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

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Message-ID: <Z6y65SnrprvnpKEa@smile.fi.intel.com>
Date: Wed, 12 Feb 2025 17:14:45 +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 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:

...

> > > +	parent = to_platform_device(pdev->dev.parent);
> >
> > Why do you need this? Can't the fwnode be propagated to the children and then
> > the respective APIs to be used?
> 
> I'm not sure to understand this correctly, what do you mean by
> propagating the fwnode to the children?
> 
> Just a quick summary of the situation and what I try to do. The device
> tree looks like this, only keeping the interesting properties:
> 
> io-expander@38 {
>   ...
>   interrupts = <23 IRQ_TYPE_LEVEL_LOW>,
>                <24 IRQ_TYPE_LEVEL_LOW>;
>   interrupt-names = "inti", "intk";
> 
>   max7360_gpio: gpio {
>     ...
>   };
> 
>   max7360_gpo: gpo {
>     ...
>   };
> };
> 
> Our pdev fwnode points either to the "gpio" or "gpo" nodes, the one from
> our parent device points to "io-expander@38". Here we need to get the
> "inti" interrupt from the parent node. What would be the correct way to
> do it?

Ah, I see now. This is being used only for IRQs, but don't you want to call
actually fwnode_irq_get_byname()? It will makes the intention clearer.

...

> > > +	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?

-- 
With Best Regards,
Andy Shevchenko