[PATCH v3 1/1] dt-bindings: iio: adc: add AD7816/AD7817/AD7818 binding

[Hungyu Lin <dennylin0707@gmail.com>]

Add Device Tree binding documentation for the Analog Devices
AD7816, AD7817 and AD7818 SPI ADC devices.

The AD7816 provides temperature monitoring only, while the
AD7817 and AD7818 provide analog input channels with an
on-chip temperature sensor.

The devices use control GPIOs for RD/WR and CONVST. BUSY is required for
AD7816 and AD7817 variants.

Signed-off-by: Hungyu Lin <dennylin0707@gmail.com>
---
Changes in v3:
- Fix commit message to match binding requirements
- Fix commit message based on input from Sanjay Chitroda
---
 .../bindings/iio/adc/adi,ad7816.yaml          | 94 +++++++++++++++++++
 1 file changed, 94 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/iio/adc/adi,ad7816.yaml

diff --git a/Documentation/devicetree/bindings/iio/adc/adi,ad7816.yaml b/Documentation/devicetree/bindings/iio/adc/adi,ad7816.yaml
new file mode 100644
index 000000000000..490e5338d7b2
--- /dev/null
+++ b/Documentation/devicetree/bindings/iio/adc/adi,ad7816.yaml
@@ -0,0 +1,94 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/iio/adc/adi,ad7816.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Analog Devices AD7816/AD7817/AD7818 ADC
+
+maintainers:
+  - Hungyu Lin <dennylin0707@gmail.com>
+
+description: |
+  Binding for Analog Devices AD7816, AD7817 and AD7818 SPI ADCs
+  with on-chip temperature sensor.
+
+  The AD7816 provides temperature monitoring only.
+  The AD7817 provides up to 4 analog input channels.
+  The AD7818 provides a single analog input channel.
+
+properties:
+  compatible:
+    enum:
+      - adi,ad7816
+      - adi,ad7817
+      - adi,ad7818
+
+  reg:
+    maxItems: 1
+
+  interrupts:
+    maxItems: 1
+    description:
+      Optional interrupt line used by the device.
+
+  rdwr-gpios:
+    maxItems: 1
+    description:
+      GPIO connected to the RD/WR pin used to control read/write cycles.
+
+  convert-gpios:
+    maxItems: 1
+    description:
+      GPIO connected to the CONVST pin used to trigger conversions.
+
+  busy-gpios:
+    maxItems: 1
+    description:
+      GPIO connected to the BUSY pin indicating conversion status.
+
+required:
+  - compatible
+  - reg
+  - rdwr-gpios
+  - convert-gpios
+
+allOf:
+  - $ref: /schemas/spi/spi-peripheral-props.yaml#
+
+  - if:
+      properties:
+        compatible:
+          contains:
+            enum:
+              - adi,ad7816
+              - adi,ad7817
+    then:
+      required:
+        - busy-gpios
+    else:
+      properties:
+        busy-gpios: false
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    gpio0: gpio {
+      gpio-controller;
+      #gpio-cells = <2>;
+    };
+
+    spi {
+      #address-cells = <1>;
+      #size-cells = <0>;
+
+      adc@0 {
+        compatible = "adi,ad7816";
+        reg = <0>;
+        spi-max-frequency = <5000000>;
+        rdwr-gpios = <&gpio0 1 0>;
+        convert-gpios = <&gpio0 2 0>;
+        busy-gpios = <&gpio0 3 0>;
+      };
+    };
-- 
2.34.1