Add inventory interfaces for OpenBMC

A first pass at a machine parseable DBus specification for the
inventory features of OpenBMC.

Change-Id: Ia061ab2d5c2ea9d06cd991940303250cef48ab66
Signed-off-by: Brad Bishop <bradleyb@fuzziesquirrel.com>
diff --git a/xyz/openbmc_project/Inventory/Item/Cacheable.interface.yaml b/xyz/openbmc_project/Inventory/Item/Cacheable.interface.yaml
new file mode 100644
index 0000000..210c132
--- /dev/null
+++ b/xyz/openbmc_project/Inventory/Item/Cacheable.interface.yaml
@@ -0,0 +1,10 @@
+description: >
+    Implement to indicate item availability changes.
+properties:
+    - name: Cached
+      type: b
+      description: >
+          Whether or not the item is cached.  When true, the item
+          and its remaining attributes are undefined.
+
+# vim: tabstop=8 expandtab shiftwidth=4 softtabstop=4