# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
%YAML 1.2
---
$id: http://devicetree.org/schemas/iio/temperature/adi,ltc2983.yaml#
$schema: http://devicetree.org/meta-schemas/core.yaml#
title: Analog Devices LTC2983, LTC2986, LTM2985 Multi-sensor Temperature system
maintainers:
- Nuno Sá <nuno.sa@analog.com>
description: |
Analog Devices LTC2983, LTC2984, LTC2986, LTM2985 Multi-Sensor Digital
Temperature Measurement Systems
https://www.analog.com/media/en/technical-documentation/data-sheets/2983fc.pdf
https://www.analog.com/media/en/technical-documentation/data-sheets/2984fb.pdf
https://www.analog.com/media/en/technical-documentation/data-sheets/29861fa.pdf
https://www.analog.com/media/en/technical-documentation/data-sheets/ltm2985.pdf
$defs:
sensor-node:
type: object
description: Sensor node common constraints
properties:
reg:
description:
Channel number. Connects the sensor to the channel with this number
of the device.
minimum: 1
maximum: 20
adi,sensor-type:
description: Type of sensor connected to the device.
$ref: /schemas/types.yaml#/definitions/uint32
required:
- reg
- adi,sensor-type
properties:
compatible:
oneOf:
- enum:
- adi,ltc2983
- adi,ltc2986
- adi,ltm2985
- items:
- const: adi,ltc2984
- const: adi,ltc2983
reg:
maxItems: 1
interrupts:
maxItems: 1
adi,mux-delay-config-us:
description: |
Extra delay prior to each conversion, in addition to the internal 1ms
delay, for the multiplexer to switch input configurations and
excitation values.
This property is supposed to be in microseconds, but to maintain
compatibility, this value will be multiplied by 100 before usage.
maximum: 255
default: 0
adi,filter-notch-freq:
description:
Notch frequency of the digital filter.
0 - 50/60Hz rejection
1 - 60Hz rejection
2 - 50Hz rejection
$ref: /schemas/types.yaml#/definitions/uint32
minimum: 0
maximum: 2
default: 0
'#address-cells':
const: 1
'#size-cells':
const: 0
patternProperties:
"^thermocouple@":
$ref: '#/$defs/sensor-node'
unevaluatedProperties: false
description: Thermocouple sensor.
properties:
adi,sensor-type:
description: |
1 - Type J Thermocouple
2 - Type K Thermocouple
3 - Type E Thermocouple
4 - Type N Thermocouple
5 - Type R Thermocouple
6 - Type S Thermocouple
7 - Type T Thermocouple
8 - Type B Thermocouple
9 - Custom Thermocouple
$ref: /schemas/types.yaml#/definitions/uint32
minimum: 1
maximum: 9
adi,single-ended:
description: Whether the sensor is single-ended.
type: boolean
adi,sensor-oc-current-microamp:
description: Pulsed current value applied during open-circuit detect.
enum: [10, 100, 500, 1000]
default: 10
adi,cold-junction-handle:
description:
Sensor responsible for measuring the thermocouple cold junction
temperature.
$ref: /schemas/types.yaml#/definitions/phandle
adi,custom-thermocouple:
description:
Used for digitizing custom thermocouples.
See Page 59 of the datasheet.
$ref: /schemas/types.yaml#/definitions/int64-matrix
minItems: 3
maxItems: 64
items:
items:
- description: Voltage point in nV, signed.
- description: Temperature point in uK.
allOf:
- if:
properties:
adi,sensor-type:
const: 9
then:
required:
- adi,custom-thermocouple
"^diode@":
$ref: '#/$defs/sensor-node'
unevaluatedProperties: false
description: Diode sensor.
properties:
adi,sensor-type:
description: Sensor type for diodes.
$ref: /schemas/types.yaml#/definitions/uint32
const: 28
adi,single-ended:
description: Whether the sensor is single-ended.
type: boolean
adi,three-conversion-cycles:
description:
Whether to use three conversion cycles to remove parasitic
resistance between the device and the diode.
type: boolean
adi,average-on:
description:
Whether to use a running average of the diode temperature
reading to reduce the noise when the diode is used as a cold
junction temperature element on an isothermal block where
temperatures change slowly.
type: boolean
adi,excitation-current-microamp:
description:
Magnitude of the 1l excitation current applied to the diode.
4l excitation current will be 4 times this value, and 8l
excitation current will be 8 times value.
enum: [10, 20, 40, 80]
default: 10
adi,ideal-factor-value:
description:
Diode ideality factor.
Set this property to 1000000 times the real value.
