[PATCH 1/2] dt-bindings: iio: adc: Add AD4000

From: Marcelo Schmitt
Date: Fri Mar 22 2024 - 18:05:52 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

Signed-off-by: Marcelo Schmitt <marcelo.schmitt@xxxxxxxxxx>
---
Pasting relevant comment from cover letter here to aid reviewers.

These devices have the same SPI (Strange Peripheral Interface) as AD7944
devices, which has been documented in ad7944.rst [1].
The device tree description for SPI connections and mode can be the same as of
ad7944 adi,spi-mode [2].
Because ad4000 driver does not currently support daisy-chain mode, I simplified
things a little bit. If having a more complete doc is preferred, I'm fine
changing to that.

[1]: https://lore.kernel.org/linux-iio/20240313-mainline-ad7944-doc-v1-2-7860416726e4@xxxxxxxxxxxx/
[2]: https://lore.kernel.org/linux-iio/20240304-ad7944-mainline-v5-1-f0a38cea8901@xxxxxxxxxxxx/

.../bindings/iio/adc/adi,ad4000.yaml | 151 ++++++++++++++++++
MAINTAINERS | 7 +
2 files changed, 158 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..9e3d6a3920ea
--- /dev/null
+++ b/Documentation/devicetree/bindings/iio/adc/adi,ad4000.yaml
@@ -0,0 +1,151 @@
+# 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 ADC device driver
+
+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
+
+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: true
+ spi-max-frequency: true
+
+ vref-supply:
+ description: Phandle to the regulator for ADC reference voltage.
+
+ 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).
+ $ref: /schemas/types.yaml#/definitions/uint32
+ enum: [454, 909, 1000, 1900]
+ default: 1000
+
+ adi,spi-cs-mode:
+ type: boolean
+ description: |
+ This property indicates the SPI wiring configuration.
+
+ When this property is omitted, it indicates that the device SDI pin is
+ connected to SPI controller CS line and device CNV pin has been connected
+ to a GPIO. Datasheets call this "4-wire mode".
+
+ When this property is present, the driver must assume standard SPI
+ connections which, for these devices, consists of connecting the
+ controller CS line to device CNV pin. This configuration is
+ (misleadingly) called "3-wire mode" in datasheets.
+
+ cnv-gpios:
+ description: The GPIO connected to the CNV pin.
+ maxItems: 1
+
+patternProperties:
+ "^channel@([0-1])$":
+ $ref: adc.yaml
+ type: object
+ description: Represents the external channel connected to the ADC.
+
+ properties:
+ reg:
+ maxItems: 1
+
+ diff-channels: true
+
+ required:
+ - reg
+
+ additionalProperties: false
+
+required:
+ - compatible
+ - reg
+ - vref-supply
+
+allOf:
+ - $ref: /schemas/spi/spi-peripheral-props.yaml#
+
+ - if:
+ properties:
+ adi,spi-cs-mode: false
+ then:
+ required:
+ - cnv-gpios
+
+unevaluatedProperties: false
+
+examples:
+ - |
+ #include <dt-bindings/gpio/gpio.h>
+ spi {
+ #address-cells = <1>;
+ #size-cells = <0>;
+ /* Example for a AD4000 devices */
+ adc@0 {
+ compatible = "adi,ad4020";
+ reg = <0>;
+ spi-max-frequency = <71000000>;
+ vref-supply = <&vref>;
+ cnv-gpios = <&gpio0 88 GPIO_ACTIVE_HIGH>;
+ #address-cells = <1>;
+ #size-cells = <0>;
+ channel@0 {
+ reg = <0>;
+ diff-channels = <0 1>;
+ };
+ };
+ };
+ - |
+ spi {
+ #address-cells = <1>;
+ #size-cells = <0>;
+ /* Example for a ADAQ4000 devices */
+ adc@0 {
+ compatible = "adi,adaq4003";
+ reg = <0>;
+ spi-max-frequency = <80000000>;
+ vref-supply = <&vref>;
+ adi,spi-cs-mode;
+ adi,gain-milli = <454>;
+ #address-cells = <1>;
+ #size-cells = <0>;
+ channel@0 {
+ reg = <0>;
+ diff-channels = <0 1>;
+ };
+ };
+ };
diff --git a/MAINTAINERS b/MAINTAINERS
index 2662ec49b297..3ca90f842298 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -1135,6 +1135,13 @@ 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