dt-bindings: iio: adc: sophgo,cv1800b-saradc: Add Sophgo CV1800B SARADC

The Sophgo CV1800B SARADC is a Successive Approximation ADC that can be
found in the Sophgo CV1800B SoC.

Signed-off-by: Thomas Bonnefille <thomas.bonnefille@bootlin.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://patch.msgid.link/20240829-sg2002-adc-v5-1-aacb381e869b@bootlin.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

Documentation/devicetree/bindings/iio/adc/sophgo,cv1800b-saradc.yaml

@@ -0,0 +1,83 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/iio/adc/sophgo,cv1800b-saradc.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title:
+  Sophgo CV1800B SoC 3 channels Successive Approximation Analog to
+  Digital Converters
+
+maintainers:
+  - Thomas Bonnefille <thomas.bonnefille@bootlin.com>
+
+description:
+  Datasheet at https://github.com/sophgo/sophgo-doc/releases
+
+properties:
+  compatible:
+    const: sophgo,cv1800b-saradc
+
+  reg:
+    maxItems: 1
+
+  interrupts:
+    maxItems: 1
+
+  clocks:
+    maxItems: 1
+
+  '#address-cells':
+    const: 1
+
+  '#size-cells':
+    const: 0
+
+patternProperties:
+  "^channel@[0-2]$":
+    $ref: adc.yaml
+
+    properties:
+      reg:
+        items:
+          - minimum: 0
+            maximum: 2
+
+    required:
+      - reg
+
+    additionalProperties: false
+
+required:
+  - compatible
+  - reg
+  - clocks
+  - '#address-cells'
+  - '#size-cells'
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/clock/sophgo,cv1800.h>
+    #include <dt-bindings/interrupt-controller/irq.h>
+    adc@30f0000 {
+        compatible = "sophgo,cv1800b-saradc";
+        reg = <0x030f0000 0x1000>;
+        clocks = <&clk CLK_SARADC>;
+        interrupts = <100 IRQ_TYPE_LEVEL_HIGH>;
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        channel@0 {
+            reg = <0>;
+        };
+
+        channel@1 {
+            reg = <1>;
+        };
+
+        channel@2 {
+            reg = <2>;
+        };
+    };