diff --git a/automotive/evs/1.0/IEvsCamera.hal b/automotive/evs/1.0/IEvsCamera.hal
index dbcaf92..464dafb 100644
--- a/automotive/evs/1.0/IEvsCamera.hal
+++ b/automotive/evs/1.0/IEvsCamera.hal
@@ -16,7 +16,6 @@
 
 package android.hardware.automotive.evs@1.0;
 
-import types;
 import IEvsCameraStream;
 
 
@@ -28,8 +27,8 @@
     /**
      * Returns the ID of this camera.
      *
-     * Returns the description of this camera. This must be the same value as reported
-     * by EvsEnumerator::getCamerList().
+     * @return info The description of this camera.  This must be the same value as
+     *              reported by EvsEnumerator::getCameraList().
      */
     getCameraInfo() generates (CameraDesc info);
 
@@ -43,16 +42,20 @@
      * in which case buffers should be added or removed from the chain as appropriate.
      * If no call is made to this entry point, the IEvsCamera must support at least one
      * frame by default. More is acceptable.
-     * BUFFER_NOT_AVAILABLE is returned if the implementation cannot support the
-     * requested number of concurrent frames.
+     *
+     * @param  bufferCount Number of buffers the client of IEvsCamera may hold concurrently.
+     * @return result EvsResult::OK is returned if this call is successful.
      */
     setMaxFramesInFlight(uint32_t bufferCount) generates (EvsResult result);
 
     /**
-     * Request delivery of EVS camera frames from this camera.
+     * Request to start EVS camera stream from this camera.
      *
-     * The IEvsCameraStream must begin receiving periodic calls with new image
-     * frames until stopVideoStream() is called.
+     * The IEvsCameraStream must begin receiving calls with various events
+     * including new image frame ready until stopVideoStream() is called.
+     *
+     * @param  receiver IEvsCameraStream implementation.
+     * @return result EvsResult::OK is returned if this call is successful.
      */
     startVideoStream(IEvsCameraStream receiver) generates (EvsResult result);
 
@@ -64,6 +67,8 @@
      * A small, finite number of buffers are available (possibly as small
      * as one), and if the supply is exhausted, no further frames may be
      * delivered until a buffer is returned.
+     *
+     * @param  buffer A buffer to be returned.
      */
     oneway doneWithFrame(BufferDesc buffer);
 
@@ -83,6 +88,11 @@
      * The values allowed for opaqueIdentifier are driver specific,
      * but no value passed in may crash the driver. The driver should
      * return 0 for any unrecognized opaqueIdentifier.
+     *
+     * @param  opaqueIdentifier An unique identifier of the information to
+     *                          request.
+     * @return value            Requested information.  Zero is returned if the
+     *                          driver does not recognize a given identifier.
      */
     getExtendedInfo(uint32_t opaqueIdentifier) generates (int32_t value);
 
@@ -94,6 +104,11 @@
      * in order to function in a default state.
      * INVALID_ARG is returned if the opaqueValue is not meaningful to
      * the driver implementation.
+     *
+     * @param  opaqueIdentifier An unique identifier of the information to
+     *                          program.
+     *         opaqueValue      A value to program.
+     * @return result           EvsResult::OK is returned if this call is successful.
      */
     setExtendedInfo(uint32_t opaqueIdentifier, int32_t opaqueValue) generates (EvsResult result);
 };
diff --git a/automotive/evs/1.0/IEvsCameraStream.hal b/automotive/evs/1.0/IEvsCameraStream.hal
index 4e743b2..ec18f6a 100644
--- a/automotive/evs/1.0/IEvsCameraStream.hal
+++ b/automotive/evs/1.0/IEvsCameraStream.hal
@@ -31,6 +31,8 @@
      * When the last frame in the stream has been delivered, a NULL bufferHandle
      * must be delivered, signifying the end of the stream. No further frame
      * deliveries may happen thereafter.
+     *
+     * @param buffer a buffer descriptor of a delivered image frame.
      */
     oneway deliverFrame(BufferDesc buffer);
 };
diff --git a/automotive/evs/1.0/IEvsDisplay.hal b/automotive/evs/1.0/IEvsDisplay.hal
index 12541f3..72f767e 100644
--- a/automotive/evs/1.0/IEvsDisplay.hal
+++ b/automotive/evs/1.0/IEvsDisplay.hal
@@ -16,8 +16,6 @@
 
 package android.hardware.automotive.evs@1.0;
 
