Re: [PATCH v13 2/3] iio: adc: ad_sigma_delta: Add optional irq selection

From: Jonathan Cameron <jic23@kernel.org>
To: Andy Shevchenko <andy@kernel.org>
Cc: "Ceclan Dumitru" <mitrutzceclan@gmail.com>,
	linus.walleij@linaro.org, brgl@bgdev.pl,
	linux-gpio@vger.kernel.org,
	"Lars-Peter Clausen" <lars@metafoo.de>,
	"Rob Herring" <robh+dt@kernel.org>,
	"Krzysztof Kozlowski" <krzysztof.kozlowski+dt@linaro.org>,
	"Conor Dooley" <conor+dt@kernel.org>,
	"Michael Walle" <michael@walle.cc>,
	"Arnd Bergmann" <arnd@arndb.de>,
	"ChiaEn Wu" <chiaen_wu@richtek.com>,
	"Niklas Schnelle" <schnelle@linux.ibm.com>,
	"Leonard Göhrs" <l.goehrs@pengutronix.de>,
	"Mike Looijmans" <mike.looijmans@topic.nl>,
	"Haibo Chen" <haibo.chen@nxp.com>,
	"Hugo Villeneuve" <hvilleneuve@dimonoff.com>,
	"David Lechner" <dlechner@baylibre.com>,
	"Ceclan Dumitru" <dumitru.ceclan@analog.com>,
	linux-iio@vger.kernel.org, devicetree@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH v13 2/3] iio: adc: ad_sigma_delta: Add optional irq selection
Date: Sat, 24 Feb 2024 17:02:25 +0000	[thread overview]
Message-ID: <20240224170225.4720f9a2@jic23-huawei> (raw)
In-Reply-To: <ZdS0kOKTWHlisuyn@smile.fi.intel.com>

On Tue, 20 Feb 2024 16:17:52 +0200
Andy Shevchenko <andy@kernel.org> wrote:

> On Tue, Feb 20, 2024 at 04:13:12PM +0200, Ceclan Dumitru wrote:
> > On 2/20/24 16:11, Andy Shevchenko wrote:  
> > > On Tue, Feb 20, 2024 at 11:43:39AM +0200, Dumitru Ceclan wrote:  
> 
> ...
> 
> > >> +	if (!info->irq_num)
> > >> +		sigma_delta->irq_num = spi->irq;
> > >> +	else
> > >> +		sigma_delta->irq_num = info->irq_num;  
> > > 
> > > Why not positive check?
> > >   
> > Considered that selecting spi->irq is usually the default case, so it should
> > be the first branch  
> 
> Let compiler do its job, the negative conditions are harder to read/parse by
> human beings.
> 
FWIW compiler almost certainly won't figure this out as it has nothing to go on
- history based branch prediction in processors will though!  We don't want to
be hinting direction to the compiler for a case like this as that will make
it very painful if we get it wrong.  Anyhow Andy's comment is valid even if
I disagree with the reason.

Jonathan