344 lines
13 KiB
YAML
344 lines
13 KiB
YAML
# SPDX-License-Identifier: (GPL-2.0)
|
|
# Copyright 2020 Linaro Ltd.
|
|
%YAML 1.2
|
|
---
|
|
$id: http://devicetree.org/schemas/thermal/thermal-zones.yaml#
|
|
$schema: http://devicetree.org/meta-schemas/base.yaml#
|
|
|
|
title: Thermal zone 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 overloads.
|
|
|
|
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 thermal-zones.
|
|
|
|
The polling-delay properties of a thermal-zone are bound to the maximum dT/dt
|
|
(temperature derivative over time) in two situations for a thermal zone:
|
|
1. when passive cooling is activated (polling-delay-passive)
|
|
2. when the zone just needs to be monitored (polling-delay) or when
|
|
active cooling is activated.
|
|
|
|
The maximum dT/dt is highly bound to hardware power consumption and
|
|
dissipation capability. The delays should be chosen to account for said
|
|
max dT/dt, such that a device does not cross several trip boundaries
|
|
unexpectedly between polls. Choosing the right polling delays shall avoid
|
|
having the device in temperature ranges that may damage the silicon structures
|
|
and reduce silicon lifetime.
|
|
|
|
properties:
|
|
$nodename:
|
|
const: thermal-zones
|
|
description:
|
|
A /thermal-zones node is required in order to use the thermal framework to
|
|
manage input from the various thermal zones in the system in order to
|
|
mitigate thermal overload conditions. It does not represent a real device
|
|
in the system, but acts as a container to link a thermal sensor device,
|
|
platform-data regarding temperature thresholds and the mitigation actions
|
|
to take when the temperature crosses those thresholds.
|
|
|
|
patternProperties:
|
|
"^[a-zA-Z][a-zA-Z0-9\\-]{1,12}-thermal$":
|
|
type: object
|
|
description:
|
|
Each thermal zone node contains information about how frequently it
|
|
must be checked, the sensor responsible for reporting temperature for
|
|
this zone, one sub-node containing the various trip points for this
|
|
zone and one sub-node containing all the zone cooling-maps.
|
|
|
|
properties:
|
|
polling-delay:
|
|
$ref: /schemas/types.yaml#/definitions/uint32
|
|
description:
|
|
The maximum number of milliseconds to wait between polls when
|
|
checking this thermal zone. Setting this to 0 disables the polling
|
|
timers setup by the thermal framework and assumes that the thermal
|
|
sensors in this zone support interrupts.
|
|
|
|
polling-delay-passive:
|
|
$ref: /schemas/types.yaml#/definitions/uint32
|
|
description:
|
|
The maximum number of milliseconds to wait between polls when
|
|
checking this thermal zone while doing passive cooling. Setting
|
|
this to 0 disables the polling timers setup by the thermal
|
|
framework and assumes that the thermal sensors in this zone
|
|
support interrupts.
|
|
|
|
thermal-sensors:
|
|
$ref: /schemas/types.yaml#/definitions/phandle-array
|
|
maxItems: 1
|
|
description:
|
|
The thermal sensor phandle and sensor specifier used to monitor this
|
|
thermal zone.
|
|
|
|
coefficients:
|
|
$ref: /schemas/types.yaml#/definitions/uint32-array
|
|
description:
|
|
An array of integers containing the coefficients of a linear equation
|
|
that binds all the sensors listed in this thermal zone.
|
|
|
|
The linear equation used is as follows,
|
|
z = c0 * x0 + c1 * x1 + ... + c(n-1) * x(n-1) + cn
|
|
where c0, c1, .., cn are the coefficients.
|
|
|
|
Coefficients default to 1 in case this property is not specified. The
|
|
coefficients are ordered and are matched with sensors by means of the
|
|
sensor ID. Additional coefficients are interpreted as constant offset.
|
|
|
|
sustainable-power:
|
|
$ref: /schemas/types.yaml#/definitions/uint32
|
|
description:
|
|
An estimate of the sustainable power (in mW) that this thermal zone
|
|
can dissipate at the desired control temperature. For reference, the
|
|
sustainable power of a 4-inch phone is typically 2000mW, while on a
|
|
10-inch tablet is around 4500mW.
