iio: dac: Add AD5413 support

The AD5413 is a single-channel, 14-bit DAC with programmable current or
voltage output. It communicates via SPI at clock rates up to 50 MHz.

The output can be configured as either voltage or current and is available
on a single terminal.

Datasheet:
https://www.analog.com/media/en/technical-documentation/data-sheets/ad5413.pdf

Signed-off-by: Bruce Tsao <[email protected]>

Author: BruceTsaoADI

Documentation/devicetree/bindings/iio/dac/adi,ad5413.yaml

@@ -0,0 +1,88 @@
+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/iio/dac/adi,ad5413.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Analog Devices AD5413 DAC
+
+maintainers:
+  - Bruce Tsao <[email protected]>
+
+properties:
+  compatible:
+    const: adi,ad5413
+
+  reg:
+    maxItems: 1
+
+  spi-max-frequency:
+    maximum: 50000000
+
+  reset-gpios: true
+
+  avdd-supply:
+    description: Analog positive supply (AVDD)
+
+  dvdd-supply:
+    description: Digital positive supply (DVDD)
+
+  avss-supply:
+    description: Analog negative supply (AVSS)
+
+  adi,range-microvolt:
+    description: Voltage output range <min, max> in microvolts
+    oneOf:
+      - items:
+          - const: -10500000
+          - const: 10500000
+      - items:
+          - const: -12600000
+          - const: 12600000
+
+  adi,range-microamp:
+    description: Current output range <min, max> in microamps
+    items:
+      - const: 0
+      - const: 24000
+
+  adi,slew-time-us:
+    description: Output digital slew control time in microseconds
+    minimum: 0
+    maximum: 1000000
+    default: 0
+
+required:
+  - compatible
+  - reg
+  - spi-max-frequency
+  - avdd-supply
+  - dvdd-supply
+  - avss-supply
+
+allOf:
+  - $ref: /schemas/spi/spi-peripheral-props.yaml#
+  - oneOf:
+      - required: ['adi,range-microamp']
+      - required: ['adi,range-microvolt']
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    spi {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        dac@0 {
+            compatible = "adi,ad5413";
+            reg = <0>;
+            spi-max-frequency = <1000000>;
+            reset-gpios = <&gpio 0 1>; /* 1 = active low */
+            avdd-supply = <&avdd>;
+            dvdd-supply = <&dvdd>;
+            avss-supply = <&avss>;
+            adi,range-microvolt = <(-10500000) 10500000>;
+            adi,slew-time-us = <125>;
+        };
+    };