[PATCH v3 7/7] dt-bindings: iio: adc: adi,ad4030: add data-lanes property

[David Lechner <dlechner@baylibre.com>]

Add data-lanes property to specify the number of data lanes used on the
ad463x chips that support reading two samples at the same time using
two data lanes with a capable SPI controller.

Signed-off-by: David Lechner <dlechner@baylibre.com>
---
v3 changes: new patch

I added this one to give a real-world use case where spi-rx-bus-width
was not sufficient to fully describe the hardware configuration.

spi-rx-bus-width = <4>; alone could be be interpreted as either:

+--------------+    +----------+
| SPI          |    | AD4630   |
| Controller   |    | ADC      |
|              |    |          |
|        SDIA0 |<---| SDOA0    |
|        SDIA1 |<---| SDOA1    |
|        SDIA2 |<---| SDOA2    |
|        SDIA3 |<---| SDOA3    |
|              |    |          |
|        SDIB0 |x   | SDOB0    |
|        SDIB1 |x   | SDOB1    |
|        SDIB2 |x   | SDOB2    |
|        SDIB3 |x   | SDOB3    |
|              |    |          |
+--------------+     +---------+

or

+--------------+    +----------+
| SPI          |    | AD4630   |
| Controller   |    | ADC      |
|              |    |          |
|        SDIA0 |<---| SDOA0    |
|        SDIA1 |<---| SDOA1    |
|        SDIA2 |x   | SDOA2    |
|        SDIA3 |x   | SDOA3    |
|              |    |          |
|        SDIB0 |<---| SDOB0    |
|        SDIB1 |<---| SDOB1    |
|        SDIB2 |x   | SDOB2    |
|        SDIB3 |x   | SDOB3    |
|              |    |          |
+--------------+     +---------+

Now, with data-lanes having a default value of [0] (inherited from
spi-peripheral-props.yaml), specifying:

    spi-rx-bus-width = <4>;

is unambiguously the first case and the example given in the binding
documentation is the second case:

    spi-rx-bus-width = <2>;
    data-lanes = <0>, <1>;
---
 .../devicetree/bindings/iio/adc/adi,ad4030.yaml    | 36 ++++++++++++++++++++++
 1 file changed, 36 insertions(+)

diff --git a/Documentation/devicetree/bindings/iio/adc/adi,ad4030.yaml b/Documentation/devicetree/bindings/iio/adc/adi,ad4030.yaml
index 54e7349317b77f032ecafde0102bf3a09f140f03..315ebcfbfa28888a4518073c1b286f0993f83673 100644
--- a/Documentation/devicetree/bindings/iio/adc/adi,ad4030.yaml
+++ b/Documentation/devicetree/bindings/iio/adc/adi,ad4030.yaml
@@ -39,6 +39,10 @@ properties:
   spi-rx-bus-width:
     enum: [1, 2, 4]
 
+  data-lanes:
+    minItems: 1
+    maxItems: 2
+
   vdd-5v-supply: true
   vdd-1v8-supply: true
   vio-supply: true
@@ -88,6 +92,17 @@ oneOf:
 
 unevaluatedProperties: false
 
+allOf:
+  - if:
+      properties:
+        compatible:
+          enum:
+            - adi,ad4030-24
+            - adi,ad4032-24
+    then:
+      properties:
+        data-lanes: false
+
 examples:
   - |
     #include <dt-bindings/gpio/gpio.h>
@@ -108,3 +123,24 @@ examples:
             reset-gpios = <&gpio0 1 GPIO_ACTIVE_LOW>;
         };
     };
+  - |
+    #include <dt-bindings/gpio/gpio.h>
+
+    spi {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        adc@0 {
+            compatible = "adi,ad4630-24";
+            reg = <0>;
+            spi-max-frequency = <80000000>;
+            spi-rx-bus-width = <2>;
+            data-lanes = <0>, <1>;
+            vdd-5v-supply = <&supply_5V>;
+            vdd-1v8-supply = <&supply_1_8V>;
+            vio-supply = <&supply_1_8V>;
+            ref-supply = <&supply_5V>;
+            cnv-gpios = <&gpio0 0 GPIO_ACTIVE_HIGH>;
+            reset-gpios = <&gpio0 1 GPIO_ACTIVE_LOW>;
+        };
+    };

-- 
2.43.0