.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/sound/soc/codecs/ad193x.c b/sound/soc/codecs/ad193x.c
index c16c9969d1a0..315ec9775118 100644
--- a/sound/soc/codecs/ad193x.c
+++ b/sound/soc/codecs/ad193x.c
@@ -228,6 +228,12 @@ static int ad193x_set_dai_fmt(struct snd_soc_dai *codec_dai,
 		return -EINVAL;
 	}
 
+	/* For DSP_*, LRCLK's polarity must be inverted */
+	if (fmt & SND_SOC_DAIFMT_DSP_A) {
+		change_bit(ffs(AD193X_DAC_LEFT_HIGH) - 1,
+			   (unsigned long *)&dac_fmt);
+	}
+
 	switch (fmt & SND_SOC_DAIFMT_MASTER_MASK) {
 	case SND_SOC_DAIFMT_CBM_CFM: /* codec clk & frm master */
 		adc_fmt |= AD193X_ADC_LCR_MASTER;
-- 
2.17.1