diff --git a/doc/README.splashprepare b/doc/README.splashprepare
index 61b4ec5..a0f0f3c 100644
--- a/doc/README.splashprepare
+++ b/doc/README.splashprepare
@@ -6,3 +6,16 @@
 sequence. It gives the board an opportunity to prepare the splash
 image data before it is processed and sent to the frame buffer by
 U-Boot.  Define your own version to use this feature.
+
+CONFIG_SPLASH_SOURCE
+
+Use the splash_source.c library. This library provides facilities to declare
+board specific splash image locations, routines for loading splash image from
+supported locations, and a way of controlling the selected splash location
+using the "splashsource" environment variable.
+
+splashsource works as follows:
+- If splashsource is set to a supported location name as defined by board code,
+  use that splash location.
+- If splashsource is undefined, use the first splash location as default.
+- If splashsource is set to an unsupported value, do not load a splash screen.