linux-kernel - Re: [PATCH 0/9] reset: rework reset-gpios handling

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Message-ID: <CAMRc=Me=atAoPSGdTOn32rEHh3djTSVveYg0QYxYdb9yivy5YQ@mail.gmail.com>
Date: Fri, 17 Oct 2025 09:12:16 +0200
From: Bartosz Golaszewski <brgl@...ev.pl>
To: Linus Walleij <linus.walleij@...aro.org>, Bartosz Golaszewski <brgl@...ev.pl>, 
	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>
Cc: linux-gpio@...r.kernel.org, linux-kernel@...r.kernel.org, 
	linux-acpi@...r.kernel.org, 
	Bartosz Golaszewski <bartosz.golaszewski@...aro.org>
Subject: Re: [PATCH 0/9] reset: rework reset-gpios handling

On Mon, Oct 6, 2025 at 3:00 PM Bartosz Golaszewski <brgl@...ev.pl> wrote:
>
> Machine GPIO lookup is a nice, if a bit clunky, mechanism when we have
> absolutely no idea what the GPIO provider is or when it will be created.
> However in the case of reset-gpios, we not only know if the chip is
> there - we also already hold a reference to its firmware node.
>
> In this case using fwnode lookup makes more sense. However, since the
> reset provider is created dynamically, it doesn't have a corresponding
> firmware node (in this case: an OF-node). That leaves us with software
> nodes which currently cannot reference other implementations of the
> fwnode API, only other struct software_node objects. This is a needless
> limitation as it's imaginable that a dynamic auxiliary device (with a
> software node attached) would want to reference a real device with an OF
> node.
>
> This series does three things: extends the software node implementation,
> allowing its properties to reference not only static software nodes but
> also existing firmware nodes, updates the GPIO property interface to use
> the reworked swnode macros and finally makes the reset-gpio code the
> first user by converting the GPIO lookup from machine to swnode.
>
> Another user of the software node changes in the future could become the
> shared GPIO modules that's in the works in parallel[1].
>
> Merging strategy: the series is logically split into three parts: driver
> core, GPIO and reset respectively. However there are build-time
> dependencies between all three parts so I suggest the reset tree as the
> right one to take it upstream with an immutable branch provided to
> driver core and GPIO.
>
> [1] https://lore.kernel.org/all/20250924-gpio-shared-v1-0-775e7efeb1a3@linaro.org/
>
> Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@...aro.org>
> ---

Are there any comments on the software node part before I respin it
with Philipp's comments addressed?

Bartosz