[PATCH 3.10 13/17] ASoC: sgtl5000: add delay before first I2C access

Greg Kroah-Hartman
2015-02-09T08:34:56Z

From: Eric Nelson <eric.nelson@boundarydevices.com>

commit 58cc9c9a175885bbf6bae3acf18233d0a8229a84 upstream.

To quote from section 1.3.1 of the data sheet:
The SGTL5000 has an internal reset that is deasserted
8 SYS_MCLK cycles after all power rails have been brought
up. After this time, communication can start

...
1.0us represents 8 SYS_MCLK cycles at the minimum 8.0 MHz SYS_MCLK.

Signed-off-by: Eric Nelson <eric.nelson@boundarydevices.com>
Reviewed-by: Fabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
sound/soc/codecs/sgtl5000.c | 3 +++
1 file changed, 3 insertions(+)

--- a/sound/soc/codecs/sgtl5000.c
+++ b/sound/soc/codecs/sgtl5000.c
@@ -1242,6 +1242,9 @@ static int sgtl5000_enable_regulators(st
/* wait for all power rails bring up */
udelay(10);

+ /* Need 8 clocks before I2C accesses */
+ udelay(1);
+
/* read chip information */
reg = snd_soc_read(codec, SGTL5000_CHIP_ID);
if (((reg & SGTL5000_PARTID_MASK) >> SGTL5000_PARTID_SHIFT) !=