Quelle  rtc-opal.txt

IBM OPAL real-time clock
------------------------

Required properties:
- compatible: Should be "ibm,opal-rtc"

Optional properties:
- wakeup-source: Decides if the wakeup is supported or not
   (Legacy property supported: "has-tpo")

Example:
 rtc {
  compatible = "ibm,opal-rtc";
  wakeup-source;
  phandle = <0x10000029>;
  linux,phandle = <0x10000029>;
 };