diff --git a/include/camera/CameraHardwareInterface.h b/include/camera/CameraHardwareInterface.h
index d877c74..1529db7 100644
--- a/include/camera/CameraHardwareInterface.h
+++ b/include/camera/CameraHardwareInterface.h
@@ -213,8 +213,15 @@
     virtual status_t dump(int fd, const Vector<String16>& args) const = 0;
 };
 
-/** factory function to instantiate a camera hardware object */
-extern "C" sp<CameraHardwareInterface> openCameraHardware();
+/**
+ * The functions need to be provided by the camera HAL.
+ *
+ * If getNumberOfCameras() returns N, the valid cameraId for getCameraInfo()
+ * and openCameraHardware() is 0 to N-1.
+ */
+extern "C" int HAL_getNumberOfCameras();
+extern "C" void HAL_getCameraInfo(int cameraId, struct CameraInfo* cameraInfo);
+extern "C" sp<CameraHardwareInterface> HAL_openCameraHardware(int cameraId);
 
 };  // namespace android