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Generic cpufreq driver
It is a generic DT based cpufreq driver for frequency management. It supports
both uniprocessor (UP) and symmetric multiprocessor (SMP) systems which share
clock and voltage across all CPUs.
Both required and optional properties listed below must be defined
under node /cpus/cpu@0.
Required properties:
- None
Optional properties:
- operating-points: Refer to Documentation/devicetree/bindings/opp/opp-v1.yaml for
details. OPPs *must* be supplied either via DT, i.e. this property, or
populated at runtime.
- clock-latency: Specify the possible maximum transition latency for clock,
in unit of nanoseconds.
- voltage-tolerance: Specify the CPU voltage tolerance in percentage.
- #cooling-cells:
Please refer to
Documentation/devicetree/bindings/thermal/thermal-cooling-devices.yaml.
Examples:
cpus {
#address-cells = <1>;
#size-cells = <0>;
cpu@0 {
compatible = "arm,cortex-a9";
reg = <0>;
next-level-cache = <&L2>;
operating-points = <
/* kHz uV */
792000 1100000
396000 950000
198000 850000
>;
clock-latency = <61036>; /* two CLK32 periods */
#cooling-cells = <2>;
};
cpu@1 {
compatible = "arm,cortex-a9";
reg = <1>;
next-level-cache = <&L2>;
};
cpu@2 {
compatible = "arm,cortex-a9";
reg = <2>;
next-level-cache = <&L2>;
};
cpu@3 {
compatible = "arm,cortex-a9";
reg = <3>;
next-level-cache = <&L2>;
};
};