arm64: dts: qcom: samsung-gtelwifiue: Add RT8555 backlight driver

This adds the RT8555 backlight driver to the device tree. Using i2c-gpio
here is necessary, as the backlight ic is not on any i2c pins.

Signed-off-by: Michael Abood <[email protected]>

Author: person4268

Diff for: arch/arm64/boot/dts/qcom/apq8016-samsung-gtelwifiue.dts

@@ -47,6 +47,26 @@
 		};
 	};
 
+	i2c-bl {
+		status = "okay";
+		compatible = "i2c-gpio";
+		sda-gpios = <&msmgpio 24 (GPIO_ACTIVE_HIGH|GPIO_OPEN_DRAIN)>;
+		scl-gpios = <&msmgpio 25 (GPIO_ACTIVE_HIGH|GPIO_OPEN_DRAIN)>;
+
+		pinctrl-names = "default";
+		pinctrl-0 = <&bl_i2c_default>;
+
+		#address-cells = <1>;
+		#size-cells = <0>;
+
+		backlight@31 {
+			status = "okay";
+			compatible = "richtek,rt8555-backlight";
+			gpio = <&msmgpio 69 GPIO_ACTIVE_HIGH>;
+			reg = <0x31>;
+		};
+	};
+
 	reg_vdd_tsp: regulator-vdd-tsp {
 		compatible = "regulator-fixed";
 		regulator-name = "vdd_tsp";
@@ -315,6 +335,22 @@
 		bias-disable;
 	};
 
+	bl_en_default: reg-lcd-en-default {
+		pins = "gpio69";
+		function = "gpio";
+
+		drive-strength = <2>;
+		bias-disable;
+	};
+
+	bl_i2c_default: muic-i2c-default {
+		pins = "gpio24", "gpio25";
+		function = "gpio";
+
+		drive-strength = <2>;
+		bias-disable;
+	};
+
 	gpio_keys_default: gpio-keys-default {
 		pins = "gpio107", "gpio109";
 		function = "gpio";

Diff for: drivers/video/backlight/rt8555-backlight.c

@@ -29,12 +29,12 @@ struct rt8555_priv {
 static int rt8555_bl_update_status(struct backlight_device *bl_dev)
 {
 	struct rt8555_priv *priv = bl_get_data(bl_dev);
-	unsigned int brightness = min(backlight_get_brightness(bl_dev), RT8555_MAX_BRIGHTNESS);
+	unsigned int brightness = min(backlight_get_brightness(bl_dev), priv->bl->props.max_brightness);
 	int ret;
 
 	/* Enable the IC before setting the brightness */
 	if (brightness)
-			if (!IS_ERR(priv->enable))
+			if (!IS_ERR_OR_NULL(priv->enable))
 				gpiod_set_value(priv->enable, 1);
 
 
@@ -48,7 +48,7 @@ static int rt8555_bl_update_status(struct backlight_device *bl_dev)
 
 	/* Disable the IC after setting it to 0 */
 	if (brightness == 0)
-			if (!IS_ERR(priv->enable))
+			if (!IS_ERR_OR_NULL(priv->enable))
 				gpiod_set_value(priv->enable, 0);
 
 	return 0;
@@ -61,7 +61,7 @@ static int rt8555_bl_get_brightness(struct backlight_device *bl_dev)
 
 	/* If the RT8555 is disabled, there's no reason to turn it on just to read
 	 * it back */
-	if (!IS_ERR(priv->enable))
+	if (!IS_ERR_OR_NULL(priv->enable))
 		if (gpiod_get_value(priv->enable) == 0)
 			return 0;
 
@@ -103,9 +103,15 @@ static int rt8555_bl_probe(struct i2c_client *client)
 	priv->dev = &client->dev;
 
 	priv->enable = devm_gpiod_get_optional(&client->dev, NULL, GPIOD_OUT_HIGH);
-	if (!IS_ERR(priv->enable))
+	if (!IS_ERR_OR_NULL(priv->enable))
 		gpiod_set_value(priv->enable, 1);
 
+	priv->regmap = devm_regmap_init_i2c(client, &rt8555_regmap_config);
+	if (!priv->regmap) {
+		dev_err(&client->dev, "Failed to init regmap\n");
+		return -ENODEV;
+	}
+
 	ret = device_property_read_u32(&client->dev, "max-brightness", &brightness);
 	if (ret)
 		brightness = RT8555_MAX_BRIGHTNESS;
@@ -144,7 +150,7 @@ static void rt8555_bl_remove(struct i2c_client *client)
 	bl_dev->props.brightness = 0;
 	backlight_update_status(priv->bl);
 
-	if (!IS_ERR(priv->enable))
+	if (!IS_ERR_OR_NULL(priv->enable))
 		gpiod_set_value(priv->enable, 0);
 }