gpio: add parameter to allow the use named gpios

The gpio binding document says that new code should always use named
gpios. Patch 40b73183 added support to parse a list of gpios from child
nodes, but does not make it possible to use named gpios. This patch adds
the con_id property and implements it is done in gpiolib.c, where the
old-style of using unnamed gpios still works.

Signed-off-by: Olliver Schinagl <oliver@schinagl.nl>
Acked-by: Bryan Wu <cooloney@gmail.com>
Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Reviewed-by: Alexandre Courbot <acourbot@nvidia.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
diff --git a/drivers/leds/leds-gpio.c b/drivers/leds/leds-gpio.c
index d26af0a..15eb3f8 100644
--- a/drivers/leds/leds-gpio.c
+++ b/drivers/leds/leds-gpio.c
@@ -184,7 +184,7 @@
 		struct gpio_led led = {};
 		const char *state = NULL;
 
-		led.gpiod = devm_get_gpiod_from_child(dev, child);
+		led.gpiod = devm_get_gpiod_from_child(dev, NULL, child);
 		if (IS_ERR(led.gpiod)) {
 			fwnode_handle_put(child);
 			ret = PTR_ERR(led.gpiod);