[PATCH v3 5/6] dt-bindings: iio: adc: Add AD4000

From: Marcelo Schmitt
Date: Tue Jun 04 2024 - 18:44:37 EST

Add device tree documentation for AD4000 series of ADC devices.

Datasheet: https://www.analog.com/media/en/technical-documentation/data-sheets/ad4000-4004-4008.pdf
Datasheet: https://www.analog.com/media/en/technical-documentation/data-sheets/ad4001-4005.pdf
Datasheet: https://www.analog.com/media/en/technical-documentation/data-sheets/ad4002-4006-4010.pdf
Datasheet: https://www.analog.com/media/en/technical-documentation/data-sheets/ad4003-4007-4011.pdf
Datasheet: https://www.analog.com/media/en/technical-documentation/data-sheets/ad4020-4021-4022.pdf
Datasheet: https://www.analog.com/media/en/technical-documentation/data-sheets/adaq4001.pdf
Datasheet: https://www.analog.com/media/en/technical-documentation/data-sheets/adaq4003.pdf

Suggested-by: David Lechner <dlechner@xxxxxxxxxxxx>
Signed-off-by: Marcelo Schmitt <marcelo.schmitt@xxxxxxxxxx>
---
Even though didn't pick all suggestions to the dt-bindings, I did pick most them
so kept David's Suggested-by tag.

.../bindings/iio/adc/adi,ad4000.yaml | 207 ++++++++++++++++++
MAINTAINERS | 7 +
2 files changed, 214 insertions(+)
create mode 100644 Documentation/devicetree/bindings/iio/adc/adi,ad4000.yaml

