dt-bindings:iio:adc:fsl,vf610-adc conversion to yaml.

A simple conversion of this freescale ADC binding from txt to yaml.
For maintainer I went with Fugang Duan as the original author of the
binding. Would be great to have confirmation of this.

Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Fugang Duan <fugang.duan@nxp.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Cc: Shawn Guo <shawnguo@kernel.org>
Cc: Sascha Hauer <s.hauer@pengutronix.de>
Link: https://lore.kernel.org/r/20200909175946.395313-2-jic23@kernel.org

Documentation/devicetree/bindings/iio/adc/fsl,vf610-adc.yaml

@@ -0,0 +1,81 @@
+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/iio/adc/fsl,vf610-adc.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: ADC found on Freescale vf610 and similar SoCs
+
+maintainers:
+  - Fugang Duan <fugang.duan@nxp.com>
+
+description:
+  ADCs found on vf610/i.MX6slx and upward SoCs from Freescale.
+
+properties:
+  compatible:
+    const: fsl,vf610-adc
+
+  reg:
+    maxItems: 1
+
+  interrupts:
+    maxItems: 1
+
+  clocks:
+    description: ADC source clock (ipg clock)
+    maxItems: 1
+
+  clock-names:
+    const: adc
+
+  vref-supply:
+    description: ADC reference voltage supply.
+
+  fsl,adck-max-frequency:
+    $ref: /schemas/types.yaml#/definitions/uint32-array
+    minItems: 3
+    maxItems: 3
+    description: |
+      Maximum frequencies from datasheet operating requirements.
+      Three values necessary to cover the 3 conversion modes.
+      * Frequency in normal mode (ADLPC=0, ADHSC=0)
+      * Frequency in high-speed mode (ADLPC=0, ADHSC=1)
+      * Frequency in low-power mode (ADLPC=1, ADHSC=0)
+
+  min-sample-time:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description:
+      Minimum sampling time in nanoseconds. This value has
+      to be chosen according to the conversion mode and the connected analog
+      source resistance (R_as) and capacitance (C_as). Refer the datasheet's
+      operating requirements. A safe default across a wide range of R_as and
+      C_as as well as conversion modes is 1000ns.
+
+  "#io-channel-cells":
+    const: 1
+
+required:
+  - compatible
+  - reg
+  - interrupts
+  - clocks
+  - clock-names
+  - vref-supply
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/clock/vf610-clock.h>
+    adc@4003b000 {
+        compatible = "fsl,vf610-adc";
+        reg = <0x4003b000 0x1000>;
+        interrupts = <0 53 0x04>;
+        clocks = <&clks VF610_CLK_ADC0>;
+        clock-names = "adc";
+        fsl,adck-max-frequency = <30000000>, <40000000>, <20000000>;
+        vref-supply = <&reg_vcc_3v3_mcu>;
+        min-sample-time = <10000>;
+    };
+...