clk: renesas: Add RZ/G2L & RZ/G2LC CPG driver

This driver provides clock and reset control for the Renesas R9A07G044L
(RZ/G2L) and R9A07G044C (RZ/G2LC) SoC. It consists of two parts:

* driver code which is applicable to all SoCs in the RZ/G2L family.

* static data describing the clocks and resets which are specific to the
  R9A07G044{L,C} SoCs. The identifier r9a07g044 (without a final letter)
  is used to indicate that both SoCs are supported.

clk_set_rate() and clk_get_rate() are implemented only for the clocks
that are actually used in u-boot.

The CPG driver is marked with DM_FLAG_PRE_RELOC to ensure that its bind
function is called before the SCIF (serial port) driver is probed. This
is required so that we can de-assert the relevant reset signal during
the serial driver probe function.

This patch is based on the corresponding Linux v6.5 driver
(commit 52e12027d50affbf60c6c9c64db8017391b0c22e).

Signed-off-by: Paul Barker <paul.barker.ct@bp.renesas.com>
Reviewed-by: Biju Das <biju.das.jz@bp.renesas.com>
Reviewed-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Reviewed-by: Marek Vasut <marek.vasut+renesas@mailbox.org>
diff --git a/drivers/clk/renesas/rzg2l-cpg.h b/drivers/clk/renesas/rzg2l-cpg.h
new file mode 100644
index 0000000..7cb6c48
--- /dev/null
+++ b/drivers/clk/renesas/rzg2l-cpg.h
@@ -0,0 +1,319 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * RZ/G2L Clock Pulse Generator
+ *
+ * Copyright (C) 2021-2023 Renesas Electronics Corp.
+ *
+ */
+
+#ifndef __RENESAS_RZG2L_CPG_H__
+#define __RENESAS_RZG2L_CPG_H__
+
+#define CPG_SIPLL5_STBY		0x140
+#define CPG_SIPLL5_CLK1		0x144
+#define CPG_SIPLL5_CLK3		0x14C
+#define CPG_SIPLL5_CLK4		0x150
+#define CPG_SIPLL5_CLK5		0x154
+#define CPG_SIPLL5_MON		0x15C
+#define CPG_PL1_DDIV		0x200
+#define CPG_PL2_DDIV		0x204
+#define CPG_PL3A_DDIV		0x208
+#define CPG_PL6_DDIV		0x210
+#define CPG_PL2SDHI_DSEL	0x218
+#define CPG_CLKSTATUS		0x280
+#define CPG_PL3_SSEL		0x408
+#define CPG_PL6_SSEL		0x414
+#define CPG_PL6_ETH_SSEL	0x418
+#define CPG_PL5_SDIV		0x420
+#define CPG_RST_MON		0x680
+#define CPG_OTHERFUNC1_REG	0xBE8
+
+#define CPG_SIPLL5_STBY_RESETB		BIT(0)
+#define CPG_SIPLL5_STBY_RESETB_WEN	BIT(16)
+#define CPG_SIPLL5_STBY_SSCG_EN_WEN	BIT(18)
+#define CPG_SIPLL5_STBY_DOWNSPREAD_WEN	BIT(20)
+#define CPG_SIPLL5_CLK4_RESV_LSB	0xFF
+#define CPG_SIPLL5_MON_PLL5_LOCK	BIT(4)
+
+#define CPG_OTHERFUNC1_REG_RES0_ON_WEN	BIT(16)
+
+#define CPG_PL5_SDIV_DIV_DSI_A_WEN	BIT(16)
+#define CPG_PL5_SDIV_DIV_DSI_B_WEN	BIT(24)
+
+#define CPG_CLKSTATUS_SELSDHI0_STS	BIT(28)
+#define CPG_CLKSTATUS_SELSDHI1_STS	BIT(29)
