dt-bindings: iio: adc: ad7380: add adaq4370-4 and adaq4380-4 compatible parts

adaq4370-4 (2MSPS) and adaq4380-4 (4MSPS) are quad-channel precision data
acquisition signal chain μModule solutions compatible with the ad738x
family, with the following differences:

- pin selectable gain in front of each 4 adc
- internal reference is 3V derived from refin-supply (5V)
- additional supplies

To select the gain a new patternProperties is added to describe each
channel. It is restricted to adaq devices.

Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Signed-off-by: Julien Stephan <jstephan@baylibre.com>
Reviewed-by: David Lechner <dlechner@baylibre.com>
Link: https://patch.msgid.link/20241030-ad7380-add-adaq4380-4-support-v4-1-864ff02babae@baylibre.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

Documentation/devicetree/bindings/iio/adc/adi,ad7380.yaml

@@ -25,6 +25,8 @@ description: |
   * https://www.analog.com/en/products/ad7386-4.html
   * https://www.analog.com/en/products/ad7387-4.html
   * https://www.analog.com/en/products/ad7388-4.html
+  * https://www.analog.com/en/products/adaq4370-4.html
+  * https://www.analog.com/en/products/adaq4380-4.html
 
 
 $ref: /schemas/spi/spi-peripheral-props.yaml#
@@ -46,6 +48,8 @@ properties:
       - adi,ad7386-4
       - adi,ad7387-4
       - adi,ad7388-4
+      - adi,adaq4370-4
+      - adi,adaq4380-4
 
   reg:
     maxItems: 1
@@ -70,6 +74,20 @@ properties:
   refin-supply:
     description:
       A 2.5V to 3.3V supply for external reference voltage, for ad7380-4 only.
+      For adaq devices, a 5V supply voltage. A 3.3V internal reference is
+      derived from it. Connect to vs-p-supply for normal operation.
+
+  vs-p-supply:
+    description:
+      Amplifiers positive supply.
+
+  vs-n-supply:
+    description:
+      Amplifiers negative supply.
+
+  ldo-supply:
+    description:
+      LDO supply. Connect to vs-p-supply or a 3.6 to 5.5 V supply.
 
   aina-supply:
     description:
@@ -97,12 +115,45 @@ properties:
       specify the ALERT interrupt.
     maxItems: 1
 
+  "#address-cells":
+    const: 1
+
+  "#size-cells":
+    const: 0
+
 required:
   - compatible
   - reg
   - vcc-supply
   - vlogic-supply
 
+patternProperties:
+  "^channel@[0-3]$":
+    $ref: adc.yaml
+    type: object
+
+    properties:
+      reg:
+        description:
+          The channel number. From 0 to 3 corresponding to channels A,B,C,D
+        minimum: 0
+        maximum: 3
+
+      adi,gain-milli:
+        description:
+          The hardware gain applied to the ADC input (in milli units).
+          If not present, default to 1000 (no actual gain applied).
+          Refer to the typical connection diagrams section of the datasheet for
+          pin wiring.
+        $ref: /schemas/types.yaml#/definitions/uint16
+        enum: [300, 600, 1000, 1600]
+        default: 1000
+
+    required:
+      - reg
+
+    additionalProperties: false
+
 unevaluatedProperties: false
 
 allOf:
@@ -140,6 +191,7 @@ allOf:
         aind-supply: false
 
   # ad7380-4 uses refin-supply as external reference.
+  # adaq devices use internal reference only, derived from refin-supply
   # All other chips from ad738x family use refio as optional external reference.
   # When refio-supply is omitted, internal reference is used.
   - if:
@@ -147,6 +199,8 @@ allOf:
         compatible:
           enum:
             - adi,ad7380-4
+            - adi,adaq4370-4
+            - adi,adaq4380-4
     then:
       properties:
         refio-supply: false
@@ -156,6 +210,27 @@ allOf:
       properties:
         refin-supply: false
 
+  # adaq devices need more supplies and using channel to declare gain property
+  # only applies to adaq devices
+  - if:
+      properties:
+        compatible:
+          enum:
+            - adi,adaq4370-4
+            - adi,adaq4380-4
+    then:
+      required:
+        - vs-p-supply
+        - vs-n-supply
+        - ldo-supply
+    else:
+      properties:
+        vs-p-supply: false
+        vs-n-supply: false
+        ldo-supply: false
+      patternProperties:
+        "^channel@[0-3]$": false
+
 examples:
   - |
     #include <dt-bindings/interrupt-controller/irq.h>
@@ -180,3 +255,48 @@ examples:
             refio-supply = <&supply_2_5V>;
         };
     };
+
+  - |
+    #include <dt-bindings/interrupt-controller/irq.h>
+
+    spi {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        adc@0 {
+            compatible = "adi,adaq4380-4";
+            reg = <0>;
+
+            spi-cpol;
+            spi-cpha;
+            spi-max-frequency = <80000000>;
+
+            interrupts = <27 IRQ_TYPE_EDGE_FALLING>;
+            interrupt-parent = <&gpio0>;
+
+            vcc-supply = <&supply_3_3V>;
+            vlogic-supply = <&supply_3_3V>;
+            refin-supply = <&supply_5V>;
+            vs-p-supply = <&supply_5V>;
+            vs-n-supply = <&supply_0V>;
+            ldo-supply = <&supply_5V>;
+
+            #address-cells = <1>;
+            #size-cells = <0>;
+
+            channel@0 {
+                reg = <0>;
+                adi,gain-milli = /bits/ 16 <300>;
+            };
+
+            channel@2 {
+                reg = <2>;
+                adi,gain-milli = /bits/ 16 <600>;
+            };
+
+            channel@3 {
+                reg = <3>;
+                adi,gain-milli = /bits/ 16 <1000>;
+            };
+        };
+    };