[alsa-devel] Patches to bind the SGTL5000 chip to AM33XX McASP

[Peter Ujfalusi]

On 03/19/2015 07:07 AM, Greg Knight wrote:
> Hi, Mark, Jaroslav,
> 
> I've attached a couple patches to provide support for the Freescale
> SGTL5000 chip when using the McASP on the AM3359.

It is more correct to say that this is needed in a custom hardware which uses
McASP and SGTL5000 codec.

> This adds an optional hack, "clock-to-talk" to the McASP subsystem which
> can start AHCLKX/AHCLKR prior to initializing the codec. This is needed
> on the SGTL5000, which depends on AHCLKX for its master clock.

SO is it so that the codec's MCLK is coming from McASP AHCLKX (or R) and this
clock need to be present all the time? W/o the MCLK the registers are not
accessible?

> These patches are based off of 3.14.31-ti-r49. What is the process for
> getting these merged?

First off, please send the patches with git send-email so people can comment
on them.

This will not work in mainline kernel. The McASP is turned off when it is not
in use (no audio activity) so the AHCLKX/R is not going to be there on the
ball output.

How do you configure the frequency of the AHCLKX/R, this hack only enables it,
so you are going to have _some_ clock going out.

You should be using set_clkdiv and set_sysclk calls from the machine driver to
configure the AHCLKX (we do not have AHCLKR supported in the driver ATM).

-- 
Péter