Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
dt-bindings: iio: adc: add ad7944 ADCs
This adds a new binding for the Analog Devices, Inc. AD7944, AD7985, and
AD7986 ADCs.
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: David Lechner <dlechner@baylibre.com>
Link: https://lore.kernel.org/r/20240304-ad7944-mainline-v5-1-f0a38cea8901@baylibre.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
authored by
David Lechner
and committed by
Jonathan Cameron
59346366
1c5aa559
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Documentation/devicetree/bindings/iio/adc/adi,ad7944.yaml
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Documentation/devicetree/bindings/iio/adc/adi,ad7944.yaml
···
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# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
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%YAML 1.2
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---
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$id: http://devicetree.org/schemas/iio/adc/adi,ad7944.yaml#
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$schema: http://devicetree.org/meta-schemas/core.yaml#
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title: Analog Devices PulSAR LFCSP Analog to Digital Converters
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maintainers:
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- Michael Hennerich <Michael.Hennerich@analog.com>
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- Nuno Sá <nuno.sa@analog.com>
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description: |
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A family of pin-compatible single channel differential analog to digital
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converters with SPI support in a LFCSP package.
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* https://www.analog.com/en/products/ad7944.html
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* https://www.analog.com/en/products/ad7985.html
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* https://www.analog.com/en/products/ad7986.html
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$ref: /schemas/spi/spi-peripheral-props.yaml#
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properties:
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compatible:
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enum:
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- adi,ad7944
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- adi,ad7985
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- adi,ad7986
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reg:
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maxItems: 1
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spi-max-frequency:
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maximum: 111111111
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spi-cpol: true
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spi-cpha: true
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adi,spi-mode:
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$ref: /schemas/types.yaml#/definitions/string
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enum: [ single, chain ]
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description: |
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This property indicates the SPI wiring configuration.
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When this property is omitted, it is assumed that the device is using what
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the datasheet calls "4-wire mode". This is the conventional SPI mode used
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when there are multiple devices on the same bus. In this mode, the CNV
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line is used to initiate the conversion and the SDI line is connected to
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CS on the SPI controller.
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When this property is present, it indicates that the device is using one
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of the following alternative wiring configurations:
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* single: The datasheet calls this "3-wire mode". (NOTE: The datasheet's
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definition of 3-wire mode is NOT at all related to the standard
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spi-3wire property!) This mode is often used when the ADC is the only
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device on the bus. In this mode, SDI is tied to VIO, and the CNV line
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can be connected to the CS line of the SPI controller or to a GPIO, in
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which case the CS line of the controller is unused.
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* chain: The datasheet calls this "chain mode". This mode is used to save
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on wiring when multiple ADCs are used. In this mode, the SDI line of
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one chip is tied to the SDO of the next chip in the chain and the SDI of
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the last chip in the chain is tied to GND. Only the first chip in the
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chain is connected to the SPI bus. The CNV line of all chips are tied
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together. The CS line of the SPI controller can be used as the CNV line
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only if it is active high.
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'#daisy-chained-devices': true
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avdd-supply:
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description: A 2.5V supply that powers the analog circuitry.
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dvdd-supply:
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description: A 2.5V supply that powers the digital circuitry.
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vio-supply:
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description:
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A 1.8V to 2.7V supply for the digital inputs and outputs.
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bvdd-supply:
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description:
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A voltage supply for the buffered power. When using an external reference
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without an internal buffer (PDREF high, REFIN low), this should be
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connected to the same supply as ref-supply. Otherwise, when using an
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internal reference or an external reference with an internal buffer, this
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is connected to a 5V supply.
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ref-supply:
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description:
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Voltage regulator for the external reference voltage (REF). This property
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is omitted when using an internal reference.
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refin-supply:
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description:
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Voltage regulator for the reference buffer input (REFIN). When using an
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external buffer with internal reference, this should be connected to a
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1.2V external reference voltage supply. Otherwise, this property is
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omitted.
