| # SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) |
| %YAML 1.2 |
| --- |
| $id: http://devicetree.org/schemas/iio/adc/adi,ad4170-4.yaml# |
| $schema: http://devicetree.org/meta-schemas/core.yaml# |
| |
| title: Analog Devices AD4170-4 and similar Analog to Digital Converters |
| |
| maintainers: |
| - Marcelo Schmitt <marcelo.schmitt@analog.com> |
| |
| description: | |
| Analog Devices AD4170-4 series of Sigma-delta Analog to Digital Converters. |
| Specifications can be found at: |
| https://www.analog.com/media/en/technical-documentation/data-sheets/ad4170-4.pdf |
| https://www.analog.com/media/en/technical-documentation/data-sheets/ad4190-4.pdf |
| https://www.analog.com/media/en/technical-documentation/data-sheets/ad4195-4.pdf |
| |
| $ref: /schemas/spi/spi-peripheral-props.yaml# |
| |
| $defs: |
| reference-buffer: |
| description: | |
| Enable precharge buffer, full buffer, or skip reference buffering of |
| the positive/negative voltage reference. Because the output impedance |
| of the source driving the voltage reference inputs may be dynamic, |
| resistive/capacitive combinations of those inputs can cause DC gain |
| errors if the reference inputs go unbuffered into the ADC. Enable |
| reference buffering if the provided reference source has dynamic high |
| impedance output. Note the absolute voltage allowed on REFINn+ and REFINn- |
| inputs is from AVSS - 50 mV to AVDD + 50 mV when the reference buffers are |
| disabled but narrows to AVSS to AVDD when reference buffering is enabled |
| or in precharge mode. |
| $ref: /schemas/types.yaml#/definitions/string |
| enum: [ precharge, full, disabled ] |
| default: full |
| |
| properties: |
| compatible: |
| enum: |
| - adi,ad4170-4 |
| - adi,ad4190-4 |
| - adi,ad4195-4 |
| |
| avss-supply: |
| description: |
| Reference voltage supply for AVSS. A −2.625V minimum and 0V maximum supply |
| that powers the chip. If not provided, AVSS is assumed to be at system |
| ground (0V). |
| |
| avdd-supply: |
| description: |
| A supply of 4.75V to 5.25V relative to AVSS that powers the chip (AVDD). |
| |
| iovdd-supply: |
| description: 1.7V to 5.25V reference supply to the serial interface (IOVDD). |
| |
| refin1p-supply: |
| description: REFIN+ supply that can be used as reference for conversion. |
| |
| refin1n-supply: |
| description: REFIN- supply that can be used as reference for conversion. |
| |
| refin2p-supply: |
| description: REFIN2+ supply that can be used as reference for conversion. |
| |
| refin2n-supply: |
| description: REFIN2- supply that can be used as reference for conversion. |
| |
| spi-cpol: true |
| |
| spi-cpha: true |
| |
| interrupts: |
| description: |
| Interrupt for signaling the completion of conversion results. The data |
| ready signal (RDY) used as interrupt is by default provided on the SDO |
| pin. Alternatively, it can be provided on the DIG_AUX1 pin in which case |
| the chip disables the RDY function on SDO. Thus, there can be only one |
| data ready interrupt enabled at a time. |
| |
| interrupt-names: |
| description: |
| Specify which pin should be configured as Data Ready interrupt. |
| enum: |
| - sdo |
| - dig_aux1 |
| |
| clocks: |
| maxItems: 1 |
| description: |
| Optional external clock source. Can specify either an external clock or |
| external crystal. |
| |
| clock-names: |
| enum: |
| - ext-clk |
| - xtal |
| default: ext-clk |
| |
| '#clock-cells': |
| const: 0 |
| |
| clock-output-names: |
| maxItems: 1 |
| |
| gpio-controller: true |
| |
| "#gpio-cells": |
| const: 2 |
| description: | |
| The first cell is for the GPIO number: 0 to 3. |
| The second cell takes standard GPIO flags. |
| |
| ldac-gpios: |
| description: |
| GPIO connected to DIG_AUX2 pin to be used as LDAC toggle to control the |
| transfer of data from the DAC_INPUT_A register to the DAC. |
| maxItems: 1 |
| |
| '#address-cells': |
