dt-bindings: clock: sophgo: add pll clocks for SG2042

Add bindings for the pll clocks for Sophgo SG2042.
Signed-off-by: Chen Wang <unicorn_wang@outlook.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Reviewed-by: Guo Ren <guoren@kernel.org>

Documentation/devicetree/bindings/clock/sophgo,sg2042-pll.yaml

+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/clock/sophgo,sg2042-pll.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Sophgo SG2042 PLL Clock Generator
+
+maintainers:
+  - Chen Wang <unicorn_wang@outlook.com>
+
+properties:
+  compatible:
+    const: sophgo,sg2042-pll
+
+  reg:
+    maxItems: 1
+
+  clocks:
+    items:
+      - description: Oscillator(Clock Generation IC) for Main/Fixed PLL (25 MHz)
+      - description: Oscillator(Clock Generation IC) for DDR PLL 0 (25 MHz)
+      - description: Oscillator(Clock Generation IC) for DDR PLL 1 (25 MHz)
+
+  clock-names:
+    items:
+      - const: cgi_main
+      - const: cgi_dpll0
+      - const: cgi_dpll1
+
+  '#clock-cells':
+    const: 1
+    description:
+      See <dt-bindings/clock/sophgo,sg2042-pll.h> for valid indices.
+
+required:
+  - compatible
+  - reg
+  - clocks
+  - clock-names
+  - '#clock-cells'
+
+additionalProperties: false
+
+examples:
+  - |
+    clock-controller@10000000 {
+      compatible = "sophgo,sg2042-pll";
+      reg = <0x10000000 0x10000>;
+      clocks = <&cgi_main>, <&cgi_dpll0>, <&cgi_dpll1>;
+      clock-names = "cgi_main", "cgi_dpll0", "cgi_dpll1";
+      #clock-cells = <1>;
+    };

include/dt-bindings/clock/sophgo,sg2042-pll.h

+/* SPDX-License-Identifier: GPL-2.0 OR BSD-2-Clause */
+/*
+ * Copyright (C) 2023 Sophgo Technology Inc. All rights reserved.
+ */
+
+#ifndef __DT_BINDINGS_SOPHGO_SG2042_PLL_H__
+#define __DT_BINDINGS_SOPHGO_SG2042_PLL_H__
+
+#define MPLL_CLK			0
+#define FPLL_CLK			1
+#define DPLL0_CLK			2
+#define DPLL1_CLK			3
+
+#endif /* __DT_BINDINGS_SOPHGO_SG2042_PLL_H__ */