|
|
|
|
trips:
|
|
type: object
|
|
description:
|
|
This node describes a set of points in the temperature domain at
|
|
which the thermal framework needs to take action. The actions to
|
|
be taken are defined in another node called cooling-maps.
|
|
|
|
patternProperties:
|
|
"^[a-zA-Z][a-zA-Z0-9\\-_]{0,63}$":
|
|
type: object
|
|
|
|
properties:
|
|
temperature:
|
|
$ref: /schemas/types.yaml#/definitions/int32
|
|
minimum: -273000
|
|
maximum: 200000
|
|
description:
|
|
An integer expressing the trip temperature in millicelsius.
|
|
|
|
hysteresis:
|
|
$ref: /schemas/types.yaml#/definitions/uint32
|
|
description:
|
|
An unsigned integer expressing the hysteresis delta with
|
|
respect to the trip temperature property above, also in
|
|
millicelsius. Any cooling action initiated by the framework is
|
|
maintained until the temperature falls below
|
|
(trip temperature - hysteresis). This potentially prevents a
|
|
situation where the trip gets constantly triggered soon after
|
|
cooling action is removed.
|
|
|
|
type:
|
|
$ref: /schemas/types.yaml#/definitions/string
|
|
enum:
|
|
- active # enable active cooling e.g. fans
|
|
- passive # enable passive cooling e.g. throttling cpu
|
|
- hot # send notification to driver
|
|
- critical # send notification to driver, trigger shutdown
|
|
description: |
|
|
There are four valid trip types: active, passive, hot,
|
|
critical.
|
|
|
|
The critical trip type is used to set the maximum
|
|
temperature threshold above which the HW becomes
|
|
unstable and underlying firmware might even trigger a
|
|
reboot. Hitting the critical threshold triggers a system
|
|
shutdown.
|
|
|
|
The hot trip type can be used to send a notification to
|
|
the thermal driver (if a .notify callback is registered).
|
|
The action to be taken is left to the driver.
|
|
|
|
The passive trip type can be used to slow down HW e.g. run
|
|
the CPU, GPU, bus at a lower frequency.
|
|
|
|
The active trip type can be used to control other HW to
|
|
help in cooling e.g. fans can be sped up or slowed down
|
|
|
|
required:
|
|
- temperature
|
|
- hysteresis
|
|
- type
|
|
additionalProperties: false
|
|
|
|
additionalProperties: false
|
|
|
|
cooling-maps:
|
|
type: object
|
|
description:
|
|
This node describes the action to be taken when a thermal zone
|
|
crosses one of the temperature thresholds described in the trips
|
|
node. The action takes the form of a mapping relation between a
|
|
trip and the target cooling device state.
|
|
|
|
patternProperties:
|
|
"^map[-a-zA-Z0-9]*$":
|
|
type: object
|
|
|
|
properties:
|
|
trip:
|
|
$ref: /schemas/types.yaml#/definitions/phandle
|
|
description:
|
|
A phandle of a trip point node within this thermal zone.
|
|
|
|
cooling-device:
|
|
$ref: /schemas/types.yaml#/definitions/phandle-array
|
|
description:
|
|
A list of cooling device phandles along with the minimum
|
|
and maximum cooling state specifiers for each cooling
|
|
device. Using the THERMAL_NO_LIMIT (-1UL) constant in the
|
|
cooling-device phandle limit specifier lets the framework
|
|
use the minimum and maximum cooling state for that cooling
|
|
device automatically.
