dt-bindings:iio:adc:adi,ad7768-1 yaml conversion

Fairly straight conversion.  The one oddity in the original binding
is that spi-cpha and spi-cpol were not marked as required, but were
in the example.  Looking at the datasheet, there isn't any documented
flexibility in the possible SPI modes, so I have moved these to requires.
For spi-max-frequency I have gone the other way.  I absolutely agree
that it is good to specify this in the dt-binding, but it's not
strictly required.

As Stefan's email is bouncing I have gone with Michael as maintainer
of this one as it falls under the ADI catch all entry in MAINTAINERS.
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Cc: Michael Hennerich <Michael.Hennerich@analog.com>
Link: https://lore.kernel.org/r/20200909175946.395313-16-jic23@kernel.org

Documentation/devicetree/bindings/iio/adc/adi,ad7768-1.txt

-Analog Devices AD7768-1 ADC device driver
-
-Required properties for the AD7768-1:
-
-- compatible: Must be "adi,ad7768-1"
-- reg: SPI chip select number for the device
-- spi-max-frequency: Max SPI frequency to use
-	see: Documentation/devicetree/bindings/spi/spi-bus.txt
-- clocks: phandle to the master clock (mclk)
-	see: Documentation/devicetree/bindings/clock/clock-bindings.txt
-- clock-names: Must be "mclk".
-- interrupts: IRQ line for the ADC
-	see: Documentation/devicetree/bindings/interrupt-controller/interrupts.txt
-- vref-supply: vref supply can be used as reference for conversion
-- adi,sync-in-gpios: must be the device tree identifier of the SYNC-IN pin. Enables
-	synchronization of multiple devices that require simultaneous sampling.
-	A pulse is always required if the configuration is changed in any way, for example
-	if the filter decimation rate changes. As the line is active low, it should
-	be marked GPIO_ACTIVE_LOW.
-
-Optional properties:
-
- - reset-gpios : GPIO spec for the RESET pin. If specified, it will be asserted during
-	driver probe. As the line is active low, it should be marked GPIO_ACTIVE_LOW.
-
-Example:
-
-	adc@0 {
-		compatible = "adi,ad7768-1";
-		reg = <0>;
-		spi-max-frequency = <2000000>;
-		spi-cpol;
-		spi-cpha;
-		vref-supply = <&adc_vref>;
-		interrupts = <25 IRQ_TYPE_EDGE_RISING>;
-		interrupt-parent = <&gpio>;
-		adi,sync-in-gpios = <&gpio 22 GPIO_ACTIVE_LOW>;
-		reset-gpios = <&gpio 27 GPIO_ACTIVE_LOW>;
-		clocks = <&ad7768_mclk>;
-		clock-names = "mclk";
-	};

Documentation/devicetree/bindings/iio/adc/adi,ad7768-1.yaml

+# SPDX-License-Identifier: GPL-2.0
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/iio/adc/adi,ad7768-1.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Analog Devices AD7768-1 ADC device driver
+
+maintainers:
+  - Michael Hennerich <michael.hennerich@analog.com>
+
+description: |
+  Datasheet at:
+    https://www.analog.com/media/en/technical-documentation/data-sheets/ad7768-1.pdf
+
+properties:
+  compatible:
+    const: adi,ad7768-1
+
+  reg:
+    maxItems: 1
+
+  clocks:
+    maxItems: 1
+
+  clock-names:
+    const: mclk
+
+  interrupts:
+    maxItems: 1
+
+  vref-supply:
+    description:
+      ADC reference voltage supply
+
+  adi,sync-in-gpios:
+    description:
+      Enables synchronization of multiple devices that require simultaneous
+      sampling. A pulse is always required if the configuration is changed
+      in any way, for example if the filter decimation rate changes.
+      As the line is active low, it should be marked GPIO_ACTIVE_LOW.
+
+  reset-gpios:
+    maxItems: 1
+
+  spi-max-frequency: true
+
+  spi-cpol: true
+  spi-cpha : true
+
+  "#io-channel-cells":
+    const: 1
+
+required:
+  - compatible
+  - reg
+  - clocks
+  - clock-names
+  - vref-supply
+  - spi-cpol
+  - spi-cpha
+  - adi,sync-in-gpios
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/interrupt-controller/irq.h>
+    #include <dt-bindings/gpio/gpio.h>
+    spi {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        adc@0 {
+            compatible = "adi,ad7768-1";
+            reg = <0>;
+            spi-max-frequency = <2000000>;
+            spi-cpol;
+            spi-cpha;
+            vref-supply = <&adc_vref>;
+            interrupts = <25 IRQ_TYPE_EDGE_RISING>;
+            interrupt-parent = <&gpio>;
+            adi,sync-in-gpios = <&gpio 22 GPIO_ACTIVE_LOW>;
+            reset-gpios = <&gpio 27 GPIO_ACTIVE_LOW>;
+            clocks = <&ad7768_mclk>;
+            clock-names = "mclk";
+        };
+    };
+...