[Arm-netbook] A10 and all things audio

[Henrik Nordström]

fre 2012-07-13 klockan 11:20 +0900 skrev Jorgen Lundman:

> Alas, the sound has some issues. I am mostly interested in audio 
> pass-through, ie, send the audio stream to the avr/amp or tv directly. More 
> than 2 channels generally. Thus, I did not try the RCA plugs. Since we are 
> not talking about decoding audio, just pass-through, the license changes 
> regarding DTS does not apply.

Gets confusing when looking at the hardware support. What is actually
wired to HDMI audio output?

There is at least 3 audio controllers in A10:

I2S / PCM controller with support for I2S 8 channels out, 2 channels in
(4 data lanes out, 1 data lane in).

AC97 controller. supports stereo only?

Embedded audio codec & headphone amplifier. Analog stereo both out and
in, plus mic support.

Not sure what the HDMI audio source is. Only reference I can find is a
DMA channel for HDMI audio, but not used anywhere in the kernel?

Digging a bit in the driver and seems HDMI audio is driven by the I2S /
PCM controller, only renamed to HDMI. Same register offsets & names.

Regards
Henrik