2 files changed, 17 insertions, 0 deletions

diff --git a/docs/feature_ps2_mouse.md b/docs/feature_ps2_mouse.md
index 00c7ee72e..776a33150 100644
--- a/docs/feature_ps2_mouse.md
+++ b/docs/feature_ps2_mouse.md
@@ -270,6 +270,16 @@ Fine control over the scrolling is supported with the following defines:
 #define PS2_MOUSE_SCROLL_DIVISOR_V 2
 ```
 
+### Invert Mouse buttons :id=invert-buttons
+
+To invert the left & right buttons you can put:
+
+```c
+#define PS2_MOUSE_INVERT_BUTTONS
+```
+
+into config.h.
+
 ### Invert Mouse and Scroll Axes :id=invert-mouse-and-scroll-axes
 
 To invert the X and Y axes you can put:
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;