[PATCH 9/9] ASoC: apple: mca: Add delay after configuring clock

[James Calligeros]

From: Hector Martin <marcan@xxxxxxxxx>

Right after the early FE setup, ADMAC gets told to start the DMA. This
can end up in a weird "slip" state with the channels transposed. Waiting
a bit fixes this; presumably this allows the clock to stabilize.

Signed-off-by: Hector Martin <marcan@xxxxxxxxx>
Signed-off-by: James Calligeros <jcalligeros99@xxxxxxxxx>
---
 sound/soc/apple/mca.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/sound/soc/apple/mca.c b/sound/soc/apple/mca.c
index 25d04b3d8a57a8551f2ac1c0cd2dbf2997d907e8..1c664c204504174df1d0af3cafbe25235c678687 100644
--- a/sound/soc/apple/mca.c
+++ b/sound/soc/apple/mca.c
@@ -231,6 +231,12 @@ static void mca_fe_early_trigger(struct snd_pcm_substream *substream, int cmd,
 			   FIELD_PREP(SERDES_CONF_SYNC_SEL, 0));
 		mca_modify(cl, serdes_conf, SERDES_CONF_SYNC_SEL,
 			   FIELD_PREP(SERDES_CONF_SYNC_SEL, cl->no + 1));
+		/*
+		 * ADMAC gets started right after this. This delay seems
+		 * to be needed for that to be reliable, e.g. ensure the
+		 * clock is stable?
+		 */
+		udelay(100);
 		break;
 	default:
 		break;

-- 
2.49.0