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>

drivers/gpio/gpio-regmap.c

@@ -249,6 +249,7 @@ struct gpio_regmap *gpio_regmap_register(const struct gpio_regmap_config *config
 
 	chip = &gpio->gpio_chip;
 	chip->parent = config->parent;
+	chip->of_node = config->of_node ?: dev_of_node(config->parent);
 	chip->base = -1;
 	chip->ngpio = config->ngpio;
 	chip->names = config->names;

include/linux/gpio/regmap.h

@@ -4,6 +4,7 @@
 #define _LINUX_GPIO_REGMAP_H
 
 struct device;
+struct device_node;
 struct gpio_regmap;
 struct irq_domain;
 struct regmap;
@@ -15,6 +16,7 @@ struct regmap;
  * struct gpio_regmap_config - Description of a generic regmap gpio_chip.
  * @parent:		The parent device
  * @regmap:		The regmap used to access the registers
+ * @of_node:		(Optional) The device node
  *			given, the name of the device is used
  * @label:		(Optional) Descriptive name for GPIO controller.
  *			If not given, the name of the device is used.
@@ -57,6 +59,7 @@ struct regmap;
 struct gpio_regmap_config {
 	struct device *parent;
 	struct regmap *regmap;
+	struct device_node *of_node;
 
 	const char *label;
 	int ngpio;