// SPDX-License-Identifier: GPL-2.0
//
// Spreadtrum gate clock driver
//
// Copyright (C) 2017 Spreadtrum, Inc.
// Author: Chunyan Zhang <chunyan.zhang@spreadtrum.com>

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

#include "gate.h"

static void clk_gate_toggle(const struct sprd_gate *sg, bool en)
{
        const struct sprd_clk_common *common = &sg->common;
        unsigned int reg;
        bool set = sg->flags & CLK_GATE_SET_TO_DISABLE ? true : false;

        set ^= en;

        regmap_read(common->regmap, common->reg, &reg);

        if (set)
                reg |= sg->enable_mask;
        else
                reg &= ~sg->enable_mask;

        regmap_write(common->regmap, common->reg, reg);
}

static void clk_sc_gate_toggle(const struct sprd_gate *sg, bool en)
{
        const struct sprd_clk_common *common = &sg->common;
        bool set = sg->flags & CLK_GATE_SET_TO_DISABLE ? 1 : 0;
        unsigned int offset;

        set ^= en;

        /*
         * Each set/clear gate clock has three registers:
         * common->reg                  - base register
         * common->reg + offset         - set register
         * common->reg + 2 * offset     - clear register
         */
        offset = set ? sg->sc_offset : sg->sc_offset * 2;

        regmap_write(common->regmap, common->reg + offset,
                          sg->enable_mask);
}

static void sprd_gate_disable(struct clk_hw *hw)
{
        struct sprd_gate *sg = hw_to_sprd_gate(hw);

        clk_gate_toggle(sg, false);
}

static int sprd_gate_enable(struct clk_hw *hw)
{
        struct sprd_gate *sg = hw_to_sprd_gate(hw);

        clk_gate_toggle(sg, true);

        return 0;
}

static void sprd_sc_gate_disable(struct clk_hw *hw)
{
        struct sprd_gate *sg = hw_to_sprd_gate(hw);

        clk_sc_gate_toggle(sg, false);
}

static int sprd_sc_gate_enable(struct clk_hw *hw)
{
        struct sprd_gate *sg = hw_to_sprd_gate(hw);

        clk_sc_gate_toggle(sg, true);

        return 0;
}

static int sprd_pll_sc_gate_prepare(struct clk_hw *hw)
{
        struct sprd_gate *sg = hw_to_sprd_gate(hw);

        clk_sc_gate_toggle(sg, true);
        udelay(sg->udelay);

        return 0;
}

static int sprd_gate_is_enabled(struct clk_hw *hw)
{
        struct sprd_gate *sg = hw_to_sprd_gate(hw);
        struct sprd_clk_common *common = &sg->common;
        struct clk_hw *parent;
        unsigned int reg;

        if (sg->flags & SPRD_GATE_NON_AON) {
                parent = clk_hw_get_parent(hw);
                if (!parent || !clk_hw_is_enabled(parent))
                        return 0;
        }

        regmap_read(common->regmap, common->reg, &reg);

        if (sg->flags & CLK_GATE_SET_TO_DISABLE)
                reg ^= sg->enable_mask;

        reg &= sg->enable_mask;

        return reg ? 1 : 0;
}

const struct clk_ops sprd_gate_ops = {
        .disable        = sprd_gate_disable,
        .enable         = sprd_gate_enable,
        .is_enabled     = sprd_gate_is_enabled,
};
EXPORT_SYMBOL_GPL(sprd_gate_ops);

const struct clk_ops sprd_sc_gate_ops = {
        .disable        = sprd_sc_gate_disable,
        .enable         = sprd_sc_gate_enable,
        .is_enabled     = sprd_gate_is_enabled,
};
EXPORT_SYMBOL_GPL(sprd_sc_gate_ops);

const struct clk_ops sprd_pll_sc_gate_ops = {
        .unprepare      = sprd_sc_gate_disable,
        .prepare        = sprd_pll_sc_gate_prepare,
        .is_enabled     = sprd_gate_is_enabled,
};
EXPORT_SYMBOL_GPL(sprd_pll_sc_gate_ops);