linux/Documentation/devicetree/bindings/power/opp.txt
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   1* Generic OPP Interface
   2
   3SoCs have a standard set of tuples consisting of frequency and
   4voltage pairs that the device will support per voltage domain. These
   5are called Operating Performance Points or OPPs.
   6
   7Properties:
   8- operating-points: An array of 2-tuples items, and each item consists
   9  of frequency and voltage like <freq-kHz vol-uV>.
  10        freq: clock frequency in kHz
  11        vol: voltage in microvolt
  12
  13Examples:
  14
  15cpu@0 {
  16        compatible = "arm,cortex-a9";
  17        reg = <0>;
  18        next-level-cache = <&L2>;
  19        operating-points = <
  20                /* kHz    uV */
  21                792000  1100000
  22                396000  950000
  23                198000  850000
  24        >;
  25};
  26