Re: [PATCH v4 3/3] ASoC: fsl: add imx-es8328 machine driver

On Wed, Jun 18, 2014 at 06:22:52PM +0800, Sean Cross wrote:

On 06/18/14 18:02, Mark Brown wrote:

quoted

This should be handled by the clock bindings not open coded in the
driver - leaving this here most likely won't play nicely when the clock
API can configure the defaults for the tree.  There is supposed to be
support for setting default clock trees going in (or perhaps already in)
the clock bindings.

Can you give me more information on it?  Currently, it looks like most
boards use a 24 MHz clock, judging from this comment in
mach-imx/clk-imx6q.c:

Look at the clock API, this stuff was introduced in the last merge
window if it's there yet at all.

This codec requires the more unusual 22.5792 MHz clock.  What is the
appropriate method of obtaining this particular frequency?

clk_set_rate() on the directly connected clock, the problem is fiddling
about with the parenting rather than setting the rate.

quoted

No, this is broken.  The CODEC should request its own supplies which
need to correspond to the supplies the physical device has and failing
to get the supplies should be a fatal error unless the device works
without power (in which case why bother enablin them at all?).

Not all codecs have power supplies.  Most don't, in fact, it's just this

The manufactuers of those that don't are being awfully quiet about what
sounds like a rather impressive feature...

Additionally, since the regulator is external to the codec (as it
physically cuts 3.3V from the power supply), it doesn't make sense to
put it in the codec driver.

I'm not sure you've quite understood what the regulator API is there
for.