[Sound-open-firmware] Handling DAI clocks in SOF

[Liam Girdwood]

On Wed, 2019-11-13 at 17:06 +0200, Daniel Baluta wrote:
> Hi all,
> 
> I am asking your opinion on how to better handle clocks / pinctrl
> configuration
> in SOF for IMX.
> 
> As far as I know Intel platforms deal with this stuff on Firmware
> side. Unfortunately
> for IMX this cannot be done easily.
> 
> The interface on touching resources (clocks, pinctrl) in i.MX8/i.MX8X
> uses a separate
> dedicated core (M4) named System Controller.
> 
> Linux kernel has a mechanism implemented to communicate with this SC
> and to request
> for clock operations (enable, disable, set rate etc).
> 
> So, would you see it fit to create (on Linux kernel side) dummy DAI
> drivers which just take
> care of resource configuration?
> 
> 
OMAP4 was like this, Linux had to program parts of the DAI IP whilst
the FW did other parts of DAI IP.

You could use the machine driver fixup() or ASoC DPCM BE DAI PCM
callbacks to program any of the host side IP.

Liam