Re: [RFC PATCH] clk: add extension API

[Saravana Kannan]

On 05/31/2012 01:23 AM, Peter De Schrijver wrote:
> On Thu, May 31, 2012 at 05:29:54AM +0200, Saravana Kannan wrote:
> > On 05/30/2012 12:40 PM, Mike Turquette wrote:
> > > On 20120530-01:52, 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.
> > >
> > > I also wonder if exposing some of these knobs should be done in the
> > > basic clock types.  Meaning that instead of having additional calls in
> > > the clk.h API those calls could be exposed by the basic clock types that
> > > map to the actions.
> > >
> > > The question that needs to be answered is this: do generic drivers need
> > > access to these additional functions (clk.h) or just the platform code
> > > which implements some of the clock logic (basic clock types&
> > > platform-speciic clock types).
> >
> > One of the main reason for the common clock framework is so that each
> > platform doesn't have it's own extension and have mostly similar code
> > repeat all over the place. So, having clock APIs outside of clk.h
> > doesn't make sense when we look at the direction we want the code base
> > to proceed in.
>
> I don't think this will lead to 'mostly similar code repeat all over the
> place'. I don't know of any intree SoC which has a similar requirement.
> So which code duplication would this cause?

It's not clear what you plan to use this API for. So, I can't really 
answer if any intree SoC needs it. But if this is about reset signals, 
it's definitely needed for MSM too. I was planning on bringing this up 
after the basic clock API implementation in the clock framework is 
usable for MSM.

-Saravana

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