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+# SPDX-License-Identifier: (GPL-2.0)
+# Copyright 2020 Linaro Ltd.
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/thermal/thermal-cooling-devices.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Thermal cooling device binding
+
+maintainers:
+ - Amit Kucheria <amitk@kernel.org>
+
+description: |
+ Thermal management is achieved in devicetree by describing the sensor hardware
+ and the software abstraction of cooling devices and thermal zones required to
+ take appropriate action to mitigate thermal overload.
+
+ The following node types are used to completely describe a thermal management
+ system in devicetree:
+ - thermal-sensor: device that measures temperature, has SoC-specific bindings
+ - cooling-device: device used to dissipate heat either passively or actively
+ - thermal-zones: a container of the following node types used to describe all
+ thermal data for the platform
+
+ This binding describes the cooling devices.
+
+ There are essentially two ways to provide control on power dissipation:
+ - Passive cooling: by means of regulating device performance. A typical
+ passive cooling mechanism is a CPU that has dynamic voltage and frequency
+ scaling (DVFS), and uses lower frequencies as cooling states.
+ - Active cooling: by means of activating devices in order to remove the
+ dissipated heat, e.g. regulating fan speeds.
+
+ Any cooling device has a range of cooling states (i.e. different levels of
+ heat dissipation). They also have a way to determine the state of cooling in
+ which the device is. For example, a fan's cooling states correspond to the
+ different fan speeds possible. Cooling states are referred to by single
+ unsigned integers, where larger numbers mean greater heat dissipation. The
+ precise set of cooling states associated with a device should be defined in
+ a particular device's binding.
+
+select: true
+
+properties:
+ "#cooling-cells":
+ description:
+ Must be 2, in order to specify minimum and maximum cooling state used in
+ the cooling-maps reference. The first cell is the minimum cooling state
+ and the second cell is the maximum cooling state requested.
+ const: 2
+
+additionalProperties: true
+
+examples:
+ - |
+ #include <dt-bindings/interrupt-controller/arm-gic.h>
+ #include <dt-bindings/thermal/thermal.h>
+
+ // Example 1: Cpufreq cooling device on CPU0
+ cpus {
+ #address-cells = <2>;
+ #size-cells = <0>;
+
+ CPU0: cpu@0 {
+ device_type = "cpu";
+ compatible = "qcom,kryo385";
+ reg = <0x0 0x0>;
+ enable-method = "psci";
+ cpu-idle-states = <&LITTLE_CPU_SLEEP_0
+ &LITTLE_CPU_SLEEP_1
+ &CLUSTER_SLEEP_0>;
+ capacity-dmips-mhz = <607>;
+ dynamic-power-coefficient = <100>;
+ qcom,freq-domain = <&cpufreq_hw 0>;
+ #cooling-cells = <2>;
+ next-level-cache = <&L2_0>;
+ L2_0: l2-cache {
+ compatible = "cache";
+ next-level-cache = <&L3_0>;
+ L3_0: l3-cache {
+ compatible = "cache";
+ };
+ };
+ };
+
+ /* ... */
+
+ };
+
+ /* ... */
+
+ thermal-zones {
+ cpu0-thermal {
+ polling-delay-passive = <250>;
+ polling-delay = <1000>;
+
+ thermal-sensors = <&tsens0 1>;
+
+ trips {
+ cpu0_alert0: trip-point0 {
+ temperature = <90000>;
+ hysteresis = <2000>;
+ type = "passive";
+ };
+ };
+
+ cooling-maps {
+ map0 {
+ trip = <&cpu0_alert0>;
+ /* Corresponds to 1000MHz in OPP table */
+ cooling-device = <&CPU0 5 5>;
+ };
+ };
+ };
+
+ /* ... */
+ };
+...