| const: 1 |
| |
| '#size-cells': |
| const: 0 |
| |
| adi,vbias-pins: |
| description: Analog inputs to apply a voltage bias of (AVDD − AVSS) / 2 to. |
| $ref: /schemas/types.yaml#/definitions/uint32-array |
| minItems: 1 |
| maxItems: 9 |
| items: |
| minimum: 0 |
| maximum: 8 |
| |
| allOf: |
| # Some devices don't have integrated DAC |
| - if: |
| properties: |
| compatible: |
| contains: |
| enum: |
| - adi,ad4190-4 |
| - adi,ad4195-4 |
| then: |
| properties: |
| ldac-gpios: false |
| |
| # Require to specify the interrupt pin when using interrupts |
| - if: |
| required: |
| - interrupts |
| then: |
| required: |
| - interrupt-names |
| |
| # If an external clock is set, the internal clock cannot go out and vice versa |
| - oneOf: |
| - required: [clocks] |
| properties: |
| '#clock-cells': false |
| - required: ['#clock-cells'] |
| properties: |
| clocks: false |
| |
| required: |
| - compatible |
| - reg |
| - avdd-supply |
| - iovdd-supply |
| - spi-cpol |
| - spi-cpha |
| |
| unevaluatedProperties: false |
| |
| patternProperties: |
| "^channel@[0-9a-f]$": |
| $ref: /schemas/iio/adc/adc.yaml# |
| unevaluatedProperties: false |
| description: |
| Represents the external channels which are connected to the ADC. |
| |
| properties: |
| reg: |
| description: |
| The channel number. |
| minimum: 0 |
| maximum: 15 |
| |
| diff-channels: |
| description: | |
| This property is used for defining the inputs of a differential |
| voltage channel. The first value is the positive input and the second |
| value is the negative input of the channel. |
| |
| Besides the analog input pins AIN0 to AIN8, there are special inputs |
| that can be selected with the following values: |
| 17: Internal temperature sensor |
| 18: (AVDD-AVSS)/5 |
| 19: (IOVDD-DGND)/5 |
| 20: DAC output |
| 21: ALDO |
| 22: DLDO |
| 23: AVSS |
| 24: DGND |
| 25: REFIN+ |
| 26: REFIN- |
| 27: REFIN2+ |
| 28: REFIN2- |
| 29: REFOUT |
| For the internal temperature sensor, use the input number for both |
| inputs (i.e. diff-channels = <17 17>). |
| items: |
| enum: [0, 1, 2, 3, 4, 5, 6, 7, 8, 17, 18, 19, 20, 21, 22, 23, 24, 25, |
| 26, 27, 28, 29] |
| |
| adi,reference-select: |
| description: | |
| Select the reference source to use when converting on the |
| specific channel. Valid values are: |
| 0: REFIN+/REFIN- |
| 1: REFIN2+/REFIN2− |
| 2: REFOUT/AVSS (internal reference) |
| 3: AVDD/AVSS |
| If not specified, REFOUT/AVSS is used. |
| $ref: /schemas/types.yaml#/definitions/uint32 |
| enum: [0, 1, 2, 3] |
| default: 1 |
| |
| adi,positive-reference-buffer: |
| $ref: '#/$defs/reference-buffer' |
| |
| adi,negative-reference-buffer: |
| $ref: '#/$defs/reference-buffer' |
| |
| adi,sensor-type: |
| description: |
| The AD4170-4 and similar designs have features to aid interfacing with |
| load cell weigh scale, RTD, and thermocouple sensors. Each of those |
| sensor types requires either distinct wiring configuration or |
| external circuitry for proper sensor operation and can use different |
| ADC chip functionality on their setups. A key characteristic of those |
| external sensors is that they must be excited either by voltage supply |
| or by ADC chip excitation signals. The sensor can then be read through |
| a pair of analog inputs. This property specifies which particular |
| sensor type is connected to the ADC so it can be properly setup and |
| handled. Omit this property for conventional (not weigh scale, RTD, or |
| thermocouple) ADC channel setups. |
| $ref: /schemas/types.yaml#/definitions/string |
| enum: [ weighscale, rtd, thermocouple ] |
| |
| adi,excitation-pin-0: |
| description: |
| Analog input to apply excitation current to while the channel |
| is active. |
| $ref: /schemas/types.yaml#/definitions/uint32 |
| minimum: 0 |
| maximum: 20 |
| default: 0 |
| |
| adi,excitation-pin-1: |
| description: |
