linux-kernel - Re: [PATCH v4 04/10] gpio: swnode: don't use the swnode's name as the key for GPIO lookup

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Message-ID: <CAMRc=MfD7ZbwU4akkCJNgmRPwgSOqSVi2-L2dJDOBHrfdD-yZw@mail.gmail.com>
Date: Tue, 18 Nov 2025 19:01:24 +0100
From: Bartosz Golaszewski <brgl@...ev.pl>
To: Charles Keepax <ckeepax@...nsource.cirrus.com>
Cc: Linus Walleij <linus.walleij@...aro.org>, 
	Andy Shevchenko <andriy.shevchenko@...ux.intel.com>, Daniel Scally <djrscally@...il.com>, 
	Heikki Krogerus <heikki.krogerus@...ux.intel.com>, 
	Sakari Ailus <sakari.ailus@...ux.intel.com>, 
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>, "Rafael J. Wysocki" <rafael@...nel.org>, 
	Danilo Krummrich <dakr@...nel.org>, Philipp Zabel <p.zabel@...gutronix.de>, 
	Krzysztof Kozlowski <krzk@...nel.org>, linux-gpio@...r.kernel.org, linux-kernel@...r.kernel.org, 
	linux-acpi@...r.kernel.org, 
	Bartosz Golaszewski <bartosz.golaszewski@...aro.org>, patches@...nsource.cirrus.com
Subject: Re: [PATCH v4 04/10] gpio: swnode: don't use the swnode's name as the
 key for GPIO lookup

On Tue, Nov 18, 2025 at 5:34 PM Charles Keepax
<ckeepax@...nsource.cirrus.com> wrote:
>
> On Mon, Nov 03, 2025 at 10:35:24AM +0100, Bartosz Golaszewski wrote:
> > From: Bartosz Golaszewski <bartosz.golaszewski@...aro.org>
> >
> > Looking up a GPIO controller by label that is the name of the software
> > node is wonky at best - the GPIO controller driver is free to set
> > a different label than the name of its firmware node. We're already being
> > passed a firmware node handle attached to the GPIO device to
> > swnode_get_gpio_device() so use it instead for a more precise lookup.
> >
> > Acked-by: Linus Walleij <linus.walleij@...aro.org>
> > Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@...aro.org>
> > ---
> >  drivers/gpio/gpiolib-swnode.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/gpio/gpiolib-swnode.c b/drivers/gpio/gpiolib-swnode.c
> > index f21dbc28cf2c8c2d06d034b7c89d302cc52bb9b5..e3806db1c0e077d76fcc71a50ca40bbf6872ca40 100644
> > --- a/drivers/gpio/gpiolib-swnode.c
> > +++ b/drivers/gpio/gpiolib-swnode.c
> > @@ -41,7 +41,7 @@ static struct gpio_device *swnode_get_gpio_device(struct fwnode_handle *fwnode)
> >           !strcmp(gdev_node->name, GPIOLIB_SWNODE_UNDEFINED_NAME))
> >               return ERR_PTR(-ENOENT);
> >
> > -     gdev = gpio_device_find_by_label(gdev_node->name);
> > +     gdev = gpio_device_find_by_fwnode(fwnode);
> >       return gdev ?: ERR_PTR(-EPROBE_DEFER);
> >  }
>
> One small problem is this does break drivers/spi/spi-cs42l43.c.

I'd say it's a big problem. :)

> That driver has to register some swnodes to specify some GPIO
> chip selects due to some squiffy ACPI from Windows land. Currently
> it relies on the sw node being called cs42l43-pinctrl to match
> the driver.
>

What is the problem exactly? The "cs42l43-pinctrl" swnode is
associated with a GPIO device I suppose? Does it not find it? I'd need
some more information in order to figure out a way to fix it.

> I guess that is not quite the right way to handle that but its
> not clear to me how to link the software node properties to the
> pinctrl otherwise, anyone have any pointers there?
>

Depends what you mean. Creating software nodes is fine, depending on
some arbitrary string not so much. As I said: I need more information
but I'm willing to help you fix it ASAP.

Bart