[alsa-devel] [PATCH] ASoC: wm8994: Lower AIFnCLK divisor when dropping to 32kHz

[Mark Brown]

When lowering SYSCLK to 50kHz for accessory detection also lower the
AIFnCLK divisor to normalise the clocking configuration within the
device. This will not disrupt audio as we cannot support active audio
with such a low SYSCLK.

Signed-off-by: Mark Brown <broonie at opensource.wolfsonmicro.com>
---
 sound/soc/codecs/wm8994.c |   12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/sound/soc/codecs/wm8994.c b/sound/soc/codecs/wm8994.c
index 0932d7a..c16a9a3 100644
--- a/sound/soc/codecs/wm8994.c
+++ b/sound/soc/codecs/wm8994.c
@@ -2443,6 +2443,18 @@ static int wm8994_set_dai_sysclk(struct snd_soc_dai *dai,
 
 	configure_clock(codec);
 
+	/*
+	 * If SYSCLK will be less than 50kHz adjust AIFnCLK dividers
+	 * for detection.
+	 */
+	if (max(wm8994->aifclk[0], wm8994->aifclk[1]) < 50000) {
+		dev_dbg(codec->dev, "Configuring AIFs for 128fs\n");
+		snd_soc_update_bits(codec, WM8994_AIF1_RATE,
+				    WM8994_AIF1CLK_RATE_MASK, 0x1);
+		snd_soc_update_bits(codec, WM8994_AIF2_RATE,
+				    WM8994_AIF2CLK_RATE_MASK, 0x1);
+	}
+
 	return 0;
 }
 
-- 
1.7.10.4