[alsa-devel] [PATCH] ASoC: generic: add generic compound card with DT support

[Jean-Francois Moine]

On Thu, 2 Jan 2014 11:56:18 +0000
Mark Brown <broonie at kernel.org> wrote:

> On Thu, Jan 02, 2014 at 12:43:31PM +0100, Jean-Francois Moine wrote:
> > Mark Brown <broonie at kernel.org> wrote:
> 
> > > I think we want an explicit object in the card representing the DAIs.
> > > This will both be useful for making it easy to find the configuration
> > > for the link and will be more extensible for the cases where multiple
> > > devices are connected, you can't just assume there's just two.
> 
> > I don't see the problem: the 'port' is the DAI. The associated
> > endpoints give the DAI links and the routing information.
> 
> > As the DT definition has been done for video, some properties may be
> > added at will for audio.
> 
> > What kind of object were you thinking of?
> 
> Like I say multiple devices on the same link - if you're just listing a
> single remote device there can't be more than one.

I still don't understand. There is already such cases in the Cubox:
the S/PDIF output from the kirkwood audio controller is connected to
both the HDMI transmitter and the S/PDIF TOSLINK. So, in the audio
controller, the port @1 defines the S/PDIF DAI and the endpoints @0 and
@1 point to the remote DAIs, creating 2 snd DAI links:

	port at 1 {
		audio_hdmi_spdif: endpoint at 0 {
			remote-endpoint = <&hdmi_spdif_audio>;
		};
		audio_spdif: endpoint at 1 {
			remote-endpoint = <&spdif_audio>;
		};
	};

in the snd card:

	- DAI link 1 = 'audio controller spdif out' <=> 'hdmi spdif'
	- DAI link 2 = 'audio controller spdif out' <=> 'spdif'

If I am wrong, may you give us an example for which such a DT would not
work?

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