// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (c) 2014 MediaTek Inc.
 */

#include <linux/mfd/syscon.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/regmap.h>
#include <linux/slab.h>

#include "reset.h"

static inline struct mtk_clk_rst_data *to_mtk_clk_rst_data(struct reset_controller_dev *rcdev)
{
        return container_of(rcdev, struct mtk_clk_rst_data, rcdev);
}

static int mtk_reset_update(struct reset_controller_dev *rcdev,
                            unsigned long id, bool deassert)
{
        struct mtk_clk_rst_data *data = to_mtk_clk_rst_data(rcdev);
        unsigned int val = deassert ? 0 : ~0;

        return regmap_update_bits(data->regmap,
                                  data->desc->rst_bank_ofs[id / RST_NR_PER_BANK],
                                  BIT(id % RST_NR_PER_BANK), val);
}

static int mtk_reset_assert(struct reset_controller_dev *rcdev,
                            unsigned long id)
{
        return mtk_reset_update(rcdev, id, false);
}

static int mtk_reset_deassert(struct reset_controller_dev *rcdev,
                              unsigned long id)
{
        return mtk_reset_update(rcdev, id, true);
}

static int mtk_reset(struct reset_controller_dev *rcdev, unsigned long id)
{
        int ret;

        ret = mtk_reset_assert(rcdev, id);
        if (ret)
                return ret;

        return mtk_reset_deassert(rcdev, id);
}

static int mtk_reset_update_set_clr(struct reset_controller_dev *rcdev,
                                    unsigned long id, bool deassert)
{
        struct mtk_clk_rst_data *data = to_mtk_clk_rst_data(rcdev);
        unsigned int deassert_ofs = deassert ? 0x4 : 0;

        return regmap_write(data->regmap,
                            data->desc->rst_bank_ofs[id / RST_NR_PER_BANK] +
                            deassert_ofs,
                            BIT(id % RST_NR_PER_BANK));
}

static int mtk_reset_assert_set_clr(struct reset_controller_dev *rcdev,
                                    unsigned long id)
{
        return mtk_reset_update_set_clr(rcdev, id, false);
}

static int mtk_reset_deassert_set_clr(struct reset_controller_dev *rcdev,
                                      unsigned long id)
{
        return mtk_reset_update_set_clr(rcdev, id, true);
}

static int mtk_reset_set_clr(struct reset_controller_dev *rcdev,
                             unsigned long id)
{
        int ret;

        ret = mtk_reset_assert_set_clr(rcdev, id);
        if (ret)
                return ret;
        return mtk_reset_deassert_set_clr(rcdev, id);
}

static const struct reset_control_ops mtk_reset_ops = {
        .assert = mtk_reset_assert,
        .deassert = mtk_reset_deassert,
        .reset = mtk_reset,
};

static const struct reset_control_ops mtk_reset_ops_set_clr = {
        .assert = mtk_reset_assert_set_clr,
        .deassert = mtk_reset_deassert_set_clr,
        .reset = mtk_reset_set_clr,
};

static int reset_xlate(struct reset_controller_dev *rcdev,
                       const struct of_phandle_args *reset_spec)
{
        struct mtk_clk_rst_data *data = to_mtk_clk_rst_data(rcdev);

        if (reset_spec->args[0] >= rcdev->nr_resets ||
            reset_spec->args[0] >= data->desc->rst_idx_map_nr)
                return -EINVAL;

        return data->desc->rst_idx_map[reset_spec->args[0]];
}

int mtk_register_reset_controller_with_dev(struct device *dev,
                                           const struct mtk_clk_rst_desc *desc)
{
        struct device_node *np = dev->of_node;
        struct regmap *regmap;
        const struct reset_control_ops *rcops = NULL;
        struct mtk_clk_rst_data *data;
        int ret;

        if (!desc) {
                dev_err(dev, "mtk clock reset desc is NULL\n");
                return -EINVAL;
        }

        switch (desc->version) {
        case MTK_RST_SIMPLE:
                rcops = &mtk_reset_ops;
                break;
        case MTK_RST_SET_CLR:
                rcops = &mtk_reset_ops_set_clr;
                break;
        default:
                dev_err(dev, "Unknown reset version %d\n", desc->version);
                return -EINVAL;
        }

        regmap = device_node_to_regmap(np);
        if (IS_ERR(regmap)) {
                dev_err(dev, "Cannot find regmap %pe\n", regmap);
                return PTR_ERR(regmap);
        }

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

        data->desc = desc;
        data->regmap = regmap;
        data->rcdev.owner = THIS_MODULE;
        data->rcdev.ops = rcops;
        data->rcdev.of_node = np;
        data->rcdev.dev = dev;

        if (data->desc->rst_idx_map_nr > 0) {
                data->rcdev.of_reset_n_cells = 1;
                data->rcdev.nr_resets = desc->rst_idx_map_nr;
                data->rcdev.of_xlate = reset_xlate;
        } else {
                data->rcdev.nr_resets = desc->rst_bank_nr * RST_NR_PER_BANK;
        }

        ret = devm_reset_controller_register(dev, &data->rcdev);
        if (ret) {
                dev_err(dev, "could not register reset controller: %d\n", ret);
                return ret;
        }

        return 0;
}
EXPORT_SYMBOL_GPL(mtk_register_reset_controller_with_dev);

MODULE_LICENSE("GPL");