dt-bindings: thermal: Add LMH DCVSh devicetree documentation

Limits Management Hardware - DCVS

The LMH-DCVS block is a hardware IP for every CPU cluster, to handle quick

changes in thermal limits. The hardware responds to thermal variation amongst

the CPUs in the cluster by requesting limits on the clock frequency and

voltage on the OSM hardware.

The LMH DCVS driver exports a virtual sensor that can be used to set the

thermal limits on the hardware. LMH DCVS driver can be a platform CPU Cooling

device, which registers with the CPU cooling device interface. All CPU device

nodes should reference the corresponding LMH DCVS hardware in device tree.

CPUs referencing the same LMH DCVS node will be associated with the

corresponding cooling device as related CPUs.

Properties:

- compatible:

	Usage: required

	Value type: <string>

	Definition: shall be "qcom,msm-hw-limits"

- interrupts:

	Usage: optional

	Value type: <interrupt_type interrupt_number interrupt_trigger_type>

	Definition: Should specify interrupt information about the debug

			interrupt generated by the LMH DCVSh hardware. LMH

			DCVSh hardware will generate this interrupt whenever

			it makes a new cpu DCVS decision.

- qcom,affinity:

	Usage: optional

	Value type: <u32>

	Definition: Should specify the cluster affinity this hardware

			corresponds to.

- isens_vref_1p8-supply:

- isens_vref_0p8-supply:

	Usage: optional

	Value type: <phandle>

	Definition: Should specify the phandle of the vref regulator used by

			the isens hardware. This active only regulator will be

			enabled by LMH DCVSh. Isens hardware needs 1.8v and

			0.8v supply regulators.

- isens-vref-1p8-settings:

- isens-vref-0p8-settings:

	Usage: optional

	Value type: <u32 array>

	Definition: Should specify the min voltage(uV), max voltage(uV) and

			max load(uA) for the isens vref regulator. This

			property is valid only if there is valid entry for

			isens_vref_1p8-supply and isens_vref_0p8-supply.

- reg:

	Usage: optional

	Value type: <a b>

	Definition: where 'a' is the starting register address of the OSM/LLM

			and 'b' is the size of OSM/LLM address space. The

			register space in index 0 should be LLM and index 1

			should be OSM.

- qcom,no-cooling-device-register:

	Usage: optional

	Value type: <none>

	Definition: Should define this property if this driver doesn't need

			to register CPU cooling devices with thermal framework.

Example:

	lmh_dcvs0: qcom,limits-dcvs@18350800 {

		compatible = "qcom,msm-hw-limits";

		interrupts = <GIC_SPI 38 IRQ_TYPE_LEVEL_HIGH>;

		qcom,affinity = <0>;

		isens_vref_1p8-supply = <&pm8998_l1_ao>;

		isens-vref-1p8-settings = <880000 880000 36000>;

		isens_vref_0p8-supply = <&pm8998_l12_ao>;

		isens-vref-0p8-settings = <880000 880000 36000>;

		reg =  <0x18350800 0x1000>, //LLM

			<0x18323000 0x1000>; //OSM

	};

	CPU0: cpu@0 {

		device_type = "cpu";

		compatible = "arm,armv8";

		reg = <0x0 0x0>;

		qcom,lmh-dcvs = <&lmh_dcvs0>;;

	};