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

[Russell King (Oracle)]

On Mon, Aug 02, 2021 at 05:27:55PM +0200, Uwe Kleine-König wrote:
> Hello Russell,
> 
> On Mon, Aug 02, 2021 at 10:48:10AM +0100, Russell King (Oracle) wrote:
> > 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"?

clkdev is maintained by me as part of the API, and provides clk_get()
functionality for all clk implementations. To then have devm_clk_get(),
which merely provides a wrapper around clk_get() adding the devm
semantics being part of CCF is not sane - devm_clk_get() isn't
specific to CCF or in fact any clk API implementation.

> > 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?

It probably depends on where you stand on power management and power
efficiency issues. Personally, I would like to see more effort put
into drivers to make them more power efficient, and I believe in the
coming years, power efficiency is going to become a big issue.

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