// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Copyright (C) 2016 Socionext Inc.
 *   Author: Masahiro Yamada <yamada.masahiro@socionext.com>
 */

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

#include "clk-uniphier.h"

#define UNIPHIER_CLK_CPUGEAR_STAT       0       /* status */
#define UNIPHIER_CLK_CPUGEAR_SET        4       /* set */
#define UNIPHIER_CLK_CPUGEAR_UPD        8       /* update */
#define   UNIPHIER_CLK_CPUGEAR_UPD_BIT  BIT(0)

struct uniphier_clk_cpugear {
        struct clk_hw hw;
        struct regmap *regmap;
        unsigned int regbase;
        unsigned int mask;
};

#define to_uniphier_clk_cpugear(_hw) \
                        container_of(_hw, struct uniphier_clk_cpugear, hw)

static int uniphier_clk_cpugear_set_parent(struct clk_hw *hw, u8 index)
{
        struct uniphier_clk_cpugear *gear = to_uniphier_clk_cpugear(hw);
        int ret;
        unsigned int val;

        ret = regmap_write_bits(gear->regmap,
                                gear->regbase + UNIPHIER_CLK_CPUGEAR_SET,
                                gear->mask, index);
        if (ret)
                return ret;

        ret = regmap_write_bits(gear->regmap,
                                gear->regbase + UNIPHIER_CLK_CPUGEAR_UPD,
                                UNIPHIER_CLK_CPUGEAR_UPD_BIT,
                                UNIPHIER_CLK_CPUGEAR_UPD_BIT);
        if (ret)
                return ret;

        return regmap_read_poll_timeout(gear->regmap,
                                gear->regbase + UNIPHIER_CLK_CPUGEAR_UPD,
                                val, !(val & UNIPHIER_CLK_CPUGEAR_UPD_BIT),
                                0, 1);
}

static u8 uniphier_clk_cpugear_get_parent(struct clk_hw *hw)
{
        struct uniphier_clk_cpugear *gear = to_uniphier_clk_cpugear(hw);
        int num_parents = clk_hw_get_num_parents(hw);
        int ret;
        unsigned int val;

        ret = regmap_read(gear->regmap,
                          gear->regbase + UNIPHIER_CLK_CPUGEAR_STAT, &val);
        if (ret)
                return ret;

        val &= gear->mask;

        return val < num_parents ? val : -EINVAL;
}

static const struct clk_ops uniphier_clk_cpugear_ops = {
        .determine_rate = __clk_mux_determine_rate,
        .set_parent = uniphier_clk_cpugear_set_parent,
        .get_parent = uniphier_clk_cpugear_get_parent,
};

struct clk_hw *uniphier_clk_register_cpugear(struct device *dev,
                                         struct regmap *regmap,
                                         const char *name,
                                const struct uniphier_clk_cpugear_data *data)
{
        struct uniphier_clk_cpugear *gear;
        struct clk_init_data init;
        int ret;

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

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

        gear->regmap = regmap;
        gear->regbase = data->regbase;
        gear->mask = data->mask;
        gear->hw.init = &init;

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

        return &gear->hw;
}