+
+#define CPG_SDHI_CLK_SWITCH_STATUS_TIMEOUT_US	20000
+
+/* n = 0/1/2 for PLL1/4/6 */
+#define CPG_SAMPLL_CLK1(n)	(0x04 + (16 * (n)))
+#define CPG_SAMPLL_CLK2(n)	(0x08 + (16 * (n)))
+
+#define PLL146_CONF(n)	(CPG_SAMPLL_CLK1(n) << 22 | CPG_SAMPLL_CLK2(n) << 12)
+
+#define DDIV_PACK(offset, bitpos, size) \
+		(((offset) << 20) | ((bitpos) << 12) | ((size) << 8))
+#define DIVPL1A		DDIV_PACK(CPG_PL1_DDIV, 0, 2)
+#define DIVPL2A		DDIV_PACK(CPG_PL2_DDIV, 0, 3)
+#define DIVDSILPCLK	DDIV_PACK(CPG_PL2_DDIV, 12, 2)
+#define DIVPL3A		DDIV_PACK(CPG_PL3A_DDIV, 0, 3)
+#define DIVPL3B		DDIV_PACK(CPG_PL3A_DDIV, 4, 3)
+#define DIVPL3C		DDIV_PACK(CPG_PL3A_DDIV, 8, 3)
+#define DIVGPU		DDIV_PACK(CPG_PL6_DDIV, 0, 2)
+
+#define SEL_PLL_PACK(offset, bitpos, size) \
+		(((offset) << 20) | ((bitpos) << 12) | ((size) << 8))
+
+#define SEL_PLL3_3	SEL_PLL_PACK(CPG_PL3_SSEL, 8, 1)
+#define SEL_PLL5_4	SEL_PLL_PACK(CPG_OTHERFUNC1_REG, 0, 1)
+#define SEL_PLL6_2	SEL_PLL_PACK(CPG_PL6_ETH_SSEL, 0, 1)
+#define SEL_GPU2	SEL_PLL_PACK(CPG_PL6_SSEL, 12, 1)
+
+#define SEL_SDHI0	DDIV_PACK(CPG_PL2SDHI_DSEL, 0, 2)
+#define SEL_SDHI1	DDIV_PACK(CPG_PL2SDHI_DSEL, 4, 2)
+
+#define SEL_SDHI_533MHz		1
+#define SEL_SDHI_400MHz		2
+#define SEL_SDHI_266MHz		3
+#define SEL_SDHI_WRITE_ENABLE	0x10000
+
+/* Unpack CPG conf value create by DDIV_PACK() or SEL_PLL_PACK(). */
+#define CPG_CONF_OFFSET(x)	((x) >> 20)
+#define CPG_CONF_BITPOS(x)	(((x) >> 12) & 0xff)
+#define CPG_CONF_SIZE(x)	(((x) >> 8) & 0xf)
+#define CPG_CONF_BITMASK(x)	GENMASK(CPG_CONF_SIZE(x) - 1, 0)
+
+#define EXTAL_FREQ_IN_MEGA_HZ	24
+
+/**
+ * Definitions of CPG Core Clocks
+ *
+ * These include:
+ *   - Clock outputs exported to DT
+ *   - External input clocks
+ *   - Internal CPG clocks
+ */
+struct cpg_core_clk {
+	const char *name;
+	unsigned int id;
+	unsigned int parent;
+	unsigned int div;
+	unsigned int mult;
+	unsigned int type;
+	unsigned int conf;
+	const struct clk_div_table *dtable;
+	const char * const *parent_names;
+	int flag;
+	int mux_flags;
+	int num_parents;
+};
+
+enum clk_types {
+	/* Generic */
+	CLK_TYPE_IN,		/* External Clock Input */
+	CLK_TYPE_FF,		/* Fixed Factor Clock */
+	CLK_TYPE_SAM_PLL,
+
+	/* Clock with divider */
+	CLK_TYPE_DIV,
+
+	/* Clock with clock source selector */
+	CLK_TYPE_MUX,
+
+	/* Clock with SD clock source selector */
+	CLK_TYPE_SD_MUX,
+
+	/* Clock for SIPLL5 */
+	CLK_TYPE_SIPLL5,
+
+	/* Clock for PLL5_4 clock source selector */
+	CLK_TYPE_PLL5_4_MUX,
+
+	/* Clock for DSI divider */
+	CLK_TYPE_DSI_DIV,
+
+};
+
+#define DEF_TYPE(_name, _id, _type...) \
