diff --git a/core/java/android/view/InputDevice.java b/core/java/android/view/InputDevice.java
index cc4598d16de9f..5592f7a42bacf 100644
--- a/core/java/android/view/InputDevice.java
+++ b/core/java/android/view/InputDevice.java
@@ -255,6 +255,15 @@ public final class InputDevice implements Parcelable {
      */
     public static final int SOURCE_TOUCH_NAVIGATION = 0x00200000 | SOURCE_CLASS_NONE;
 
+    /**
+     * The input source is a rotating encoder device whose motions should be interpreted as akin to
+     * those of a scroll wheel.
+     *
+     * @see #SOURCE_CLASS_NONE
+     * {@hide}
+     */
+    public static final int SOURCE_ROTARY_ENCODER = 0x00400000 | SOURCE_CLASS_NONE;
+
     /**
      * The input source is a joystick.
      * (It may also be a {@link #SOURCE_GAMEPAD}).
diff --git a/core/java/android/view/MotionEvent.java b/core/java/android/view/MotionEvent.java
index 6026d04a1f21b..527d7e51c3e32 100644
--- a/core/java/android/view/MotionEvent.java
+++ b/core/java/android/view/MotionEvent.java
@@ -961,6 +961,22 @@ public final class MotionEvent extends InputEvent implements Parcelable {
      */
     public static final int AXIS_TILT = 25;
 
+    /**
+     * Axis constant: Generic scroll axis of a motion event.
+     * <p>
+     * <ul>
+     * <li>Reports the relative movement of the generic scrolling device.
+     * </ul>
+     * </p><p>
+     * This axis should be used for scroll events that are neither strictly vertical nor horizontal.
+     * A good example would be the rotation of a rotary encoder input device.
+     * </p>
+     *
+     * @see #getAxisValue(int, int)
+     * {@hide}
+     */
+    public static final int AXIS_SCROLL = 26;
+
     /**
      * Axis constant: Generic 1 axis of a motion event.
      * The interpretation of a generic axis is device-specific.
@@ -1171,6 +1187,7 @@ public final class MotionEvent extends InputEvent implements Parcelable {
         names.append(AXIS_BRAKE, "AXIS_BRAKE");
         names.append(AXIS_DISTANCE, "AXIS_DISTANCE");
         names.append(AXIS_TILT, "AXIS_TILT");
+        names.append(AXIS_SCROLL, "AXIS_SCROLL");
         names.append(AXIS_GENERIC_1, "AXIS_GENERIC_1");
         names.append(AXIS_GENERIC_2, "AXIS_GENERIC_2");
         names.append(AXIS_GENERIC_3, "AXIS_GENERIC_3");