|
|
|
|
contribution:
|
|
$ref: /schemas/types.yaml#/definitions/uint32
|
|
minimum: 0
|
|
maximum: 100
|
|
description:
|
|
The percentage contribution of the cooling devices at the
|
|
specific trip temperature referenced in this map
|
|
to this thermal zone
|
|
|
|
required:
|
|
- trip
|
|
- cooling-device
|
|
additionalProperties: false
|
|
|
|
required:
|
|
- polling-delay
|
|
- polling-delay-passive
|
|
- thermal-sensors
|
|
|
|
additionalProperties: false
|
|
|
|
additionalProperties: false
|
|
|
|
examples:
|
|
- |
|
|
#include <dt-bindings/interrupt-controller/arm-gic.h>
|
|
#include <dt-bindings/thermal/thermal.h>
|
|
|
|
// Example 1: SDM845 TSENS
|
|
soc {
|
|
#address-cells = <2>;
|
|
#size-cells = <2>;
|
|
|
|
/* ... */
|
|
|
|
tsens0: thermal-sensor@c263000 {
|
|
compatible = "qcom,sdm845-tsens", "qcom,tsens-v2";
|
|
reg = <0 0x0c263000 0 0x1ff>, /* TM */
|
|
<0 0x0c222000 0 0x1ff>; /* SROT */
|
|
#qcom,sensors = <13>;
|
|
interrupts = <GIC_SPI 506 IRQ_TYPE_LEVEL_HIGH>,
|
|
<GIC_SPI 508 IRQ_TYPE_LEVEL_HIGH>;
|
|
interrupt-names = "uplow", "critical";
|
|
#thermal-sensor-cells = <1>;
|
|
};
|
|
|
|
tsens1: thermal-sensor@c265000 {
|
|
compatible = "qcom,sdm845-tsens", "qcom,tsens-v2";
|
|
reg = <0 0x0c265000 0 0x1ff>, /* TM */
|
|
<0 0x0c223000 0 0x1ff>; /* SROT */
|
|
#qcom,sensors = <8>;
|
|
interrupts = <GIC_SPI 507 IRQ_TYPE_LEVEL_HIGH>,
|
|
<GIC_SPI 509 IRQ_TYPE_LEVEL_HIGH>;
|
|
interrupt-names = "uplow", "critical";
|
|
#thermal-sensor-cells = <1>;
|
|
};
|
|
};
|
|
|
|
/* ... */
|
|
|
|
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";
|
|
};
|
|
|
|
cpu0_alert1: trip-point1 {
|
|
temperature = <95000>;
|
|
hysteresis = <2000>;
|
|
type = "passive";
|
|
};
|
|
|
|
cpu0_crit: cpu_crit {
|
|
temperature = <110000>;
|
|
hysteresis = <1000>;
|
|
type = "critical";
|
|
};
|
|
};
|
|
|
|
cooling-maps {
|
|
map0 {
|
|
trip = <&cpu0_alert0>;
|
|
/* Corresponds to 1400MHz in OPP table */
|
|
cooling-device = <&CPU0 3 3>, <&CPU1 3 3>,
|
|
<&CPU2 3 3>, <&CPU3 3 3>;
|
|
};
|
|
|
|
map1 {
|
|
trip = <&cpu0_alert1>;
|
|
/* Corresponds to 1000MHz in OPP table */
|
|
cooling-device = <&CPU0 5 5>, <&CPU1 5 5>,
|
|
<&CPU2 5 5>, <&CPU3 5 5>;
|
|
};
|
|
};
|
|
};
|
|
|
|
/* ... */
|
|
|
|
cluster0-thermal {
|
|
polling-delay-passive = <250>;
|
|
polling-delay = <1000>;
|
|
|
|
thermal-sensors = <&tsens0 5>;
|
|
|
|
trips {
|
|
cluster0_alert0: trip-point0 {
|
|
temperature = <90000>;
|
|
hysteresis = <2000>;
|
|
type = "hot";
|
|
};
|
|
cluster0_crit: cluster0_crit {
|
|
temperature = <110000>;
|
|
hysteresis = <2000>;
|
|
type = "critical";
|
|
};
|
|
};
|
|
};
|
|
|
|
/* ... */
|
|
|
|
gpu-top-thermal {
|
|
polling-delay-passive = <250>;
|
|
polling-delay = <1000>;
|
|
|
|
thermal-sensors = <&tsens0 11>;
|
|
|
|
trips {
|
|
gpu1_alert0: trip-point0 {
|
|
temperature = <90000>;
|
|
hysteresis = <2000>;
|
|
type = "hot";
|
|
};
|
|
};
|
|
};
|
|
};
|
|
...
|