linux-kernel - Re: [PATCH v2 9/9] iio: adc: ad4062: Add GPIO Controller support

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Message-ID: <3izg5lyxjye24pvzoibk4tmnxbdfokr53abkpbjo5epqjoz55j@6wc7i4wsgwkt>
Date: Thu, 4 Dec 2025 22:38:09 +0100
From: Jorge Marques <gastmaier@...il.com>
To: Andy Shevchenko <andriy.shevchenko@...el.com>
Cc: Jorge Marques <jorge.marques@...log.com>, 
	Lars-Peter Clausen <lars@...afoo.de>, Michael Hennerich <Michael.Hennerich@...log.com>, 
	Jonathan Cameron <jic23@...nel.org>, David Lechner <dlechner@...libre.com>, 
	Nuno Sá <nuno.sa@...log.com>, Andy Shevchenko <andy@...nel.org>, Rob Herring <robh@...nel.org>, 
	Krzysztof Kozlowski <krzk+dt@...nel.org>, Conor Dooley <conor+dt@...nel.org>, 
	Jonathan Corbet <corbet@....net>, Linus Walleij <linus.walleij@...aro.org>, 
	Bartosz Golaszewski <brgl@...ev.pl>, linux-iio@...r.kernel.org, devicetree@...r.kernel.org, 
	linux-kernel@...r.kernel.org, linux-doc@...r.kernel.org, linux-gpio@...r.kernel.org
Subject: Re: [PATCH v2 9/9] iio: adc: ad4062: Add GPIO Controller support

On Thu, Nov 27, 2025 at 11:20:54AM +0200, Andy Shevchenko wrote:
Hi Andy,
> On Wed, Nov 26, 2025 at 04:55:41PM +0100, Jorge Marques wrote:
> > On Mon, Nov 24, 2025 at 12:40:37PM +0200, Andy Shevchenko wrote:
> > > On Mon, Nov 24, 2025 at 10:18:08AM +0100, Jorge Marques wrote:
> 
> ...
> 
> > > > +	return reg_val == AD4062_GP_STATIC_HIGH ? 1 : 0;
> > > 
> > > 	return !!(reg_val == AD4062_GP_STATIC_HIGH);
> > > 
> > > also will work.
> > >
> >  	return reg_val == AD4062_GP_STATIC_HIGH;
> 
> Hmm... This will include implicit bool->int. The !! guarantees values 0 or 1,
> but I don't remember about implicit bool->int case.
> 
> ...
I don't think the implicit bool->int is an issue, grepping `return .* == .*;`
matches a few methods that return int.
Experimenting with the _Bool type (gcc 15, clang 19, any std version),

	int main()
	{
	    int a = 1;
	    int b = 2;
	
	    return (_Bool)(a == b);
	}

with
gcc -Wall -W -pedantic -std=c23 -c test.c
clang -Wall -Wextra -Wbool-conversion -std=c11 -O2 test.c

also doesn't raise warnings.

> 
> > > > +static int ad4062_gpio_init_valid_mask(struct gpio_chip *gc,
> > > > +				       unsigned long *valid_mask,
> > > > +				       unsigned int ngpios)
> > > > +{
> > > > +	struct ad4062_state *st = gpiochip_get_data(gc);
> > > > +
> > > > +	bitmap_zero(valid_mask, ngpios);
> > > > +
> > > > +	if (!st->gpo_irq[0])
> > > > +		set_bit(0, valid_mask);
> > > > +	if (!st->gpo_irq[1])
> > > > +		set_bit(1, valid_mask);
> > > 
> > > Why atomic bit set:s?
> > > 
> > Not needed, will use
> 
> Note, bitops are xxx_bit() -- atomic, __xxx_bit() -- non-atomic,
> that's what I had in mind.
> 
> > 	if (!st->gpo_irq[0])
> > 		*valid_mask |= BIT(0);
> > 	if (!st->gpo_irq[1])
> > 		*valid_mask |= BIT(1);
> 
> Can't it be rather something like
> 
> 	for (unsigned int i = 0; i < ...; i++)
> 		__assign_bit(i, valid_mask, st->gpo_irq[i]);
> 
> ?
> This shorter and does the same independently on the length of the bitmask
> (and effectively the array size of gpo_irq)
> 
Sure, just
 		__assign_bit(i, valid_mask, !st->gpo_irq[i]);

"Set as valid gpo if not used as irq"
> > > > +	return 0;
> > > > +}
> 
> -- 
> With Best Regards,
> Andy Shevchenko
> 
> 
Best Regards,
Jorge