dt-bindings: iio: dac: Add adi,ad3552r.yaml

Add documentation for ad3552r and ad3542r
Signed-off-by: Mihail Chindris <mihail.chindris@analog.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

Documentation/devicetree/bindings/iio/dac/adi,ad3552r.yaml

+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+# Copyright 2020 Analog Devices Inc.
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/iio/dac/adi,ad3552r.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Analog Devices AD2552R DAC device driver
+
+maintainers:
+  - Mihail Chindris <mihail.chindris@analog.com>
+
+description: |
+  Bindings for the Analog Devices AD3552R DAC device and similar.
+  Datasheet can be found here:
+    https://www.analog.com/media/en/technical-documentation/data-sheets/ad3542r.pdf
+    https://www.analog.com/media/en/technical-documentation/data-sheets/ad3552r.pdf
+
+properties:
+  compatible:
+    enum:
+      - adi,ad3542r
+      - adi,ad3552r
+
+  reg:
+    maxItems: 1
+
+  spi-max-frequency:
+    maximum: 30000000
+
+  reset-gpios:
+    maxItems: 1
+
+  ldac-gpios:
+    description: |
+      LDAC pin to be used as a hardware trigger to update the DAC channels.
+    maxItems: 1
+
+  vref-supply:
+    description:
+      The regulator to use as an external reference. If it does not exists the
+      internal reference will be used. External reference must be 2.5V
+
+  adi,vref-out-en:
+    description: Vref I/O driven by internal vref to 2.5V. If not set, Vref pin
+      will be floating.
+    type: boolean
+
+  adi,sdo-drive-strength:
+    description: |
+      Configure SDIO0 and SDIO1 strength levels:
+        - 0: low SDO drive strength.
+        - 1: medium low SDO drive strength.
+        - 2: medium high SDO drive strength.
+        - 3: high SDO drive strength
+    $ref: /schemas/types.yaml#/definitions/uint32
+    enum: [0, 1, 2, 3]
+
+  '#address-cells':
+    const: 1
+
+  '#size-cells':
+    const: 0
+
+patternProperties:
+  "^channel@([0-1])$":
+    type: object
+    description: Configurations of the DAC Channels
+
+    additionalProperties: false
+
+    properties:
+      reg:
+        description: Channel number
+        enum: [0, 1]
+
+      adi,output-range-microvolt: true
+
+      custom-output-range-config:
+        type: object
+        description: Configuration of custom range when
+          adi,output-range-microvolt is not present.
+          The formulas for calculation the output voltages are
+            Vout_fs = 2.5 + [(GainN + Offset/1024) * 2.5 * Rfbx * 1.03]
+            Vout_zs = 2.5 - [(GainP + Offset/1024) * 2.5 * Rfbx * 1.03]
+
+        properties:
+          adi,gain-offset:
+            description: Gain offset used in the above formula
+            $ref: /schemas/types.yaml#/definitions/int32
+            maximum: 511
+            minimum: -511
+
+          adi,gain-scaling-p-inv-log2:
+            description: GainP = 1 / ( 2 ^ adi,gain-scaling-p-inv-log2)
+            $ref: /schemas/types.yaml#/definitions/uint32
+            enum: [0, 1, 2, 3]
+
+          adi,gain-scaling-n-inv-log2:
+            description: GainN = 1 / ( 2 ^ adi,gain-scaling-n-inv-log2)
+            $ref: /schemas/types.yaml#/definitions/uint32
+            enum: [0, 1, 2, 3]
+
+          adi,rfb-ohms:
+            description: Feedback Resistor
+
+        required:
+          - adi,gain-offset
+          - adi,gain-scaling-p-inv-log2
+          - adi,gain-scaling-n-inv-log2
+          - adi,rfb-ohms
+
+    required:
+      - reg
+
+    oneOf:
+      # If adi,output-range-microvolt is missing,
+      # custom-output-range-config must be used
+      - required:
+          - adi,output-range-microvolt
+
+      - required:
+          - custom-output-range-config
+
+allOf:
+  - if:
+      properties:
+        compatible:
+          contains:
+            const: adi,ad3542r
+    then:
+      patternProperties:
+        "^channel@([0-1])$":
+          type: object
+          properties:
+            adi,output-range-microvolt:
+              description: |
+                Voltage output range of the channel as <minimum, maximum>
+                Required connections:
+                  Rfb1x for: 0 to 2.5 V; 0 to 3V; 0 to 5 V;
+                  Rfb2x for: 0 to 10 V; 2.5 to 7.5V; -5 to 5 V;
+              oneOf:
+                - items:
+                    - const: 0
+                    - enum: [2500000, 3000000, 5000000, 10000000]
+                - items:
+                    - const: -2500000
+                    - const: 7500000
+                - items:
+                    - const: -5000000
+                    - const: 5000000
+
+          required:
+            - adi,output-range-microvolt
+
+  - if:
+      properties:
+        compatible:
+          contains:
+            const: adi,ad3552r
+    then:
+      patternProperties:
+        "^channel@([0-1])$":
+          type: object
+          properties:
+            adi,output-range-microvolt:
+              description: |
+                Voltage output range of the channel as <minimum, maximum>
+                Required connections:
+                  Rfb1x for: 0 to 2.5 V; 0 to 5 V;
+                  Rfb2x for: 0 to 10 V; -5 to 5 V;
+                  Rfb4x for: -10 to 10V
+              oneOf:
+                - items:
+                    - const: 0
+                    - enum: [2500000, 5000000, 10000000]
+                - items:
+                    - const: -5000000
+                    - const: 5000000
+                - items:
+                    - const: -10000000
+                    - const: 10000000
+
+required:
+  - compatible
+  - reg
+  - spi-max-frequency
+
+additionalProperties: false
+
+examples:
+  - |
+    spi {
+      #address-cells = <1>;
+      #size-cells = <0>;
+      ad3552r@0 {
+              compatible = "adi,ad3552r";
+              reg = <0>;
+              spi-max-frequency = <20000000>;
+              #address-cells = <1>;
+              #size-cells = <0>;
+              channel@0 {
+                      reg = <0>;
+                      adi,output-range-microvolt = <0 10000000>;
+              };
+              channel@1 {
+                      reg = <1>;
+                      custom-output-range-config {
+                              adi,gain-offset = <5>;
+                              adi,gain-scaling-p-inv-log2 = <1>;
+                              adi,gain-scaling-n-inv-log2 = <2>;
+                              adi,rfb-ohms = <1>;
+                      };
+            };
+        };
+    };
+...