1 files changed, 7 insertions, 0 deletions

diff --git a/tmk_core/protocol/ps2_mouse.c b/tmk_core/protocol/ps2_mouse.c
index 525aeb45a..39251a643 100644
--- a/tmk_core/protocol/ps2_mouse.c
+++ b/tmk_core/protocol/ps2_mouse.c
@@ -156,8 +156,15 @@ static inline void ps2_mouse_convert_report_to_hid(report_mouse_t *mouse_report)
     mouse_report->x = X_IS_NEG ? ((!X_IS_OVF && -127 <= mouse_report->x && mouse_report->x <= -1) ? mouse_report->x : -127) : ((!X_IS_OVF && 0 <= mouse_report->x && mouse_report->x <= 127) ? mouse_report->x : 127);
     mouse_report->y = Y_IS_NEG ? ((!Y_IS_OVF && -127 <= mouse_report->y && mouse_report->y <= -1) ? mouse_report->y : -127) : ((!Y_IS_OVF && 0 <= mouse_report->y && mouse_report->y <= 127) ? mouse_report->y : 127);
 
+#ifdef PS2_MOUSE_INVERT_BUTTONS
+    // swap left & right buttons
+    uint8_t needs_left = mouse_report->buttons & PS2_MOUSE_BTN_RIGHT;
+    uint8_t needs_right = mouse_report->buttons & PS2_MOUSE_BTN_LEFT;
+    mouse_report->buttons = (mouse_report->buttons & ~(PS2_MOUSE_BTN_MASK)) | (needs_left ? PS2_MOUSE_BTN_LEFT : 0) | (needs_right ? PS2_MOUSE_BTN_RIGHT : 0);
+#else
     // remove sign and overflow flags
     mouse_report->buttons &= PS2_MOUSE_BTN_MASK;
+#endif
 
 #ifdef PS2_MOUSE_INVERT_X
     mouse_report->x = -mouse_report->x;