Re: OMAP Audio

[Jarkko Nikula <jhnikula@gmail.com>]

On Tue, 16 Feb 2010 11:19:25 -0700
Gary Thomas <gary@mlbassoc.com> wrote:

> I need to connect the OMAP (3530) to a 24bit CODEC.  So far
> my attempts at getting this to go have not gone well.  Then
> I ran across this comment in sound/soc/omap/omap-pcm.c:
> 	/*
> 	 * Note: Regardless of interface data formats supported by OMAP McBSP
> 	 * or EAC blocks, internal representation is always fixed 16-bit/sample
> 	 */
> 
> Does this mean that this setup is just not supported?  even though
> the hardware can handle it?
> 
Yep, comment is bit misleading but true until some patch will remove
it. IRCC, the EAC was limited to 16-bit and also there wasn't need and
HW to test other formats than S16_LE in McBSP DAI.

> Thanks for any pointers or ideas on how to get this going.
> 
I would first start adding support for the S32_LE into omap-pcm.c (DMA
part). Worth to look this thread:

http://mailman.alsa-project.org/pipermail/alsa-devel/2010-January/024704.html

Then add support for this format to the omap-mcbsp.c (link
configuration part).

Next step would be to add support for the S24_LE on 4-byte boundaries.
I.e. the DMA is moving 32-bit samples between the memory and McBSP but
only 24-bits are transferred over the McBSP and codec.


-- 
Jarkko