| Analog input to apply excitation current to while the channel |
| is active. |
| $ref: /schemas/types.yaml#/definitions/uint32 |
| minimum: 0 |
| maximum: 20 |
| default: 0 |
| |
| adi,excitation-pin-2: |
| description: |
| Analog input to apply excitation current to while the channel |
| is active. |
| $ref: /schemas/types.yaml#/definitions/uint32 |
| minimum: 0 |
| maximum: 20 |
| default: 0 |
| |
| adi,excitation-pin-3: |
| description: |
| Analog input to apply excitation current to while the channel |
| is active. |
| $ref: /schemas/types.yaml#/definitions/uint32 |
| minimum: 0 |
| maximum: 20 |
| default: 0 |
| |
| adi,excitation-current-0-microamp: |
| description: |
| Excitation current in microamperes to be applied to pin specified in |
| adi,excitation-pin-0 while this channel is active. |
| enum: [0, 10, 50, 100, 250, 500, 1000, 1500] |
| default: 0 |
| |
| adi,excitation-current-1-microamp: |
| description: |
| Excitation current in microamperes to be applied to pin specified in |
| adi,excitation-pin-1 while this channel is active. |
| enum: [0, 10, 50, 100, 250, 500, 1000, 1500] |
| default: 0 |
| |
| adi,excitation-current-2-microamp: |
| description: |
| Excitation current in microamperes to be applied to pin specified in |
| adi,excitation-pin-2 while this channel is active. |
| enum: [0, 10, 50, 100, 250, 500, 1000, 1500] |
| default: 0 |
| |
| adi,excitation-current-3-microamp: |
| description: |
| Excitation current in microamperes to be applied to pin specified in |
| adi,excitation-pin-3 while this channel is active. |
| enum: [0, 10, 50, 100, 250, 500, 1000, 1500] |
| default: 0 |
| |
| adi,excitation-ac: |
| type: boolean |
| description: |
| Whether the external sensor has to be AC or DC excited. When omitted, |
| it is DC excited. |
| |
| allOf: |
| - oneOf: |
| - required: [single-channel, common-mode-channel] |
| properties: |
| diff-channels: false |
| - required: [diff-channels] |
| properties: |
| single-channel: false |
| common-mode-channel: false |
| # Usual ADC channels don't need external circuitry excitation. |
| - if: |
| not: |
| required: |
| - adi,sensor-type |
| then: |
| properties: |
| adi,excitation-pin-0: false |
| adi,excitation-pin-1: false |
| adi,excitation-pin-2: false |
| adi,excitation-pin-3: false |
| adi,excitation-current-0-microamp: false |
| adi,excitation-current-1-microamp: false |
| adi,excitation-current-2-microamp: false |
| adi,excitation-current-3-microamp: false |
| adi,excitation-ac: false |
| # Weigh scale bridge AC excited with one pair of predefined signals. |
| - if: |
| allOf: |
| - properties: |
| adi,sensor-type: |
| contains: |
| const: weighscale |
| - required: |
| - adi,excitation-ac |
| - adi,excitation-pin-2 |
| - adi,excitation-pin-3 |
| - not: |
| required: |
| - adi,excitation-current-2-microamp |
| - adi,excitation-current-3-microamp |
| then: |
| properties: |
| adi,excitation-pin-2: |
| const: 19 |
| adi,excitation-pin-3: |
| const: 20 |
| # Weigh scale bridge AC excited with two pairs of predefined signals. |
| - if: |
| allOf: |
| - properties: |
| adi,sensor-type: |
| contains: |
| const: weighscale |
| - required: |
| - adi,excitation-ac |
| - adi,excitation-pin-0 |
| - adi,excitation-pin-1 |
| - adi,excitation-pin-2 |
| - adi,excitation-pin-3 |
| - not: |
| required: |
| - adi,excitation-current-0-microamp |
| - adi,excitation-current-1-microamp |
| - adi,excitation-current-2-microamp |
| - adi,excitation-current-3-microamp |
| then: |
| properties: |
| adi,excitation-pin-0: |
| const: 17 |
| adi,excitation-pin-1: |
| const: 18 |
| adi,excitation-pin-2: |
| const: 19 |
| adi,excitation-pin-3: |
| const: 20 |
| |
| examples: |
| - | |
| #include <dt-bindings/interrupt-controller/irq.h> |
| spi { |
| #address-cells = <1>; |
| #size-cells = <0>; |
| |
| adc@0 { |
| compatible = "adi,ad4170-4"; |
| reg = <0>; |
