[PATCH v2] Input: xpad - fix button mapping on Razer Atrox Xbox One

[Vernon Di Carlo <vernondicarlo@gmail.com>]

The Razer Atrox Arcade Stick for Xbox One (1532:0a00) does not use
the standard Xbox One input layout for its shoulder and trigger
buttons.

USB captures show that LB and RB are reported in bits 5 and 4 of
byte 5 respectively, opposite to the standard Xbox One mapping.
The digital LT and RT states are reported in bits 7 and 6 of byte
22 instead of the standard analog trigger fields.

As a result, xpad currently reports LB and RB swapped and does not
report LT or RT at all.

Add an Atrox-specific mapping quirk to swap LB/RB and report LT/RT
from their actual locations.

Tested with a Razer Atrox Arcade Stick for Xbox One, USB ID
1532:0a00.

Signed-off-by: Vernon Di Carlo <vernondicarlo@gmail.com>
---

Notes:
    Changes in v2:
    - Reject short Atrox input packets instead of falling back to the
      standard Xbox One trigger layout.

 drivers/input/joystick/xpad.c | 29 ++++++++++++++++++++++-------
 1 file changed, 22 insertions(+), 7 deletions(-)

diff --git a/drivers/input/joystick/xpad.c b/drivers/input/joystick/xpad.c
index feb8f368f..00de9145e 100644
--- a/drivers/input/joystick/xpad.c
+++ b/drivers/input/joystick/xpad.c
@@ -50,6 +50,7 @@
 #define MAP_PADDLES			BIT(4)
 #define MAP_PROFILE_BUTTON		BIT(5)
 #define MAP_SHARE_OFFSET		BIT(6)
+#define MAP_ATROX			BIT(7)
 
 #define DANCEPAD_MAP_CONFIG	(MAP_DPAD_TO_BUTTONS |			\
 				MAP_TRIGGERS_TO_BUTTONS | MAP_STICKS_TO_NULL)
@@ -280,7 +281,8 @@ static const struct xpad_device {
 	{ 0x1430, 0xf801, "RedOctane Controller", 0, XTYPE_XBOX360 },
 	{ 0x146b, 0x0601, "BigBen Interactive XBOX 360 Controller", 0, XTYPE_XBOX360 },
 	{ 0x146b, 0x0604, "Bigben Interactive DAIJA Arcade Stick", MAP_TRIGGERS_TO_BUTTONS, XTYPE_XBOX360 },
-	{ 0x1532, 0x0a00, "Razer Atrox Arcade Stick", MAP_TRIGGERS_TO_BUTTONS, XTYPE_XBOXONE },
+	{ 0x1532, 0x0a00, "Razer Atrox Arcade Stick",
+	  MAP_TRIGGERS_TO_BUTTONS | MAP_ATROX, XTYPE_XBOXONE },
 	{ 0x1532, 0x0a03, "Razer Wildcat", 0, XTYPE_XBOXONE },
 	{ 0x1532, 0x0a29, "Razer Wolverine V2", 0, XTYPE_XBOXONE },
 	{ 0x1532, 0x0a57, "Razer Wolverine V3 Pro (Wired)", 0, XTYPE_XBOX360 },
@@ -1079,6 +1081,9 @@ static void xpadone_process_packet(struct usb_xpad *xpad, u16 cmd, unsigned char
 					 error);
 		}
 	} else if (data[0] == GIP_CMD_INPUT) { /* The main valid packet type for inputs */
+		if ((xpad->mapping & MAP_ATROX) && len <= 22)
+			return;
+
 		/* menu/view buttons */
 		input_report_key(dev, BTN_START,  data[4] & BIT(2));
 		input_report_key(dev, BTN_SELECT, data[4] & BIT(3));
@@ -1110,8 +1115,13 @@ static void xpadone_process_packet(struct usb_xpad *xpad, u16 cmd, unsigned char
 		}
 
 		/* TL/TR */
-		input_report_key(dev, BTN_TL,	data[5] & BIT(4));
-		input_report_key(dev, BTN_TR,	data[5] & BIT(5));
+		if (xpad->mapping & MAP_ATROX) {
+			input_report_key(dev, BTN_TL, data[5] & BIT(5));
+			input_report_key(dev, BTN_TR, data[5] & BIT(4));
+		} else {
+			input_report_key(dev, BTN_TL, data[5] & BIT(4));
+			input_report_key(dev, BTN_TR, data[5] & BIT(5));
+		}
 
 		/* stick press left/right */
 		input_report_key(dev, BTN_THUMBL, data[5] & BIT(6));
@@ -1133,10 +1143,15 @@ static void xpadone_process_packet(struct usb_xpad *xpad, u16 cmd, unsigned char
 
 		/* triggers left/right */
 		if (xpad->mapping & MAP_TRIGGERS_TO_BUTTONS) {
-			input_report_key(dev, BTN_TL2,
-					(__u16) le16_to_cpup((__le16 *)(data + 6)));
-			input_report_key(dev, BTN_TR2,
-					(__u16) le16_to_cpup((__le16 *)(data + 8)));
+			if (xpad->mapping & MAP_ATROX) {
+				input_report_key(dev, BTN_TL2, data[22] & BIT(7));
+				input_report_key(dev, BTN_TR2, data[22] & BIT(6));
+			} else {
+				input_report_key(dev, BTN_TL2,
+						(__u16) le16_to_cpup((__le16 *)(data + 6)));
+				input_report_key(dev, BTN_TR2,
+						(__u16) le16_to_cpup((__le16 *)(data + 8)));
+			}
 		} else {
 			input_report_abs(dev, ABS_Z,
 					(__u16) le16_to_cpup((__le16 *)(data + 6)));
-- 
2.53.0