BACKPORT: FROMLIST: platform/loongarch: laptop: Support backlight power control

loongson_laptop_turn_{on,off}_backlight() are designed for controlling
power of the backlight, but they aren't really used in the driver
previously.

Unify these two functions since they only differ in arguments passed to
ACPI method, and wire up loongson_laptop_backlight_update() to update
power state of the backlight as well. Tested on TongFang L860-T2 3A5000
laptop.

Signed-off-by: Yao Zi <[email protected]>

Link: https://lore.kernel.org/loongarch/[email protected]/
Signed-off-by: Mingcong Bai <[email protected]>

Author: ziyao233

drivers/platform/loongarch/loongson-laptop.c

@@ -56,8 +56,6 @@ static struct input_dev *generic_inputdev;
 static acpi_handle hotkey_handle;
 static struct key_entry hotkey_keycode_map[GENERIC_HOTKEY_MAP_MAX];
 
-int loongson_laptop_turn_on_backlight(void);
-int loongson_laptop_turn_off_backlight(void);
 static int loongson_laptop_backlight_update(struct backlight_device *bd);
 
 /* 2. ACPI Helpers and device model */
@@ -354,6 +352,22 @@ static int ec_backlight_level(u8 level)
 	return level;
 }
 
+static int ec_backlight_set_power(bool state)
+{
+	int status;
+	union acpi_object arg0 = { ACPI_TYPE_INTEGER };
+	struct acpi_object_list args = { 1, &arg0 };
+
+	arg0.integer.value = state;
+	status = acpi_evaluate_object(NULL, "\\BLSW", &args, NULL);
+	if (ACPI_FAILURE(status)) {
+		pr_info("Loongson lvds error: 0x%x\n", status);
+		return -EIO;
+	}
+
+	return 0;
+}
+
 static int loongson_laptop_backlight_update(struct backlight_device *bd)
 {
 	int lvl = ec_backlight_level(bd->props.brightness);
@@ -363,6 +377,8 @@ static int loongson_laptop_backlight_update(struct backlight_device *bd)
 	if (ec_set_brightness(lvl))
 		return -EIO;
 
+	ec_backlight_set_power(bd->props.power == BACKLIGHT_POWER_ON ? true : false);
+
 	return 0;
 }
 
@@ -394,6 +410,7 @@ static int laptop_backlight_register(void)
 
 	props.brightness = ec_get_brightness();
 	props.max_brightness = status;
+	props.power = BACKLIGHT_POWER_ON;
 	props.type = BACKLIGHT_PLATFORM;
 
 	backlight_device_register("loongson_laptop",
@@ -402,38 +419,6 @@ static int laptop_backlight_register(void)
 	return 0;
 }
 
-int loongson_laptop_turn_on_backlight(void)
-{
-	int status;
-	union acpi_object arg0 = { ACPI_TYPE_INTEGER };
-	struct acpi_object_list args = { 1, &arg0 };
-
-	arg0.integer.value = 1;
-	status = acpi_evaluate_object(NULL, "\\BLSW", &args, NULL);
-	if (ACPI_FAILURE(status)) {
-		pr_info("Loongson lvds error: 0x%x\n", status);
-		return -ENODEV;
-	}
-
-	return 0;
-}
-
-int loongson_laptop_turn_off_backlight(void)
-{
-	int status;
-	union acpi_object arg0 = { ACPI_TYPE_INTEGER };
-	struct acpi_object_list args = { 1, &arg0 };
-
-	arg0.integer.value = 0;
-	status = acpi_evaluate_object(NULL, "\\BLSW", &args, NULL);
-	if (ACPI_FAILURE(status)) {
-		pr_info("Loongson lvds error: 0x%x\n", status);
-		return -ENODEV;
-	}
-
-	return 0;
-}
-
 static int __init event_init(struct generic_sub_driver *sub_driver)
 {
 	int ret;