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

[Jean-Francois Moine]

On Tue, 13 Jan 2015 16:03:13 +0000
Russell King - ARM Linux <linux at arm.linux.org.uk> wrote:

> On Tue, Jan 13, 2015 at 04:54:11PM +0100, Jean-Francois Moine wrote:
> > 4 streams on 4 different APs (sources) should work, but 4 streams from
> > a same source should be detailed.
> 
> I'd like to know how you intend to wire up four different I2S sources
> to the TDA998x.
> 
> Remember, an I2S source produces the I2S data and the word clock - that's
> two outputs.  You can't electronically wire the word clocks together.

From the spec, the tda998x gets independently the serial clock and the
serial word select from each I2S (stereo) input channel (= audio pin),
so, you may have 4 audio chips giving 4 independent audio streams.
I don't know what can be the result in HDMI if these streams are actived
at the same time!

In the other configuration, an audio chip may have 4 synchronized stereo
channels (software PCMs). These ones may be considered as one link (one
port out from the audio chip to one port in to the tda998x), the AP
configuration being 0x1f.

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Jef		|		http://moinejf.free.fr/