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From: "Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>
To: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: Oleksandr Suvorov <oleksandr.suvorov@toradex.com>,
	devicetree@vger.kernel.org, linux-pwm@vger.kernel.org,
	Paul Barker <pbarker@konsulko.com>,
	Marcel Ziswiler <marcel.ziswiler@toradex.com>,
	Igor Opaniuk <igor.opaniuk@toradex.com>,
	Philippe Schenker <philippe.schenker@toradex.com>,
	Rob Herring <robh+dt@kernel.org>,
	linux-kernel@vger.kernel.org
Subject: Re: [RFC PATCH 3/7] dt-bindings: pwm: add normal PWM polarity flag
Date: Wed, 18 Mar 2020 10:20:47 +0100	[thread overview]
Message-ID: <20200318092047.25gjkx43jwfyywsl@pengutronix.de> (raw)
In-Reply-To: <20200317225656.GK2527@pendragon.ideasonboard.com>

Hello Laurent,

On Wed, Mar 18, 2020 at 12:56:56AM +0200, Laurent Pinchart wrote:
> On Tue, Mar 17, 2020 at 02:32:27PM +0200, Oleksandr Suvorov wrote:
> > PWM can have a normal polarity and a reverted one. The reverted polarity
> > value is defined.
> 
> I would squash this patch with 2/7, apart from that it looks fine.
> However, I also agree with Thierry that the PWM cell that contains this
> value is a bitmask, so once we get more flags it may get a bit awkward.

For me the usefulness of PWM_POLARITY_NORMAL increases with more bits
used. That's because if there are 5 things that can be set there and the
patch author mentions only the two that are non-zero, I as a reviewer
don't know if the author actually know and thought about the other
three. If however they spell out PWM_POLARITY_NORMAL it's quite sure
they want normal polarity.

> Will we have one macro for each flag that will evaluate to 0 to report
> that the flag isn't set ?

Yes. Given the above mentioned advantage this is cheap enough in my
eyes.

> Or should we define a single PWM_FLAG_NONE (or
> similarly named) macro ?

I like one macro for each bit field better for the above mentioned
reason.

> In retrospect, maybe PWM_POLARITY_INVERTED
> should have been named PWM_FLAG_POLARITY_INVERTED.

Seems to be subjective. I don't see much added semantic that justifies
the longer name.

Best regards
Uwe

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

  reply	other threads:[~2020-03-18  9:20 UTC|newest]

Thread overview: 41+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20200317123231.2843297-1-oleksandr.suvorov@toradex.com>
2020-03-17 12:32 ` [RFC PATCH 1/7] pwm: rename the PWM_POLARITY_INVERSED enum Oleksandr Suvorov
2020-03-17 13:34   ` Paul Barker
2020-03-17 21:32     ` Uwe Kleine-König
2020-03-17 16:26   ` Claudiu.Beznea
2020-03-17 16:39     ` Oleksandr Suvorov
2020-03-17 17:40   ` Thierry Reding
2020-03-17 21:00     ` Uwe Kleine-König
2020-03-18 22:59       ` Thierry Reding
2020-03-19  6:50         ` Uwe Kleine-König
2020-03-19 16:37           ` Thierry Reding
2020-03-19 17:30             ` Uwe Kleine-König
2020-03-19 11:40         ` Oleksandr Suvorov
2020-03-19 12:10           ` Uwe Kleine-König
2020-03-19 12:57             ` Oleksandr Suvorov
2020-03-19 16:44           ` Thierry Reding
2020-03-18 11:47     ` Oleksandr Suvorov
2020-03-17 12:32 ` [RFC PATCH 2/7] dt-bindings: pwm: document the PWM polarity flag Oleksandr Suvorov
2020-03-17 17:43   ` Thierry Reding
2020-03-17 21:30     ` Uwe Kleine-König
2020-03-18 23:05       ` Thierry Reding
2020-03-19  7:05         ` Uwe Kleine-König
2020-03-19 17:04           ` Thierry Reding
2020-03-30 21:00             ` Rob Herring
2020-03-18 23:19       ` Thierry Reding
2020-03-17 22:58   ` Laurent Pinchart
2020-03-17 12:32 ` [RFC PATCH 3/7] dt-bindings: pwm: add normal " Oleksandr Suvorov
2020-03-17 13:36   ` Paul Barker
2020-03-17 14:06     ` Oleksandr Suvorov
2020-03-17 21:36   ` Uwe Kleine-König
2020-03-17 22:56   ` Laurent Pinchart
2020-03-18  9:20     ` Uwe Kleine-König [this message]
2020-03-17 12:32 ` [RFC PATCH 4/7] dt-bindings: pwm: add description of PWM polarity Oleksandr Suvorov
2020-03-17 23:01   ` Laurent Pinchart
2020-03-18 11:37     ` Oleksandr Suvorov
2020-03-18 12:29       ` Laurent Pinchart
2020-03-18 12:36         ` Oleksandr Suvorov
2020-03-17 12:32 ` [RFC PATCH 5/7] pwm: replace polarity enum with macros Oleksandr Suvorov
2020-03-17 12:32 ` [RFC PATCH 6/7] arm64: dts: pwm: replace polarity constant with macro Oleksandr Suvorov
2020-03-20 10:03   ` Krzysztof Kozlowski
2020-03-17 12:32 ` [RFC PATCH 7/7] arm: " Oleksandr Suvorov
2020-03-20 10:02   ` Krzysztof Kozlowski

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