HID: asus: move vendor initialization to probe

ROG NKEY devices have multiple HID endpoints, around 3-4. One of those
endpoints has a usage page of 0xff31, and is the one that emits keyboard
shortcuts and controls RGB/backlight. Currently, this driver places
the usage page check under asus_input_mapping and then inits backlight
in asus_input_configured which is unnecessarily complicated and prevents
probe from performing customizations on the vendor endpoint.

Simplify the logic by introducing an is_vendor variable into probe that
checks for usage page 0xff31. Then, use this variable to move backlight
initialization into probe instead of asus_input_configured, and remove
the backlight check from asus_input_mapping.

Acked-by: Benjamin Tissoires <bentiss@kernel.org>
Reviewed-by: Denis Benato <benato.denis96@gmail.com>
Signed-off-by: Antheas Kapenekakis <lkml@antheas.dev>
Link: https://patch.msgid.link/20260122075044.5070-6-lkml@antheas.dev
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>

Author: antheas

drivers/hid/hid-asus.c

@@ -48,6 +48,7 @@ MODULE_DESCRIPTION("Asus HID Keyboard and TouchPad");
 #define T100CHI_MOUSE_REPORT_ID 0x06
 #define FEATURE_REPORT_ID 0x0d
 #define INPUT_REPORT_ID 0x5d
+#define HID_USAGE_PAGE_VENDOR 0xff310000
 #define FEATURE_KBD_REPORT_ID 0x5a
 #define FEATURE_KBD_REPORT_SIZE 64
 #define FEATURE_KBD_LED_REPORT_ID1 0x5d
@@ -127,7 +128,6 @@ struct asus_drvdata {
 	struct input_dev *tp_kbd_input;
 	struct asus_kbd_leds *kbd_backlight;
 	const struct asus_touchpad_info *tp;
-	bool enable_backlight;
 	struct power_supply *battery;
 	struct power_supply_desc battery_desc;
 	int battery_capacity;
@@ -318,7 +318,7 @@ 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)
 {
-	if ((usage->hid & HID_USAGE_PAGE) == 0xff310000 &&
+	if ((usage->hid & HID_USAGE_PAGE) == HID_USAGE_PAGE_VENDOR &&
 	    (usage->hid & HID_USAGE) != 0x00 &&
 	    (usage->hid & HID_USAGE) != 0xff && !usage->type) {
 		hid_warn(hdev, "Unmapped Asus vendor usagepage code 0x%02x\n",
@@ -938,11 +938,6 @@ static int asus_input_configured(struct hid_device *hdev, struct hid_input *hi)
 
 	drvdata->input = input;
 
-	if (drvdata->enable_backlight &&
-	    !asus_kbd_wmi_led_control_present(hdev) &&
-	    asus_kbd_register_leds(hdev))
-		hid_warn(hdev, "Failed to initialize backlight.\n");
-
 	return 0;
 }
 
@@ -1015,15 +1010,6 @@ static int asus_input_mapping(struct hid_device *hdev,
 			return -1;
 		}
 
-		/*
-		 * Check and enable backlight only on devices with UsagePage ==
-		 * 0xff31 to avoid initializing the keyboard firmware multiple
-		 * times on devices with multiple HID descriptors but same
-		 * PID/VID.
-		 */
-		if (drvdata->quirks & QUIRK_USE_KBD_BACKLIGHT)
-			drvdata->enable_backlight = true;
-
 		set_bit(EV_REP, hi->input->evbit);
 		return 1;
 	}
@@ -1140,8 +1126,11 @@ static int __maybe_unused asus_reset_resume(struct hid_device *hdev)
 
 static int asus_probe(struct hid_device *hdev, const struct hid_device_id *id)
 {
-	int ret;
+	struct hid_report_enum *rep_enum;
 	struct asus_drvdata *drvdata;
+	struct hid_report *rep;
+	bool is_vendor = false;
+	int ret;
 
 	drvdata = devm_kzalloc(&hdev->dev, sizeof(*drvdata), GFP_KERNEL);
 	if (drvdata == NULL) {
@@ -1225,12 +1214,24 @@ static int asus_probe(struct hid_device *hdev, const struct hid_device_id *id)
 		return ret;
 	}
 
+	/* Check for vendor for RGB init and handle generic devices properly. */
+	rep_enum = &hdev->report_enum[HID_INPUT_REPORT];
+	list_for_each_entry(rep, &rep_enum->report_list, list) {
+		if ((rep->application & HID_USAGE_PAGE) == HID_USAGE_PAGE_VENDOR)
+			is_vendor = true;
+	}
+
 	ret = hid_hw_start(hdev, HID_CONNECT_DEFAULT);
 	if (ret) {
 		hid_err(hdev, "Asus hw start failed: %d\n", ret);
 		return ret;
 	}
 
+	if (is_vendor && (drvdata->quirks & QUIRK_USE_KBD_BACKLIGHT) &&
+	    !asus_kbd_wmi_led_control_present(hdev) &&
+	    asus_kbd_register_leds(hdev))
+		hid_warn(hdev, "Failed to initialize backlight.\n");
+
 	/*
 	 * Check that input registration succeeded. Checking that
 	 * HID_CLAIMED_INPUT is set prevents a UAF when all input devices