[alsa-devel] <alsa-dev> RFC for OMAP4 audio driver

[pl bossart]

>> They will also have their DAIs which should be connected to the
>> physical outputs of ABE (McPDM, McBSP, ...), and that confuses me.
>> AFAIK, SoC allows to have multiple CODECs attached to the same
>> processor, but not a CODEC connected to the output of another CODEC.
>
> At the minute it's a bit tricky but it's definitely something that ought
> to be supported - you may remember the refactoring that was done to
> unify the CODEC and CPU DAI structures, this sort of use case was one of
> the motivators for that.  Where there's problems the core isn't a fixed
> thing, we can change it if required.

Very interesting thread.
My 2 cents: I find the notion of codec confusing.
In most products from Wolfson and others, you have a digital/mixing
part, and a second one for digital/analog conversions. OMAP4 and
others have a digital part on the application processor, but the
partition is still the same, only implemented on two chips instead of
one. It shouldn't really matter software-wise where the digital part
is done, as long as you can express the connection between these two
parts. A logical split would avoid having a description of a codec
connected to another codec, you would only have a digital part and an
analog part. With a CPU/digital/analog split, you could address all
topologies without developers incurring any risk of brain damage.
-Pierre