dt-bindings: clock: adi,axi-clkgen: convert old binding to yaml format

This change converts the old binding for the AXI clkgen driver to a yaml
format.

As maintainers, added:
 - Lars-Peter Clausen <lars@metafoo.de> - as original author of driver &
   binding
 - Michael Hennerich <michael.hennerich@analog.com> - as supporter of
   Analog Devices drivers
Acked-by: Michael Hennerich <michael.hennerich@analog.com>
Acked-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Link: https://lore.kernel.org/r/20201013143421.84188-1-alexandru.ardelean@analog.comReviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>

Documentation/devicetree/bindings/clock/adi,axi-clkgen.yaml

+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/clock/adi,axi-clkgen.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Binding for Analog Devices AXI clkgen pcore clock generator
+
+maintainers:
+  - Lars-Peter Clausen <lars@metafoo.de>
+  - Michael Hennerich <michael.hennerich@analog.com>
+
+description: |
+  The axi_clkgen IP core is a software programmable clock generator,
+  that can be synthesized on various FPGA platforms.
+
+  Link: https://wiki.analog.com/resources/fpga/docs/axi_clkgen
+
+properties:
+  compatible:
+    enum:
+      - adi,axi-clkgen-2.00.a
+
+  clocks:
+    description:
+      Specifies the reference clock(s) from which the output frequency is
+      derived. This must either reference one clock if only the first clock
+      input is connected or two if both clock inputs are connected.
+    minItems: 1
+    maxItems: 2
+
+  '#clock-cells':
+    const: 0
+
+  reg:
+    maxItems: 1
+
+required:
+  - compatible
+  - reg
+  - clocks
+  - '#clock-cells'
+
+additionalProperties: false
+
+examples:
+  - |
+    clock-controller@ff000000 {
+      compatible = "adi,axi-clkgen-2.00.a";
+      #clock-cells = <0>;
+      reg = <0xff000000 0x1000>;
+      clocks = <&osc 1>;
+    };

Documentation/devicetree/bindings/clock/axi-clkgen.txt

-Binding for the axi-clkgen clock generator
-
-This binding uses the common clock binding[1].
-
-[1] Documentation/devicetree/bindings/clock/clock-bindings.txt
-
-Required properties:
-- compatible : shall be "adi,axi-clkgen-1.00.a" or "adi,axi-clkgen-2.00.a".
-- #clock-cells : from common clock binding; Should always be set to 0.
-- reg : Address and length of the axi-clkgen register set.
-- clocks : Phandle and clock specifier for the parent clock(s). This must
-	either reference one clock if only the first clock input is connected or two
-	if both clock inputs are connected. For the later case the clock connected
-	to the first input must be specified first.
-
-Optional properties:
-- clock-output-names : From common clock binding.
-
-Example:
-	clock@ff000000 {
-		compatible = "adi,axi-clkgen";
-		#clock-cells = <0>;
-		reg = <0xff000000 0x1000>;
-		clocks = <&osc 1>;
-	};