expo: Support building an expo from a description file

The only way to create an expo at present is by calling the functions to
create each object. It is useful to have more data-driven approach, where
the objects can be specified in a suitable file format and created from
that. This makes testing easier as well.

Add support for describing an expo in a devicetree node. This allows more
complex tests to be set up, as well as providing an easier format for
users. It also provides a better basis for the upcoming configuration
editor.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/include/test/cedit-test.h b/include/test/cedit-test.h
new file mode 100644
index 0000000..349df75
--- /dev/null
+++ b/include/test/cedit-test.h
@@ -0,0 +1,29 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * Binding shared between cedit.dtsi and test/boot/expo.c
+ *
+ * Copyright 2023 Google LLC
+ * Written by Simon Glass <sjg@chromium.org>
+ */
+
+#ifndef __cedit_test_h
+#define __cedit_test_h
+
+#define ID_PROMPT		1
+#define ID_SCENE1		2
+#define ID_SCENE1_TITLE		3
+
+#define ID_CPU_SPEED		4
+#define ID_CPU_SPEED_TITLE	5
+#define ID_CPU_SPEED_1		6
+#define ID_CPU_SPEED_2		7
+#define ID_CPU_SPEED_3		8
+
+#define ID_POWER_LOSS		9
+#define ID_AC_OFF		10
+#define ID_AC_ON		11
+#define ID_AC_MEMORY		12
+
+#define ID_DYNAMIC_START	13
+
+#endif