// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Copyright (c) 2016-2017 Linaro Ltd.
 * Copyright (c) 2016-2017 HiSilicon Technologies Co., Ltd.
 */
#include <linux/kernel.h>
#include <linux/mfd/syscon.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/regmap.h>
#include <linux/reset-controller.h>

struct hi3660_reset_controller {
        struct reset_controller_dev rst;
        struct regmap *map;
};

#define to_hi3660_reset_controller(_rst) \
        container_of(_rst, struct hi3660_reset_controller, rst)

static int hi3660_reset_program_hw(struct reset_controller_dev *rcdev,
                                   unsigned long idx, bool assert)
{
        struct hi3660_reset_controller *rc = to_hi3660_reset_controller(rcdev);
        unsigned int offset = idx >> 8;
        unsigned int mask = BIT(idx & 0x1f);

        if (assert)
                return regmap_write(rc->map, offset, mask);
        else
                return regmap_write(rc->map, offset + 4, mask);
}

static int hi3660_reset_assert(struct reset_controller_dev *rcdev,
                               unsigned long idx)
{
        return hi3660_reset_program_hw(rcdev, idx, true);
}

static int hi3660_reset_deassert(struct reset_controller_dev *rcdev,
                                 unsigned long idx)
{
        return hi3660_reset_program_hw(rcdev, idx, false);
}

static int hi3660_reset_dev(struct reset_controller_dev *rcdev,
                            unsigned long idx)
{
        int err;

        err = hi3660_reset_assert(rcdev, idx);
        if (err)
                return err;

        return hi3660_reset_deassert(rcdev, idx);
}

static const struct reset_control_ops hi3660_reset_ops = {
        .reset    = hi3660_reset_dev,
        .assert   = hi3660_reset_assert,
        .deassert = hi3660_reset_deassert,
};

static int hi3660_reset_xlate(struct reset_controller_dev *rcdev,
                              const struct of_phandle_args *reset_spec)
{
        unsigned int offset, bit;

        offset = reset_spec->args[0];
        bit = reset_spec->args[1];

        return (offset << 8) | bit;
}

static int hi3660_reset_probe(struct platform_device *pdev)
{
        struct hi3660_reset_controller *rc;
        struct device_node *np = pdev->dev.of_node;
        struct device *dev = &pdev->dev;

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

        rc->map = syscon_regmap_lookup_by_phandle(np, "hisilicon,rst-syscon");
        if (rc->map == ERR_PTR(-ENODEV)) {
                /* fall back to the deprecated compatible */
                rc->map = syscon_regmap_lookup_by_phandle(np,
                                                          "hisi,rst-syscon");
        }
        if (IS_ERR(rc->map)) {
                return dev_err_probe(dev, PTR_ERR(rc->map),
                        "failed to get hisilicon,rst-syscon\n");
        }

        rc->rst.ops = &hi3660_reset_ops,
        rc->rst.of_node = np;
        rc->rst.of_reset_n_cells = 2;
        rc->rst.of_xlate = hi3660_reset_xlate;

        return reset_controller_register(&rc->rst);
}

static const struct of_device_id hi3660_reset_match[] = {
        { .compatible = "hisilicon,hi3660-reset", },
        {},
};
MODULE_DEVICE_TABLE(of, hi3660_reset_match);

static struct platform_driver hi3660_reset_driver = {
        .probe = hi3660_reset_probe,
        .driver = {
                .name = "hi3660-reset",
                .of_match_table = hi3660_reset_match,
        },
};

static int __init hi3660_reset_init(void)
{
        return platform_driver_register(&hi3660_reset_driver);
}
arch_initcall(hi3660_reset_init);

MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:hi3660-reset");
MODULE_DESCRIPTION("HiSilicon Hi3660 Reset Driver");