leds: leds-gpio: Defer probing in case of deferred gpio probing

This patch makes leds-gpio's probe() return -EPROBE_DEFER if any of the gpios
to register are deferred themselves. This makes a change of
gpio_leds_create_of()'s return value necessary: Instead of returning NULL on
error, we now use ERR_PTR() error coding.
Signed-off-by: Roland Stigge <stigge@antcom.de>
Signed-off-by: Bryan Wu <cooloney@gmail.com>

drivers/leds/leds-gpio.c

@@ -21,6 +21,7 @@
 #include <linux/workqueue.h>
 #include <linux/module.h>
 #include <linux/pinctrl/consumer.h>
+#include <linux/err.h>
 
 struct gpio_led_data {
 	struct led_classdev cdev;
@@ -174,12 +175,16 @@ static struct gpio_leds_priv * __devinit gpio_leds_create_of(struct platform_dev
 	/* count LEDs in this device, so we know how much to allocate */
 	count = of_get_child_count(np);
 	if (!count)
-		return NULL;
+		return ERR_PTR(-ENODEV);
+
+	for_each_child_of_node(np, child)
+		if (of_get_gpio(child, 0) == -EPROBE_DEFER)
+			return ERR_PTR(-EPROBE_DEFER);
 
 	priv = devm_kzalloc(&pdev->dev, sizeof_gpio_leds_priv(count),
 			GFP_KERNEL);
 	if (!priv)
-		return NULL;
+		return ERR_PTR(-ENOMEM);
 
 	for_each_child_of_node(np, child) {
 		struct gpio_led led = {};
@@ -214,7 +219,7 @@ static struct gpio_leds_priv * __devinit gpio_leds_create_of(struct platform_dev
 err:
 	for (count = priv->num_leds - 2; count >= 0; count--)
 		delete_gpio_led(&priv->leds[count]);
-	return NULL;
+	return ERR_PTR(-ENODEV);
 }
 
 static const struct of_device_id of_gpio_leds_match[] = {
@@ -224,7 +229,7 @@ static const struct of_device_id of_gpio_leds_match[] = {
 #else /* CONFIG_OF_GPIO */
 static struct gpio_leds_priv * __devinit gpio_leds_create_of(struct platform_device *pdev)
 {
-	return NULL;
+	return ERR_PTR(-ENODEV);
 }
 #endif /* CONFIG_OF_GPIO */
 
@@ -262,8 +267,8 @@ static int __devinit gpio_led_probe(struct platform_device *pdev)
 		}
 	} else {
 		priv = gpio_leds_create_of(pdev);
-		if (!priv)
-			return -ENODEV;
+		if (IS_ERR(priv))
+			return PTR_ERR(priv);
 	}
 
 	platform_set_drvdata(pdev, priv);