Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/drivers/video/backlight/gpio_backlight.c b/drivers/video/backlight/gpio_backlight.c
index e470da9..18e053e 100644
--- a/drivers/video/backlight/gpio_backlight.c
+++ b/drivers/video/backlight/gpio_backlight.c
@@ -1,9 +1,6 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * gpio_backlight.c - Simple GPIO-controlled backlight
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
  */
 
 #include <linux/backlight.h>
@@ -18,6 +15,7 @@
 #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 {
@@ -61,14 +59,11 @@
 				   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");
-	flags = gbl->def_value ? GPIOD_OUT_HIGH : GPIOD_OUT_LOW;
+	gbl->def_value = device_property_read_bool(dev, "default-on");
 
-	gbl->gpiod = devm_gpiod_get(dev, NULL, flags);
+	gbl->gpiod = devm_gpiod_get(dev, NULL, GPIOD_ASIS);
 	if (IS_ERR(gbl->gpiod)) {
 		ret = PTR_ERR(gbl->gpiod);
 
@@ -82,6 +77,22 @@
 	return 0;
 }
 
+static int gpio_backlight_initial_power_state(struct gpio_backlight *gbl)
+{
+	struct device_node *node = gbl->dev->of_node;
+
+	/* Not booted with device tree or no phandle link to the node */
+	if (!node || !node->phandle)
+		return gbl->def_value ? FB_BLANK_UNBLANK : FB_BLANK_POWERDOWN;
+
+	/* if the enable GPIO is disabled, do not enable the backlight */
+	if (gpiod_get_value_cansleep(gbl->gpiod) == 0)
+		return FB_BLANK_POWERDOWN;
+
+	return FB_BLANK_UNBLANK;
+}
+
+
 static int gpio_backlight_probe(struct platform_device *pdev)
 {
 	struct gpio_backlight_platform_data *pdata =
@@ -89,26 +100,19 @@
 	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 +133,10 @@
 		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));
@@ -142,26 +150,26 @@
 		return PTR_ERR(bl);
 	}
 
-	bl->props.brightness = gbl->def_value;
+	bl->props.power = gpio_backlight_initial_power_state(gbl);
+	bl->props.brightness = 1;
+
 	backlight_update_status(bl);
 
 	platform_set_drvdata(pdev, bl);
 	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,
 };