| spi-max-frequency = <20000000>; |
| spi-cpol; |
| spi-cpha; |
| avdd-supply = <&avdd>; |
| iovdd-supply = <&iovdd>; |
| clocks = <&clk>; |
| clock-names = "xtal"; |
| interrupts = <0 IRQ_TYPE_EDGE_FALLING>; |
| interrupt-names = "dig_aux1"; |
| adi,vbias-pins = <8>; |
| #address-cells = <1>; |
| #size-cells = <0>; |
| |
| // Sample AIN0 with respect to DGND throughout AVDD/DGND input range |
| // Pseudo-differential unipolar |
| channel@0 { |
| reg = <0>; |
| single-channel = <0>; |
| common-mode-channel = <24>; |
| adi,reference-select = <3>; |
| }; |
| // Weigh scale sensor |
| channel@1 { |
| reg = <1>; |
| bipolar; |
| diff-channels = <1 2>; |
| adi,reference-select = <0>; |
| adi,positive-reference-buffer = "precharge"; |
| adi,negative-reference-buffer = "precharge"; |
| adi,sensor-type = "weighscale"; |
| adi,excitation-pin-2 = <19>; |
| adi,excitation-pin-3 = <20>; |
| adi,excitation-ac; |
| }; |
| // RTD sensor |
| channel@2 { |
| reg = <2>; |
| bipolar; |
| diff-channels = <3 4>; |
| adi,reference-select = <0>; |
| adi,sensor-type = "rtd"; |
| adi,excitation-pin-0 = <5>; |
| adi,excitation-pin-1 = <6>; |
| adi,excitation-current-0-microamp = <500>; |
| adi,excitation-current-1-microamp = <500>; |
| adi,excitation-ac; |
| }; |
| // Thermocouple sensor |
| channel@3 { |
| reg = <3>; |
| bipolar; |
| diff-channels = <7 8>; |
| adi,reference-select = <0>; |
| adi,sensor-type = "thermocouple"; |
| adi,excitation-pin-0 = <18>; |
| adi,excitation-current-0-microamp = <500>; |
| }; |
| }; |
| }; |
| - | |
| #include <dt-bindings/interrupt-controller/irq.h> |
| spi { |
| #address-cells = <1>; |
| #size-cells = <0>; |
| |
| adc@0 { |
| compatible = "adi,ad4170-4"; |
| reg = <0>; |
| spi-max-frequency = <20000000>; |
| spi-cpol; |
| spi-cpha; |
| avdd-supply = <&avdd>; |
| iovdd-supply = <&iovdd>; |
| #clock-cells = <0>; |
| clock-output-names = "ad4170-clk16mhz"; |
| interrupts = <0 IRQ_TYPE_EDGE_FALLING>; |
| interrupt-names = "dig_aux1"; |
| #address-cells = <1>; |
| #size-cells = <0>; |
| |
| // Sample AIN0 with respect to AIN1 throughout AVDD/AVSS input range |
| // Differential bipolar. If AVSS < 0V, differential true bipolar |
| channel@0 { |
| reg = <0>; |
| bipolar; |
| diff-channels = <0 1>; |
| adi,reference-select = <3>; |
| }; |
| // Sample AIN2 with respect to DGND throughout AVDD/DGND input range |
| // Pseudo-differential unipolar |
| channel@1 { |
| reg = <1>; |
| single-channel = <2>; |
| common-mode-channel = <24>; |
| adi,reference-select = <3>; |
| }; |
| // Sample AIN3 with respect to 2.5V throughout AVDD/AVSS input range |
| // Pseudo-differential bipolar |
| channel@2 { |
| reg = <2>; |
| bipolar; |
| single-channel = <3>; |
| common-mode-channel = <29>; |
| adi,reference-select = <3>; |
| }; |
| // Sample AIN4 with respect to DGND throughout AVDD/AVSS input range |
| // Pseudo-differential bipolar |
| channel@3 { |
| reg = <3>; |
| bipolar; |
| single-channel = <4>; |
| common-mode-channel = <24>; |
| adi,reference-select = <3>; |
| }; |
| // Sample AIN5 with respect to 2.5V throughout AVDD/AVSS input range |
| // Pseudo-differential unipolar (AD4170-4 datasheet page 46 example) |
| channel@4 { |
| reg = <4>; |
| single-channel = <5>; |
| common-mode-channel = <29>; |
| adi,reference-select = <3>; |
| }; |
| // Sample AIN6 with respect to 2.5V throughout REFIN+/REFIN- input range |
| // Pseudo-differential bipolar |
| channel@5 { |
| reg = <5>; |
| bipolar; |
| single-channel = <6>; |
| common-mode-channel = <29>; |
| adi,reference-select = <0>; |
| }; |
| // Weigh scale sensor |
| channel@6 { |
| reg = <6>; |
| bipolar; |
| diff-channels = <7 8>; |
| adi,reference-select = <0>; |
| adi,sensor-type = "weighscale"; |
| adi,excitation-pin-0 = <17>; |
| adi,excitation-pin-1 = <18>; |
| adi,excitation-pin-2 = <19>; |
| adi,excitation-pin-3 = <20>; |
| adi,excitation-ac; |
| }; |
| }; |
| }; |
| ... |
