dt-bindings: clock: renesas: Document RZ/V2H(P) SoC CPG

Document the device tree bindings for the Renesas RZ/V2H(P) SoC
Clock Pulse Generator (CPG).

CPG block handles the below operations:
- Generation and control of clock signals for the IP modules
- Generation and control of resets
- Control over booting
- Low power consumption and power supply domains

Also define constants for the core clocks of the RZ/V2H(P) SoC. Note the
core clocks are a subset of the ones which are listed as part of section
4.4.2 of HW manual Rev.1.01 which cannot be controlled by CLKON register.

Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/20240729202645.263525-2-prabhakar.mahadev-lad.rj@bp.renesas.com
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>

Author: prabhakarlad

Documentation/devicetree/bindings/clock/renesas,rzv2h-cpg.yaml

@@ -0,0 +1,80 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/clock/renesas,rzv2h-cpg.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Renesas RZ/V2H(P) Clock Pulse Generator (CPG)
+
+maintainers:
+  - Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
+
+description:
+  On Renesas RZ/V2H(P) SoCs, the CPG (Clock Pulse Generator) handles generation
+  and control of clock signals for the IP modules, generation and control of resets,
+  and control over booting, low power consumption and power supply domains.
+
+properties:
+  compatible:
+    const: renesas,r9a09g057-cpg
+
+  reg:
+    maxItems: 1
+
+  clocks:
+    items:
+      - description: AUDIO_EXTAL clock input
+      - description: RTXIN clock input
+      - description: QEXTAL clock input
+
+  clock-names:
+    items:
+      - const: audio_extal
+      - const: rtxin
+      - const: qextal
+
+  '#clock-cells':
+    description: |
+      - For CPG core clocks, the two clock specifier cells must be "CPG_CORE"
+        and a core clock reference, as defined in
+        <dt-bindings/clock/renesas,r9a09g057-cpg.h>,
+      - For module clocks, the two clock specifier cells must be "CPG_MOD" and
+        a module number.  The module number is calculated as the CLKON register
+        offset index multiplied by 16, plus the actual bit in the register
+        used to turn the CLK ON. For example, for CGC_GIC_0_GICCLK, the
+        calculation is (1 * 16 + 3) = 0x13.
+    const: 2
+
+  '#power-domain-cells':
+    const: 0
+
+  '#reset-cells':
+    description:
+      The single reset specifier cell must be the reset number. The reset number
+      is calculated as the reset register offset index multiplied by 16, plus the
+      actual bit in the register used to reset the specific IP block. For example,
+      for SYS_0_PRESETN, the calculation is (3 * 16 + 0) = 0x30.
+    const: 1
+
+required:
+  - compatible
+  - reg
+  - clocks
+  - clock-names
+  - '#clock-cells'
+  - '#power-domain-cells'
+  - '#reset-cells'
+
+additionalProperties: false
+
+examples:
+  - |
+    clock-controller@10420000 {
+        compatible = "renesas,r9a09g057-cpg";
+        reg = <0x10420000 0x10000>;
+        clocks = <&audio_extal_clk>, <&rtxin_clk>, <&qextal_clk>;
+        clock-names = "audio_extal", "rtxin", "qextal";
+        #clock-cells = <2>;
+        #power-domain-cells = <0>;
+        #reset-cells = <1>;
+    };

include/dt-bindings/clock/renesas,r9a09g057-cpg.h

@@ -0,0 +1,21 @@
+/* SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+ *
+ * Copyright (C) 2024 Renesas Electronics Corp.
+ */
+#ifndef __DT_BINDINGS_CLOCK_RENESAS_R9A09G057_CPG_H__
+#define __DT_BINDINGS_CLOCK_RENESAS_R9A09G057_CPG_H__
+
+#include <dt-bindings/clock/renesas-cpg-mssr.h>
+
+/* Core Clock list */
+#define R9A09G057_SYS_0_PCLK			0
+#define R9A09G057_CA55_0_CORE_CLK0		1
+#define R9A09G057_CA55_0_CORE_CLK1		2
+#define R9A09G057_CA55_0_CORE_CLK2		3
+#define R9A09G057_CA55_0_CORE_CLK3		4
+#define R9A09G057_CA55_0_PERIPHCLK		5
+#define R9A09G057_CM33_CLK0			6
+#define R9A09G057_CST_0_SWCLKTCK		7
+#define R9A09G057_IOTOP_0_SHCLK			8
+
+#endif /* __DT_BINDINGS_CLOCK_RENESAS_R9A09G057_CPG_H__ */