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From: Marcelo Schmitt <marcelo.schmitt@analog.com>
To: <lars@metafoo.de>, <Michael.Hennerich@analog.com>, <jic23@kernel.org>,
        <robh+dt@kernel.org>, <krzysztof.kozlowski+dt@linaro.org>,
        <conor+dt@kernel.org>, <marcelo.schmitt1@gmail.com>
CC: <linux-iio@vger.kernel.org>, <devicetree@vger.kernel.org>,
        <linux-kernel@vger.kernel.org>
Subject: [PATCH 1/2] dt-bindings: iio: adc: Add AD4000
Date: Fri, 22 Mar 2024 19:05:08 -0300
Message-ID: <81665b5f0d37d593e6d299528de8d68da8574077.1711131830.git.marcelo.schmitt@analog.com>
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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@analog.com>
---
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@baylibre.com/
[2]: https://lore.kernel.org/linux-iio/20240304-ad7944-mainline-v5-1-f0a38cea8901@baylibre.com/

 .../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@analog.com>
+
+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@analog.com>
+L:	linux-iio@vger.kernel.org
+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@analog.com>
 L:	linux-iio@vger.kernel.org
-- 
2.43.0