+	{ .name = _name, .id = _id, .type = _type }
+#define DEF_BASE(_name, _id, _type, _parent...) \
+	DEF_TYPE(_name, _id, _type, .parent = _parent)
+#define DEF_SAMPLL(_name, _id, _parent, _conf) \
+	DEF_TYPE(_name, _id, CLK_TYPE_SAM_PLL, .parent = _parent, .conf = _conf)
+#define DEF_INPUT(_name, _id) \
+	DEF_TYPE(_name, _id, CLK_TYPE_IN)
+#define DEF_FIXED(_name, _id, _parent, _mult, _div) \
+	DEF_BASE(_name, _id, CLK_TYPE_FF, _parent, .div = _div, .mult = _mult)
+#define DEF_DIV(_name, _id, _parent, _conf, _dtable) \
+	DEF_TYPE(_name, _id, CLK_TYPE_DIV, .conf = _conf, \
+		 .parent = _parent, .dtable = _dtable, \
+		 .flag = CLK_DIVIDER_HIWORD_MASK)
+#define DEF_DIV_RO(_name, _id, _parent, _conf, _dtable) \
+	DEF_TYPE(_name, _id, CLK_TYPE_DIV, .conf = _conf, \
+		 .parent = _parent, .dtable = _dtable, \
+		 .flag = CLK_DIVIDER_READ_ONLY)
+#define DEF_MUX(_name, _id, _conf, _parent_names) \
+	DEF_TYPE(_name, _id, CLK_TYPE_MUX, .conf = _conf, \
+		 .parent_names = _parent_names, \
+		 .num_parents = ARRAY_SIZE(_parent_names), \
+		 .mux_flags = CLK_MUX_HIWORD_MASK)
+#define DEF_MUX_RO(_name, _id, _conf, _parent_names) \
+	DEF_TYPE(_name, _id, CLK_TYPE_MUX, .conf = _conf, \
+		 .parent_names = _parent_names, \
+		 .num_parents = ARRAY_SIZE(_parent_names), \
+		 .mux_flags = CLK_MUX_READ_ONLY)
+#define DEF_SD_MUX(_name, _id, _conf, _parent_names) \
+	DEF_TYPE(_name, _id, CLK_TYPE_SD_MUX, .conf = _conf, \
+		 .parent_names = _parent_names, \
+		 .num_parents = ARRAY_SIZE(_parent_names))
+#define DEF_PLL5_FOUTPOSTDIV(_name, _id, _parent) \
+	DEF_TYPE(_name, _id, CLK_TYPE_SIPLL5, .parent = _parent)
+#define DEF_PLL5_4_MUX(_name, _id, _conf, _parent_names) \
+	DEF_TYPE(_name, _id, CLK_TYPE_PLL5_4_MUX, .conf = _conf, \
+		 .parent_names = _parent_names, \
+		 .num_parents = ARRAY_SIZE(_parent_names))
+#define DEF_DSI_DIV(_name, _id, _parent, _flag) \
+	DEF_TYPE(_name, _id, CLK_TYPE_DSI_DIV, .parent = _parent, .flag = _flag)
+
+/**
+ * struct rzg2l_mod_clk - Module Clocks definitions
+ *
+ * @name: handle between common and hardware-specific interfaces
+ * @id: clock index in array containing all Core and Module Clocks
+ * @parent: id of parent clock
+ * @off: register offset
+ * @bit: ON/MON bit
+ * @is_coupled: flag to indicate coupled clock
+ */
+struct rzg2l_mod_clk {
+	const char *name;
+	unsigned int id;
+	unsigned int parent;
+	u16 off;
+	u8 bit;
+	bool is_coupled;
+};
+
+#define DEF_MOD_BASE(_name, _id, _parent, _off, _bit, _is_coupled)	\
+	{ \
+		.name = (_name), \
+		.id = (_id), \
+		.parent = (_parent), \
+		.off = (_off), \
