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

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Message-ID: <20210802152755.ibisunvibmwhiyry@pengutronix.de>
Date:   Mon, 2 Aug 2021 17:27:55 +0200
From:   Uwe Kleine-König <u.kleine-koenig@...gutronix.de>
To:     "Russell King (Oracle)" <linux@...linux.org.uk>
Cc:     alexandre.belloni@...tlin.com,
        Michael Turquette <mturquette@...libre.com>,
        thierry.reding@...il.com, lee.jones@...aro.org,
        linux-clk@...r.kernel.org, linux-rtc@...r.kernel.org,
        Ludovic.Desroches@...rochip.com, o.rempel@...gutronix.de,
        andy.shevchenko@...il.com, aardelean@...iqon.com,
        linux-pwm@...r.kernel.org, Arnd Bergmann <arnd@...db.de>,
        broonie@...nel.org, Jonathan.Cameron@...wei.com,
        linux-arm-kernel@...ts.infradead.org, a.zummo@...ertech.it,
        Stephen Boyd <sboyd@...nel.org>, linux-kernel@...r.kernel.org,
        linux-spi@...r.kernel.org, wsa@...nel.org, kernel@...gutronix.de,
        akpm@...ux-foundation.org, torvalds@...ux-foundation.org,
        Claudiu.Beznea@...rochip.com
Subject: Re: About clk maintainership [Was: Re: [PULL] Add variants of
 devm_clk_get for prepared and enabled clocks enabled clocks]

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            |
Industrial Linux Solutions                 | https://www.pengutronix.de/ |

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