Required properties:
- compatible : shall be:
"st,flexgen"
+ "st,flexgen-audio", "st,flexgen" (enable clock propagation on parent for
+ audio use case)
+ "st,flexgen-video", "st,flexgen" (enable clock propagation on parent
+ and activate synchronous mode)
- #clock-cells : from common clock binding; shall be set to 1 (multiple clock
outputs).