Documentation/devicetree/bindings/cpufreq/nvidia,tegra20-cpufreq.txt

Source file repositories/reference/linux-study-clean/Documentation/devicetree/bindings/cpufreq/nvidia,tegra20-cpufreq.txt

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Linux kernel
Corpus path
Documentation/devicetree/bindings/cpufreq/nvidia,tegra20-cpufreq.txt
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.txt
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1312 bytes
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57
Domain
Support Tooling And Documentation
Bucket
Documentation
Inferred role
Support Tooling And Documentation: documentation
Status
atlas-only

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Repository support layer: documentation, build tooling, samples, user-space helper tools, generated initramfs support, licenses, and validation utilities.

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Annotated Snippet

Binding for NVIDIA Tegra20 CPUFreq
==================================

Required properties:
- clocks: Must contain an entry for the CPU clock.
  See ../clocks/clock-bindings.txt for details.
- operating-points-v2: See ../bindings/opp/opp-v2.yaml for details.
- #cooling-cells: Should be 2. See ../thermal/thermal-cooling-devices.yaml for details.

For each opp entry in 'operating-points-v2' table:
- opp-supported-hw: Two bitfields indicating:
	On Tegra20:
	1. CPU process ID mask
	2. SoC speedo ID mask

	On Tegra30:
	1. CPU process ID mask
	2. CPU speedo ID mask

	A bitwise AND is performed against these values and if any bit
	matches, the OPP gets enabled.

- opp-microvolt: CPU voltage triplet.

Optional properties:
- cpu-supply: Phandle to the CPU power supply.

Example:
	regulators {
		cpu_reg: regulator0 {
			regulator-name = "vdd_cpu";
		};
	};

	cpu0_opp_table: opp_table0 {
		compatible = "operating-points-v2";

		opp@456000000 {
			clock-latency-ns = <125000>;
			opp-microvolt = <825000 825000 1125000>;
			opp-supported-hw = <0x03 0x0001>;
			opp-hz = /bits/ 64 <456000000>;
		};

		...
	};

	cpus {
		cpu@0 {
			compatible = "arm,cortex-a9";
			clocks = <&tegra_car TEGRA20_CLK_CCLK>;
			operating-points-v2 = <&cpu0_opp_table>;
			cpu-supply = <&cpu_reg>;
			#cooling-cells = <2>;
		};
	};

Annotation

Implementation Notes