David Venhoff
cfcea9ee67
Based off b80915eb99
and compacted into a single commit so that it will fit on the uni git server
96 lines
2.4 KiB
Plaintext
96 lines
2.4 KiB
Plaintext
General Purpose Analog To Digital Converter (ADC) based thermal sensor.
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On some of platforms, thermal sensor like thermistors are connected to
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one of ADC channel and sensor resistance is read via voltage across the
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sensor resistor. The voltage read across the sensor is mapped to
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temperature using voltage-temperature lookup table.
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Required properties:
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===================
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- compatible: Must be "generic-adc-thermal".
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- #thermal-sensor-cells: Should be 1. See Documentation/devicetree/bindings/thermal/thermal-sensor.yaml for a description
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of this property.
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Optional properties:
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===================
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- temperature-lookup-table: Two dimensional array of Integer; lookup table
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to map the relation between ADC value and
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temperature. When ADC is read, the value is
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looked up on the table to get the equivalent
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temperature.
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The first value of the each row of array is the
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temperature in milliCelsius and second value of
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the each row of array is the ADC read value.
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If not specified, driver assumes the ADC channel
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gives milliCelsius directly.
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Example :
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#include <dt-bindings/thermal/thermal.h>
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i2c@7000c400 {
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ads1015: ads1015@4a {
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reg = <0x4a>;
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compatible = "ads1015";
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sampling-frequency = <3300>;
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#io-channel-cells = <1>;
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};
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};
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tboard_thermistor: thermal-sensor {
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compatible = "generic-adc-thermal";
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#thermal-sensor-cells = <0>;
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io-channels = <&ads1015 1>;
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io-channel-names = "sensor-channel";
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temperature-lookup-table = < (-40000) 2578
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(-39000) 2577
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(-38000) 2576
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(-37000) 2575
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(-36000) 2574
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(-35000) 2573
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(-34000) 2572
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(-33000) 2571
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(-32000) 2569
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(-31000) 2568
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(-30000) 2567
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::::::::::
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118000 254
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119000 247
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120000 240
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121000 233
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122000 226
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123000 220
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124000 214
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125000 208>;
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};
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dummy_cool_dev: dummy-cool-dev {
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compatible = "dummy-cooling-dev";
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#cooling-cells = <2>; /* min followed by max */
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};
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thermal-zones {
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Tboard {
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polling-delay = <15000>; /* milliseconds */
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polling-delay-passive = <0>; /* milliseconds */
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thermal-sensors = <&tboard_thermistor>;
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trips {
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therm_est_trip: therm_est_trip {
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temperature = <40000>;
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type = "active";
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hysteresis = <1000>;
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};
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};
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cooling-maps {
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map0 {
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trip = <&therm_est_trip>;
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cooling-device = <&dummy_cool_dev THERMAL_NO_LIMIT THERMAL_NO_LIMIT>;
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contribution = <100>;
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};
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};
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};
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};
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