# 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 Multi-sensor Temperature system
maintainers:
- Nuno Sá <nuno.sa@analog.com>
description: |
Analog Devices LTC2983 Multi-Sensor Digital Temperature Measurement System
https://www.analog.com/media/en/technical-documentation/data-sheets/2983fc.pdf
properties:
compatible:
enum:
- adi,ltc2983
reg:
maxItems: 1
interrupts:
maxItems: 1
adi,mux-delay-config-us:
description:
The LTC2983 performs 2 or 3 internal conversion cycles per temperature
result. Each conversion cycle is performed with different excitation and
input multiplexer configurations. Prior to each conversion, these
excitation circuits and input switch configurations are changed and an
internal 1ms delay ensures settling prior to the conversion cycle in most
cases. An extra delay can be configured using this property. The value is
rounded to nearest 100us.
maximum: 255
adi,filter-notch-freq:
description:
Set's the default setting of the digital filter. The default is
simultaneous 50/60Hz rejection.
0 - 50/60Hz rejection
1 - 60Hz rejection
2 - 50Hz rejection
$ref: /schemas/types.yaml#/definitions/uint32
minimum: 0
maximum: 2
'#address-cells':
const: 1
'#size-cells':
const: 0
patternProperties:
"@([1-9]|1[0-9]|20)$":
type: object
properties:
reg:
description:
The channel number. It can be connected to one of the 20 channels of
the device.
minimum: 1
maximum: 20
adi,sensor-type:
description: Identifies the type of sensor connected to the device.
$ref: /schemas/types.yaml#/definitions/uint32
required:
- reg
- adi,sensor-type
"^thermocouple@":
type: object
description:
Represents a thermocouple sensor which is connected to one of the device
channels.
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:
Boolean property which set's the thermocouple as single-ended.
type: boolean
adi,sensor-oc-current-microamp:
description:
This property set's the pulsed current value applied during
open-circuit detect.
enum: [10, 100, 500, 1000]
adi,cold-junction-handle:
description:
Phandle which points to a sensor object responsible for measuring
the thermocouple cold junction temperature.
$ref: "/schemas/types.yaml#/definitions/phandle"
adi,custom-thermocouple:
description:
This is a table, where each entry should be a pair of
voltage(mv)-temperature(K). The entries must be given in nv and uK
so that, the original values must be multiplied by 1000000. For
more details look at table 69 and 70.
Note should be signed, but dtc doesn't currently maintain the
sign.
$ref: /schemas/types.yaml#/definitions/uint64-matrix
minItems: 3
maxItems: 64
items:
minItems: 2
maxItems: 2
"^diode@":
type: object
description:
Represents a diode sensor which is connected to one of the device
channels.
properties:
adi,sensor-type:
description: Identifies the sensor as a diode.
$ref: /schemas/types.yaml#/definitions/uint32
const: 28
adi,single-ended:
description: Boolean property which set's the diode as single-ended.
type: boolean
adi,three-conversion-cycles:
description:
Boolean property which set's three conversion cycles removing
parasitic resistance effects between the LTC2983 and the diode.
type: boolean
adi,average-on:
description:
Boolean property which enables a running average of the diode
temperature reading. This reduces 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:
This property controls the magnitude of the excitation current
applied to the diode. Depending on the number of conversions
cycles, this property will assume different predefined values on
each cycle. Just set the value of the first cycle (1l).
enum: [10, 20, 40, 80]
adi,ideal-factor-value:
description:
This property sets the diode ideality factor. The real value must
be multiplied by 1000000 to remove the fractional part. For more
information look at table 20 of the datasheet.
$ref: /schemas/types.yaml#/definitions/uint32
"^rtd@":
type: object
description:
Represents a rtd sensor which is connected to one of the device channels.
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:
Phandle pointing to a rsense object associated with this RTD.
$ref: "/schemas/types.yaml#/definitions/phandle"
adi,number-of-wires:
description:
Identifies the number of wires used by the RTD. Setting this
property to 5 means 4 wires with Kelvin Rsense.
