Re: [PATCH v9 1/4] drm/i2c: tda998x: Add DT support for audio

From: Jean-Francois Moine
Date: Thu Jan 08 2015 - 11:40:48 EST


On Thu, 8 Jan 2015 16:53:41 +0200
Jyri Sarha <jsarha@xxxxxx> wrote:

> > + - audio-ports: must contain one or two values selecting the source
> > + in the audio port.
> > + The source type is given by the corresponding entry in
> > + the audio-port-names property.
> > +
>
> This binding does not allow multi channel i2s setups with multiple i2s
> pins. It would be nice to support that in the DT binding, even if the
> code is not yet ready for it.
>
> How about having these two optional properties instead of audio-ports
> and audio-port-names:
>
> audio-port-i2s: Upto 4 values for selecting pins for i2s port
> audio-port-spdif: Value for selecting input pin for spdif port
>
> Presence of one of the properties would be mandatory and both are allowed.
>
> Sorry to notice this only now, but I have not yet looked the drm side
> changes too closely.

>From Andrew's datasheet, the TDA998x's which are handled by the tda998x
driver have only 4 input audio pins, the first two ones being either
S/PDIF or I2s, the last ones being I2S only.

So, the DT description could be reduced to a simple list indexed by
the pin number (= DAI number) and defining the protocol type.

Examples:

- for the Cubox:

audio-inputs = "i2s", "spdif";

- for some other board with I2S on the pins 3 and 4 only:

audio-inputs = "none", "none", "i2s", "i2s";

- for a fully wired TDA9983B (no driver yet):

audio-inputs = "i2s", "i2s", "i2s", "i2s", "spdif";

--
Ken ar c'hentaà | ** Breizh ha Linux atav! **
Jef | http://moinejf.free.fr/
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