diff --git a/xc7/family.cmake b/xc7/family.cmake
index 9de869ee..6d24b405 100644
--- a/xc7/family.cmake
+++ b/xc7/family.cmake
@@ -1,3 +1,19 @@
+# Adapted https://cliutils.gitlab.io/modern-cmake/chapters/projects/submodule.html
+find_package(Git QUIET)
+if(GIT_FOUND AND EXISTS ".gitmodules")
+# Update submodules as needed
+    option(GIT_SUBMODULE "Check submodules during build" ON)
+    if(GIT_SUBMODULE)
+        message(STATUS "Submodule update")
+        execute_process(COMMAND ${GIT_EXECUTABLE} submodule update --init --recursive
+                        WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}
+                        RESULT_VARIABLE GIT_SUBMOD_RESULT)
+        if(NOT GIT_SUBMOD_RESULT EQUAL "0")
+            message(FATAL_ERROR "git submodule update --init failed with ${GIT_SUBMOD_RESULT}, please checkout submodules")
+        endif()
+    endif()
+endif()
+
 add_dependencies(nextpnr-${family} torc)
 add_custom_target(torc ALL
                   COMMAND $(MAKE) > /dev/null 2> /dev/null