Re: [PATCH v4 4/4] gnss: add driver for mediatek receivers

From: Pavel Machek <pavel@ucw.cz>
To: Johan Hovold <johan@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>,
	devicetree@vger.kernel.org,
	Martin Blumenstingl <martin.blumenstingl@googlemail.com>,
	Kevin Hilman <khilman@baylibre.com>,
	Loys Ollivier <lollivier@baylibre.com>,
	linux-kernel@vger.kernel.org, Rob Herring <robh+dt@kernel.org>,
	Corentin Labbe <clabbe.montjoie@gmail.com>,
	linux-amlogic@lists.infradead.org,
	linux-mediatek@lists.infradead.org,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v4 4/4] gnss: add driver for mediatek receivers
Date: Mon, 11 Mar 2019 12:21:14 +0100	[thread overview]
Message-ID: <20190311112114.GD14118@amd> (raw)
In-Reply-To: <20190214101212.GJ28278@localhost>


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On Thu 2019-02-14 11:12:12, Johan Hovold wrote:
> On Thu, Feb 14, 2019 at 11:00:19AM +0100, Corentin Labbe wrote:
> > On Wed, Feb 13, 2019 at 04:09:29PM +0100, Loys Ollivier wrote:
> > > Add driver for serial-connected Mediatek-based GNSS receivers.
> > > 
> > > These devices typically boot transmitting vendor specific NMEA output
> > > sequences. The serial port bit rate is read from the device tree
> > > "current-speed".
> > > 
> > > Note that the driver uses the generic GNSS serial implementation and
> > > therefore essentially only manages power abstracted into three power
> > > states: ACTIVE, STANDBY, and OFF.
> > > 
> > > For mediatek receivers with a main supply and no enable-gpios, this simply
> > > means that the main supply is disabled in STANDBY and OFF (the optional
> > > backup supply is kept enabled while the driver is bound).
> > > 
> > > Note that the timepulse-support is left unimplemented.
> > > 
> > > Signed-off-by: Loys Ollivier <lollivier@baylibre.com>
> 
> > > +static int mtk_set_active(struct gnss_serial *gserial)
> > > +{
> > > +	struct mtk_data *data = gnss_serial_get_drvdata(gserial);
> > > +	int ret;
> > > +
> > > +	ret = regulator_enable(data->vcc);
> > > +	if (ret)
> > > +		return ret;
> > > +
> > > +	return 0;
> > > +}
> > 
> > Hello
> > 
> > This could be simplified to return regulator_enable(data->vcc);
> 
> Indeed, but I prefer this style which clearly separates the error path
> from the success path while making the success return value explicit.

What is clear about useless code? That function can be two lines, this
only leads people to wonder "what is going on here?".
								Pavel
-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

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