HID: quirks: Allow inverting the absolute X/Y values

Add a HID_QUIRK_X_INVERT/HID_QUIRK_Y_INVERT quirk that can be used
to invert the X/Y values.
Signed-off-by: Alistair Francis <alistair@alistair23.me>
[bentiss: silence checkpatch warning]
Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Link: https://lore.kernel.org/r/20211208124045.61815-2-alistair@alistair23.me

drivers/hid/hid-input.c

@@ -1329,6 +1329,12 @@ void hidinput_hid_event(struct hid_device *hid, struct hid_field *field, struct
 
 	input = field->hidinput->input;
 
+	if (usage->type == EV_ABS &&
+	    (((*quirks & HID_QUIRK_X_INVERT) && usage->code == ABS_X) ||
+	     ((*quirks & HID_QUIRK_Y_INVERT) && usage->code == ABS_Y))) {
+		value = field->logical_maximum - value;
+	}
+
 	if (usage->hat_min < usage->hat_max || usage->hat_dir) {
 		int hat_dir = usage->hat_dir;
 		if (!hat_dir)

include/linux/hid.h

@@ -359,6 +359,8 @@ struct hid_item {
 /* BIT(9) reserved for backward compatibility, was NO_INIT_INPUT_REPORTS */
 #define HID_QUIRK_ALWAYS_POLL			BIT(10)
 #define HID_QUIRK_INPUT_PER_APP			BIT(11)
+#define HID_QUIRK_X_INVERT			BIT(12)
+#define HID_QUIRK_Y_INVERT			BIT(13)
 #define HID_QUIRK_SKIP_OUTPUT_REPORTS		BIT(16)
 #define HID_QUIRK_SKIP_OUTPUT_REPORT_ID		BIT(17)
 #define HID_QUIRK_NO_OUTPUT_REPORTS_ON_INTR_EP	BIT(18)