dt-bindings: pinctrl-zynq: Replace 'io-standard' with 'power-source'

Replace custom pin configuration option 'io-standard' with generic property
'power-source' for Zynq pinctrl also add dt-binding file contains pin
configuration defines for Zynq pinctrl.

Signed-off-by: Sai Krishna Potthuri <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Linus Walleij <[e-mail]>

Documentation/devicetree/bindings/pinctrl/xlnx,zynq-pinctrl.yaml

···
           slew-rate:
             enum: [0, 1]
 
-          io-standard:
-            description:
-              Selects the IO standard for MIO pins, this is driver specific.
-            $ref: "/schemas/types.yaml#/definitions/uint32"
+          power-source:
             enum: [1, 2, 3, 4]
 
         oneOf:
···
 
 examples:
   - |
+    #include <dt-bindings/pinctrl/pinctrl-zynq.h>
     pinctrl0: pinctrl@700 {
        compatible = "xlnx,zynq-pinctrl";
        reg = <0x700 0x200>;
···
            conf {
                groups = "uart1_10_grp";
                slew-rate = <0>;
-               io-standard = <1>;
+               power-source = <IO_STANDARD_LVCMOS18>;
            };
 
            conf-rx {

include/dt-bindings/pinctrl/pinctrl-zynq.h

···
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * MIO pin configuration defines for Xilinx Zynq
+ *
+ * Copyright (C) 2021 Xilinx, Inc.
+ */
+
+#ifndef _DT_BINDINGS_PINCTRL_ZYNQ_H
+#define _DT_BINDINGS_PINCTRL_ZYNQ_H
+
+/* Configuration options for different power supplies */
+#define IO_STANDARD_LVCMOS18	1
+#define IO_STANDARD_LVCMOS25	2
+#define IO_STANDARD_LVCMOS33	3
+#define IO_STANDARD_HSTL	4
+
+#endif /* _DT_BINDINGS_PINCTRL_ZYNQ_H */