-import types;
-
 
 /**
  * Represents a single camera and is the primary interface for capturing images.
@@ -28,6 +26,9 @@
      * Returns basic information about the EVS display provided by the system.
      *
      * See the description of the DisplayDesc structure for details.
+     *
+     * @return info The description of this display.  Please see the description
+     *              of the DisplayDesc structure for details.
      */
      getDisplayInfo() generates (DisplayDesc info);
 
@@ -42,6 +43,9 @@
      * video. When the display is no longer required, the client is expected to request
      * the NOT_VISIBLE state after passing the last video frame.
      * Returns INVALID_ARG if the requested state is not a recognized value.
+     *
+     * @param  state  Desired new DisplayState.
+     * @return result EvsResult::OK is returned if this call is successful.
      */
      setDisplayState(DisplayState state) generates (EvsResult result);
 
@@ -54,6 +58,8 @@
      * the logic responsible for changing display states should generally live above
      * the device layer, making it undesirable for the HAL implementation to spontaneously
      * change display states.
+     *
+     * @return state Current DisplayState of this Display.
      */
      getDisplayState() generates (DisplayState state);
 
@@ -61,9 +67,11 @@
     /**
      * This call returns a handle to a frame buffer associated with the display.
      *
-     * The returned buffer may be locked and written to by software and/or GL. This buffer
-     * must be returned via a call to returnTargetBufferForDisplay() even if the
-     * display is no longer visible.
+     * @return buffer A handle to a frame buffer.  The returned buffer may be
+     *                locked and written to by software and/or GL.  This buffer
+     *                must be returned via a call to
+     *                returnTargetBufferForDisplay() even if the display is no
+     *                longer visible.
      */
      getTargetBuffer() generates (BufferDesc buffer);
 
@@ -75,6 +83,9 @@
      * There is no maximum time the caller may hold onto the buffer before making this
      * call. The buffer may be returned at any time and in any DisplayState, but all
      * buffers are expected to be returned before the IEvsDisplay interface is destroyed.
+     *
+     * @param  buffer A buffer handle to the frame that is ready for display.
+     * @return result EvsResult::OK is returned if this call is successful.
      */
     returnTargetBufferForDisplay(BufferDesc buffer) generates (EvsResult result);
 };
diff --git a/automotive/evs/1.0/IEvsEnumerator.hal b/automotive/evs/1.0/IEvsEnumerator.hal
index ee51e7e..e5633df 100644
--- a/automotive/evs/1.0/IEvsEnumerator.hal
+++ b/automotive/evs/1.0/IEvsEnumerator.hal
@@ -16,7 +16,6 @@
 
 package android.hardware.automotive.evs@1.0;
 
-import types;
 import IEvsCamera;
 import IEvsDisplay;
 
@@ -28,6 +27,8 @@
 
     /**
      * Returns a list of all EVS cameras available to the system
+     *
+     * @return cameras A list of cameras availale for EVS service.
      */
     getCameraList() generates (vec<CameraDesc> cameras);
 
@@ -37,9 +38,9 @@
      * Given a camera's unique cameraId from CameraDesc, returns the
      * IEvsCamera interface associated with the specified camera. When
      * done using the camera, the caller may release it by calling closeCamera().
-     * Note: Reliance on the sp<> going out of scope is not recommended
-     * because the resources may not be released right away due to asynchronos
-     * behavior in the hardware binder (ref b/36122635).
+     *
+     * @param  cameraId  A unique identifier of the camera.
+     * @return carCamera EvsCamera object associated with a given cameraId.
      */
     openCamera(string cameraId) generates (IEvsCamera carCamera);
 
@@ -48,6 +49,8 @@
      *
      * When the IEvsCamera object is no longer required, it must be released.
      * NOTE: Video streaming must be cleanly stopped before making this call.
+     *
+     * @param  carCamera EvsCamera object to be closed.
      */
     closeCamera(IEvsCamera carCamera);
 
