Message-Id: <20251006-reset-gpios-swnodes-v1-0-6d3325b9af42@linaro.org>
Date: Mon, 06 Oct 2025 15:00:15 +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: [PATCH 0/9] reset: rework reset-gpios handling

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>
---
Bartosz Golaszewski (9):
      software node: read the reference args via the fwnode API
      software node: increase the reference of the swnode by its fwnode
      software node: allow referencing firmware nodes
      gpio: swnode: don't use the swnode's name as the key for GPIO lookup
      gpio: swnode: update the property definitions
      reset: order includes alphabetically in reset/core.c
      reset: make the provider of reset-gpios the parent of the reset device
      reset: gpio: convert the driver to using the auxiliary bus
      reset: gpio: use software nodes to setup the GPIO lookup

 drivers/base/swnode.c         |  28 +++++---
 drivers/gpio/gpiolib-swnode.c |  16 ++---
 drivers/reset/Kconfig         |   1 +
 drivers/reset/core.c          | 151 ++++++++++++++++++++++++------------------
 drivers/reset/reset-gpio.c    |  19 +++---
 include/linux/gpio/property.h |   5 +-
 include/linux/property.h      |  51 ++++++++++++--
 7 files changed, 174 insertions(+), 97 deletions(-)
---
base-commit: 097d5ce7a680da489516958e943910fa962e574a
change-id: 20250925-reset-gpios-swnodes-db553e67095b

Best regards,
-- 
Bartosz Golaszewski <bartosz.golaszewski@...aro.org>

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