gpio: of: Allow overriding the device node

When registering a GPIO chip, drivers can override the device tree node
associated with the chip by setting the chip's ->of_node field. If set,
this field is supposed to take precedence over the ->parent->of_node
field, but the code doesn't actually do that.

Commit 762c2e46 ("gpio: of: remove of_gpiochip_and_xlate() and
struct gg_data") exposes this because it now no longer matches on the
GPIO chip's ->of_node field, but the GPIO device's ->of_node field that
is set using the procedure described above.
Signed-off-by: NThierry Reding <treding@nvidia.com>
Acked-by: NAlexandre Courbot <acourbot@nvidia.com>
Reviewed-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

drivers/gpio/gpiolib.c

@@ -1049,13 +1049,14 @@ int gpiochip_add_data(struct gpio_chip *chip, void *data)
 	if (chip->parent) {
 		gdev->dev.parent = chip->parent;
 		gdev->dev.of_node = chip->parent->of_node;
-	} else {
+	}
+
 #ifdef CONFIG_OF_GPIO
 	/* If the gpiochip has an assigned OF node this takes precedence */
-		if (chip->of_node)
-			gdev->dev.of_node = chip->of_node;
+	if (chip->of_node)
+		gdev->dev.of_node = chip->of_node;
 #endif
-	}
+
 	gdev->id = ida_simple_get(&gpio_ida, 0, 0, GFP_KERNEL);
 	if (gdev->id < 0) {
 		status = gdev->id;