diff --git a/doc/CMakeLists.txt b/doc/CMakeLists.txt
index 079c62b2..7bcc0d67 100644
--- a/doc/CMakeLists.txt
+++ b/doc/CMakeLists.txt
@@ -5,5 +5,6 @@ find_package(Doxygen)
 
 if (DOXYGEN_FOUND)
     doxygen_add_docs(docs
+                     ${CMAKE_SOURCE_DIR}/src
                      ${CMAKE_CURRENT_SOURCE_DIR})
 endif()