Qualcomm Resource Power Manager (RPM) over SMD

This driver is used to interface with the Resource Power Manager (RPM) found in
various Qualcomm platforms. The RPM allows each component in the system to vote
for state of the system resources, such as clocks, regulators and bus
frequencies.

The SMD information for the RPM edge should be filled out.  See qcom,smd.txt for
the required edge properties.  All SMD related properties will reside within the
RPM node itself.

= SUBDEVICES

The RPM exposes resources to its subnodes.  The rpm_requests node must be
present and this subnode may contain children that designate regulator
resources.

- compatible:
	Usage: required
	Value type: <string>
	Definition: must be one of:
		    "qcom,rpm-apq8084"
		    "qcom,rpm-msm8916"
		    "qcom,rpm-msm8974"
		    "qcom,rpm-msm8998"
		    "qcom,rpm-sdm660"
		    "qcom,rpm-qcs404"

- qcom,smd-channels:
	Usage: required
	Value type: <string>
	Definition: must be "rpm_requests"

Refer to Documentation/devicetree/bindings/regulator/qcom,smd-rpm-regulator.txt
for information on the regulator subnodes that can exist under the rpm_requests.

Example:

	soc {
		apcs: syscon@f9011000 {
			compatible = "syscon";
			reg = <0xf9011000 0x1000>;
		};
	};

	smd {
		compatible = "qcom,smd";

		rpm {
			interrupts = <0 168 1>;
			qcom,ipc = <&apcs 8 0>;
			qcom,smd-edge = <15>;

			rpm_requests {
				compatible = "qcom,rpm-msm8974";
				qcom,smd-channels = "rpm_requests";

				...
			};
		};
	};