[alsa-devel] AT32AP7000 (AVR32) + WM8510

Mark Brown broonie at opensource.wolfsonmicro.com
Fri May 23 00:48:41 CEST 2008

On Thu, May 22, 2008 at 02:57:41PM -0500, Geoffrey Wossum wrote:

> Looks like it should work to me.  Note that I do hear a pop from the speaker 
> the first time I try to play a file.  Here's a dump of the registers while 
> I'm trying to play a file with aplay.  I'm combing through them right now to 
> see if I can find anything that looks off.

Yes, it looks like the output paths are OK from the DAPM point of view.

> Wish I had known about this register dump earlier today.  I added code to do 
> the same thing with debugfs.

I'll have a look at it at some point, but not right now :) .  I should
also have asked you if you could post your machine driver - if you'd
rather post it off-list that'd be fine.

> > I'll need to check this out in more detail - the WM8510 is a mono codec
> > so it can only play one channel.

> Not sure about this either, since I can't get it to play anything yet.  But it 
> looks from the WM8510 data sheet that even though the WM8510 is mono, it 
> expects a stereo I2S stream, and just ignores one of the channels based on 
> the value of DACLRSWAP register bit.

Indeed, the main thing I need to check is to confirm what is normally
done with mono channels - in any case, the codec should at least make
some noise providing the rates are correct and there's stereo data.

I take it the digital audio looks fine with a scope - clocks at the
correct rate, sensible looking data and so on?

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