# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) %YAML 1.2 --- $id: http://devicetree.org/schemas/iio/adc/adi,ad7944.yaml# $schema: http://devicetree.org/meta-schemas/core.yaml# title: Analog Devices PulSAR LFCSP Analog to Digital Converters maintainers: - Michael Hennerich - Nuno Sá description: | A family of pin-compatible single channel differential analog to digital converters with SPI support in a LFCSP package. * https://www.analog.com/en/products/ad7944.html * https://www.analog.com/en/products/ad7985.html * https://www.analog.com/en/products/ad7986.html $ref: /schemas/spi/spi-peripheral-props.yaml# properties: compatible: enum: - adi,ad7944 - adi,ad7985 - adi,ad7986 reg: maxItems: 1 spi-max-frequency: maximum: 111111111 spi-cpol: true spi-cpha: true adi,spi-mode: $ref: /schemas/types.yaml#/definitions/string enum: [ single, chain ] description: | This property indicates the SPI wiring configuration. When this property is omitted, it is assumed that the device is using what the datasheet calls "4-wire mode". This is the conventional SPI mode used when there are multiple devices on the same bus. In this mode, the CNV line is used to initiate the conversion and the SDI line is connected to CS on the SPI controller. When this property is present, it indicates that the device is using one of the following alternative wiring configurations: * single: The datasheet calls this "3-wire mode". (NOTE: The datasheet's definition of 3-wire mode is NOT at all related to the standard spi-3wire property!) This mode is often used when the ADC is the only device on the bus. In this mode, SDI is tied to VIO, and the CNV line can be connected to the CS line of the SPI controller or to a GPIO, in which case the CS line of the controller is unused. * chain: The datasheet calls this "chain mode". This mode is used to save on wiring when multiple ADCs are used. In this mode, the SDI line of one chip is tied to the SDO of the next chip in the chain and the SDI of the last chip in the chain is tied to GND. Only the first chip in the chain is connected to the SPI bus. The CNV line of all chips are tied together. The CS line of the SPI controller can be used as the CNV line only if it is active high. '#daisy-chained-devices': true avdd-supply: description: A 2.5V supply that powers the analog circuitry. dvdd-supply: description: A 2.5V supply that powers the digital circuitry. vio-supply: description: A 1.8V to 2.7V supply for the digital inputs and outputs. bvdd-supply: description: A voltage supply for the buffered power. When using an external reference without an internal buffer (PDREF high, REFIN low), this should be connected to the same supply as ref-supply. Otherwise, when using an internal reference or an external reference with an internal buffer, this is connected to a 5V supply. ref-supply: description: Voltage regulator for the external reference voltage (REF). This property is omitted when using an internal reference. refin-supply: description: Voltage regulator for the reference buffer input (REFIN). When using an external buffer with internal reference, this should be connected to a 1.2V external reference voltage supply. Otherwise, this property is omitted. cnv-gpios: description: The Convert Input (CNV). This input has multiple functions. It initiates the conversions and selects the SPI mode of the device (chain or CS). In 'single' mode, this property is omitted if the CNV pin is connected to the CS line of the SPI controller. maxItems: 1 turbo-gpios: description: GPIO connected to the TURBO line. If omitted, it is assumed that the TURBO line is hard-wired and the state is determined by the adi,always-turbo property. maxItems: 1 adi,always-turbo: type: boolean description: When present, this property indicates that the TURBO line is hard-wired and the state is always high. If neither this property nor turbo-gpios is present, the TURBO line is assumed to be hard-wired and the state is always low. interrupts: description: The SDO pin can also function as a busy indicator. This node should be connected to an interrupt that is triggered when the SDO line goes low while the SDI line is high and the CNV line is low ('single' mode) or the SDI line is low and the CNV line is high ('multi' mode); or when the SDO line goes high while the SDI and CNV lines are high (chain mode), maxItems: 1 required: - compatible - reg - avdd-supply - dvdd-supply - vio-supply - bvdd-supply allOf: # ref-supply and refin-supply are mutually exclusive (neither is also valid) - if: required: - ref-supply then: properties: refin-supply: false - if: required: - refin-supply then: properties: ref-supply: false # in '4-wire' mode, cnv-gpios is required, for other modes it is optional - if: not: required: - adi,spi-mode then: required: - cnv-gpios # chain mode has lower SCLK max rate and doesn't work when TURBO is enabled - if: required: - adi,spi-mode properties: adi,spi-mode: const: chain then: properties: spi-max-frequency: maximum: 90909090 adi,always-turbo: false required: - '#daisy-chained-devices' else: properties: '#daisy-chained-devices': false # turbo-gpios and adi,always-turbo are mutually exclusive - if: required: - turbo-gpios then: properties: adi,always-turbo: false - if: required: - adi,always-turbo then: properties: turbo-gpios: false unevaluatedProperties: false examples: - | #include spi { #address-cells = <1>; #size-cells = <0>; adc@0 { compatible = "adi,ad7944"; reg = <0>; spi-cpha; spi-max-frequency = <111111111>; avdd-supply = <&supply_2_5V>; dvdd-supply = <&supply_2_5V>; vio-supply = <&supply_1_8V>; bvdd-supply = <&supply_5V>; cnv-gpios = <&gpio 0 GPIO_ACTIVE_HIGH>; turbo-gpios = <&gpio 1 GPIO_ACTIVE_HIGH>; }; };