Re: [RFC PATCH 1/7] pwm: rename the PWM_POLARITY_INVERSED enum - Uwe Kleine-König

From: "Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>
To: Thierry Reding <thierry.reding@gmail.com>
Cc: Oleksandr Suvorov <oleksandr.suvorov@toradex.com>,
	devicetree@vger.kernel.org, linux-pwm@vger.kernel.org,
	Paul Barker <pbarker@konsulko.com>,
	Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
	Marcel Ziswiler <marcel.ziswiler@toradex.com>,
	Igor Opaniuk <igor.opaniuk@toradex.com>,
	Philippe Schenker <philippe.schenker@toradex.com>,
	Alexandre Belloni <alexandre.belloni@bootlin.com>,
	Chen-Yu Tsai <wens@csie.org>,
	Claudiu Beznea <claudiu.beznea@microchip.com>,
	Fabio Estevam <festevam@gmail.com>,
	Florian Fainelli <f.fainelli@gmail.com>,
	Heiko Stuebner <heiko@sntech.de>,
	Kevin Hilman <khilman@baylibre.com>,
	Ludovic Desroches <ludovic.desroches@microchip.com>,
	Maxime Ripard <mripard@kernel.org>,
	NXP Linux Team <linux-imx@nxp.com>,
	Nicolas Ferre <nicolas.ferre@microchip.com>,
	Palmer Dabbelt <palmer@dabbelt.com>,
	Paul Cercueil <paul@crapouillou.net>,
	Paul Walmsley <paul.walmsley@sifive.com>,
	Pengutronix Kernel Team <kernel@pengutronix.de>,
	Ray Jui <rjui@broadcom.com>,
	Sascha Hauer <s.hauer@pengutronix.de>,
	Scott Branden <sbranden@broadcom.com>,
	Shawn Guo <shawnguo@kernel.org>,
	Tony Prisk <linux@prisktech.co.nz>,
	bcm-kernel-feedback-list@broadcom.com,
	linux-amlogic@lists.infradead.org,
	linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org,
	linux-rockchip@lists.infradead.org
Subject: Re: [RFC PATCH 1/7] pwm: rename the PWM_POLARITY_INVERSED enum
Date: Tue, 17 Mar 2020 22:00:42 +0100	[thread overview]
Message-ID: <20200317210042.ryrof3amr7fxp4w5@pengutronix.de> (raw)
In-Reply-To: <20200317174043.GA1464607@ulmo>

Hello,

On Tue, Mar 17, 2020 at 06:40:43PM +0100, Thierry Reding wrote:
> On Tue, Mar 17, 2020 at 02:32:25PM +0200, Oleksandr Suvorov wrote:
> > The polarity enum definition PWM_POLARITY_INVERSED is misspelled.
> > Rename it to PWM_POLARITY_INVERTED.
> 
> It isn't misspelled. "inversed" is a synonym for "inverted". Both
> spellings are correct.

Some time ago I stumbled about "inversed", too. My spell checker doesn't
know it and I checked some dictionaries and none of them knew that word:

https://www.lexico.com/search?utf8=%E2%9C%93&filter=dictionary&dictionary=en&query=inversed
https://de.pons.com/%C3%BCbersetzung/englisch-deutsch/inversed
https://dictionary.cambridge.org/spellcheck/english-german/?q=inversed

https://en.wiktionary.org/wiki/inverse#Verb mentions "inverse" as a verb
having "inversed" as past participle.

Having said this I think (independent of the question if "inversed"
exists) using two similar terms for the same thing just results in
confusion. I hit that in the past already and I like it being addressed.

> And as you noted in the cover letter, there's a conflict between the
> macro defined in dt-bindings/pwm/pwm.txt. If they end up being included
> in the wrong order you'll get a compile error.

There are also other symbols that exist twice (GPIO_ACTIVE_HIGH was the
first to come to my mind). I'm not aware of any problems related to
these. What am I missing?

> The enum was named this way on purpose to make it separate from the
> definition for the DT bindings.

Then please let's make it different by picking a different prefix or
something like that.

> Note that DT bindings are an ABI and can
> never change, whereas the enum pwm_polarity is part of a Linux internal
> API and doesn't have the same restrictions as an ABI.

I thought only binary device trees (dtb) are supposed to be ABI.

Best regards
Uwe

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