/*
 * Copyright (C) 2016 Socionext Inc.
 *   Author: Masahiro Yamada <yamada.masahiro@socionext.com>
 *
 * 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; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 */

#include <linux/clk-provider.h>
#include <linux/device.h>
#include <linux/regmap.h>

#include "clk-uniphier.h"

struct uniphier_clk_mux {
	struct clk_hw hw;
	struct regmap *regmap;
	unsigned int reg;
	const unsigned int *masks;
	const unsigned int *vals;
};

#define to_uniphier_clk_mux(_hw) container_of(_hw, struct uniphier_clk_mux, hw)

static int uniphier_clk_mux_set_parent(struct clk_hw *hw, u8 index)
{
	struct uniphier_clk_mux *mux = to_uniphier_clk_mux(hw);

	return regmap_write_bits(mux->regmap, mux->reg, mux->masks[index],
				 mux->vals[index]);
}

static u8 uniphier_clk_mux_get_parent(struct clk_hw *hw)
{
	struct uniphier_clk_mux *mux = to_uniphier_clk_mux(hw);
	unsigned int num_parents = clk_hw_get_num_parents(hw);
	int ret;
	unsigned int val;
	unsigned int i;

	ret = regmap_read(mux->regmap, mux->reg, &val);
	if (ret)
		return ret;

	for (i = 0; i < num_parents; i++)
		if ((mux->masks[i] & val) == mux->vals[i])
			return i;

	return -EINVAL;
}

static const struct clk_ops uniphier_clk_mux_ops = {
	.determine_rate = __clk_mux_determine_rate,
	.set_parent = uniphier_clk_mux_set_parent,
	.get_parent = uniphier_clk_mux_get_parent,
};

struct clk_hw *uniphier_clk_register_mux(struct device *dev,
					 struct regmap *regmap,
					 const char *name,
				const struct uniphier_clk_mux_data *data)
{
	struct uniphier_clk_mux *mux;
	struct clk_init_data init = {};
	int ret;

	mux = devm_kzalloc(dev, sizeof(*mux), GFP_KERNEL);
	if (!mux)
		return ERR_PTR(-ENOMEM);

	init.name = name;
	init.ops = &uniphier_clk_mux_ops;
	init.flags = CLK_SET_RATE_PARENT;
	init.parent_names = data->parent_names;
	init.num_parents = data->num_parents,

	mux->regmap = regmap;
	mux->reg = data->reg;
	mux->masks = data->masks;
	mux->vals = data->vals;
	mux->hw.init = &init;

	ret = devm_clk_hw_register(dev, &mux->hw);
	if (ret)
		return ERR_PTR(ret);

	return &mux->hw;
}