xref: /linux/Documentation/devicetree/bindings/thermal/generic-adc-thermal.yaml (revision c532de5a67a70f8533d495f8f2aaa9a0491c3ad0) 
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
7title: General Purpose Analog To Digital Converter (ADC) based thermal sensor
8
9maintainers:
10  - Laxman Dewangan <ldewangan@nvidia.com>
11
12description:
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$ref: thermal-sensor.yaml#
19
20properties:
21  compatible:
22    const: generic-adc-thermal
23
24  '#thermal-sensor-cells':
25    const: 0
26
27  io-channels:
28    maxItems: 1
29
30  io-channel-names:
31    const: sensor-channel
32
33  temperature-lookup-table:
34    description: |
35      Lookup table to map the relation between ADC value and temperature.
36      When ADC is read, the value is looked up on the table to get the
37      equivalent temperature.
38
39      If not specified, driver assumes the ADC channel gives milliCelsius
40      directly.
41    $ref: /schemas/types.yaml#/definitions/int32-matrix
42    items:
43      items:
44        - description: Temperature in milliCelsius
45        - description: ADC read value
46
47required:
48  - compatible
49  - io-channels
50  - io-channel-names
51
52unevaluatedProperties: false
53
54examples:
55  - |
56    #include <dt-bindings/thermal/thermal.h>
57
58    thermal-sensor {
59        compatible = "generic-adc-thermal";
60        #thermal-sensor-cells = <0>;
61        io-channels = <&ads1015 1>;
62        io-channel-names = "sensor-channel";
63        temperature-lookup-table = <
64              (-40000) 2578
65              (-39000) 2577
66              (-38000) 2576
67              (-37000) 2575
68              (-36000) 2574
69              (-35000) 2573
70              (-34000) 2572
71              (-33000) 2571
72              (-32000) 2569
73              (-31000) 2568
74              (-30000) 2567
75              /* skip */
76              118000 254
77              119000 247
78              120000 240
79              121000 233
80              122000 226
81              123000 220
82              124000 214
83              125000 208>;
84    };
85...
86