96 lines
2.4 KiB
Plaintext
96 lines
2.4 KiB
Plaintext
|
General Purpose Analog To Digital Converter (ADC) based thermal sensor.
|
||
|
|
|
||
|
|
On some of platforms, thermal sensor like thermistors are connected to
|
||
|
|
one of ADC channel and sensor resistance is read via voltage across the
|
||
|
|
sensor resistor. The voltage read across the sensor is mapped to
|
||
|
|
temperature using voltage-temperature lookup table.
|
||
|
|
|
||
|
|
Required properties:
|
||
|
|
===================
|
||
|
|
- compatible: Must be "generic-adc-thermal".
|
||
|
|
- #thermal-sensor-cells: Should be 1. See Documentation/devicetree/bindings/thermal/thermal-sensor.yaml for a description
|
||
|
|
of this property.
|
||
|
|
Optional properties:
|
||
|
|
===================
|
||
|
|
- temperature-lookup-table: Two dimensional array of Integer; lookup table
|
||
|
|
to map the relation between ADC value and
|
||
|
|
temperature. When ADC is read, the value is
|
||
|
|
looked up on the table to get the equivalent
|
||
|
|
temperature.
|
||
|
|
|
||
|
|
The first value of the each row of array is the
|
||
|
|
temperature in milliCelsius and second value of
|
||
|
|
the each row of array is the ADC read value.
|
||
|
|
|
||
|
|
If not specified, driver assumes the ADC channel
|
||
|
|
gives milliCelsius directly.
|
||
|
|
|
||
|
|
Example :
|
||
|
|
#include <dt-bindings/thermal/thermal.h>
|
||
|
|
|
||
|
|
i2c@7000c400 {
|
||
|
|
ads1015: ads1015@4a {
|
||
|
|
reg = <0x4a>;
|
||
|
|
compatible = "ads1015";
|
||
|
|
sampling-frequency = <3300>;
|
||
|
|
#io-channel-cells = <1>;
|
||
|
|
};
|
||
|
|
};
|
||
|
|
|
||
|
|
tboard_thermistor: thermal-sensor {
|
||
|
|
compatible = "generic-adc-thermal";
|
||
|
|
#thermal-sensor-cells = <0>;
|
||
|
|
io-channels = <&ads1015 1>;
|
||
|
|
io-channel-names = "sensor-channel";
|
||
|
|
temperature-lookup-table = < (-40000) 2578
|
||
|
|
(-39000) 2577
|
||
|
|
(-38000) 2576
|
||
|
|
(-37000) 2575
|
||
|
|
(-36000) 2574
|
||
|
|
(-35000) 2573
|
||
|
|
(-34000) 2572
|
||
|
|
(-33000) 2571
|
||
|
|
(-32000) 2569
|
||
|
|
(-31000) 2568
|
||
|
|
(-30000) 2567
|
||
|
|
::::::::::
|
||
|
|
118000 254
|
||
|
|
119000 247
|
||
|
|
120000 240
|
||
|
|
121000 233
|
||
|
|
122000 226
|
||
|
|
123000 220
|
||
|
|
124000 214
|
||
|
|
125000 208>;
|
||
|
|
};
|
||
|
|
|
||
|
|
dummy_cool_dev: dummy-cool-dev {
|
||
|
|
compatible = "dummy-cooling-dev";
|
||
|
|
#cooling-cells = <2>; /* min followed by max */
|
||
|
|
};
|
||
|
|
|
||
|
|
thermal-zones {
|
||
|
|
Tboard {
|
||
|
|
polling-delay = <15000>; /* milliseconds */
|
||
|
|
polling-delay-passive = <0>; /* milliseconds */
|
||
|
|
thermal-sensors = <&tboard_thermistor>;
|
||
|
|
|
||
|
|
trips {
|
||
|
|
therm_est_trip: therm_est_trip {
|
||
|
|
temperature = <40000>;
|
||
|
|
type = "active";
|
||
|
|
hysteresis = <1000>;
|
||
|
|
};
|
||
|
|
};
|
||
|
|
|
||
|
|
cooling-maps {
|
||
|
|
map0 {
|
||
|
|
trip = <&therm_est_trip>;
|
||
|
|
cooling-device = <&dummy_cool_dev THERMAL_NO_LIMIT THERMAL_NO_LIMIT>;
|
||
|
|
contribution = <100>;
|
||
|
|
};
|
||
|
|
|
||
|
|
};
|
||
|
|
};
|
||
|
|
};
|