Documentation/devicetree/bindings/cpufreq/cpufreq-dt.txt

   1 Generic cpufreq driver
   2
   3 It is a generic DT based cpufreq driver for frequency management.  It supports
   4 both uniprocessor (UP) and symmetric multiprocessor (SMP) systems which share
   5 clock and voltage across all CPUs.
   6
   7 Both required and optional properties listed below must be defined
   8 under node /cpus/cpu@0.
   9
  10 Required properties:
  11 - None
  12
  13 Optional properties:
  14 - operating-points: Refer to Documentation/devicetree/bindings/opp/opp.txt for
  15   details. OPPs *must* be supplied either via DT, i.e. this property, or
  16   populated at runtime.
  17 - clock-latency: Specify the possible maximum transition latency for clock,
  18   in unit of nanoseconds.
  19 - voltage-tolerance: Specify the CPU voltage tolerance in percentage.
  20 - #cooling-cells:
  21 - cooling-min-level:
  22 - cooling-max-level:
  23      Please refer to Documentation/devicetree/bindings/thermal/thermal.txt.
  24
  25 Examples:
  26
  27 cpus {
  28         #address-cells = <1>;
  29         #size-cells = <0>;
  30
  31         cpu@0 {
  32                 compatible = "arm,cortex-a9";
  33                 reg = <0>;
  34                 next-level-cache = <&L2>;
  35                 operating-points = <
  36                         /* kHz    uV */
  37                         792000  1100000
  38                         396000  950000
  39                         198000  850000
  40                 >;
  41                 clock-latency = <61036>; /* two CLK32 periods */
  42                 #cooling-cells = <2>;
  43                 cooling-min-level = <0>;
  44                 cooling-max-level = <2>;
  45         };
  46
  47         cpu@1 {
  48                 compatible = "arm,cortex-a9";
  49                 reg = <1>;
  50                 next-level-cache = <&L2>;
  51         };
  52
  53         cpu@2 {
  54                 compatible = "arm,cortex-a9";
  55                 reg = <2>;
  56                 next-level-cache = <&L2>;
  57         };
  58
  59         cpu@3 {
  60                 compatible = "arm,cortex-a9";
  61                 reg = <3>;
  62                 next-level-cache = <&L2>;
  63         };
  64 };