[PATCH] codecs: mc13783: add spi errate fix

[PATCH] codecs: mc13783: add spi errate fix

[Steffen Trumtrar]

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@pengutronix.de>
Cc: stable@vger.kernel.org
---
 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 4d3c8fd..e78353d 100644
--- a/sound/soc/codecs/mc13783.c
+++ b/sound/soc/codecs/mc13783.c
@@ -125,6 +125,10 @@ 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 == PMIC_AUDIO_CODEC || reg == PMIC_AUDIO_DAC)
+		ret = mc13xxx_reg_write(priv->mc13xxx, reg, value);
+
 	mc13xxx_unlock(priv->mc13xxx);
 
 	return ret;
-- 
1.8.4.rc3

Re: [PATCH] codecs: mc13783: add spi errate fix

[Mark Brown]

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On Mon, Sep 09, 2013 at 04:12:36PM +0200, Steffen Trumtrar wrote:
> 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.

Applied, thanks.

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Re: [PATCH] codecs: mc13783: add spi errate fix

[Mark Brown]

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On Mon, Sep 09, 2013 at 03:57:30PM +0100, Mark Brown wrote:
> On Mon, Sep 09, 2013 at 04:12:36PM +0200, Steffen Trumtrar wrote:
> > 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.
> 
> Applied, thanks.

...and reverted since PMIC_AUDIO_CODEC isn't defined.  Please fix and
resend.

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Re: [PATCH] codecs: mc13783: add spi errate fix

[Steffen Trumtrar]

On Mon, Sep 09, 2013 at 04:33:28PM +0100, Mark Brown wrote:
> On Mon, Sep 09, 2013 at 03:57:30PM +0100, Mark Brown wrote:
> > On Mon, Sep 09, 2013 at 04:12:36PM +0200, Steffen Trumtrar wrote:
> > > 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.
> > 
> > Applied, thanks.
> 
> ...and reverted since PMIC_AUDIO_CODEC isn't defined.  Please fix and
> resend.

Ah, damn. Will resend ASAP. Sorry.

str

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