+Pin configuration nodes contain pin configuration properties, either directly
+or grouped in child subnodes. Both pin muxing and configuration parameters can
+be grouped in that way and referenced as a single pin configuration node by
+client devices.
+
+A configuration node or subnode must reference at least one pin (through the
+pins or pin groups properties) and contain at least a function or one
+configuration parameter. When the function is present only pin groups can be
+used to reference pins.