[PATCH] HID: hid-asus: Implement fn lock for Asus ProArt P16

[Connor Belli <connorbelli2003@gmail.com>]

This patch implements support for the fn lock key on the 2025 Asus
ProArt P16. The implementation for this is based on how fn lock is
implemented in the hid-lenovo driver. Unfortunately, I am not too
experienced with driver development, so I'm not sure adding the
handler directly in asus_event is the best solution for this.

Signed-off-by: Connor Belli <connorbelli2003@gmail.com>
---
 drivers/hid/hid-asus.c | 36 +++++++++++++++++++++++++++++++++++-
 1 file changed, 35 insertions(+), 1 deletion(-)

diff --git a/drivers/hid/hid-asus.c b/drivers/hid/hid-asus.c
index a444d41e53b6..402b3e5d1a5c 100644
--- a/drivers/hid/hid-asus.c
+++ b/drivers/hid/hid-asus.c
@@ -89,6 +89,7 @@ MODULE_DESCRIPTION("Asus HID Keyboard and TouchPad");
 #define QUIRK_ROG_NKEY_KEYBOARD		BIT(11)
 #define QUIRK_ROG_CLAYMORE_II_KEYBOARD BIT(12)
 #define QUIRK_ROG_ALLY_XPAD		BIT(13)
+#define QUIRK_HID_FN_LOCK		BIT(14)
 
 #define I2C_KEYBOARD_QUIRKS			(QUIRK_FIX_NOTEBOOK_REPORT | \
 						 QUIRK_NO_INIT_REPORTS | \
@@ -132,6 +133,8 @@ struct asus_drvdata {
 	int battery_stat;
 	bool battery_in_query;
 	unsigned long battery_next_query;
+	struct work_struct fn_lock_sync_work;
+	bool fn_lock;
 };
 
 static int asus_report_battery(struct asus_drvdata *, u8 *, int);
@@ -316,6 +319,7 @@ static int asus_e1239t_event(struct asus_drvdata *drvdat, u8 *data, int size)
 static int asus_event(struct hid_device *hdev, struct hid_field *field,
 		      struct hid_usage *usage, __s32 value)
 {
+	struct asus_drvdata *drvdata = hid_get_drvdata(hdev);
 	if ((usage->hid & HID_USAGE_PAGE) == 0xff310000 &&
 	    (usage->hid & HID_USAGE) != 0x00 &&
 	    (usage->hid & HID_USAGE) != 0xff && !usage->type) {
@@ -323,6 +327,12 @@ static int asus_event(struct hid_device *hdev, struct hid_field *field,
 			 usage->hid & HID_USAGE);
 	}
 
+	if (drvdata->quirks & QUIRK_HID_FN_LOCK &&
+		usage->type == EV_KEY && usage->code == KEY_FN_ESC && value == 1) {
+		drvdata->fn_lock = !drvdata->fn_lock;
+		schedule_work(&drvdata->fn_lock_sync_work);
+	}
+
 	return 0;
 }
 
@@ -457,6 +467,21 @@ static int asus_kbd_disable_oobe(struct hid_device *hdev)
 	return 0;
 }
 
+static int asus_kbd_set_fn_lock(struct hid_device *hdev, bool enabled)
+{
+	u8 buf[] = { FEATURE_KBD_REPORT_ID, 0xd0, 0x4e, !!enabled };
+
+	return asus_kbd_set_report(hdev, buf, sizeof(buf));
+}
+
+static void asus_sync_fn_lock(struct work_struct *work)
+{
+	struct asus_drvdata *drvdata =
+	container_of(work, struct asus_drvdata, fn_lock_sync_work);
+
+	asus_kbd_set_fn_lock(drvdata->hdev, drvdata->fn_lock);
+}
+
 static void asus_schedule_work(struct asus_kbd_leds *led)
 {
 	unsigned long flags;
@@ -928,6 +953,12 @@ static int asus_input_configured(struct hid_device *hdev, struct hid_input *hi)
 	    asus_kbd_register_leds(hdev))
 		hid_warn(hdev, "Failed to initialize backlight.\n");
 
+	if (drvdata->quirks & QUIRK_HID_FN_LOCK) {
+		drvdata->fn_lock = true;
+		INIT_WORK(&drvdata->fn_lock_sync_work, asus_sync_fn_lock);
+		asus_kbd_set_fn_lock(hdev, true);
+	}
+
 	return 0;
 }
 
@@ -1259,6 +1290,9 @@ static void asus_remove(struct hid_device *hdev)
 		cancel_work_sync(&drvdata->kbd_backlight->work);
 	}
 
+	if (drvdata->quirks & QUIRK_HID_FN_LOCK)
+		cancel_work_sync(&drvdata->fn_lock_sync_work);
+
 	hid_hw_stop(hdev);
 }
 
@@ -1386,7 +1420,7 @@ static const struct hid_device_id asus_devices[] = {
 	  QUIRK_USE_KBD_BACKLIGHT | QUIRK_ROG_NKEY_KEYBOARD },
 	{ HID_USB_DEVICE(USB_VENDOR_ID_ASUSTEK,
 	    USB_DEVICE_ID_ASUSTEK_ROG_NKEY_KEYBOARD2),
-	  QUIRK_USE_KBD_BACKLIGHT | QUIRK_ROG_NKEY_KEYBOARD },
+	  QUIRK_USE_KBD_BACKLIGHT | QUIRK_ROG_NKEY_KEYBOARD | QUIRK_HID_FN_LOCK },
 	{ HID_USB_DEVICE(USB_VENDOR_ID_ASUSTEK,
 	    USB_DEVICE_ID_ASUSTEK_ROG_Z13_LIGHTBAR),
 	  QUIRK_USE_KBD_BACKLIGHT | QUIRK_ROG_NKEY_KEYBOARD },
-- 
2.52.0