diff --git a/Documentation/devicetree/bindings/iio/adc/adi,ad4000.yaml b/Documentation/devicetree/bindings/iio/adc/adi,ad4000.yaml
new file mode 100644
index 000000000000..7470d386906b
--- /dev/null
+++ b/Documentation/devicetree/bindings/iio/adc/adi,ad4000.yaml
@@ -0,0 +1,207 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/iio/adc/adi,ad4000.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Analog Devices AD4000 and similar Analog to Digital Converters
+
+maintainers:
+ - Marcelo Schmitt <marcelo.schmitt@xxxxxxxxxx>
+
+description: |
+ Analog Devices AD4000 family of Analog to Digital Converters with SPI support.
+ Specifications can be found at:
+ https://www.analog.com/media/en/technical-documentation/data-sheets/ad4000-4004-4008.pdf
+ https://www.analog.com/media/en/technical-documentation/data-sheets/ad4001-4005.pdf
+ https://www.analog.com/media/en/technical-documentation/data-sheets/ad4002-4006-4010.pdf
+ https://www.analog.com/media/en/technical-documentation/data-sheets/ad4003-4007-4011.pdf
+ https://www.analog.com/media/en/technical-documentation/data-sheets/ad4020-4021-4022.pdf
+ https://www.analog.com/media/en/technical-documentation/data-sheets/adaq4001.pdf
+ https://www.analog.com/media/en/technical-documentation/data-sheets/adaq4003.pdf
+
+$ref: /schemas/spi/spi-peripheral-props.yaml#
+
+properties:
+ compatible:
+ enum:
+ - adi,ad4000
+ - adi,ad4001
+ - adi,ad4002
+ - adi,ad4003
+ - adi,ad4004
+ - adi,ad4005
+ - adi,ad4006
+ - adi,ad4007
+ - adi,ad4008
+ - adi,ad4010
+ - adi,ad4011
+ - adi,ad4020
+ - adi,ad4021
+ - adi,ad4022
+ - adi,adaq4001
+ - adi,adaq4003
+
+ reg:
+ maxItems: 1
+
+ spi-max-frequency:
+ maximum: 102040816 # for VIO > 2.7 V, 81300813 for VIO > 1.7 V
+
+ 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 connected to MOSI or 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
+
+ vdd-supply:
+ description: A 1.8V supply that powers the chip (VDD).
+
+ vio-supply:
+ description:
+ A 1.8V to 5.5V supply for the digital inputs and outputs (VIO).
+
+ ref-supply:
+ description:
+ A 2.5 to 5V supply for the external reference voltage (REF).
+
+ 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
+
+ adi,high-z-input:
+ type: boolean
+ description:
+ High-Z mode allows the amplifier and RC filter in front of the ADC to be
+ chosen based on the signal bandwidth of interest, rather than the settling
+ requirements of the switched capacitor SAR ADC inputs.
+
+ adi,gain-milli:
+ description: |
+ The hardware gain applied to the ADC input (in milli units).
+ The gain provided by the ADC input scaler is defined by the hardware
+ connections between chip pins OUT+, R1K-, R1K1-, R1K+, R1K1+, and OUT-.
+ If not present, default to 1000 (no actual gain applied).
+ $ref: /schemas/types.yaml#/definitions/uint32
+ enum: [454, 909, 1000, 1900]
+ default: 1000
+
+ 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
+ - vdd-supply
+ - vio-supply
+ - ref-supply
+
+allOf:
+ # 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
+ - if:
+ required:
+ - adi,spi-mode
+ properties:
+ adi,spi-mode:
+ const: chain
+ then:
+ properties:
+ spi-max-frequency:
+ maximum: 50000000 # for VIO > 2.7 V, 40000000 for VIO > 1.7 V
+ required:
+ - '#daisy-chained-devices'
+ else:
+ properties:
+ '#daisy-chained-devices': false
+ # Gain property only applies to ADAQ devices
+ - if:
+ properties:
+ compatible:
+ not:
+ contains:
+ enum:
+ - adi,adaq4001
+ - adi,adaq4003
+ then:
+ properties:
+ adi,gain-milli: false
+
+unevaluatedProperties: false
+
+examples:
+ - |
+ #include <dt-bindings/gpio/gpio.h>
+ spi {
+ #address-cells = <1>;
+ #size-cells = <0>;
+ /* Example for a AD devices */
+ adc@0 {
+ compatible = "adi,ad4020";
+ reg = <0>;
+ spi-max-frequency = <71000000>;
+ vdd-supply = <&supply_1_8V>;
+ vio-supply = <&supply_1_8V>;
+ ref-supply = <&supply_5V>;
+ cnv-gpios = <&gpio0 88 GPIO_ACTIVE_HIGH>;
+ };
+ };
+ - |
+ spi {
+ #address-cells = <1>;
+ #size-cells = <0>;
+ /* Example for a ADAQ devices */
+ adc@0 {
+ compatible = "adi,adaq4003";
+ reg = <0>;
+ adi,spi-mode = "single";
+ spi-max-frequency = <80000000>;
+ vdd-supply = <&supply_1_8V>;
+ vio-supply = <&supply_1_8V>;
+ ref-supply = <&supply_5V>;
+ adi,high-z-input;
+ adi,gain-milli = <454>;
+ };
+ };
diff --git a/MAINTAINERS b/MAINTAINERS
index bff979a507ba..1f052b9cd912 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -1200,6 +1200,13 @@ W: https://ez.analog.com/linux-software-drivers
F: Documentation/devicetree/bindings/iio/dac/adi,ad3552r.yaml
F: drivers/iio/dac/ad3552r.c

+ANALOG DEVICES INC AD4000 DRIVER
+M: Marcelo Schmitt <marcelo.schmitt@xxxxxxxxxx>
+L: linux-iio@xxxxxxxxxxxxxxx
+S: Supported
+W: https://ez.analog.com/linux-software-drivers
+F: Documentation/devicetree/bindings/iio/adc/adi,ad4000.yaml
+
ANALOG DEVICES INC AD4130 DRIVER
M: Cosmin Tanislav <cosmin.tanislav@xxxxxxxxxx>
L: linux-iio@xxxxxxxxxxxxxxx
--
2.43.0