diff --git a/include/hardware/input.h b/include/hardware/input.h
index 91354aa..c4a4cb5 100644
--- a/include/hardware/input.h
+++ b/include/hardware/input.h
@@ -318,6 +318,12 @@
     // axes
     INPUT_USAGE_AXIS_X,
     INPUT_USAGE_AXIS_Y,
+    INPUT_USAGE_AXIS_Z,
+    INPUT_USAGE_AXIS_RX,
+    INPUT_USAGE_AXIS_RY,
+    INPUT_USAGE_AXIS_RZ,
+    INPUT_USAGE_AXIS_HAT_X,
+    INPUT_USAGE_AXIS_HAT_Y,
     INPUT_USAGE_AXIS_PRESSURE,
     INPUT_USAGE_AXIS_SIZE,
     INPUT_USAGE_AXIS_TOUCH_MAJOR,
@@ -327,12 +333,6 @@
     INPUT_USAGE_AXIS_ORIENTATION,
     INPUT_USAGE_AXIS_VSCROLL,
     INPUT_USAGE_AXIS_HSCROLL,
-    INPUT_USAGE_AXIS_Z,
-    INPUT_USAGE_AXIS_RX,
-    INPUT_USAGE_AXIS_RY,
-    INPUT_USAGE_AXIS_RZ,
-    INPUT_USAGE_AXIS_HAT_X,
-    INPUT_USAGE_AXIS_HAT_Y,
     INPUT_USAGE_AXIS_LTRIGGER,
     INPUT_USAGE_AXIS_RTRIGGER,
     INPUT_USAGE_AXIS_THROTTLE,
@@ -384,6 +384,15 @@
     INPUT_USAGE_SWITCH_MICROPHONE_INSERT,
     INPUT_USAGE_SWITCH_LINEOUT_INSERT,
     INPUT_USAGE_SWITCH_CAMERA_LENS_COVER,
+
+    // mouse buttons
+    // (see android.view.MotionEvent)
+    INPUT_USAGE_BUTTON_UNKNOWN,
+    INPUT_USAGE_BUTTON_PRIMARY,   // left
+    INPUT_USAGE_BUTTON_SECONDARY, // right
+    INPUT_USAGE_BUTTON_TERTIARY,  // middle
+    INPUT_USAGE_BUTTON_FORWARD,
+    INPUT_USAGE_BUTTON_BACK,
 } input_usage_t;
 
 typedef enum input_collection_id {