linux-kernel - Re: [PATCH v3 4/7] gpio: max7360: Add MAX7360 gpio support

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Message-ID: <Z6zJljphfTuEhBTP@smile.fi.intel.com>
Date: Wed, 12 Feb 2025 18:17:26 +0200
From: Andy Shevchenko <andriy.shevchenko@...el.com>
To: Mathieu Dubois-Briand <mathieu.dubois-briand@...tlin.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>,
	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 v3 4/7] gpio: max7360: Add MAX7360 gpio support

On Wed, Feb 12, 2025 at 05:08:56PM +0100, Mathieu Dubois-Briand wrote:
> On Wed Feb 12, 2025 at 4:14 PM CET, Andy Shevchenko wrote:
> > On Wed, Feb 12, 2025 at 01:57:34PM +0100, Mathieu Dubois-Briand wrote:
> > > On Mon Jan 27, 2025 at 2:07 PM CET, Andy Shevchenko wrote:
> > > > On Mon, Jan 13, 2025 at 01:42:28PM +0100, Mathieu Dubois-Briand wrote:

...

> > > > > +	if (of_property_read_u32(pdev->dev.of_node, "ngpios", &ngpios)) {
> > > > > +		dev_err(&pdev->dev, "Missing ngpios OF property\n");
> > > > > +		return -ENODEV;
> > > > > +	}
> > > >
> > > > This is not needed, it is already done in GPIOLIB core.
> > > 
> > > I believe this is still needed:
> > > - For gpos, we need the gpio count to correctly set the partition
> > >   between gpo and keypad columns in max7360_set_gpos_count().
> >
> > Shouldn't be that done somewhere in the GPIO valid mask initialisation?
> >
> > > - For gpios, we need the gpio count to setup the IRQs.
> >
> > Doesn't GPIOLIB parse the property before initializing the IRQ valid mask
> > and other init callbacks?
> 
> No, I believe I have to register the IRQ before registering the GPIO, so
> I can get the IRQ domain.
> 
> Right now I have something like:
> 
> irq_chip->num_irqs = ngpios;
> devm_regmap_add_irq_chip_fwnode(dev, dev_fwnode(dev), max7360_gpio->regmap,
> irq, flags, 0, irq_chip, &irq_chip_data);
> gpio_config.irq_domain = regmap_irq_get_domain(irq_chip_data);
> devm_gpio_regmap_register(dev, &gpio_config);
> 
> Also, gpiolib will store ngpios in the gpio_chip structure, but while
> using gpio-regmap, this structure is masked behind the opaque
> gpio_regmap structure. So I believe there is no easy way to retrieve its
> value.
> 
> This part of the code changed a lot, maybe it would be easier if I push
> a new version of the series and we continue the discussion there?

So, what seems need to be added is some flag to GPIO regmap configuration
data structure and a code that is called after gpiochip_add_data() in
gpio_regmap_register() to create a domain. This will solve the above issue
and helps other drivers to get rid of potential duplication of
devm_regmap_add_irq_chip_fwnode() calls.

Have you researched this path?

-- 
With Best Regards,
Andy Shevchenko