/*
 * r8a7779 Core CPG Clocks
 *
 * Copyright (C) 2013, 2014 Horms Solutions Ltd.
 *
 * Contact: Simon Horman <horms@verge.net.au>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; version 2 of the License.
 */

#include <linux/clk-provider.h>
#include <linux/clk/renesas.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/slab.h>
#include <linux/spinlock.h>

#include <dt-bindings/clock/r8a7779-clock.h>

#define CPG_NUM_CLOCKS			(R8A7779_CLK_OUT + 1)

struct r8a7779_cpg {
	struct clk_onecell_data data;
	spinlock_t lock;
	void __iomem *reg;
};

/* -----------------------------------------------------------------------------
 * CPG Clock Data
 */

/*
 *		MD1 = 1			MD1 = 0
 *		(PLLA = 1500)		(PLLA = 1600)
 *		(MHz)			(MHz)
 *------------------------------------------------+--------------------
 * clkz		1000   (2/3)		800   (1/2)
 * clkzs	 250   (1/6)		200   (1/8)
 * clki		 750   (1/2)		800   (1/2)
 * clks		 250   (1/6)		200   (1/8)
 * clks1	 125   (1/12)		100   (1/16)
 * clks3	 187.5 (1/8)		200   (1/8)
 * clks4	  93.7 (1/16)		100   (1/16)
 * clkp		  62.5 (1/24)		 50   (1/32)
 * clkg		  62.5 (1/24)		 66.6 (1/24)
 * clkb, CLKOUT
 * (MD2 = 0)	  62.5 (1/24)		 66.6 (1/24)
 * (MD2 = 1)	  41.6 (1/36)		 50   (1/32)
 */

#define CPG_CLK_CONFIG_INDEX(md)	(((md) & (BIT(2)|BIT(1))) >> 1)

struct cpg_clk_config {
	unsigned int z_mult;
	unsigned int z_div;
	unsigned int zs_and_s_div;
	unsigned int s1_div;
	unsigned int p_div;
	unsigned int b_and_out_div;
};

static const struct cpg_clk_config cpg_clk_configs[4] __initconst = {
	{ 1, 2, 8, 16, 32, 24 },
	{ 2, 3, 6, 12, 24, 24 },
	{ 1, 2, 8, 16, 32, 32 },
	{ 2, 3, 6, 12, 24, 36 },
};

/*
 *   MD		PLLA Ratio
 * 12 11
 *------------------------
 * 0  0		x42
 * 0  1		x48
 * 1  0		x56
 * 1  1		x64
 */

#define CPG_PLLA_MULT_INDEX(md)	(((md) & (BIT(12)|BIT(11))) >> 11)

static const unsigned int cpg_plla_mult[4] __initconst = { 42, 48, 56, 64 };

/* -----------------------------------------------------------------------------
 * Initialization
 */

static u32 cpg_mode __initdata;

static struct clk * __init
r8a7779_cpg_register_clock(struct device_node *np, struct r8a7779_cpg *cpg,
			   const struct cpg_clk_config *config,
			   unsigned int plla_mult, const char *name)
{
	const char *parent_name = "plla";
	unsigned int mult = 1;
	unsigned int div = 1;

	if (!strcmp(name, "plla")) {
		parent_name = of_clk_get_parent_name(np, 0);
		mult = plla_mult;
	} else if (!strcmp(name, "z")) {
		div = config->z_div;
		mult = config->z_mult;
	} else if (!strcmp(name, "zs") || !strcmp(name, "s")) {
		div = config->zs_and_s_div;
	} else if (!strcmp(name, "s1")) {
		div = config->s1_div;
	} else if (!strcmp(name, "p")) {
		div = config->p_div;
	} else if (!strcmp(name, "b") || !strcmp(name, "out")) {
		div = config->b_and_out_div;
	} else {
		return ERR_PTR(-EINVAL);
	}

	return clk_register_fixed_factor(NULL, name, parent_name, 0, mult, div);
}

static void __init r8a7779_cpg_clocks_init(struct device_node *np)
{
	const struct cpg_clk_config *config;
	struct r8a7779_cpg *cpg;
	struct clk **clks;
	unsigned int i, plla_mult;
	int num_clks;

	num_clks = of_property_count_strings(np, "clock-output-names");
	if (num_clks < 0) {
		pr_err("%s: failed to count clocks\n", __func__);
		return;
	}

	cpg = kzalloc(sizeof(*cpg), GFP_KERNEL);
	clks = kzalloc(CPG_NUM_CLOCKS * sizeof(*clks), GFP_KERNEL);
	if (cpg == NULL || clks == NULL) {
		/* We're leaking memory on purpose, there's no point in cleaning
		 * up as the system won't boot anyway.
		 */
		return;
	}

	spin_lock_init(&cpg->lock);

	cpg->data.clks = clks;
	cpg->data.clk_num = num_clks;

	config = &cpg_clk_configs[CPG_CLK_CONFIG_INDEX(cpg_mode)];
	plla_mult = cpg_plla_mult[CPG_PLLA_MULT_INDEX(cpg_mode)];

	for (i = 0; i < num_clks; ++i) {
		const char *name;
		struct clk *clk;

		of_property_read_string_index(np, "clock-output-names", i,
					      &name);

		clk = r8a7779_cpg_register_clock(np, cpg, config,
						 plla_mult, name);
		if (IS_ERR(clk))
			pr_err("%s: failed to register %s %s clock (%ld)\n",
			       __func__, np->name, name, PTR_ERR(clk));
		else
			cpg->data.clks[i] = clk;
	}

	of_clk_add_provider(np, of_clk_src_onecell_get, &cpg->data);

	cpg_mstp_add_clk_domain(np);
}
CLK_OF_DECLARE(r8a7779_cpg_clks, "renesas,r8a7779-cpg-clocks",
	       r8a7779_cpg_clocks_init);

void __init r8a7779_clocks_init(u32 mode)
{
	cpg_mode = mode;

	of_clk_init(NULL);
}