@@ -60,8 +63,8 @@
      * the old instance shall be closed and give the new caller exclusive
      * access.
      * When done using the display, the caller may release it by calling closeDisplay().
-     * TODO(b/36122635) Reliance on the sp<> going out of scope is not recommended because the
-     * resources may not be released right away due to asynchronos behavior in the hardware binder.
+     *
+     * @return display EvsDisplay object to be used.
      */
     openDisplay() generates (IEvsDisplay display);
 
@@ -70,6 +73,8 @@
      *
      * When the IEvsDisplay object is no longer required, it must be released.
      * NOTE: All buffers must have been returned to the display before making this call.
+     *
+     * @param  display EvsDisplay object to be closed.
      */
     closeDisplay(IEvsDisplay display);
 
@@ -80,6 +85,8 @@
      * the actual state of the active display.  This call is replicated on the IEvsEnumerator
      * interface in order to allow secondary clients to monitor the state of the EVS display
      * without acquiring exclusive ownership of the display.
+     *
+     * @return state Current DisplayState of this Display.
      */
     getDisplayState() generates (DisplayState state);
 };
diff --git a/automotive/evs/1.0/types.hal b/automotive/evs/1.0/types.hal
index 7cebf6d..1efd5eb 100644
--- a/automotive/evs/1.0/types.hal
+++ b/automotive/evs/1.0/types.hal
@@ -24,8 +24,15 @@
  * EVS camera in the system.
  */
 struct CameraDesc {
+    /* Unique identifier for camera devices.  This may be a path to detected
+     * camera device; for example, "/dev/video0".
+     */
     string      cameraId;
-    uint32_t    vendorFlags;    // Opaque value from driver
+
+    /* Opaque value from driver.  Vendor may use this field to store additional
+     * information; for example, sensor and bridge chip id.
+     */
+    uint32_t    vendorFlags;
 };
 
 
@@ -38,8 +45,11 @@
  * presentation device.
  */
 struct DisplayDesc {
+    /* Unique identifier for the display */
     string      displayId;
-    uint32_t    vendorFlags;    // Opaque value from driver
+
+    /* Opaque value from driver */
+    uint32_t    vendorFlags;
 };
 
 
@@ -56,14 +66,31 @@
  *        Specifically consider if format and/or usage should become enumerated types.
  */
 struct BufferDesc {
-    uint32_t    width;      // Units of pixels
-    uint32_t    height;     // Units of pixels
-    uint32_t    stride;     // Units of pixels to match gralloc
-    uint32_t    pixelSize;  // Units of bytes
-    uint32_t    format;     // May contain values from android_pixel_format_t
-    uint32_t    usage;      // May contain values from from Gralloc.h
-    uint32_t    bufferId;   // Opaque value from driver
-    handle      memHandle;  // gralloc memory buffer handle
+    /* A frame width in the units of pixels */
+    uint32_t    width;
+
+    /* A frame height in the units of pixels */
+    uint32_t    height;
+
+    /* A frame stride in the units of pixels, to match gralloc */
+    uint32_t    stride;
+
+    /* The size of a pixel in the units of bytes */
+    uint32_t    pixelSize;
+
+    /* The image format of the frame; may contain values from
+     * android_pixel_format_t
+     */
+    uint32_t    format;
+
+    /* May contain values from Gralloc.h */
+    uint32_t    usage;
+
+    /* Opaque value from driver */
+    uint32_t    bufferId;
+
+    /* Gralloc memory buffer handle */
+    handle      memHandle;
 };
 
 
@@ -77,12 +104,23 @@
  * presentation device.
  */
 enum DisplayState : uint32_t {
-    NOT_OPEN = 0,           // Display has not been requested by any application
-    NOT_VISIBLE,            // Display is inhibited
-    VISIBLE_ON_NEXT_FRAME,  // Will become visible with next frame
-    VISIBLE,                // Display is currently active
-    DEAD,                   // Driver is in an undefined state.  Interface should be closed.
-    NUM_STATES              // Must be last
+    /* Display has not been requested by any application yet */
+    NOT_OPEN = 0,
+
+    /* Display is inhibited */
+    NOT_VISIBLE,
+
+    /* Will become visible with next frame */
+    VISIBLE_ON_NEXT_FRAME,
+
+    /* Display is currently active */
+    VISIBLE,
+
+    /* Driver is in an undefined state.  Interface should be closed. */
+    DEAD,
+
+    /* Must be the last */
+    NUM_STATES
 };