Re: About clk maintainership [Was: Re: [PULL] Add variants of devm_clk_get for prepared and enabled clocks enabled clocks]

From: Uwe Kleine-König
Date: Mon Aug 02 2021 - 11:28:22 EST


Hello Russell,

On Mon, Aug 02, 2021 at 10:48:10AM +0100, Russell King (Oracle) wrote:
> On Sat, Jul 31, 2021 at 02:00:04PM +0200, Uwe Kleine-König wrote:
> > Hi Russell, hi Stephen,
> >
> > On Sat, Jul 31, 2021 at 12:41:19AM -0700, Stephen Boyd wrote:
> > > +1 This patch doesn't fall under CCF maintainer.
> >
> > Given that CCF is the only implementer of devm_clk_get at least an Ack
> > from your side would still be good I guess?
>
> I think devm_clk_get() should not be part of CCF but should be
> part of the interface level - it's silly to have devm_clk_get()
> being CCF but not clk_get(). The same should go for the other
> devm wrappers around the plain clk_* interfaces.

What is the practical difference between "Function X is part of CCF" and
"Function X is part of the clk interface and there is only CCF who
implements it"?

> > I found a patch set adding devm variants of clk_enable (e.g.
> > https://lore.kernel.org/patchwork/patch/755667/) but this approach is
> > different as it also contains clk_get which IMHO makes more sense
> > The discussion considered wrapping get+enable at one point, but I didn't
> > find a followup.
>
> There have been several different approaches to wrapping things up,
> but here's a question: should we make it easier to do the lazy thing
> (get+enable) or should we make it easier to be power efficient?
> Shouldn't we be encouraging people to write power efficient drivers?

Yeah, sounds compelling, but I wonder if that's of practical importance.
How many driver authors do you expect to lure into making a better
driver just because devm_clk_get_prepared() doesn't exist? In contrast:
How many drivers become simpler with devm_clk_get_prepared() and so
it becomes easier to maintain them and easier to spot bugs?
In the absence of devm_clk_get_prepared(), is it better that several
frameworks (or drivers) open code it?

Best regards
Uwe

--
Pengutronix e.K. | Uwe Kleine-König |
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