[ 3.5.y.z extended stable ] Patch "ASoC: mc13783: add spi errata fix" has been added to staging queue

[Luis Henriques]

This is a note to let you know that I have just added a patch titled

    ASoC: mc13783: add spi errata fix

to the linux-3.5.y-queue branch of the 3.5.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.5.y-queue

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.5.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From 36d339d53cca09475b6a2df6fb9895a40d83d40a Mon Sep 17 00:00:00 2001
From: Steffen Trumtrar <s.trumtrar at pengutronix.de>
Date: Mon, 9 Sep 2013 18:09:12 +0200
Subject: [PATCH] ASoC: mc13783: add spi errata fix

commit 9f6f0afbb9fdabf6dcac642dfec457f28981e3f8 upstream.

The MC13783 Chip Errata, Rev. 4 says, that depending on SPI clock
and main audio clock speed, the Audio Codec or Stereo DAC do sometimes
not start when programmed to do so. This is due to an internal clock
timing issue related to the loading of the SPI bits into the audio block.

On an i.MX27 based system, this issue lead to switched audio channels under
certain circumstances: RTC + Touch + Audio are used and loaded at startup.

The mentioned workaround of writing registers 40 and 41 two times is implemented
here.

Signed-off-by: Steffen Trumtrar <s.trumtrar at pengutronix.de>
Signed-off-by: Mark Brown <broonie at linaro.org>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 sound/soc/codecs/mc13783.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/sound/soc/codecs/mc13783.c b/sound/soc/codecs/mc13783.c
index 6276e35..3086194 100644
--- a/sound/soc/codecs/mc13783.c
+++ b/sound/soc/codecs/mc13783.c
@@ -126,6 +126,10 @@ static int mc13783_write(struct snd_soc_codec *codec,

 	ret = mc13xxx_reg_write(priv->mc13xxx, reg, value);

+	/* include errata fix for spi audio problems */
+	if (reg == MC13783_AUDIO_CODEC || reg == MC13783_AUDIO_DAC)
+		ret = mc13xxx_reg_write(priv->mc13xxx, reg, value);
+
 	mc13xxx_unlock(priv->mc13xxx);

 	return ret;
--
1.8.3.2