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cnv-gpios:
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description:
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The Convert Input (CNV). This input has multiple functions. It initiates
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the conversions and selects the SPI mode of the device (chain or CS). In
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'single' mode, this property is omitted if the CNV pin is connected to the
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CS line of the SPI controller.
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maxItems: 1
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turbo-gpios:
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description:
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GPIO connected to the TURBO line. If omitted, it is assumed that the TURBO
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line is hard-wired and the state is determined by the adi,always-turbo
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property.
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maxItems: 1
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adi,always-turbo:
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type: boolean
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description:
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When present, this property indicates that the TURBO line is hard-wired
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and the state is always high. If neither this property nor turbo-gpios is
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present, the TURBO line is assumed to be hard-wired and the state is
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always low.
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interrupts:
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description:
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The SDO pin can also function as a busy indicator. This node should be
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connected to an interrupt that is triggered when the SDO line goes low
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while the SDI line is high and the CNV line is low ('single' mode) or the
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SDI line is low and the CNV line is high ('multi' mode); or when the SDO
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line goes high while the SDI and CNV lines are high (chain mode),
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maxItems: 1
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required:
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- compatible
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- reg
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- avdd-supply
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- dvdd-supply
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- vio-supply
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- bvdd-supply
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allOf:
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# ref-supply and refin-supply are mutually exclusive (neither is also valid)
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- if:
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required:
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- ref-supply
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then:
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properties:
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refin-supply: false
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- if:
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required:
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- refin-supply
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then:
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properties:
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ref-supply: false
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# in '4-wire' mode, cnv-gpios is required, for other modes it is optional
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- if:
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not:
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required:
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- adi,spi-mode
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then:
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required:
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- cnv-gpios
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# chain mode has lower SCLK max rate and doesn't work when TURBO is enabled
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- if:
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required:
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- adi,spi-mode
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properties:
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adi,spi-mode:
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const: chain
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then:
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properties:
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spi-max-frequency:
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maximum: 90909090
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adi,always-turbo: false
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required:
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- '#daisy-chained-devices'
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else:
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properties:
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'#daisy-chained-devices': false
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# turbo-gpios and adi,always-turbo are mutually exclusive
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- if:
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required:
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- turbo-gpios
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then:
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properties:
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adi,always-turbo: false
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- if:
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required:
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- adi,always-turbo
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then:
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properties:
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turbo-gpios: false
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unevaluatedProperties: false
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examples:
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- |
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#include <dt-bindings/gpio/gpio.h>
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spi {
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#address-cells = <1>;
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#size-cells = <0>;
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adc@0 {
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compatible = "adi,ad7944";
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reg = <0>;
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spi-cpha;
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spi-max-frequency = <111111111>;
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avdd-supply = <&supply_2_5V>;
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dvdd-supply = <&supply_2_5V>;
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vio-supply = <&supply_1_8V>;
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bvdd-supply = <&supply_5V>;
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cnv-gpios = <&gpio 0 GPIO_ACTIVE_HIGH>;
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turbo-gpios = <&gpio 1 GPIO_ACTIVE_HIGH>;
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};
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};
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MAINTAINERS
+8
MAINTAINERS
···
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W: https://ez.analog.com/linux-software-drivers
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F: drivers/input/touchscreen/ad7879.c
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AD7944 ADC DRIVER (AD7944/AD7985/AD7986)
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M: Michael Hennerich <michael.hennerich@analog.com>
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M: Nuno Sá <nuno.sa@analog.com>
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R: David Lechner <dlechner@baylibre.com>
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S: Supported
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W: https://ez.analog.com/linux-software-drivers
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F: Documentation/devicetree/bindings/iio/adc/adi,ad7944.yaml
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ADAFRUIT MINI I2C GAMEPAD
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M: Anshul Dalal <anshulusr@gmail.com>
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L: linux-input@vger.kernel.org