[alsa-devel] ASOC: For SND_SOC_DAIFMT_IB_IF what is invert baseed on?

Richard Zhao linuxzsc at gmail.com
Mon Oct 27 14:24:48 CET 2008


> Not quite, the clock is simply inverted compared to it's normal level.
>

Well, what's the normal level? i2s LRCLK 's normal level is low for
frame start, but pcm's normal level is high for frame start.

Different chips may have different meaning of "invert", because
"normal level" is not well defined. SND_SOC_DAIFMT_NB_NF is a common
macro, so it cannot depend on any chip.  So, could you please explain
in details what normal level and invert level of LRCLK/BCLK are in
i2s, pcm, left/right justified?

Yes, wm8350 audio driver works. The problem is, when I write drivers
from some cpu/codec DAIs, I'm often confused about the normal/invert
levels.

Thanks
Richard


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