Re: [alsa-devel] [PATCH 4/4] ASoC: simple-card: Support for selecting system clocks by ID

From: Tero Kristo
Date: Fri Apr 22 2016 - 08:08:58 EST


On 22/04/16 14:52, Peter Ujfalusi wrote:
On 04/22/16 01:29, Stephen Boyd wrote:
The first issue with converting the McASP to use CCF internally for clock
selection, muxing and rate configuration is that the daVinci platform does not
use CCF at all. Given that the davinci-mcasp driver is used by daVinci, we
need to have non CCF way supported in ASoC...

Well, at least long term we do need daVinci converting to CCF - this is
going to continue to cause problems, devices not part of the SoC can and
do contain clocks and are going to end up being supported via the clock
API.

Does anyone here know what's involved in converting daVinci to
CCF? It doesn't look too far off from what is in the CCF today,
so I'm not sure what's blocking the transition.

Not entirely sure, but most likely new clk driver(s) for daVinci under
drivers/clk/ti/ new set of structures to describe the clocks if the ti_clk* is
not applicable I guess for starter. Support for DT, non DT boots as most of
daVinci is not booting with DT and most likely never will.
It might help to have different daVinci boards for testing the transition. I
only have OMAP-L138-evm. I don't think it is enough for testing an entire
architecture for this big change...

Tero might have better estimates on what is involved when switching an
architecture to CCF from custom, but at least synchronized API - so we don't
need to convert drivers at least.


Davinci is currently a mutant architecture, it is overriding the common clk APIs and using its own. Converting these to CCF may open a can of worms in many ways.

All the clock data should be converted to support CCF, (from arch/arm/mach-davinci/), along with whatever Peter said.

This also in a situation where many/most upstream people don't even have davinci devices... Personally I have a grand total of zero davinci boards on my desk so at least I am unable to work on this right now.

-Tero