xref: /kernel/linux/linux-5.10/Documentation/devicetree/bindings/power/avs/qcom,cpr.txt

QCOM CPR (Core Power Reduction)

CPR (Core Power Reduction) is a technology to reduce core power on a CPU
or other device. Each OPP of a device corresponds to a "corner" that has
a range of valid voltages for a particular frequency. While the device is
running at a particular frequency, CPR monitors dynamic factors such as
temperature, etc. and suggests adjustments to the voltage to save power
and meet silicon characteristic requirements.

- compatible:
	Usage: required
	Value type: <string>
	Definition: should be "qcom,qcs404-cpr", "qcom,cpr" for qcs404

- reg:
	Usage: required
	Value type: <prop-encoded-array>
	Definition: base address and size of the rbcpr register region

- interrupts:
	Usage: required
	Value type: <prop-encoded-array>
	Definition: should specify the CPR interrupt

- clocks:
	Usage: required
	Value type: <prop-encoded-array>
	Definition: phandle to the reference clock

- clock-names:
	Usage: required
	Value type: <stringlist>
	Definition: must be "ref"

- vdd-apc-supply:
	Usage: required
	Value type: <phandle>
	Definition: phandle to the vdd-apc-supply regulator

- #power-domain-cells:
	Usage: required
	Value type: <u32>
	Definition: should be 0

- operating-points-v2:
	Usage: required
	Value type: <phandle>
	Definition: A phandle to the OPP table containing the
		    performance states supported by the CPR
		    power domain

- acc-syscon:
	Usage: optional
	Value type: <phandle>
	Definition: phandle to syscon for writing ACC settings

- nvmem-cells:
	Usage: required
	Value type: <phandle>
	Definition: phandle to nvmem cells containing the data
		    that makes up a fuse corner, for each fuse corner.
		    As well as the CPR fuse revision.

- nvmem-cell-names:
	Usage: required
	Value type: <stringlist>
	Definition: should be "cpr_quotient_offset1", "cpr_quotient_offset2",
		    "cpr_quotient_offset3", "cpr_init_voltage1",
		    "cpr_init_voltage2", "cpr_init_voltage3", "cpr_quotient1",
		    "cpr_quotient2", "cpr_quotient3", "cpr_ring_osc1",
		    "cpr_ring_osc2", "cpr_ring_osc3", "cpr_fuse_revision"
		    for qcs404.

Example:

	cpr_opp_table: cpr-opp-table {
		compatible = "operating-points-v2-qcom-level";

		cpr_opp1: opp1 {
			opp-level = <1>;
			qcom,opp-fuse-level = <1>;
		};
		cpr_opp2: opp2 {
			opp-level = <2>;
			qcom,opp-fuse-level = <2>;
		};
		cpr_opp3: opp3 {
			opp-level = <3>;
			qcom,opp-fuse-level = <3>;
		};
	};

	power-controller@b018000 {
		compatible = "qcom,qcs404-cpr", "qcom,cpr";
		reg = <0x0b018000 0x1000>;
		interrupts = <0 15 IRQ_TYPE_EDGE_RISING>;
		clocks = <&xo_board>;
		clock-names = "ref";
		vdd-apc-supply = <&pms405_s3>;
		#power-domain-cells = <0>;
		operating-points-v2 = <&cpr_opp_table>;
		acc-syscon = <&tcsr>;

		nvmem-cells = <&cpr_efuse_quot_offset1>,
			<&cpr_efuse_quot_offset2>,
			<&cpr_efuse_quot_offset3>,
			<&cpr_efuse_init_voltage1>,
			<&cpr_efuse_init_voltage2>,
			<&cpr_efuse_init_voltage3>,
			<&cpr_efuse_quot1>,
			<&cpr_efuse_quot2>,
			<&cpr_efuse_quot3>,
			<&cpr_efuse_ring1>,
			<&cpr_efuse_ring2>,
			<&cpr_efuse_ring3>,
			<&cpr_efuse_revision>;
		nvmem-cell-names = "cpr_quotient_offset1",
			"cpr_quotient_offset2",
			"cpr_quotient_offset3",
			"cpr_init_voltage1",
			"cpr_init_voltage2",
			"cpr_init_voltage3",
			"cpr_quotient1",
			"cpr_quotient2",
			"cpr_quotient3",
			"cpr_ring_osc1",
			"cpr_ring_osc2",
			"cpr_ring_osc3",
			"cpr_fuse_revision";
	};