dt-bindings: iio: adc: ad7476: Add ROHM bd79105

The ROHM BD79105 is a simple, 16-bit, 1-channel ADC with a 'CONVSTART'
pin used to start the ADC conversion. Other than the 'CONVSTART', there
are 3 supply pins (one used as a reference), analog inputs, ground and
communication pins. It's worth noting that the pin somewhat confusingly
labeled as 'DIN', is a pin which should be used as a chip-select. The IC
does not have any writable registers.

The device is designed so that the output pin can, in addition to
outputting the data, be used as a 'data-ready'-IRQ. There are cases
where the IRQ can't be used (because it is delivered via SPI data-line).
Hence, some systems may use a GPIO for polling the data readiness.

Add a compatible for the bd79105 and add the data-ready GPIO to the
binding.

Signed-off-by: Matti Vaittinen <mazziesaccount@gmail.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://patch.msgid.link/3f70f68665225be3091f8a0412e74037b6a2a88e.1754901948.git.mazziesaccount@gmail.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

Documentation/devicetree/bindings/iio/adc/adi,ad7476.yaml

@@ -41,6 +41,7 @@ properties:
               - adi,ad7910
               - adi,ad7920
               - adi,ad7940
+              - rohm,bd79105
               - ti,adc081s
               - ti,adc101s
               - ti,adc121s
@@ -55,6 +56,11 @@ properties:
   reg:
     maxItems: 1
 
+  interrupts:
+    description:
+      The data-ready interrupt. Provided via DOUT pin.
+    maxItems: 1
+
   vcc-supply:
     description:
       Main powersupply voltage for the chips, sometimes referred to as VDD on
@@ -75,6 +81,10 @@ properties:
     description: A GPIO used to trigger the start of a conversion
     maxItems: 1
 
+  rdy-gpios:
+    description: A GPIO for detecting the data-ready.
+    maxItems: 1
+
 required:
   - compatible
   - reg
@@ -82,6 +92,20 @@ required:
 allOf:
   - $ref: /schemas/spi/spi-peripheral-props.yaml#
 
+# Devices with an IRQ
+  - if:
+      properties:
+        compatible:
+          contains:
+            enum:
+              - rohm,bd79105
+    then:
+      properties:
+        interrupts: true
+    else:
+      properties:
+        interrupts: false
+
   # Devices where reference is vcc
   - if:
       properties:
@@ -116,6 +140,7 @@ allOf:
                 - adi,ad7274
                 - adi,ad7475
                 - lltc,ltc2314-14
+                - rohm,bd79105
     then:
       properties:
         vref-supply: false
@@ -129,6 +154,7 @@ allOf:
               - adi,ad7274
               - adi,ad7475
               - lltc,ltc2314-14
+              - rohm,bd79105
     then:
       required:
         - vref-supply
@@ -140,9 +166,23 @@ allOf:
               enum:
                 - adi,ad7475
                 - adi,ad7495
+                - rohm,bd79105
     then:
       properties:
         vdrive-supply: false
+
+  # Devices which support polling the data-ready via GPIO
+  - if:
+      not:
+        properties:
+          compatible:
+            contains:
+              enum:
+                - rohm,bd79105
+    then:
+      properties:
+        rdy-gpios: false
+
   - if:
       not:
         properties:
@@ -151,10 +191,22 @@ allOf:
               enum:
                 - adi,ad7091
                 - adi,ad7091r
+                - rohm,bd79105
     then:
       properties:
         adi,conversion-start-gpios: false
 
+  # Devices with a convstart GPIO where it is not optional
+  - if:
+      properties:
+        compatible:
+          contains:
+            enum:
+              - rohm,bd79105
+    then:
+      required:
+        - adi,conversion-start-gpios
+
 unevaluatedProperties: false
 
 examples: