[alsa-devel] define confusion

Mark Brown broonie at sirena.org.uk
Tue Oct 14 14:17:42 CEST 2008

On Tue, Oct 14, 2008 at 01:52:20PM +0200, John Kacur wrote:

> I want to use an MCLK generated from an ocillator from i2s, so by
> definition, that is the master. I thought that the frames are always
> generated by the master (or can it be the other way around if you have
> a codec device that can capture?) so does this mean, I should choose

The clock configuration for the link refers specifically to the device
that is generating the clock for that link - it will derive this clock
from some other source but the question is what device is driving each
of the clock signals on the link.  This could be anything on the link
for either clock, any restrictions will be a function of the devices
used and the way they are connected in your system.  All that "master"
refers to is the source of the clock.

It's not clear from what you write above what applies in your case.
I *think* that you mean that you want to derive both frame and bit
clocks from a crystal attached to the codec - if that is the case then
you want to use SND_SOC_DAIFMT_CBM_CFM.  Otherwise, could you please
clarify what your system configuration is - which devices do you want to
drive which clock signals?

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