linux-kernel - [PATCH for 6.1/6.6] platform/loongarch: laptop: Add backlight power control support

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [day] [month] [year] [list]

Message-ID: <20250623081337.3767935-1-chenhuacai@loongson.cn>
Date: Mon, 23 Jun 2025 16:13:37 +0800
From: Huacai Chen <chenhuacai@...ngson.cn>
To: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Sasha Levin <sashal@...nel.org>,
	Huacai Chen <chenhuacai@...nel.org>
Cc: Xuerui Wang <kernel@...0n.name>,
	stable@...r.kernel.org,
	ziyao@...root.org,
	linux-kernel@...r.kernel.org,
	loongarch@...ts.linux.dev,
	Huacai Chen <chenhuacai@...ngson.cn>
Subject: [PATCH for 6.1/6.6] platform/loongarch: laptop: Add backlight power control support

From: Yao Zi <ziyao@...root.org>

commit 53c762b47f726e4079a1f06f684bce2fc0d56fba upstream.

loongson_laptop_turn_{on,off}_backlight() are designed for controlling
the 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
the power state of the backlight as well. Tested on the TongFang L860-T2
Loongson-3A5000 laptop.

Cc: stable@...r.kernel.org
Fixes: 6246ed09111f ("LoongArch: Add ACPI-based generic laptop driver")
Signed-off-by: Yao Zi <ziyao@...root.org>
Signed-off-by: Huacai Chen <chenhuacai@...ngson.cn>
---
 drivers/platform/loongarch/loongson-laptop.c | 73 ++++++++++----------
 1 file changed, 37 insertions(+), 36 deletions(-)

diff --git a/drivers/platform/loongarch/loongson-laptop.c b/drivers/platform/loongarch/loongson-laptop.c
index ba9a90818c92..9ba4c06252b6 100644
--- a/drivers/platform/loongarch/loongson-laptop.c
+++ b/drivers/platform/loongarch/loongson-laptop.c
@@ -56,8 +56,7 @@ 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 bool bl_powered;
 static int loongson_laptop_backlight_update(struct backlight_device *bd);
 
 /* 2. ACPI Helpers and device model */
@@ -354,16 +353,42 @@ 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);
+	bool target_powered = !backlight_is_blank(bd);
+	int ret = 0, lvl = ec_backlight_level(bd->props.brightness);
 
 	if (lvl < 0)
 		return -EIO;
+
 	if (ec_set_brightness(lvl))
 		return -EIO;
 
-	return 0;
+	if (target_powered != bl_powered) {
+		ret = ec_backlight_set_power(target_powered);
+		if (ret < 0)
+			return ret;
+
+		bl_powered = target_powered;
+	}
+
+	return ret;
 }
 
 static int loongson_laptop_get_brightness(struct backlight_device *bd)
@@ -384,7 +409,7 @@ static const struct backlight_ops backlight_laptop_ops = {
 
 static int laptop_backlight_register(void)
 {
-	int status = 0;
+	int status = 0, ret;
 	struct backlight_properties props;
 
 	memset(&props, 0, sizeof(props));
@@ -392,44 +417,20 @@ static int laptop_backlight_register(void)
 	if (!acpi_evalf(hotkey_handle, &status, "ECLL", "d"))
 		return -EIO;
 
+	ret = ec_backlight_set_power(true);
+	if (ret)
+		return ret;
+
+	bl_powered = true;
+
 	props.max_brightness = status;
 	props.brightness = ec_get_brightness();
+	props.power = FB_BLANK_UNBLANK;
 	props.type = BACKLIGHT_PLATFORM;
 
 	backlight_device_register("loongson_laptop",
 				NULL, NULL, &backlight_laptop_ops, &props);
 
-	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;
 }
-- 
2.47.1