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From: David Lechner <dlechner@baylibre.com>
To: linux-iio@vger.kernel.org
Cc: David Lechner <dlechner@baylibre.com>,
	Michael Hennerich <Michael.Hennerich@analog.com>,
	Jonathan Cameron <jic23@kernel.org>,
	Rob Herring <robh+dt@kernel.org>,
	Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
	Conor Dooley <conor+dt@kernel.org>,
	=?utf-8?q?Nuno_S=C3=A1?= <nuno.sa@analog.com>,
	Liam Girdwood <lgirdwood@gmail.com>,
	Mark Brown <broonie@kernel.org>,
	devicetree@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: [PATCH v2 1/2] dt-bindings: iio: adc: add ad7944 ADCs
Date: Fri, 16 Feb 2024 13:46:18 -0600
Message-ID: <20240216-ad7944-mainline-v2-1-7eb69651e592@baylibre.com>
In-Reply-To: <20240216-ad7944-mainline-v2-0-7eb69651e592@baylibre.com>
References: <20240216-ad7944-mainline-v2-0-7eb69651e592@baylibre.com>
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This adds a new binding for the Analog Devices, Inc. AD7944, AD7985, and
AD7986 ADCs.

Signed-off-by: David Lechner <dlechner@baylibre.com>
---
 .../devicetree/bindings/iio/adc/adi,ad7944.yaml    | 204 +++++++++++++++++++++
 MAINTAINERS                                        |   8 +
 2 files changed, 212 insertions(+)

diff --git a/Documentation/devicetree/bindings/iio/adc/adi,ad7944.yaml b/Documentation/devicetree/bindings/iio/adc/adi,ad7944.yaml
new file mode 100644
index 000000000000..61ee81326660
--- /dev/null
+++ b/Documentation/devicetree/bindings/iio/adc/adi,ad7944.yaml
@@ -0,0 +1,204 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/iio/adc/adi,ad7944.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Analog Devices PulSAR LFCSP Analog to Digital Converters
+
+maintainers:
+  - Michael Hennerich <Michael.Hennerich@analog.com>
+  - Nuno Sá <nuno.sa@analog.com>
+
+description: |
+  A family of pin-compatible single channel differential analog to digital
+  converters with SPI support in a LFCSP package.
+
+  * https://www.analog.com/en/products/ad7944.html
+  * https://www.analog.com/en/products/ad7985.html
+  * https://www.analog.com/en/products/ad7986.html
+
+$ref: /schemas/spi/spi-peripheral-props.yaml#
+
+properties:
+  compatible:
+    enum:
+      - adi,ad7944
+      - adi,ad7985
+      - adi,ad7986
+
+  reg:
+    maxItems: 1
+
+  spi-max-frequency:
+    maximum: 111111111
+
+  spi-cpol: true
+  spi-cpha: true
+
+  adi,spi-mode:
+    $ref: /schemas/types.yaml#/definitions/string
+    enum: [ single, multi, chain ]
+    default: multi
+    description: |
+      * single: The datasheet calls this "3-wire mode". It 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.
+      * multi: The datasheet calls this "4-wire mode". This is the convential
+        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.
+      * 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 is unused.
+
+  avdd-supply:
+    description: A 2.5V supply that powers the analog circuitry.
+
+  dvdd-supply:
+    description: A 2.5V supply that powers the digital circuitry.
+
+  vio-supply:
+    description:
+      A 1.8V to 2.7V supply for the digital inputs and outputs.
+
+  bvdd-supply:
+    description:
+      A voltage supply for the buffered power. When using an external reference
+      without an internal buffer (PDREF high, REFIN low), this should be
+      connected to the same supply as ref-supply. Otherwise, when using an
+      internal reference or an external reference with an internal buffer, this
+      is connected to a 5V supply.
+
+  ref-supply:
+    description:
+      Voltage regulator for the external reference voltage (REF). This property
+      is omitted when using an internal reference.
+
+  refin-supply:
+    description:
+      Voltage regulator for the reference buffer input (REFIN). When using an
+      external buffer with internal reference, this should be connected to a
+      1.2V external reference voltage supply. Otherwise, this property is
+      omitted.
+
+  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
+
+  turbo-gpios:
+    description:
+      GPIO connected to the TURBO line. If omitted, it is assumed that the TURBO
+      line is hard-wired and the state is determined by the adi,always-turbo
+      property.
+    maxItems: 1
+
+  adi,always-turbo:
+    type: boolean
+    description:
+      When present, this property indicates that the TURBO line is hard-wired
+      and the state is always high. If neither this property nor turbo-gpios is
+      present, the TURBO line is assumed to be hard-wired and the state is
+      always low.
+
+  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
+  - avdd-supply
+  - dvdd-supply
+  - vio-supply
+  - bvdd-supply
+
+allOf:
+  # ref-supply and refin-supply are mutually exclusive (neither is also valid)
+  - if:
+      required:
+        - ref-supply
+    then:
+      properties:
+        refin-supply: false
+  - if:
+      required:
+        - refin-supply
+    then:
+      properties:
+        ref-supply: false
+  # in 'single' mode, cnv-gpios is optional, for other modes it is required
+  - if:
+      required:
+        - adi,spi-mode
+    then:
+      if:
+        properties:
+          adi,spi-mode:
+            enum: [ multi, chain ]
+      then:
+        required:
+          - cnv-gpios
+    else:
+      required:
+        - cnv-gpios
+  # chain mode has lower SCLK max rate and doesn't work when TURBO is enabled
+  - if:
+      required:
+        - adi,spi-mode
+      properties:
+        adi,spi-mode:
+          const: chain
+    then:
+      properties:
+        spi-max-frequency:
+          maximum: 90909090
+        adi,always-turbo: false
+  # turbo-gpios and adi,always-turbo are mutually exclusive
+  - if:
+      required:
+        - turbo-gpios
+    then:
+      properties:
+        adi,always-turbo: false
+  - if:
+      required:
+        - adi,always-turbo
+    then:
+      properties:
+        turbo-gpios: false
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/gpio/gpio.h>
+    spi {
+        #address-cells = <1>;
+        #size-cells = <0>;
+        adc@0 {
+            compatible = "adi,ad7944";
+            reg = <0>;
+            spi-cpha;
+            spi-max-frequency = <111111111>;
+            avdd-supply = <&supply_2_5V>;
+            dvdd-supply = <&supply_2_5V>;
+            vio-supply = <&supply_1_8V>;
+            bvdd-supply = <&supply_5V>;
+            cnv-gpios = <&gpio 0 GPIO_ACTIVE_HIGH>;
+            turbo-gpios = <&gpio 1 GPIO_ACTIVE_HIGH>;
+        };
+    };
diff --git a/MAINTAINERS b/MAINTAINERS
index 00d354af10f5..4f1e658e1e0d 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -451,6 +451,14 @@ W:	http://wiki.analog.com/AD7879
 W:	https://ez.analog.com/linux-software-drivers
 F:	drivers/input/touchscreen/ad7879.c
 
+AD7944 ADC DRIVER (AD7944/AD7985/AD7986)
+M:	Michael Hennerich <michael.hennerich@analog.com>
+M:	Nuno Sá <nuno.sa@analog.com>
+R:	David Lechner <dlechner@baylibre.com>
+S:	Supported
+W:	https://ez.analog.com/linux-software-drivers
+F:	Documentation/devicetree/bindings/iio/adc/adi,ad7944.yaml
+
 ADAFRUIT MINI I2C GAMEPAD
 M:	Anshul Dalal <anshulusr@gmail.com>
 L:	linux-input@vger.kernel.org

-- 
2.43.2