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| -rw-r--r-- | Documentation/devicetree/bindings/thermal/thermal-idle.yaml | 146 |
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diff --git a/Documentation/devicetree/bindings/thermal/thermal-idle.yaml b/Documentation/devicetree/bindings/thermal/thermal-idle.yaml new file mode 100644 index 000000000..cc938d7ad --- /dev/null +++ b/Documentation/devicetree/bindings/thermal/thermal-idle.yaml @@ -0,0 +1,146 @@ +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) +# Copyright 2020 Linaro Ltd. +%YAML 1.2 +--- +$id: http://devicetree.org/schemas/thermal/thermal-idle.yaml# +$schema: http://devicetree.org/meta-schemas/core.yaml# + +title: Thermal idle cooling device binding + +maintainers: + - Daniel Lezcano <daniel.lezcano@linaro.org> + +description: | + The thermal idle cooling device allows the system to passively + mitigate the temperature on the device by injecting idle cycles, + forcing it to cool down. + + This binding describes the thermal idle node. + +properties: + $nodename: + const: thermal-idle + description: | + A thermal-idle node describes the idle cooling device properties to + cool down efficiently the attached thermal zone. + + '#cooling-cells': + const: 2 + 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. + + duration-us: + description: | + The idle duration in microsecond the device should cool down. + + exit-latency-us: + description: | + The exit latency constraint in microsecond for the injected idle state + for the device. It is the latency constraint to apply when selecting an + idle state from among all the present ones. + +required: + - '#cooling-cells' + +additionalProperties: false + +examples: + - | + #include <dt-bindings/thermal/thermal.h> + + // Example: Combining idle cooling device on big CPUs with cpufreq cooling device + cpus { + #address-cells = <2>; + #size-cells = <0>; + + /* ... */ + + cpu_b0: cpu@100 { + device_type = "cpu"; + compatible = "arm,cortex-a72"; + reg = <0x0 0x100>; + enable-method = "psci"; + capacity-dmips-mhz = <1024>; + dynamic-power-coefficient = <436>; + #cooling-cells = <2>; /* min followed by max */ + cpu-idle-states = <&CPU_SLEEP>, <&CLUSTER_SLEEP>; + thermal-idle { + #cooling-cells = <2>; + duration-us = <10000>; + exit-latency-us = <500>; + }; + }; + + cpu_b1: cpu@101 { + device_type = "cpu"; + compatible = "arm,cortex-a72"; + reg = <0x0 0x101>; + enable-method = "psci"; + capacity-dmips-mhz = <1024>; + dynamic-power-coefficient = <436>; + #cooling-cells = <2>; /* min followed by max */ + cpu-idle-states = <&CPU_SLEEP>, <&CLUSTER_SLEEP>; + thermal-idle { + #cooling-cells = <2>; + duration-us = <10000>; + exit-latency-us = <500>; + }; + }; + + /* ... */ + + }; + + /* ... */ + + thermal_zones { + cpu_thermal: cpu { + polling-delay-passive = <100>; + polling-delay = <1000>; + + /* ... */ + + trips { + cpu_alert0: cpu_alert0 { + temperature = <65000>; + hysteresis = <2000>; + type = "passive"; + }; + + cpu_alert1: cpu_alert1 { + temperature = <70000>; + hysteresis = <2000>; + type = "passive"; + }; + + cpu_alert2: cpu_alert2 { + temperature = <75000>; + hysteresis = <2000>; + type = "passive"; + }; + + cpu_crit: cpu_crit { + temperature = <95000>; + hysteresis = <2000>; + type = "critical"; + }; + }; + + cooling-maps { + map0 { + trip = <&cpu_alert1>; + cooling-device = <&{/cpus/cpu@100/thermal-idle} 0 15 >, + <&{/cpus/cpu@101/thermal-idle} 0 15>; + }; + + map1 { + trip = <&cpu_alert2>; + cooling-device = + <&cpu_b0 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>, + <&cpu_b1 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>; + }; + }; + }; + }; |