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 <bruce.tsao@analog.com>

Author: BruceTsaoADI

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

@@ -0,0 +1,72 @@
+# 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 <bruce.tsao@analog.com>
+
+properties:
+  compatible:
+    const: adi,ad5413
+
+  reg:
+    maxItems: 1
+
+  spi-max-frequency:
+    maximum: 50000000
+
+  adi,range-microvolt:
+    description: Voltage output range <min, max> in microvolts
+    enum:
+      - [-10500000, 10500000]
+      - [-12600000, 12600000]
+
+  adi,range-microamp:
+    description: Current output range <min, max> in microamps
+    enum:
+      - [0, 24000]
+
+  adi,slew-time-us:
+    description: |
+      Output digital slew control time in microseconds
+    minimum: 0
+    maximum: 1000000
+
+required:
+  - compatible
+  - reg
+  - spi-max-frequency
+
+allOf:
+  - $ref: /schemas/spi/spi-peripheral-props.yaml#
+  - if:
+      required: [adi, range-microamp]
+    then:
+      properties:
+        adi,range-microvolt: false
+  - if:
+      required: [adi, range-microvolt]
+    then:
+      properties:
+        adi,range-microamp: false
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    spi {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        dac@0 {
+            compatible = "adi,ad5413";
+            reg = <0>;
+            spi-max-frequency = <1000000>;
+            adi,range-microvolt = <(-10500000) 10500000>;
+            adi,slew-time-us = <125>;
+        };
+    };

drivers/iio/dac/Kconfig

@@ -564,4 +564,13 @@ config VF610_DAC
 	  This driver can also be built as a module. If so, the module will
 	  be called vf610_dac.
 
+config AD5413
+	tristate "Analog Devices AD5413 DAC driver"
+	depends on SPI_MASTER
+	help
+	  Say yes here to build support for Analog Devices AD5413 single channel
+	  Digital to Analog Converter.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called ad5758.
 endmenu

drivers/iio/dac/Makefile

@@ -57,3 +57,4 @@ obj-$(CONFIG_TI_DAC5571) += ti-dac5571.o
 obj-$(CONFIG_TI_DAC7311) += ti-dac7311.o
 obj-$(CONFIG_TI_DAC7612) += ti-dac7612.o
 obj-$(CONFIG_VF610_DAC) += vf610_dac.o
+obj-$(CONFIG_AD5413) += ad5413.o