[alsa-devel] [PATCH 1/4] ASoC: sgtl5000: give it a ramping time before writting
shawn.guo at linaro.org
Mon Jul 1 10:16:08 CEST 2013
Since commit af8ee11 (ASoC: sgtl5000: Fix driver probe after reset),
it's very ofen to run into the following probe error on imx28. It is
caused by the regmap_write() failure in sgtl5000_fill_defaults().
However, the regmap_read() before this has already been working. It
seems that sgtl5000 takes a longer ramping time to get the registers
ready for write than read.
[ 1.991579] sgtl5000 0-000a: sgtl5000 revision 0x11
[ 2.021655] mxs-sgtl5000 sound.12: ASoC: CODEC (null) not registered
[ 2.039087] mxs-sgtl5000 sound.12: snd_soc_register_card failed (-517)
[ 2.046299] platform sound.12: Driver mxs-sgtl5000 requests probe deferral
Fix the regression by giving it a ramping time before the first write.
Signed-off-by: Shawn Guo <shawn.guo at linaro.org>
sound/soc/codecs/sgtl5000.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/sound/soc/codecs/sgtl5000.c b/sound/soc/codecs/sgtl5000.c
index d441559..20bca03 100644
@@ -1552,6 +1552,13 @@ static int sgtl5000_i2c_probe(struct i2c_client *client,
+ * It seems that sgtl5000 takes a longer time to get the registers
+ * ready for write than bread. Let's give it a ramping time before
+ * the first write goes.
/* Ensure sgtl5000 will start with sane register values */
ret = sgtl5000_fill_defaults(sgtl5000);
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