[PATCH v15 1/3] HID: quirks: Allow inverting the absolute X/Y values

[Alistair Francis <alistair@alistair23.me>]

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>
---
 drivers/hid/hid-input.c | 6 ++++++
 include/linux/hid.h     | 2 ++
 2 files changed, 8 insertions(+)

diff --git a/drivers/hid/hid-input.c b/drivers/hid/hid-input.c
index 217f2d1b91c5..83ee803186a1 100644
--- a/drivers/hid/hid-input.c
+++ b/drivers/hid/hid-input.c
@@ -1331,6 +1331,12 @@ 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)
diff --git a/include/linux/hid.h b/include/linux/hid.h
index 9e067f937dbc..4959385ca588 100644
--- a/include/linux/hid.h
+++ b/include/linux/hid.h
@@ -349,6 +349,8 @@ 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)
-- 
2.31.1