$ref: /schemas/types.yaml#/definitions/uint32
default: 0
"^rtd@":
$ref: '#/$defs/sensor-node'
unevaluatedProperties: false
description: RTD sensor.
properties:
reg:
minimum: 2
maximum: 20
adi,sensor-type:
description: |
10 - RTD PT-10
11 - RTD PT-50
12 - RTD PT-100
13 - RTD PT-200
14 - RTD PT-500
15 - RTD PT-1000
16 - RTD PT-1000 (0.00375)
17 - RTD NI-120
18 - RTD Custom
$ref: /schemas/types.yaml#/definitions/uint32
minimum: 10
maximum: 18
adi,rsense-handle:
description: Associated sense resistor sensor.
$ref: /schemas/types.yaml#/definitions/phandle
adi,number-of-wires:
description:
Number of wires used by the RTD.
5 means 4 wires with Kelvin sense resistor.
$ref: /schemas/types.yaml#/definitions/uint32
enum: [2, 3, 4, 5]
default: 2
adi,rsense-share:
description:
Whether to enable sense resistor sharing, where one sense
resistor is used by multiple sensors.
type: boolean
adi,excitation-current-microamp:
description: Excitation current applied to the RTD.
enum: [5, 10, 25, 50, 100, 250, 500, 1000]
default: 5
adi,rtd-curve:
description: |
RTD curve and the corresponding Callendar-VanDusen constants.
0 - European
1 - American
2 - Japanese
3 - ITS-90
$ref: /schemas/types.yaml#/definitions/uint32
minimum: 0
maximum: 3
default: 0
adi,custom-rtd:
description:
Used for digitizing custom RTDs.
See Page 62 of the datasheet.
$ref: /schemas/types.yaml#/definitions/uint64-matrix
minItems: 3
maxItems: 64
items:
items:
- description: Resistance point in uOhms.
- description: Temperature point in uK.
required:
- adi,rsense-handle
allOf:
- if:
properties:
adi,number-of-wires:
const: 4
then:
properties:
adi,current-rotate:
description:
Whether to enable excitation current rotation to automatically
remove parasitic thermocouple effects.
type: boolean
dependencies:
adi,current-rotate: [ "adi,rsense-share" ]
- if:
properties:
adi,sensor-type:
const: 18
then:
required:
- adi,custom-rtd
"^thermistor@":
$ref: '#/$defs/sensor-node'
unevaluatedProperties: false
description: Thermistor sensor.
properties:
adi,sensor-type:
description:
19 - Thermistor 44004/44033 2.252kohm at 25°C
20 - Thermistor 44005/44030 3kohm at 25°C
21 - Thermistor 44007/44034 5kohm at 25°C
22 - Thermistor 44006/44031 10kohm at 25°C
23 - Thermistor 44008/44032 30kohm at 25°C
24 - Thermistor YSI 400 2.252kohm at 25°C
25 - Thermistor Spectrum 1003k 1kohm
26 - Thermistor Custom Steinhart-Hart
27 - Custom Thermistor
$ref: /schemas/types.yaml#/definitions/uint32
minimum: 19
maximum: 27
adi,rsense-handle:
description: Associated sense resistor sensor.
$ref: /schemas/types.yaml#/definitions/phandle
adi,single-ended:
description: Whether the sensor is single-ended.
type: boolean
adi,rsense-share:
description:
Whether to enable sense resistor sharing, where one sense
resistor is used by multiple sensors.
type: boolean
adi,current-rotate:
description:
Whether to enable excitation current rotation to automatically
remove parasitic thermocouple effects.
type: boolean
adi,excitation-current-nanoamp:
description:
Excitation current applied to the thermistor.
0 sets the sensor in auto-range mode.
enum: [0, 250, 500, 1000, 5000, 10000, 25000, 50000, 100000, 250000,
500000, 1000000]
default: 0
adi,custom-thermistor:
description:
Used for digitizing custom thermistors.
See Page 65 of the datasheet.
$ref: /schemas/types.yaml#/definitions/uint64-matrix
minItems: 3
maxItems: 64
items:
items:
- description: Resistance point in uOhms.
- description: Temperature point in uK.
adi,custom-steinhart:
description:
Steinhart-Hart coefficients in raw format, used for digitizing
custom thermistors.
See Page 68 of the datasheet.
