Re: [PATCHv2 1/3] Input: twl4030-keypad - add device tree support

From: Pavel Machek <pavel@ucw.cz>
To: linux-input@vger.kernel.org,
	"'Beno?t Cousson'" <bcousson@baylibre.com>,
	Tony Lindgren <tony@atomide.com>,
	Rob Herring <rob.herring@calxeda.com>,
	Pawel Moll <pawel.moll@arm.com>,
	Mark Rutland <mark.rutland@arm.com>,
	Stephen Warren <swarren@wwwdotorg.org>,
	Ian Campbell <ijc+devicetree@hellion.org.uk>,
	Rob Landley <rob@landley.net>,
	Russell King <linux@arm.linux.org.uk>,
	Dmitry Torokhov <dmitry.torokhov@gmail.com>,
	Grant Likely <grant.likely@linaro.org>,
	devicetree@vger.kernel.org, linux-doc@vger.kernel.org,
	linux-kernel@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org, linux-omap@vger.kernel.org
Subject: Re: [PATCHv2 1/3] Input: twl4030-keypad - add device tree support
Date: Sun, 27 Oct 2013 12:47:53 +0100	[thread overview]
Message-ID: <20131027114753.GB14901@amd.pavel.ucw.cz> (raw)
In-Reply-To: <20131027114026.GB14091@earth.universe>

Hi!

> > > + * keypad,num-rows and keypad,num-columns are required.
> > Is "keypad," prefix neccessary here?
> 
> See Documentation/devicetree/bindings/input/matrix-keymap.txt
> 
> > > +Optional Properties specific to linux:
> > > +- linux,keypad-no-autorepeat: do no enable autorepeat feature.
> > 
> > "do not autorepeat". Plus I do not see what is Linux specifc about not
> > autorepeating... Other systems will likely know about autorepeat, too.
> 
> This property has already been used like this for
> samsung-keypad, stmpe-keypad, omap-keypad and
> gpio-matrix-keypad.

Ok. But you still have a typo. "do no enable" => "do not enable".

> > > +#if IS_ENABLED(CONFIG_OF)
> > I'm probably missing something here, but why not #ifdef CONFIG_OF?
> 
> I have been told for other drivers, that IS_ENABLED() is
> the prefered way to check for configuration these days.

CONFIG_OF can not be module, using IS_ENABLED() on it is just wrong.

> > > @@ -381,7 +426,7 @@ static int twl4030_kp_probe(struct platform_device *pdev)
> > >  
> > >  	input_set_capability(input, EV_MSC, MSC_SCAN);
> > >  	/* Enable auto repeat feature of Linux input subsystem */
> > > -	if (pdata->rep)
> > > +	if (!kp->no_autorepeat)
> > >  		__set_bit(EV_REP, input->evbit);
> > >
> > 
> > Double negation is nasty to read. I believe code would be more
> > readable if you switched logic to kp->autorepeat.
> 
> I was thinking about the same when writing it, but decided
> against it, since it will just move the double negation to
> the variable initialization.

Well, the property should be linux,keypad-autorepeat in the first
place, but it is too late to change that.

Thanks,
								Pavel
-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html