gpio: regmap: set gpio_chip of_node

This is needed for properly registering GPIO regmap as a child of a regmap
pin controller.

Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
Reviewed-by: Michael Walle <michael@walle.cc>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Acked-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Link: https://lore.kernel.org/r/20210324081923.20379-3-noltari@gmail.com
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/gpio/gpio-regmap.c

@@ -254,6 +254,11 @@ struct gpio_regmap *gpio_regmap_register(const struct gpio_regmap_config *config
 	chip->names = config->names;
 	chip->label = config->label ?: dev_name(config->parent);
 
+#if defined(CONFIG_OF_GPIO)
+	/* gpiolib will use of_node of the parent if chip->of_node is NULL */
+	chip->of_node = to_of_node(config->fwnode);
+#endif /* CONFIG_OF_GPIO */
+
 	/*
 	 * If our regmap is fast_io we should probably set can_sleep to false.
 	 * Right now, the regmap doesn't save this property, nor is there any

include/linux/gpio/regmap.h

@@ -4,6 +4,7 @@
 #define _LINUX_GPIO_REGMAP_H
 
 struct device;
+struct fwnode_handle;
 struct gpio_regmap;
 struct irq_domain;
 struct regmap;
@@ -16,6 +17,8 @@ struct regmap;
  * @parent:		The parent device
  * @regmap:		The regmap used to access the registers
  *			given, the name of the device is used
+ * @fwnode:		(Optional) The firmware node.
+ *			If not given, the fwnode of the parent is used.
  * @label:		(Optional) Descriptive name for GPIO controller.
  *			If not given, the name of the device is used.
  * @ngpio:		Number of GPIOs
@@ -57,6 +60,7 @@ struct regmap;
 struct gpio_regmap_config {
 	struct device *parent;
 	struct regmap *regmap;
+	struct fwnode_handle *fwnode;
 
 	const char *label;
 	int ngpio;