bindings/thermal/thermal-zones.yaml

1 # SPDX-License-Identifier: (GPL-2.0)
4 ---
5 $id: http://devicetree.org/schemas/thermal/thermal-zones.yaml#
6 $schema: http://devicetree.org/meta-schemas/base.yaml#
11   - Daniel Lezcano <daniel.lezcano@linaro.org>
14   Thermal management is achieved in devicetree by describing the sensor hardware
18   The following node types are used to completely describe a thermal management
20    - thermal-sensor: device that measures temperature, has SoC-specific bindings
21    - cooling-device: device used to dissipate heat either passively or actively
22    - thermal-zones: a container of the following node types used to describe all
25   This binding describes the thermal-zones.
27   The polling-delay properties of a thermal-zone are bound to the maximum dT/dt
29     1. when passive cooling is activated (polling-delay-passive)
30     2. when the zone just needs to be monitored (polling-delay) or when
42     const: thermal-zones
44       A /thermal-zones node is required in order to use the thermal framework to
47       in the system, but acts as a container to link a thermal sensor device,
48       platform-data regarding temperature thresholds and the mitigation actions
52   # Node name is limited in size due to Linux kernel requirements - 19
55   "^[a-zA-Z][a-zA-Z0-9\\-]{1,10}-thermal$":
58       Each thermal zone node contains information about how frequently it
59       must be checked, the sensor responsible for reporting temperature for
60       this zone, one sub-node containing the various trip points for this
61       zone and one sub-node containing all the zone cooling-maps.
64       polling-delay:
72       polling-delay-passive:
81       critical-action:
94           - shutdown
95           - reboot
97       thermal-sensors:
98         $ref: /schemas/types.yaml#/definitions/phandle-array
101           The thermal sensor phandle and sensor specifier used to monitor this
105         $ref: /schemas/types.yaml#/definitions/uint32-array
111             z = c0 * x0 + c1 * x1 + ... + c(n-1) * x(n-1) + cn
116           sensor ID. Additional coefficients are interpreted as constant offset.
118       sustainable-power:
123           sustainable power of a 4-inch phone is typically 2000mW, while on a
124           10-inch tablet is around 4500mW.
129           This node describes a set of points in the temperature domain at
131           be taken are defined in another node called cooling-maps.
134           "^[a-zA-Z][a-zA-Z0-9\\-_]{0,63}$":
140                 minimum: -273000
152                   (trip temperature - hysteresis). This potentially prevents a
159                   - active   # enable active cooling e.g. fans
160                   - passive  # enable passive cooling e.g. throttling cpu
161                   - hot      # send notification to driver
162                   - critical # send notification to driver, trigger shutdown
184               - temperature
185               - hysteresis
186               - type
191       cooling-maps:
195           This node describes the action to be taken when a thermal zone
197           node. The action takes the form of a mapping relation between a
201           "^map[-a-zA-Z0-9]*$":
208                   A phandle of a trip point node within this thermal zone.
210               cooling-device:
211                 $ref: /schemas/types.yaml#/definitions/phandle-array
215                   device. Using the THERMAL_NO_LIMIT (-1UL) constant in the
216                   cooling-device phandle limit specifier lets the framework
229               - trip
230               - cooling-device
234       - thermal-sensors
241   - |
242     #include <dt-bindings/interrupt-controller/arm-gic.h>
243     #include <dt-bindings/thermal/thermal.h>
247             #address-cells = <2>;
248             #size-cells = <2>;
252             tsens0: thermal-sensor@c263000 {
253                     compatible = "qcom,sdm845-tsens", "qcom,tsens-v2";
259                     interrupt-names = "uplow", "critical";
260                     #thermal-sensor-cells = <1>;
263             tsens1: thermal-sensor@c265000 {
264                     compatible = "qcom,sdm845-tsens", "qcom,tsens-v2";
270                     interrupt-names = "uplow", "critical";
271                     #thermal-sensor-cells = <1>;
277     thermal-zones {
278             cpu0-thermal {
279                     polling-delay-passive = <250>;
280                     polling-delay = <1000>;
282                     thermal-sensors = <&tsens0 1>;
285                             cpu0_alert0: trip-point0 {
291                             cpu0_alert1: trip-point1 {
304                     cooling-maps {
308                                     cooling-device = <&CPU0 3 3>, <&CPU1 3 3>,
315                                     cooling-device = <&CPU0 5 5>, <&CPU1 5 5>,
323             cluster0-thermal {
324                     polling-delay-passive = <250>;
325                     polling-delay = <1000>;
327                     thermal-sensors = <&tsens0 5>;
330                             cluster0_alert0: trip-point0 {
345             gpu-top-thermal {
346                     polling-delay-passive = <250>;
347                     polling-delay = <1000>;
349                     thermal-sensors = <&tsens0 11>;
352                             gpu1_alert0: trip-point0 {