leds: regulator: Make probeable from device tree

The regulator LED can easily be adapted to probe from the
device tree.

We switch led_classdev_register() to led_classdev_register_ext()
passing some struct led_init_data init_data that we leave NULL
save the fwnode if platform data isn't present so that it will be
populated from the device tree.

If we have platform data we set up the name from the platform
data but using init_data instead.

Cc: Antonio Ospite <ao2@ao2.it>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Pavel Machek <pavel@ucw.cz>

drivers/leds/leds-regulator.c

@@ -8,6 +8,7 @@
  */
 
 #include <linux/module.h>
+#include <linux/mod_devicetable.h>
 #include <linux/err.h>
 #include <linux/slab.h>
 #include <linux/leds.h>
@@ -124,18 +125,14 @@ static int regulator_led_probe(struct platform_device *pdev)
 	struct led_regulator_platform_data *pdata =
 			dev_get_platdata(&pdev->dev);
 	struct device *dev = &pdev->dev;
+	struct led_init_data init_data = {};
 	struct regulator_led *led;
 	struct regulator *vcc;
 	int ret = 0;
 
-	if (pdata == NULL) {
-		dev_err(dev, "no platform data\n");
-		return -ENODEV;
-	}
-
 	vcc = devm_regulator_get_exclusive(dev, "vled");
 	if (IS_ERR(vcc)) {
-		dev_err(dev, "Cannot get vcc for %s\n", pdata->name);
+		dev_err(dev, "Cannot get vcc\n");
 		return PTR_ERR(vcc);
 	}
 
@@ -143,15 +140,21 @@ static int regulator_led_probe(struct platform_device *pdev)
 	if (led == NULL)
 		return -ENOMEM;
 
+	init_data.fwnode = dev->fwnode;
+
 	led->cdev.max_brightness = led_regulator_get_max_brightness(vcc);
-	if (pdata->brightness > led->cdev.max_brightness) {
-		dev_err(dev, "Invalid default brightness %d\n",
+	/* Legacy platform data label assignment */
+	if (pdata) {
+		if (pdata->brightness > led->cdev.max_brightness) {
+			dev_err(dev, "Invalid default brightness %d\n",
 				pdata->brightness);
-		return -EINVAL;
+			return -EINVAL;
+		}
+		led->cdev.brightness = pdata->brightness;
+		init_data.default_label = pdata->name;
 	}
 
 	led->cdev.brightness_set_blocking = regulator_led_brightness_set;
-	led->cdev.name = pdata->name;
 	led->cdev.flags |= LED_CORE_SUSPENDRESUME;
 	led->vcc = vcc;
 
@@ -163,16 +166,10 @@ static int regulator_led_probe(struct platform_device *pdev)
 
 	platform_set_drvdata(pdev, led);
 
-	ret = led_classdev_register(dev, &led->cdev);
+	ret = led_classdev_register_ext(dev, &led->cdev, &init_data);
 	if (ret < 0)
 		return ret;
 
-	/* to expose the default value to userspace */
-	led->cdev.brightness = pdata->brightness;
-
-	/* Set the default led status */
-	regulator_led_brightness_set(&led->cdev, led->cdev.brightness);
-
 	return 0;
 }
 
@@ -185,10 +182,17 @@ static int regulator_led_remove(struct platform_device *pdev)
 	return 0;
 }
 
+static const struct of_device_id regulator_led_of_match[] = {
+	{ .compatible = "regulator-led", },
+	{}
+};
+MODULE_DEVICE_TABLE(of, regulator_led_of_match);
+
 static struct platform_driver regulator_led_driver = {
 	.driver = {
-		   .name  = "leds-regulator",
-		   },
+		.name  = "leds-regulator",
+		.of_match_table = regulator_led_of_match,
+	},
 	.probe  = regulator_led_probe,
 	.remove = regulator_led_remove,
 };