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

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.

Signed-off-by: Connor Belli <connorbelli2003@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.com>

Author: connor-belli

drivers/hid/hid-asus.c

@@ -100,6 +100,7 @@ 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 | \
@@ -143,6 +144,8 @@ 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);
@@ -350,13 +353,21 @@ static int asus_wmi_send_event(struct asus_drvdata *drvdata, u8 code)
 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) == HID_UP_ASUSVENDOR &&
 	    (usage->hid & HID_USAGE) != 0x00 &&
 	    (usage->hid & HID_USAGE) != 0xff && !usage->type) {
 		hid_warn(hdev, "Unmapped Asus vendor usagepage code 0x%02x\n",
 			 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;
 }
 
@@ -528,6 +539,21 @@ 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;
@@ -999,6 +1025,12 @@ 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;
 }
 
@@ -1330,6 +1362,9 @@ 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);
 }
 
@@ -1457,7 +1492,7 @@ 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 },