bindings/thermal/thermal-zones.yaml

1 # SPDX-License-Identifier: (GPL-2.0)
4 ---
5 $id: http://devicetree.org/schemas/thermal/thermal-zones.yaml#
6 $schema: http://devicetree.org/meta-schemas/base.yaml#
11   - Amit Kucheria <amitk@kernel.org>
15   and the software abstraction of cooling devices and thermal zones required to
20    - thermal-sensor: device that measures temperature, has SoC-specific bindings
21    - cooling-device: device used to dissipate heat either passively or actively
22    - thermal-zones: a container of the following node types used to describe all
25   This binding describes the thermal-zones.
27   The polling-delay properties of a thermal-zone are bound to the maximum dT/dt
29     1. when passive cooling is activated (polling-delay-passive)
30     2. when the zone just needs to be monitored (polling-delay) or when
31        active cooling is activated.
35   max dT/dt, such that a device does not cross several trip boundaries
37   having the device in temperature ranges that may damage the silicon structures
42     const: thermal-zones
44       A /thermal-zones node is required in order to use the thermal framework to
46       mitigate thermal overload conditions. It does not represent a real device
47       in the system, but acts as a container to link a thermal sensor device,
48       platform-data regarding temperature thresholds and the mitigation actions
52   "^[a-zA-Z][a-zA-Z0-9\\-]{1,12}-thermal$":
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:
73           checking this thermal zone while doing passive cooling. Setting
78       thermal-sensors:
79         $ref: /schemas/types.yaml#/definitions/phandle-array
86         $ref: /schemas/types.yaml#/definitions/uint32-array
92             z = c0 * x0 + c1 * x1 + ... + c(n-1) * x(n-1) + cn
99       sustainable-power:
104           sustainable power of a 4-inch phone is typically 2000mW, while on a
105           10-inch tablet is around 4500mW.
112           be taken are defined in another node called cooling-maps.
115           "^[a-zA-Z][a-zA-Z0-9\\-_]{0,63}$":
121                 minimum: -273000
131                   millicelsius. Any cooling action initiated by the framework is
133                   (trip temperature - hysteresis). This potentially prevents a
135                   cooling action is removed.
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
162                   help in cooling e.g. fans can be sped up or slowed down
165               - temperature
166               - hysteresis
167               - type
172       cooling-maps:
178           trip and the target cooling device state.
181           "^map[-a-zA-Z0-9]*$":
190               cooling-device:
191                 $ref: /schemas/types.yaml#/definitions/phandle-array
193                   A list of cooling device phandles along with the minimum
194                   and maximum cooling state specifiers for each cooling
195                   device. Using the THERMAL_NO_LIMIT (-1UL) constant in the
196                   cooling-device phandle limit specifier lets the framework
197                   use the minimum and maximum cooling state for that cooling
198                   device automatically.
203                   The cooling contribution to the thermal zone of the referred
204                   cooling device at the referred trip point. The contribution is
205                   a ratio of the sum of all cooling contributions within a
209               - trip
210               - cooling-device
214       - polling-delay
215       - polling-delay-passive
216       - thermal-sensors
217       - trips
223   - |
224     #include <dt-bindings/interrupt-controller/arm-gic.h>
225     #include <dt-bindings/thermal/thermal.h>
229             #address-cells = <2>;
230             #size-cells = <2>;
234             tsens0: thermal-sensor@c263000 {
235                     compatible = "qcom,sdm845-tsens", "qcom,tsens-v2";
241                     interrupt-names = "uplow", "critical";
242                     #thermal-sensor-cells = <1>;
245             tsens1: thermal-sensor@c265000 {
246                     compatible = "qcom,sdm845-tsens", "qcom,tsens-v2";
252                     interrupt-names = "uplow", "critical";
253                     #thermal-sensor-cells = <1>;
259     thermal-zones {
260             cpu0-thermal {
261                     polling-delay-passive = <250>;
262                     polling-delay = <1000>;
264                     thermal-sensors = <&tsens0 1>;
267                             cpu0_alert0: trip-point0 {
273                             cpu0_alert1: trip-point1 {
286                     cooling-maps {
290                                     cooling-device = <&CPU0 3 3>, <&CPU1 3 3>,
297                                     cooling-device = <&CPU0 5 5>, <&CPU1 5 5>,
305             cluster0-thermal {
306                     polling-delay-passive = <250>;
307                     polling-delay = <1000>;
309                     thermal-sensors = <&tsens0 5>;
312                             cluster0_alert0: trip-point0 {
327             gpu-top-thermal {
328                     polling-delay-passive = <250>;
329                     polling-delay = <1000>;
331                     thermal-sensors = <&tsens0 11>;
334                             gpu1_alert0: trip-point0 {