[alsa-devel] WM8731 using I2S on omap3 McBSP2 issues

Mark Brown broonie at opensource.wolfsonmicro.com
Thu Sep 24 20:52:46 CEST 2009

On Thu, Sep 24, 2009 at 11:00:52AM -0700, Rick Bronson wrote:
> Mark,

> > This suggests that the DMA isn't happening which usually means that the
> > CPU isn't seeing all the clocks it's supposed to.  I'm not familiar
> > enough with the OMAP internals to know if you've set the CPU up
> > properly.

>   I've poured over the relavent code for this and am pretty sure I
> don't need to touch it.  The same code works on the beagleboard, at
> least the DMA part.  But you never know...

You shouldn't need to touch the DMA code itself, it's normally an issue
with the clocks and/or the pinmux code not managing to get the signals
required to clock the data transfer.

>   BTW, when I do a aplay, the trace looks the same except ACDDAT is
> low.

Yes, that's what I'd expect - this was just an attempt to confirm that
the CODEC is happy.

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