[alsa-devel] [RFC] ASoC: core: Add support for DAI multicodec

Mark Brown broonie at kernel.org
Wed Mar 12 01:28:22 CET 2014

On Tue, Mar 11, 2014 at 12:17:24PM +0100, Benoit Cousson wrote:
> From: Misael Lopez Cruz <misael.lopez at ti.com>
> DAI link assumes a one to one mapping between CPU DAI and CODEC. In
> some cases, the same CPU DAI can be connected to several codecs.
> This is the case for example, if you connect two mono codecs to the
> same I2S link in order to have a stereo card.
> The current ASoC implementation does not allow such setup.

First up thanks for working on this, it's a feature which has been
requested for a long time but nobody stepped forward to do it before

This is rather large so I've not had time to review it today, I'll try
to get at least a first pass at that done tomorrow.  I did notice that
in your comment about rebasing you mentioned a series - it'd be good if
we could see this as a series, splitting it up would make review easier.

> CPU DAI in a multicodec DAI link can have more channels than what each
> CODEC has. The number of channels each CODEC is responsible for is
> machine specific, hence it's fixed up in machine drivers in a similar
> way to what DPCM does.

This one is interesting.  It feels like most things will want a static
mapping because that's what the hardware does but there will doubtless
be things that could use flexibility.  Liam has looked at this in the
past (more for TDM IIRC, I thought about it for that as well and I seem
to recall Liam's ideas covering it).  It feels like we should start out
with static mappings and build up dynamic later on but equally well
getting something merged would mean we could improve on it.

> The patch is based on 3.14-rc6.

For such an invasive set of changes it's probably worth working off
-next, I forsee conflicts.
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