reset: make the provider of reset-gpios the parent of the reset device

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 benefit
of bailing out earlier, before allocating resources for the virtual
device, if the chip is not up yet.

Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>

Author: Bartosz Golaszewski

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;
@@ -926,6 +922,11 @@ static int __reset_add_reset_gpio_device(const struct of_phandle_args *args)
 	 */
 	lockdep_assert_not_held(&reset_list_mutex);
 
+	struct gpio_device *gdev __free(gpio_device_put) =
+		gpio_device_find_by_fwnode(of_fwnode_handle(args->np));
+	if (!gdev)
+		return -EPROBE_DEFER;
+
 	guard(mutex)(&reset_gpio_lookup_mutex);
 
 	list_for_each_entry(rgpio_dev, &reset_gpio_lookup_list, list) {
@@ -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);