Re: [RFC PATCH] clk: add extension API

[Peter De Schrijver <pdeschrijver@nvidia.com>]

On Thu, May 31, 2012 at 11:04:36AM +0200, Stephen Boyd wrote:
> On 5/31/2012 12:51 AM, Peter De Schrijver wrote:
> > On Wed, May 30, 2012 at 10:52:31AM +0200, Stephen Boyd wrote:
> >> On 5/29/2012 2:58 AM, Peter De Schrijver wrote:
> >>> Add an extension API for clocks. This allows clocktypes to provide extensions
> >>> for features which are uncommon and cannot be easily mapped onto normal clock
> >>> framework concecpts. eg: resetting blocks, configuring clock phase etc.
> >> This seems rather generic. Why not add more specific APIs/concepts like
> >> clk_reset(), clk_set_phase(), etc.? If they don't map, maybe we should
> >> make them map.
> >>
> > Some of those might be very SoC specific. Eg OMAP doesn't need software
> > controlled modulereset. I don't think we should add a new function to the
> > clock framework for clock related features which only exist in a single
> > SoC or family. Ideally we could use inheritance to add methods to derived
> > clocktypes, but that's not really possible in C unfortunately.
> 
> Most likely your hardware is not that special and the functionality you
> think exists only on your SoC actually exists on 5 others. MSM needs
> software resets too and we also associate them with each clock (there
> can be many clocks for one device and one reset for each clock). We use
> them mostly for the power domain code (looks like tegra and omap do the
> same thing albeit slightly differently).
> 
> What do you plan to support under this API?

Anything which isn't available on other SoCs. If it is available, then we
could indeed add another method. I guess this will need to be decided on
a case by case basis.

Cheers,

Peter.