bindings/thermal/thermal-zones.yaml

1 # SPDX-License-Identifier: (GPL-2.0)
4 ---
5 $id: http://devicetree.org/schemas/thermal/thermal-zones.yaml#
6 $schema: http://devicetree.org/meta-schemas/base.yaml#
11   - Amit Kucheria <amitk@kernel.org>
18   The following node types are used to completely describe a thermal management
20    - thermal-sensor: device that measures temperature, has SoC-specific bindings
21    - cooling-device: device used to dissipate heat either passively or actively
22    - thermal-zones: a container of the following node types used to describe all
25   This binding describes the thermal-zones.
27   The polling-delay properties of a thermal-zone are bound to the maximum dT/dt
28   (temperature derivative over time) in two situations for a thermal zone:
29     1. when passive cooling is activated (polling-delay-passive)
30     2. when the zone just needs to be monitored (polling-delay) or when
35   max dT/dt, such that a device does not cross several trip boundaries
42     const: thermal-zones
44       A /thermal-zones node is required in order to use the thermal framework to
46       mitigate thermal overload conditions. It does not represent a real device
47       in the system, but acts as a container to link a thermal sensor device,
48       platform-data regarding temperature thresholds and the mitigation actions
52   "^[a-zA-Z][a-zA-Z0-9\\-]{1,12}-thermal$":
57       this zone, one sub-node containing the various trip points for this
58       zone and one sub-node containing all the zone cooling-maps.
61       polling-delay:
69       polling-delay-passive:
78       thermal-sensors:
79         $ref: /schemas/types.yaml#/definitions/phandle-array
86         $ref: /schemas/types.yaml#/definitions/uint32-array
88           An array of integers containing the coefficients of a linear equation
92             z = c0 * x0 + c1 * x1 + ... + c(n-1) * x(n-1) + cn
99       sustainable-power:
104           sustainable power of a 4-inch phone is typically 2000mW, while on a
105           10-inch tablet is around 4500mW.
110           This node describes a set of points in the temperature domain at
112           be taken are defined in another node called cooling-maps.
115           "^[a-zA-Z][a-zA-Z0-9\\-_]{0,63}$":
121                 minimum: -273000
133                   (trip temperature - hysteresis). This potentially prevents a
140                   - active   # enable active cooling e.g. fans
141                   - passive  # enable passive cooling e.g. throttling cpu
142                   - hot      # send notification to driver
143                   - critical # send notification to driver, trigger shutdown
150                   unstable and underlying firmware might even trigger a
151                   reboot. Hitting the critical threshold triggers a system
154                   The hot trip type can be used to send a notification to
155                   the thermal driver (if a .notify callback is registered).
159                   the CPU, GPU, bus at a lower frequency.
165               - temperature
166               - hysteresis
167               - type
172       cooling-maps:
175           This node describes the action to be taken when a thermal zone
177           node. The action takes the form of a mapping relation between a
181           "^map[-a-zA-Z0-9]*$":
188                   A phandle of a trip point node within this thermal zone.
190               cooling-device:
191                 $ref: /schemas/types.yaml#/definitions/phandle-array
193                   A list of cooling device phandles along with the minimum
195                   device. Using the THERMAL_NO_LIMIT (-1UL) constant in the
196                   cooling-device phandle limit specifier lets the framework
210               - trip
211               - cooling-device
215       - polling-delay
216       - polling-delay-passive
217       - thermal-sensors
218       - trips
224   - |
225     #include <dt-bindings/interrupt-controller/arm-gic.h>
226     #include <dt-bindings/thermal/thermal.h>
230             #address-cells = <2>;
231             #size-cells = <2>;
235             tsens0: thermal-sensor@c263000 {
236                     compatible = "qcom,sdm845-tsens", "qcom,tsens-v2";
242                     interrupt-names = "uplow", "critical";
243                     #thermal-sensor-cells = <1>;
246             tsens1: thermal-sensor@c265000 {
247                     compatible = "qcom,sdm845-tsens", "qcom,tsens-v2";
253                     interrupt-names = "uplow", "critical";
254                     #thermal-sensor-cells = <1>;
260     thermal-zones {
261             cpu0-thermal {
262                     polling-delay-passive = <250>;
263                     polling-delay = <1000>;
265                     thermal-sensors = <&tsens0 1>;
268                             cpu0_alert0: trip-point0 {
274                             cpu0_alert1: trip-point1 {
287                     cooling-maps {
291                                     cooling-device = <&CPU0 3 3>, <&CPU1 3 3>,
298                                     cooling-device = <&CPU0 5 5>, <&CPU1 5 5>,
306             cluster0-thermal {
307                     polling-delay-passive = <250>;
308                     polling-delay = <1000>;
310                     thermal-sensors = <&tsens0 5>;
313                             cluster0_alert0: trip-point0 {
328             gpu-top-thermal {
329                     polling-delay-passive = <250>;
330                     polling-delay = <1000>;
332                     thermal-sensors = <&tsens0 11>;
335                             gpu1_alert0: trip-point0 {