+		.bit = (_bit), \
+		.is_coupled = (_is_coupled), \
+	}
+
+#define DEF_MOD(_name, _id, _parent, _off, _bit)	\
+	DEF_MOD_BASE(_name, _id, _parent, _off, _bit, false)
+
+#define DEF_COUPLED(_name, _id, _parent, _off, _bit)	\
+	DEF_MOD_BASE(_name, _id, _parent, _off, _bit, true)
+
+/**
+ * struct rzg2l_reset - Reset definitions
+ *
+ * @off: register offset
+ * @bit: reset bit
+ * @monbit: monitor bit in CPG_RST_MON register, -1 if none
+ */
+struct rzg2l_reset {
+	u16 off;
+	u8 bit;
+	s8 monbit;
+};
+
+#define DEF_RST_MON(_id, _off, _bit, _monbit)	\
+	[_id] = { \
+		.off = (_off), \
+		.bit = (_bit), \
+		.monbit = (_monbit) \
+	}
+#define DEF_RST(_id, _off, _bit)	\
+	DEF_RST_MON(_id, _off, _bit, -1)
+
+/**
+ * struct rzg2l_cpg_info - SoC-specific CPG Description
+ *
+ * @core_clks: Array of Core Clock definitions
+ * @num_core_clks: Number of entries in core_clks[]
+ *
+ * @mod_clks: Array of Module Clock definitions
+ * @num_mod_clks: Number of entries in mod_clks[]
+ * @num_hw_mod_clks: Number of Module Clocks supported by the hardware
+ *
+ * @resets: Array of Module Reset definitions
+ * @num_resets: Number of entries in resets[]
+ *
+ * @has_clk_mon_regs: Flag indicating whether the SoC has CLK_MON registers
+ */
+struct rzg2l_cpg_info {
+	/* Core Clocks */
+	const struct cpg_core_clk *core_clks;
+	unsigned int num_core_clks;
+
+	/* Module Clocks */
+	const struct rzg2l_mod_clk *mod_clks;
+	unsigned int num_mod_clks;
+	unsigned int num_hw_mod_clks;
+
+	/* Resets */
+	const struct rzg2l_reset *resets;
+	unsigned int num_resets;
+
+	bool has_clk_mon_regs;
+};
+
+extern const struct rzg2l_cpg_info r9a07g044_cpg_info;
+
+int rzg2l_cpg_bind(struct udevice *parent);
+
+/*
+ * Clock IDs start at an offset to avoid overlapping with core & module clock
+ * IDs defined in the dt-bindings headers.
+ */
+enum clk_ids {
+	/* External Input Clocks */
+	CLK_EXTAL = 0x100,
+
+	/* Internal Core Clocks */
+	CLK_OSC_DIV1000 = 0x200,
+	CLK_PLL1,
+	CLK_PLL2,
+	CLK_PLL2_DIV2,
+	CLK_PLL2_DIV2_8,
+	CLK_PLL2_DIV2_10,
+	CLK_PLL3,
+	CLK_PLL3_400,
+	CLK_PLL3_533,
+	CLK_M2_DIV2,
+	CLK_PLL3_DIV2,
+	CLK_PLL3_DIV2_2,
+	CLK_PLL3_DIV2_4,
+	CLK_PLL3_DIV2_4_2,
+	CLK_SEL_PLL3_3,
+	CLK_DIV_PLL3_C,
+	CLK_PLL4,
+	CLK_PLL5,
+	CLK_PLL5_FOUTPOSTDIV,
+	CLK_PLL5_FOUT1PH0,
+	CLK_PLL5_FOUT3,
+	CLK_PLL5_250,
+	CLK_PLL6,
+	CLK_PLL6_250,
+	CLK_P1_DIV2,
+	CLK_PLL2_800,
+	CLK_PLL2_SDHI_533,
+	CLK_PLL2_SDHI_400,
+	CLK_PLL2_SDHI_266,
+	CLK_SD0_DIV4,
+	CLK_SD1_DIV4,
+	CLK_SEL_GPU2,
+	CLK_SEL_PLL5_4,
+	CLK_DSI_DIV,
+	CLK_PLL2_533,
+	CLK_PLL2_533_DIV2,
+	CLK_DIV_DSI_LPCLK,
+};
+
+#endif