bindings/thermal/generic-adc-thermal.yaml

   1 # SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
   2 %YAML 1.2
   3 ---
   4 $id: http://devicetree.org/schemas/thermal/generic-adc-thermal.yaml#
   5 $schema: http://devicetree.org/meta-schemas/core.yaml#
   6
   7 title: General Purpose Analog To Digital Converter (ADC) based thermal sensor
   8
   9 maintainers:
  10   - Laxman Dewangan <ldewangan@nvidia.com>
  11
  12 description:
  13   On some of platforms, thermal sensor like thermistors are connected to
  14   one of ADC channel and sensor resistance is read via voltage across the
  15   sensor resistor. The voltage read across the sensor is mapped to
  16   temperature using voltage-temperature lookup table.
  17
  18 properties:
  19   compatible:
  20     const: generic-adc-thermal
  21
  22   '#thermal-sensor-cells':
  23     const: 0
  24
  25   io-channels:
  26     maxItems: 1
  27
  28   io-channel-names:
  29     const: sensor-channel
  30
  31   temperature-lookup-table:
  32     description: |
  33       Lookup table to map the relation between ADC value and temperature.
  34       When ADC is read, the value is looked up on the table to get the
  35       equivalent temperature.
  36
  37       If not specified, driver assumes the ADC channel gives milliCelsius
  38       directly.
  39     $ref: /schemas/types.yaml#/definitions/int32-matrix
  40     items:
  41       items:
  42         - description: Temperature in milliCelsius
  43         - description: ADC read value
  44
  45 required:
  46   - compatible
  47   - '#thermal-sensor-cells'
  48   - io-channels
  49   - io-channel-names
  50
  51 additionalProperties: false
  52
  53 examples:
  54   - |
  55     #include <dt-bindings/thermal/thermal.h>
  56
  57     thermal-sensor {
  58         compatible = "generic-adc-thermal";
  59         #thermal-sensor-cells = <0>;
  60         io-channels = <&ads1015 1>;
  61         io-channel-names = "sensor-channel";
  62         temperature-lookup-table = <
  63               (-40000) 2578
  64               (-39000) 2577
  65               (-38000) 2576
  66               (-37000) 2575
  67               (-36000) 2574
  68               (-35000) 2573
  69               (-34000) 2572
  70               (-33000) 2571
  71               (-32000) 2569
  72               (-31000) 2568
  73               (-30000) 2567
  74               /* skip */
  75               118000 254
  76               119000 247
  77               120000 240
  78               121000 233
  79               122000 226
  80               123000 220
  81               124000 214
  82               125000 208>;
  83     };
  84 ...