[alsa-devel] [PATCH 0/6] ASoC: 4 channel support for twl4030 and omap-mcbsp

Peter Ujfalusi peter.ujfalusi at nokia.com
Tue Apr 7 08:32:02 CEST 2009

On Tuesday 07 April 2009 08:45:36 Nikula Jarkko (Nokia-D/Helsinki) wrote:
> On Mon, 6 Apr 2009 14:19:26 +0200
> "Ujfalusi Peter (Nokia-D/Tampere)" <peter.ujfalusi at nokia.com> wrote:
> > As an example, the board file for Beagle is modified to add support
> > for stereo and TDM mode depending on the stream's channel count, so
> > the stereo and the four channel mode are supported on Beagle.
> Peter, before starting to hack on this, did I interpret TWL block
> diagram correctly so that I can route both R1/R2 and L1/L2 into same
> outputs? It seems that only codec outputs available in Beagle are the
> HSOL and HSOR. There seems to be no test pads for PreDriv and IHF
> outputs.

With the current implementation there is a mux on Headset outputs:
'HeadsetL Mux': Off, DACL1, DACL2
'HeadsetR Mux': Off, DACR1, DACR2

So you can select which Left channel (Channel 1 or 2 in TDM) goes to HSOL and 
which Right channel (channel 3 or 4 in TDM) goes to HSOR.

In i2s/stereo mode the codec receives the data on DACL2/DACR2.

I have been misled by the TRM on these, since it seams that these can be mixed 
on the output (and not muxes, as they are implemented at the moment).

There has been proposed patches sent to alsa-devel some time ago, which fixed 
these mistakes...

> Jarkko


More information about the Alsa-devel mailing list