$ref: /schemas/types.yaml#/definitions/uint32
enum: [2, 3, 4, 5]
adi,rsense-share:
description:
Boolean property which enables Rsense sharing, where one sense
resistor is used for multiple 2-, 3-, and/or 4-wire RTDs.
type: boolean
adi,current-rotate:
description:
Boolean property which enables excitation current rotation to
automatically remove parasitic thermocouple effects. Note that
this property is not allowed for 2- and 3-wire RTDs.
type: boolean
adi,excitation-current-microamp:
description:
This property controls the magnitude of the excitation current
applied to the RTD.
enum: [5, 10, 25, 50, 100, 250, 500, 1000]
adi,rtd-curve:
description:
This property set the RTD curve used and the corresponding
Callendar-VanDusen constants. Look at table 30 of the datasheet.
$ref: /schemas/types.yaml#/definitions/uint32
minimum: 0
maximum: 3
adi,custom-rtd:
description:
This is a table, where each entry should be a pair of
resistance(ohm)-temperature(K). The entries added here are in uohm
and uK. For more details values look at table 74 and 75.
$ref: /schemas/types.yaml#/definitions/uint64-matrix
items:
minItems: 3
maxItems: 64
items:
minItems: 2
maxItems: 2
required:
- adi,rsense-handle
dependencies:
adi,current-rotate: [ "adi,rsense-share" ]
"^thermistor@":
type: object
description:
Represents a thermistor sensor which is connected to one of the device
channels.
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:
Phandle pointing to a rsense object associated with this
thermistor.
$ref: "/schemas/types.yaml#/definitions/phandle"
adi,single-ended:
description:
Boolean property which set's the thermistor as single-ended.
type: boolean
adi,rsense-share:
description:
Boolean property which enables Rsense sharing, where one sense
resistor is used for multiple thermistors. Note that this property
is ignored if adi,single-ended is set.
type: boolean
adi,current-rotate:
description:
Boolean property which enables excitation current rotation to
automatically remove parasitic thermocouple effects.
type: boolean
adi,excitation-current-nanoamp:
description:
This property controls the magnitude of the excitation current
applied to the thermistor. Value 0 set's the sensor in auto-range
mode.
$ref: /schemas/types.yaml#/definitions/uint32
enum: [0, 250, 500, 1000, 5000, 10000, 25000, 50000, 100000, 250000,
500000, 1000000]
adi,custom-thermistor:
description:
This is a table, where each entry should be a pair of
resistance(ohm)-temperature(K). The entries added here are in uohm
and uK only for custom thermistors. For more details look at table
78 and 79.
$ref: /schemas/types.yaml#/definitions/uint64-matrix
minItems: 3
maxItems: 64
items:
minItems: 2
maxItems: 2
adi,custom-steinhart:
description:
Steinhart-Hart coefficients are also supported and can
be programmed into the device memory using this property. For
Steinhart sensors the coefficients are given in the raw
format. Look at table 82 for more information.
$ref: /schemas/types.yaml#/definitions/uint32-array
items:
minItems: 6
maxItems: 6
required:
- adi,rsense-handle
dependencies:
adi,current-rotate: [ "adi,rsense-share" ]
"^adc@":
type: object
description: Represents a channel which is being used as a direct adc.
properties:
adi,sensor-type:
description: Identifies the sensor as a direct adc.
$ref: /schemas/types.yaml#/definitions/uint32
const: 30
adi,single-ended:
description: Boolean property which set's the adc as single-ended.
type: boolean
"^rsense@":
type: object
description:
Represents a rsense which is connected to one of the device channels.
Rsense are used by thermistors and RTD's.
properties:
reg:
minimum: 2
maximum: 20
adi,sensor-type:
description: Identifies the sensor as a rsense.
$ref: /schemas/types.yaml#/definitions/uint32
const: 29
adi,rsense-val-milli-ohms:
description:
Sets the value of the sense resistor. Look at table 20 of the
datasheet for information.
required:
- adi,rsense-val-milli-ohms
required:
- compatible
- reg
- interrupts
additionalProperties: false
examples:
- |
#include <dt-bindings/interrupt-controller/irq.h>
spi {
#address-cells = <1>;
#size-cells = <0>;
sensor_ltc2983: ltc2983@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>,
<(-30200000) 99100000>,
<(-5300000) 135400000>,
<0 273150000>,
<40200000 361200000>,
<55300000 522100000>,
<88300000 720300000>,
<132200000 811200000>,
<188700000 922500000>,
<460400000 1000000000>; //10 pairs
};
};
};
...
