linux-kernel - Re: [PATCH] platform/x86: barco-p50-gpio: use software nodes for gpio-leds/keys

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Message-ID: <uakyig6sp2sfuwtt2aq7ds5dcbsjrgcijenunefqzc46inpees@xc6bfr4mjnan>
Date: Mon, 11 Aug 2025 08:49:21 -0700
From: Dmitry Torokhov <dmitry.torokhov@...il.com>
To: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Cc: Hans de Goede <hansg@...nel.org>, 
	Santosh Kumar Yadav <santoshkumar.yadav@...co.com>, Peter Korsgaard <peter.korsgaard@...co.com>, 
	Bartosz Golaszewski <bartosz.golaszewski@...aro.org>, Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>, 
	Arnd Bergmann <arnd@...db.de>, platform-driver-x86@...r.kernel.org, 
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] platform/x86: barco-p50-gpio: use software nodes for
 gpio-leds/keys

On Mon, Aug 11, 2025 at 06:45:23PM +0300, Andy Shevchenko wrote:
> On Mon, Aug 11, 2025 at 04:20:33PM +0200, Hans de Goede wrote:
> > On 11-Aug-25 2:44 PM, Andy Shevchenko wrote:
> > > On Sun, Aug 10, 2025 at 09:31:37PM -0700, Dmitry Torokhov wrote:
> 
> ...
> 
> > > Otherwise LGTM as here it looks like we establish platform device ourselves and
> > > hence no need some additional magic Hans mentioned in the other series.
> > 
> > Not entirely like with the x86-android-tablets patches this
> > declares a software-node for the gpiochip:
> > 
> > static const struct software_node gpiochip_node = {
> > 	.name = DRIVER_NAME,
> > };
> > 
> > and registers that node, but nowhere does it actually
> > get assigned to the gpiochip.
> > 
> > This is going to need a line like this added to probe():
> > 
> > 	p50->gc.fwnode = software_node_fwnode(&gpiochip_node);
> > 
> > note the software_node_fwnode() call MUST be made after
> > registering the software-nodes (group).
> > 
> > Other then needing this single line things are indeed
> > much easier when the code containing the software
> > properties / nodes is the same code as which is
> > registering the gpiochip.
> 
> Ah, good point!

This is wrong though, the software node need not be attached to the
gpiochip (and I wonder if it is even safe to do so). It simply provides
a name by which gpiochip is looked up in swnode_get_gpio_device().

Thanks.

-- 
Dmitry