Re: [PATCH] pwm: Rename pwm_get_state() to better reflect its semantic - Uwe Kleine-König

From: "Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>
To: Thierry Reding <thierry.reding@gmail.com>
Cc: Alexandre Belloni <alexandre.belloni@bootlin.com>,
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Subject: Re: [PATCH] pwm: Rename pwm_get_state() to better reflect its semantic
Date: Tue, 6 Apr 2021 15:43:56 +0200	[thread overview]
Message-ID: <20210406134356.dda74heeshkwdarw@pengutronix.de> (raw)
In-Reply-To: <YGxDD4jVZx/H/Zdr@orome.fritz.box>

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Hello Thierry,

On Tue, Apr 06, 2021 at 01:16:31PM +0200, Thierry Reding wrote:
> On Tue, Apr 06, 2021 at 09:30:36AM +0200, Uwe Kleine-König wrote:
> > Given that lowlevel drivers usually cannot implement exactly what a
> > consumer requests with pwm_apply_state() there is some rounding involved.
> > 
> > pwm_get_state() traditionally returned the setting that was requested most
> > recently by the consumer (opposed to what was actually implemented in
> > hardware in reply to the last request). To make this semantic obvious
> > rename the function.
> > 
> > Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
> > ---
> >  Documentation/driver-api/pwm.rst           |  6 +++-
> >  drivers/clk/clk-pwm.c                      |  2 +-
> >  drivers/gpu/drm/i915/display/intel_panel.c |  4 +--
> >  drivers/input/misc/da7280.c                |  2 +-
> >  drivers/input/misc/pwm-beeper.c            |  2 +-
> >  drivers/input/misc/pwm-vibra.c             |  4 +--
> >  drivers/pwm/core.c                         |  4 +--
> >  drivers/pwm/pwm-atmel-hlcdc.c              |  2 +-
> >  drivers/pwm/pwm-atmel.c                    |  2 +-
> >  drivers/pwm/pwm-imx27.c                    |  2 +-
> >  drivers/pwm/pwm-rockchip.c                 |  2 +-
> >  drivers/pwm/pwm-stm32-lp.c                 |  4 +--
> >  drivers/pwm/pwm-sun4i.c                    |  2 +-
> >  drivers/pwm/sysfs.c                        | 18 ++++++------
> >  drivers/regulator/pwm-regulator.c          |  4 +--
> >  drivers/video/backlight/pwm_bl.c           | 10 +++----
> >  include/linux/pwm.h                        | 34 ++++++++++++++--------
> >  17 files changed, 59 insertions(+), 45 deletions(-)
> 
> Honestly, I don't think this is worth the churn. If you think people
> will easily get confused by this then a better solution might be to more
> explicitly document the pwm_get_state() function to say exactly what it
> returns.

I'm not so optimistic that people become aware of the semantic just
because there is documentation describing it and I strongly believe that
a good name for functions is more important than accurate documentation.

If you don't agree, what do you think about the updated wording in
Documentation/driver-api/pwm.rst?

> But there's no need to make life difficult for everyone by
> renaming this to something as cumbersome as this.

I don't expect any merge conflicts (and if still a problem occurs
resolving should be trivial enough). So I obviously don't agree to your
weighing.

Best regards
Uwe

-- 
Pengutronix e.K.                           | Uwe Kleine-König            |
Industrial Linux Solutions                 | https://www.pengutronix.de/ |

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