[alsa-devel] [PATCH] ASoC: Document DAI signal polarity

[Anatol Pomozov]

Hi

On Wed, Sep 30, 2015 at 11:10 AM, Mark Brown <broonie at kernel.org> wrote:
> I don't think that's true, the expectation is that a left/right sample
> pair is time aligned so the left channel is definitely the start of
> frame for all meaningful purposes.  It's certainly what I'd expect most
> people to understand - choosing a counterintuitive definition to make
> this one statement convenient is going to lead to constant confusion for
> the mode which is clearest.

To clarify, you propose following definition of normal FSYNC polarity:
 - for I2S/left/right justified - frame starts with falling FSYNC edge
 - for DSP A/B - frame starts with rising edge of FSYNC edge (plus offset)
 - for AC97 my guess it is the same as DSP - frame starts with rising
FSYNC edge.

Is it correct?