backlight: gpio_backlight: Enable ACPI enumeration

ACPI allows to enumerate specific devices by using compatible strings.
Enable that enumeration for GPIO based backlight devices.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

drivers/video/backlight/gpio_backlight.c

@@ -18,6 +18,7 @@
 #include <linux/of_gpio.h>
 #include <linux/platform_data/gpio_backlight.h>
 #include <linux/platform_device.h>
+#include <linux/property.h>
 #include <linux/slab.h>
 
 struct gpio_backlight {
@@ -61,11 +62,10 @@ static int gpio_backlight_probe_dt(struct platform_device *pdev,
 				   struct gpio_backlight *gbl)
 {
 	struct device *dev = &pdev->dev;
-	struct device_node *np = dev->of_node;
 	enum gpiod_flags flags;
 	int ret;
 
-	gbl->def_value = of_property_read_bool(np, "default-on");
+	gbl->def_value = device_property_read_bool(dev, "default-on");
 	flags = gbl->def_value ? GPIOD_OUT_HIGH : GPIOD_OUT_LOW;
 
 	gbl->gpiod = devm_gpiod_get(dev, NULL, flags);
@@ -89,26 +89,19 @@ static int gpio_backlight_probe(struct platform_device *pdev)
 	struct backlight_properties props;
 	struct backlight_device *bl;
 	struct gpio_backlight *gbl;
-	struct device_node *np = pdev->dev.of_node;
 	int ret;
 
-	if (!pdata && !np) {
-		dev_err(&pdev->dev,
-			"failed to find platform data or device tree node.\n");
-		return -ENODEV;
-	}
-
 	gbl = devm_kzalloc(&pdev->dev, sizeof(*gbl), GFP_KERNEL);
 	if (gbl == NULL)
 		return -ENOMEM;
 
 	gbl->dev = &pdev->dev;
 
-	if (np) {
+	if (pdev->dev.fwnode) {
 		ret = gpio_backlight_probe_dt(pdev, gbl);
 		if (ret)
 			return ret;
-	} else {
+	} else if (pdata) {
 		/*
 		 * Legacy platform data GPIO retrieveal. Do not expand
 		 * the use of this code path, currently only used by one
@@ -129,6 +122,10 @@ static int gpio_backlight_probe(struct platform_device *pdev)
 		gbl->gpiod = gpio_to_desc(pdata->gpio);
 		if (!gbl->gpiod)
 			return -EINVAL;
+	} else {
+		dev_err(&pdev->dev,
+			"failed to find platform data or device tree node.\n");
+		return -ENODEV;
 	}
 
 	memset(&props, 0, sizeof(props));
@@ -149,19 +146,17 @@ static int gpio_backlight_probe(struct platform_device *pdev)
 	return 0;
 }
 
-#ifdef CONFIG_OF
 static struct of_device_id gpio_backlight_of_match[] = {
 	{ .compatible = "gpio-backlight" },
 	{ /* sentinel */ }
 };
 
 MODULE_DEVICE_TABLE(of, gpio_backlight_of_match);
-#endif
 
 static struct platform_driver gpio_backlight_driver = {
 	.driver		= {
 		.name		= "gpio-backlight",
-		.of_match_table = of_match_ptr(gpio_backlight_of_match),
+		.of_match_table = gpio_backlight_of_match,
 	},
 	.probe		= gpio_backlight_probe,
 };