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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 v2 1/2] dt-bindings: iio: adc: Add AD4000
Date: Mon, 8 Apr 2024 11:31:20 -0300
Message-ID: <7c877c865f0b7da28d9f1f177b3b2692b0ae20b9.1712585500.git.marcelo.schmitt@analog.com>
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Add device tree documentation for AD4000 family 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>
---
 .../bindings/iio/adc/adi,ad4000.yaml          | 201 ++++++++++++++++++
 MAINTAINERS                                   |   7 +
 2 files changed, 208 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..ca06afb5149e
--- /dev/null
+++ b/Documentation/devicetree/bindings/iio/adc/adi,ad4000.yaml
@@ -0,0 +1,201 @@
+# 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@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
+
+$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
+
+  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
+
+  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. If 'single' mode is selected and this GPIO
+      is provided, it must be active low.
+    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
+  - spi-cpha
+  - 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
+
+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-cpha;
+            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>;
+            spi-cpha;
+            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 a7287cf44869..5dfe118a5dd3 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -1159,6 +1159,13 @@ 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