$ref: /schemas/types.yaml#/definitions/uint32-array
minItems: 6
maxItems: 6
required:
- adi,rsense-handle
dependencies:
adi,current-rotate: [ "adi,rsense-share" ]
allOf:
- if:
properties:
adi,sensor-type:
const: 26
then:
properties:
adi,excitation-current-nanoamp:
enum: [250, 500, 1000, 5000, 10000, 25000, 50000, 100000,
250000, 500000, 1000000]
default: 1000
required:
- adi,custom-steinhart
- if:
properties:
adi,sensor-type:
const: 27
then:
properties:
adi,excitation-current-nanoamp:
enum: [250, 500, 1000, 5000, 10000, 25000, 50000, 100000,
250000, 500000, 1000000]
default: 1000
required:
- adi,custom-thermistor
"^adc@":
$ref: '#/$defs/sensor-node'
unevaluatedProperties: false
description: Direct ADC sensor.
properties:
adi,sensor-type:
description: Sensor type for direct ADC sensors.
$ref: /schemas/types.yaml#/definitions/uint32
const: 30
adi,single-ended:
description: Whether the sensor is single-ended.
type: boolean
"^temp@":
$ref: '#/$defs/sensor-node'
unevaluatedProperties: false
description: Active analog temperature sensor.
properties:
adi,sensor-type:
description: Sensor type for active analog temperature sensors.
$ref: /schemas/types.yaml#/definitions/uint32
const: 31
adi,single-ended:
description: Whether the sensor is single-ended.
type: boolean
adi,custom-temp:
description:
Used for digitizing active analog temperature sensors.
See Page 67 of the LTM2985 datasheet.
$ref: /schemas/types.yaml#/definitions/uint64-matrix
minItems: 3
maxItems: 64
items:
items:
- description: Voltage point in nV, signed.
- description: Temperature point in uK.
required:
- adi,custom-temp
"^rsense@":
$ref: '#/$defs/sensor-node'
unevaluatedProperties: false
description: Sense resistor sensor.
properties:
reg:
minimum: 2
maximum: 20
adi,sensor-type:
description: Sensor type sense resistor sensors.
$ref: /schemas/types.yaml#/definitions/uint32
const: 29
adi,rsense-val-milli-ohms:
description: Value of the sense resistor.
required:
- adi,rsense-val-milli-ohms
required:
- compatible
- reg
- interrupts
additionalProperties: false
allOf:
- if:
properties:
compatible:
contains:
enum:
- adi,ltc2983
- adi,ltc2984
then:
patternProperties:
"^temp@": false
examples:
- |
#include <dt-bindings/interrupt-controller/irq.h>
spi {
#address-cells = <1>;
#size-cells = <0>;
temperature-sensor@0 {
compatible = "adi,ltc2983";
reg = <0>;
#address-cells = <1>;
#size-cells = <0>;
interrupts = <20 IRQ_TYPE_EDGE_RISING>;
interrupt-parent = <&gpio>;
thermocouple@18 {
reg = <18>;
adi,sensor-type = <8>; //Type B
adi,sensor-oc-current-microamp = <10>;
adi,cold-junction-handle = <&diode5>;
};
diode5: diode@5 {
reg = <5>;
adi,sensor-type = <28>;
};
rsense2: rsense@2 {
reg = <2>;
adi,sensor-type = <29>;
adi,rsense-val-milli-ohms = <1200000>; //1.2Kohms
};
rtd@14 {
reg = <14>;
adi,sensor-type = <15>; //PT1000
/*2-wire, internal gnd, no current rotation*/
adi,number-of-wires = <2>;
adi,rsense-share;
adi,excitation-current-microamp = <500>;
adi,rsense-handle = <&rsense2>;
};
adc@10 {
reg = <10>;
adi,sensor-type = <30>;
adi,single-ended;
};
thermistor@12 {
reg = <12>;
adi,sensor-type = <26>; //Steinhart
adi,rsense-handle = <&rsense2>;
adi,custom-steinhart = <0x00f371ec 0x12345678
0x2c0f8733 0x10018c66 0xa0feaccd
0x90021d99>; //6 entries
};
thermocouple@20 {
reg = <20>;
adi,sensor-type = <9>; //custom thermocouple
adi,single-ended;
adi,custom-thermocouple =
/bits/ 64 <(-50220000) 0>,
/bits/ 64 <(-30200000) 99100000>,
/bits/ 64 <(-5300000) 135400000>,
/bits/ 64 <0 273150000>,
/bits/ 64 <40200000 361200000>,
/bits/ 64 <55300000 522100000>,
/bits/ 64 <88300000 720300000>,
/bits/ 64 <132200000 811200000>,
/bits/ 64 <188700000 922500000>,
/bits/ 64 <460400000 1000000000>; //10 pairs
};
};
};
...