Resource Power Manager(RPM)

RPM is a dedicated hardware engine for managing shared SoC resources,
which includes buses, clocks, power rails, etc.  The goal of RPM is
to achieve the maximum power savings while satisfying the SoC's
operational and performance requirements.  RPM accepts resource
requests from multiple RPM masters.  It arbitrates and aggregates the
requests, and configures the shared resources.  The RPM masters are
the application processor, the modem processor, as well as hardware
accelerators. The RPM driver communicates with the hardware engine using
SMD.

The devicetree representation of the SPM block should be:

Required properties

- compatible: "qcom,rpm-smd"
- rpm-channel-name: The string corresponding to the channel name of the
			peripheral subsystem
- rpm-channel-type: The interal SMD edge for this subsystem found in
			<mach/msm_smd.h>

Optional properties
- rpm-standlone: Allow the driver to run in standalone mode. This is a
			suggestion to the RPM driver and if the SMD
			channel is made available for RPM, the driver
			would continue to send requests to RPM processor,
			but if the SMD channel is unavailable, driver will
			return success even though the data is not sent
			to the RPM processor. In the absence of this
			option, the driver will fail if the SMD channel
			is unavailable.

Example:

	qcom,rpm-smd {
		compatible = "qcom,rpm-smd"
		qcom,rpm-channel-name = "rpm_requests";
		qcom,rpm-channel-type = 15; /* SMD_APPS_RPM */
	}
}