linux-kernel - [PATCH 7/9] reset: make the provider of reset-gpios the parent of the reset device

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Message-Id: <20251006-reset-gpios-swnodes-v1-7-6d3325b9af42@linaro.org>
Date: Mon, 06 Oct 2025 15:00:22 +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 7/9] reset: make the provider of reset-gpios the parent of
 the reset device

From: Bartosz Golaszewski <bartosz.golaszewski@...aro.org>

Auxiliary devices really do need a parent so ahead of converting the
reset-gpios driver to registering on the auxiliary bus, make the GPIO
device that provides the reset GPIO the parent of the reset-gpio device.
To that end move the lookup of the GPIO device by fwnode to the
beginning of __reset_add_reset_gpio_device() which has the added benefor
of bailing out earlier, before allocating resources for the virtual
device, if the chip is not up yet.

Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@...aro.org>
---
 drivers/reset/core.c | 18 ++++++++++--------
 1 file changed, 10 insertions(+), 8 deletions(-)

diff --git a/drivers/reset/core.c b/drivers/reset/core.c
index 5a696e2dbcc224a633e2b321da53b7bc699cb5f3..ad85ddc8dd9fcf8b512cb09168586e0afca257f1 100644
--- a/drivers/reset/core.c
+++ b/drivers/reset/core.c
@@ -849,11 +849,11 @@ static void __reset_control_put_internal(struct reset_control *rstc)
 	kref_put(&rstc->refcnt, __reset_control_release);
 }

-static int __reset_add_reset_gpio_lookup(int id, struct device_node *np,
+static int __reset_add_reset_gpio_lookup(struct gpio_device *gdev, int id,
+					 struct device_node *np,
 					 unsigned int gpio,
 					 unsigned int of_flags)
 {
-	const struct fwnode_handle *fwnode = of_fwnode_handle(np);
 	unsigned int lookup_flags;
 	const char *label_tmp;

@@ -868,10 +868,6 @@ static int __reset_add_reset_gpio_lookup(int id, struct device_node *np,
 		return -EINVAL;
 	}

-	struct gpio_device *gdev __free(gpio_device_put) = gpio_device_find_by_fwnode(fwnode);
-	if (!gdev)
-		return -EPROBE_DEFER;
-
 	label_tmp = gpio_device_get_label(gdev);
 	if (!label_tmp)
 		return -EINVAL;
@@ -919,6 +915,11 @@ static int __reset_add_reset_gpio_device(const struct of_phandle_args *args)
 	if (args->args_count != 2)
 		return -ENOENT;

+	struct gpio_device *gdev __free(gpio_device_put) =
+		gpio_device_find_by_fwnode(of_fwnode_handle(args->np));
+	if (!gdev)
+		return -EPROBE_DEFER;
+
 	/*
 	 * Registering reset-gpio device might cause immediate
 	 * bind, resulting in its probe() registering new reset controller thus
@@ -946,7 +947,7 @@ static int __reset_add_reset_gpio_device(const struct of_phandle_args *args)
 		goto err_ida_free;
 	}

-	ret = __reset_add_reset_gpio_lookup(id, args->np, args->args[0],
+	ret = __reset_add_reset_gpio_lookup(gdev, id, args->np, args->args[0],
 					    args->args[1]);
 	if (ret < 0)
 		goto err_kfree;
@@ -958,7 +959,8 @@ static int __reset_add_reset_gpio_device(const struct of_phandle_args *args)
 	 * Hold reference as long as rgpio_dev memory is valid.
 	 */
 	of_node_get(rgpio_dev->of_args.np);
-	pdev = platform_device_register_data(NULL, "reset-gpio", id,
+	pdev = platform_device_register_data(gpio_device_to_device(gdev),
+					     "reset-gpio", id,
 					     &rgpio_dev->of_args,
 					     sizeof(rgpio_dev->of_args));
 	ret = PTR_ERR_OR_ZERO(pdev);

-- 
2.48.1