dt-bindings: clock: cs2000-cp: document aux-output-source

This new optional property can be used to control the function of the
auxiliary output pin. Introduce a new dt-bindings include file that
contains the numerical values.

Signed-off-by: Daniel Mack <[e-mail]>
Acked-by: Rob Herring <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Stephen Boyd <[e-mail]>

Documentation/devicetree/bindings/clock/cirrus,cs2000-cp.yaml

···
   reg:
     maxItems: 1
 
+  cirrus,aux-output-source:
+    description:
+      Specifies the function of the auxiliary clock output pin
+    $ref: /schemas/types.yaml#/definitions/uint32
+    enum:
+      - 0 # CS2000CP_AUX_OUTPUT_REF_CLK:  ref_clk input
+      - 1 # CS2000CP_AUX_OUTPUT_CLK_IN:   clk_in input
+      - 2 # CS2000CP_AUX_OUTPUT_CLK_OUT:  clk_out output
+      - 3 # CS2000CP_AUX_OUTPUT_PLL_LOCK: pll lock status
+    default: 0
+
 required:
   - compatible
   - reg
···
 
 examples:
   - |
+    #include <dt-bindings/clock/cirrus,cs2000-cp.h>
+
     i2c@0 {
       reg = <0x0 0x100>;
       #address-cells = <1>;
···
         reg = <0x4f>;
         clocks = <&rcar_sound 0>, <&x12_clk>;
         clock-names = "clk_in", "ref_clk";
+        cirrus,aux-output-source = <CS2000CP_AUX_OUTPUT_CLK_OUT>;
       };
     };

include/dt-bindings/clock/cirrus,cs2000-cp.h

···
+/* SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) */
+/*
+ * Copyright (C) 2021 Daniel Mack
+ */
+
+#ifndef __DT_BINDINGS_CS2000CP_CLK_H
+#define __DT_BINDINGS_CS2000CP_CLK_H
+
+#define CS2000CP_AUX_OUTPUT_REF_CLK	0
+#define CS2000CP_AUX_OUTPUT_CLK_IN	1
+#define CS2000CP_AUX_OUTPUT_CLK_OUT	2
+#define CS2000CP_AUX_OUTPUT_PLL_LOCK	3
+
+#endif /* __DT_BINDINGS_CS2000CP_CLK_H */