The thermal-sensor property of the thermal zone node accepts phandles to thermal sensors. However, thermal zones can be created as an aggregation of other thermal zones. Extend the thermal-sensors property to allow phandles to other thermal zones. This patch also adds an example that showcases how a board thermal zone can be created from the aggregation of the cpu, gpu and lcd thermal zones.
Cc: Zhang Rui <[email protected]> Cc: Eduardo Valentin <[email protected]> Cc: Rob Herring <[email protected]> Cc: Pawel Moll <[email protected]> Cc: Mark Rutland <[email protected]> Cc: Ian Campbell <[email protected]> Cc: Kumar Gala <[email protected]> Cc: [email protected] Signed-off-by: Javi Merino <[email protected]> --- Notes: Hi devicetree, Is it ok to extend the definition of the thermal-sensors property like this? IOW are phandles strongly typed? .../devicetree/bindings/thermal/thermal.txt | 154 ++++++++++++++++++++- 1 file changed, 151 insertions(+), 3 deletions(-) diff --git a/Documentation/devicetree/bindings/thermal/thermal.txt b/Documentation/devicetree/bindings/thermal/thermal.txt index 41b817f7b670..52b7e9ae3b4d 100644 --- a/Documentation/devicetree/bindings/thermal/thermal.txt +++ b/Documentation/devicetree/bindings/thermal/thermal.txt @@ -145,9 +145,12 @@ Required properties: Size: one cell - thermal-sensors: A list of thermal sensor phandles and sensor specifier - Type: list of used while monitoring the thermal zone. - phandles + sensor - specifier + Type: list of used while monitoring the thermal zone. The phandles + phandles + sensor can point to thermal sensors or other thermal zone + specifier nodes. If it points to other thermal zone + nodes you should omit the sensor specifier + and set #thermal-sensor-cells to 0 for the + thermal zone. - trips: A sub-node which is a container of only trip point nodes Type: sub-node required to describe the thermal zone. @@ -603,3 +606,148 @@ thermal-zones { The above example is a mix of previous examples, a sensor IP with several internal sensors used to monitor different zones, one of them is composed by several sensors and with different cooling devices. + +(e) Board thermal with stacked thermal zones + +Instead of setting up one thermal zone combining multiple thermal +zones and multiple trip points for each cooling device, we can create +a hierarchy of thermal zones. + +#include <dt-bindings/thermal/thermal.h> + +&i2c1 { + ... + /* + * An IC with several temperature sensor. + */ + adc_dummy: sensor@0x50 { + ... + #thermal-sensor-cells = <1>; /* sensor internal ID */ + }; +}; + +thermal-zones { + + cpu_thermal: cpu_thermal { + polling-delay-passive = <1000>; /* milliseconds */ + polling-delay = <2500>; /* milliseconds */ + + sustainable-power = <2500>; + + thermal-sensors = <&adc_dummy 0> + + trips { + cpu_trip: cpu-trip { + temperature = <60000>; /* millicelsius */ + hysteresis = <2000>; /* millicelsius */ + type = "passive"; + }; + }; + + cooling-maps { + map0 { + trip = <&cpu_trip>; + cooling-device = <&cpu0 0 2>; + }; + }; + }; + + gpu_thermal: gpu_thermal { + polling-delay-passive = <1000>; /* milliseconds */ + polling-delay = <2500>; /* milliseconds */ + + sustainable-power = <2500>; + + thermal-sensors = <&adc_dummy 2> + + trips { + gpu_trip: gpu-trip { + temperature = <55000>; /* millicelsius */ + hysteresis = <2000>; /* millicelsius */ + type = "passive"; + } + }; + + cooling-maps { + map0 { + trip = <&gpu_trip>; + cooling-device = <&gpu0 0 2>; + }; + }; + }; + + lcd_thermal: lcd_thermal { + polling-delay-passive = <1000>; /* milliseconds */ + polling-delay = <2500>; /* milliseconds */ + + sustainable-power = <2500>; + + thermal-sensors = <&adc_dummy 1> + + trips { + lcd_trip: lcp-trip { + temperature = <53000>; /* millicelsius */ + hysteresis = <2000>; /* millicelsius */ + type = "passive"; + }; + }; + + cooling-maps { + map0 { + trip = <&lcd_trip>; + cooling-device = <&lcd0 5 10>; + }; + }; + }; + + board_thermal: board-thermal { + polling-delay-passive = <1000>; /* milliseconds */ + polling-delay = <2500>; /* milliseconds */ + + thermal-sensors = <&cpu_thermal &gpu_thermal &lcd_thermal> + + sustainable-power = <2500>; + + trips { + warm_trip: warm-trip { + temperature = <62000>; /* millicelsius */ + hysteresis = <2000>; /* millicelsius */ + type = "passive"; + }; + crit_trip: crit-trip { + temperature = <68000>; /* millicelsius */ + hysteresis = <2000>; /* millicelsius */ + type = "critical"; + }; + }; + + cooling-maps { + map0 { + trip = <&warm_trip>; + cooling-device = <&cpu0 2 2>; + contribution = <55>; + }; + map1 { + trip = <&warm_trip>; + cooling-device = <&gpu0 2 2>; + contribution = <20>; + }; + map2 { + trip = <&lcd_trip>; + cooling-device = <&lcd0 7 10>; + contribution = <15>; + }; + }; + }; +}; + +The above example is a different take at example (d). We create one +thermal zone per sensor: cpu_thermal, gpu_thermal and lcd_thermal. +Each of which has its own trip point for each own cooling device. We +then define a board_thermal thermal zone that is a combination of all +the other thermal zones. If the board hits its warm_trip, then all +cooling devices are throttled. + +This example illustrates how we can throttle each device individually +if its too hot and at the same time have some control over the whole +system. -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
