linux-kernel - Re: [PATCH v7 0/9] reset: rework reset-gpios handling

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Message-ID: <4e26c38c17fdcecc0e3fc119222568bc543f870b.camel@pengutronix.de>
Date: Thu, 20 Nov 2025 17:32:46 +0100
From: Philipp Zabel <p.zabel@...gutronix.de>
To: Bartosz Golaszewski <brgl@...ev.pl>, 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>, Krzysztof Kozlowski	 <krzk@...nel.org>,
 David Rhodes <david.rhodes@...rus.com>, Richard Fitzgerald	
 <rf@...nsource.cirrus.com>, Mark Brown <broonie@...nel.org>, Maciej Strozek
	 <mstrozek@...nsource.cirrus.com>, Charles Keepax
 <ckeepax@...nsource.cirrus.com>,  Andy Shevchenko	 <andy@...nel.org>,
 Bartosz Golaszewski <brgl@...nel.org>
Cc: linux-gpio@...r.kernel.org, linux-kernel@...r.kernel.org, 
	linux-acpi@...r.kernel.org, linux-sound@...r.kernel.org, 
	patches@...nsource.cirrus.com, linux-spi@...r.kernel.org, Bartosz
 Golaszewski	 <bartosz.golaszewski@...aro.org>, stable+noautosel@...nel.org
Subject: Re: [PATCH v7 0/9] reset: rework reset-gpios handling

On Do, 2025-11-20 at 14:23 +0100, Bartosz Golaszewski 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 four parts: driver
> core, SPI, 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, SPI and GPIO.

Applied to reset/next, thanks!

[1/9] software node: read the reference args via the fwnode API
      https://git.pengutronix.de/cgit/pza/linux/commit/?id=f11a8e996d5e
[2/9] software node: increase the reference of the swnode by its fwnode
      https://git.pengutronix.de/cgit/pza/linux/commit/?id=0651933c117e
[3/9] software node: allow referencing firmware nodes
      https://git.pengutronix.de/cgit/pza/linux/commit/?id=d7cdbbc93c56
[4/9] spi: cs42l43: Use actual ACPI firmware node for chip selects
      https://git.pengutronix.de/cgit/pza/linux/commit/?id=d2a6cea44acc
[5/9] gpio: swnode: allow referencing GPIO chips by firmware nodes
      https://git.pengutronix.de/cgit/pza/linux/commit/?id=216c12047571
[6/9] reset: order includes alphabetically in reset/core.c
      https://git.pengutronix.de/cgit/pza/linux/commit/?id=97d85328e3dc
[7/9] reset: make the provider of reset-gpios the parent of the reset device
      https://git.pengutronix.de/cgit/pza/linux/commit/?id=46dae84a90f9
[8/9] reset: gpio: convert the driver to using the auxiliary bus
      https://git.pengutronix.de/cgit/pza/linux/commit/?id=109ce747ac22
[9/9] reset: gpio: use software nodes to setup the GPIO lookup
      https://git.pengutronix.de/cgit/pza/linux/commit/?id=5fc4e4cf7a22

5fc4e4cf7a22 is tagged as reset-gpio-for-v6.19. I'll send a separate
pull request for it.

regards
Philipp