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CPU Voltage cooling device:
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A single cluster can have CPUs with different frequency plans.
Mitigating individual CPU may or may not bring down the CPU cluster
voltage depending on the operating level of the other CPUs.

CPU voltage cooling device will provide support to apply CPU frequency
mitigation on the different CPUs in a cluster to achieve a reduction in
cluster voltage. This is achieved by building a mitigation table mapping
the CPU frequency levels to a voltage.

Required Parameters:
- compatible: must be 'qcom,cc-cooling-devices' for cpu voltage cooling device
  driver.

	voltage cooling device node properties:
	-qcom,cpus:
		Usage: required
		Value type: An array of CPU phandle
		Definition: Specify array of 2 CPU phandles, which needs to be
			used for building a voltage based mitigation table.

	-#cooling-cells:
		Usage: required
		Value type: <integer>
		Definition: Must be 2. Needed for of_thermal as cooling device
			identifier. Please refer to
			<devicetree/bindings/thermal/thermal.txt> for more
			details.


Optional Parameters:

Example:
	qcom,cpu-voltage-cdev {
		compatible = "qcom,cc-cooling-devices";
		apc1_cluster: qcom,apc1-cluster {
			qcom,cpus = <&CPU4 &CPU7>;
			#cooling-cells = <2>;
		};
	};
