See Section 3. for an example of driver implementing this
callback, or Section 2.4 for further documentation on this API
+Registration of EM using DT
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+The EM can also be registered using OPP framework and information in DT
+"operating-points-v2". Each OPP entry in DT can be extended with a property
+"opp-microwatt" containing micro-Watts power value. This OPP DT property
+allows a platform to register EM power values which are reflecting total power
+(static + dynamic). These power values might be coming directly from
+experiments and measurements.
+
Registration of 'simple' EM
~~~~~~~~~~~~~~~~~~~~~~~~~~~