[alsa-devel] No pcm device?

Mark Brown broonie at sirena.org.uk
Mon Oct 20 15:24:24 CEST 2008

On Mon, Oct 20, 2008 at 03:16:27PM +0200, John Kacur wrote:

> ...but I'm still scratching my head when I look at files like
> sound/soc/s3c24xx/s3c24xx-pcm.c
> It appears to be part of the DAI that connects the i2s driver and

No, there is no direct connection between any of the platform drivers
and the codec drivers - the platform drivers will be configured to
produce and understand signals on I2S as configured by a combination of
the machine drivers and core.  The codec will be configured compatibly
but at no point should the codec and platform drivers directly know
anything about each other.

> codec together? So, back to my current source of confusion, do I need
> to implement some basic kind of pcm driver for my scenario?

There should be at least a stub platform driver.  The driver is
responsible for things that apply over the entire platform - for most
platforms this is DMA since the DMA control is the same for all the
different audio interfaces the platform has.

This is nothing to do with creating a card, that is initiated by the
machine driver.

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