[PATCH v2] platform/x86: asus-wmi: fix camera key led on Zenbook S14

["José Guilherme de Castro Rodrigues" <jose.guilherme.cr.bh@gmail.com>]

Fix key led not turning on/off when the camera key is pressed. The
asus_wmi_dev_is_present(ASUS_WMI_DEVID_CAMERA_LED) check fails on
Zenbook S14, and no sysfs attribute for the camera key led is
created.

The check succeeds for ASUS_WMI_DEVID_CAMERA_LED_NEG, though,
and when it is read, the led state is synchronized. By doing a read after
every key press, the led is guaranteed to stay in sync with the actual
camera state.

This change is not visible to userspace, as no sysfs attribute for
ASUS_WMI_DEVID_CAMERA_LED_NEG exists.

Tested on an ASUS Zenbook S14 with BIOS version UX5406SA.309.

Signed-off-by: José Guilherme de Castro Rodrigues <jose.guilherme.cr.bh@gmail.com>
---
Changes in v2:
 - Do not return after triggering the update.
 - Use tabs for indentation on new defines.
---
 drivers/platform/x86/asus-wmi.c            | 19 +++++++++++++++++++
 include/linux/platform_data/x86/asus-wmi.h |  2 +-
 2 files changed, 20 insertions(+), 1 deletion(-)

diff --git a/drivers/platform/x86/asus-wmi.c b/drivers/platform/x86/asus-wmi.c
index 80144c412b90..32d0d4ce60ff 100644
--- a/drivers/platform/x86/asus-wmi.c
+++ b/drivers/platform/x86/asus-wmi.c
@@ -70,6 +70,8 @@ module_param(fnlock_default, bool, 0444);
 #define NOTIFY_KBD_TTP			0xae
 #define NOTIFY_LID_FLIP			0xfa
 #define NOTIFY_LID_FLIP_ROG		0xbd
+#define NOTIFY_CAMERA_TOGGLE_1		0x82
+#define NOTIFY_CAMERA_TOGGLE_2		0x85
 
 #define ASUS_WMI_FNLOCK_BIOS_DISABLED	BIT(0)
 
@@ -307,6 +309,7 @@ struct asus_wmi {
 	u32 kbd_rgb_dev;
 	bool kbd_rgb_state_available;
 	bool oobe_state_available;
+	bool camera_neg_led_available;
 
 	u8 throttle_thermal_policy_mode;
 	u32 throttle_thermal_policy_dev;
@@ -1982,6 +1985,18 @@ static int micmute_led_set(struct led_classdev *led_cdev,
 	return err < 0 ? err : 0;
 }
 
+static bool is_camera_toggle(int code)
+{
+	return code == NOTIFY_CAMERA_TOGGLE_1 || code == NOTIFY_CAMERA_TOGGLE_2;
+}
+
+static void camera_neg_led_trigger_update(struct asus_wmi *asus)
+{
+	u32 result;
+
+	asus_wmi_get_devstate(asus, ASUS_WMI_DEVID_CAMERA_LED_NEG, &result);
+}
+
 static enum led_brightness camera_led_get(struct led_classdev *led_cdev)
 {
 	struct asus_wmi *asus;
@@ -4587,6 +4602,9 @@ static void asus_wmi_handle_event_code(int code, struct asus_wmi *asus)
 	if (is_display_toggle(code) && asus->driver->quirks->no_display_toggle)
 		return;
 
+	if (is_camera_toggle(code) && asus->camera_neg_led_available)
+		camera_neg_led_trigger_update(asus);
+
 	if (!sparse_keymap_report_event(asus->inputdev, code,
 					key_value, autorelease))
 		pr_info("Unknown key code 0x%x\n", code);
@@ -5062,6 +5080,7 @@ static int asus_wmi_add(struct platform_device *pdev)
 #endif /* IS_ENABLED(CONFIG_ASUS_WMI_DEPRECATED_ATTRS) */
 
 	asus->oobe_state_available = asus_wmi_dev_is_present(asus, ASUS_WMI_DEVID_OOBE);
+	asus->camera_neg_led_available = asus_wmi_dev_is_present(asus, ASUS_WMI_DEVID_CAMERA_LED_NEG);
 
 	if (asus_wmi_dev_is_present(asus, ASUS_WMI_DEVID_THROTTLE_THERMAL_POLICY))
 		asus->throttle_thermal_policy_dev = ASUS_WMI_DEVID_THROTTLE_THERMAL_POLICY;
diff --git a/include/linux/platform_data/x86/asus-wmi.h b/include/linux/platform_data/x86/asus-wmi.h
index 554f41b827e1..1a9349da6069 100644
--- a/include/linux/platform_data/x86/asus-wmi.h
+++ b/include/linux/platform_data/x86/asus-wmi.h
@@ -56,7 +56,7 @@
 #define ASUS_WMI_DEVID_MICMUTE_LED		0x00040017
 
 /* Disable Camera LED */
-#define ASUS_WMI_DEVID_CAMERA_LED_NEG	0x00060078 /* 0 = on (unused) */
+#define ASUS_WMI_DEVID_CAMERA_LED_NEG	0x00060078 /* 0 = on */
 #define ASUS_WMI_DEVID_CAMERA_LED	0x00060079 /* 1 = on */
 
 /* Backlight and Brightness */
-- 
2.53.0