From: Marek Vasut <marex@denx.de>
To: Fabio Estevam <festevam@gmail.com>
Cc: Estevam Fabio-R49496 <r49496@freescale.com>,
"alsa-devel@alsa-project.org" <alsa-devel@alsa-project.org>,
Mark Brown <broonie@kernel.org>
Subject: Re: [PATCH] ASoC: sgtl5000: Do not read registers prior to turning on the supplies
Date: Fri, 31 May 2013 17:45:50 +0200 [thread overview]
Message-ID: <201305311745.50326.marex@denx.de> (raw)
In-Reply-To: <CAOMZO5Ab1gfTr4Fi3jXAXtR2LEdBcT6nyNRgm3djpBeRnaz-qg@mail.gmail.com>
Hi Fabio,
> On Fri, May 31, 2013 at 12:32 PM, Marek Vasut <marex@denx.de> wrote:
> > There was no problem without these patches though. With your patches, I
> > see NAK happening on the I2C lines upon first 2-byte write.
>
> Yes, but prior to these patches there were no register writes in sgtl5000.
How would volume adjustment work with no writes ? ;-)
> These addditional writes does work and solve the reset issues on
> mx6qsabrelite/mx51evk.
>
> It is only on mx28evk that we have this timeout issue.
>
> I think we need to turn on the SAIF clock (that connects to the
> sgtl5000 MCLK) prior to doing the I2C writes.
Ah, that's _very_ likely. I think the chip will NAK I2C communication without
having clock supplied to it. I did look into this stuff with an LA yesterday
night and I saw the 2-byte write followed by I2C NAK.
Best regards,
Marek Vasut
next prev parent reply other threads:[~2013-05-31 15:45 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-05-28 14:04 [PATCH] ASoC: sgtl5000: Do not read registers prior to turning on the supplies Fabio Estevam
2013-05-28 14:32 ` Mark Brown
2013-05-30 22:36 ` Marek Vasut
2013-05-31 5:09 ` Estevam Fabio-R49496
2013-05-31 15:32 ` Marek Vasut
2013-05-31 15:36 ` Fabio Estevam
2013-05-31 15:45 ` Marek Vasut [this message]
2013-05-31 15:52 ` Fabio Estevam
2013-05-31 17:20 ` Marek Vasut
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