linux-kernel - Re: [PATCH v5 06/11] gpio: regmap: Allow to allocate regmap-irq device

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Message-Id: <D8KXKZ53OKGH.4LG4L2LRY9XS@bootlin.com>
Date: Thu, 20 Mar 2025 08:55:57 +0100
From: "Mathieu Dubois-Briand" <mathieu.dubois-briand@...tlin.com>
To: "Andy Shevchenko" <andriy.shevchenko@...el.com>
Cc: "Lee Jones" <lee@...nel.org>, "Rob Herring" <robh@...nel.org>,
 "Krzysztof Kozlowski" <krzk+dt@...nel.org>, "Conor Dooley"
 <conor+dt@...nel.org>, "Kamel Bouhara" <kamel.bouhara@...tlin.com>, "Linus
 Walleij" <linus.walleij@...aro.org>, "Bartosz Golaszewski" <brgl@...ev.pl>,
 "Dmitry Torokhov" <dmitry.torokhov@...il.com>,
 Uwe Kleine-König <ukleinek@...nel.org>, "Michael Walle"
 <mwalle@...nel.org>, "Mark Brown" <broonie@...nel.org>, "Greg
 Kroah-Hartman" <gregkh@...uxfoundation.org>, "Rafael J. Wysocki"
 <rafael@...nel.org>, "Danilo Krummrich" <dakr@...nel.org>,
 <devicetree@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
 <linux-gpio@...r.kernel.org>, <linux-input@...r.kernel.org>,
 <linux-pwm@...r.kernel.org>, Grégory Clement
 <gregory.clement@...tlin.com>, "Thomas Petazzoni"
 <thomas.petazzoni@...tlin.com>
Subject: Re: [PATCH v5 06/11] gpio: regmap: Allow to allocate regmap-irq
 device

On Tue Mar 18, 2025 at 5:52 PM CET, Andy Shevchenko wrote:
> On Tue, Mar 18, 2025 at 05:26:22PM +0100, Mathieu Dubois-Briand wrote:
> > GPIO controller often have support for IRQ: allow to easily allocate
> > both gpio-regmap and regmap-irq in one operation.
>
> ...
>
> > -	if (config->irq_domain) {
> > -		ret = gpiochip_irqchip_add_domain(chip, config->irq_domain);
>
> > +	irq_domain = config->irq_domain;
>
> Better to move it into #else, so we avoid double assignment (see below).
>

OK

> > +#ifdef CONFIG_GPIOLIB_IRQCHIP
> > +	if (config->regmap_irq_chip) {
> > +		struct regmap_irq_chip_data *irq_chip_data;
> > +
> > +		ret = devm_regmap_add_irq_chip_fwnode(config->parent, dev_fwnode(config->parent),
> > +						      config->regmap, config->regmap_irq_irqno,
> > +						      config->regmap_irq_flags, 0,
> > +						      config->regmap_irq_chip, &irq_chip_data);
> > +		if (ret)
> > +			goto err_free_gpio;
> > +
> > +		irq_domain = regmap_irq_get_domain(irq_chip_data);
> > +		if (config->regmap_irq_chip_data)
> > +			*config->regmap_irq_chip_data = irq_chip_data;
>
> Hmm... I was under impression that we don't need this to be returned.
> Do we have any user of it right now? If not, no need to export until
> it is needed.
>

Right, I will remove it.

> > +	}
>
> 	} else
>
> > +#endif
>
> 	irq_domain = config->irq_domain;
>
> > +
> > +	if (irq_domain) {
> > +		ret = gpiochip_irqchip_add_domain(chip, irq_domain);
> >  		if (ret)
> >  			goto err_remove_gpiochip;
> >  	}
>
> ...
>
> > +#ifdef CONFIG_GPIOLIB_IRQCHIP
> > +	struct regmap_irq_chip *regmap_irq_chip;
> > +	struct regmap_irq_chip_data **regmap_irq_chip_data;
>
> But why double pointer?
>

I believe this has to be a double pointer, as it is going to be assigned
a pointer value: data buffer is allocated inside of
devm_regmap_add_irq_chip_fwnode().

But as you said, it's better to remove it and add it later if there is
an use case.

> > +	int regmap_irq_irqno;
> > +	unsigned long regmap_irq_flags;
> > +#endif

Thanks for your review.

-- 
Mathieu Dubois-Briand, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com