// SPDX-License-Identifier: GPL-2.0-only
/*
 *  Copyright Intel Corporation (C) 2017. All Rights Reserved
 *
 * Reset driver for Altera Arria10 MAX5 System Resource Chip
 *
 * Adapted from reset-socfpga.c
 */

#include <linux/err.h>
#include <linux/mfd/altera-a10sr.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/reset-controller.h>

#include <dt-bindings/reset/altr,rst-mgr-a10sr.h>

struct a10sr_reset {
        struct reset_controller_dev     rcdev;
        struct regmap *regmap;
};

static inline struct a10sr_reset *to_a10sr_rst(struct reset_controller_dev *rc)
{
        return container_of(rc, struct a10sr_reset, rcdev);
}

static inline int a10sr_reset_shift(unsigned long id)
{
        switch (id) {
        case A10SR_RESET_ENET_HPS:
                return 1;
        case A10SR_RESET_PCIE:
        case A10SR_RESET_FILE:
        case A10SR_RESET_BQSPI:
        case A10SR_RESET_USB:
                return id + 11;
        default:
                return -EINVAL;
        }
}

static int a10sr_reset_update(struct reset_controller_dev *rcdev,
                              unsigned long id, bool assert)
{
        struct a10sr_reset *a10r = to_a10sr_rst(rcdev);
        int offset = a10sr_reset_shift(id);
        u8 mask = ALTR_A10SR_REG_BIT_MASK(offset);
        int index = ALTR_A10SR_HPS_RST_REG + ALTR_A10SR_REG_OFFSET(offset);

        return regmap_update_bits(a10r->regmap, index, mask, assert ? 0 : mask);
}

static int a10sr_reset_assert(struct reset_controller_dev *rcdev,
                              unsigned long id)
{
        return a10sr_reset_update(rcdev, id, true);
}

static int a10sr_reset_deassert(struct reset_controller_dev *rcdev,
                                unsigned long id)
{
        return a10sr_reset_update(rcdev, id, false);
}

static int a10sr_reset_status(struct reset_controller_dev *rcdev,
                              unsigned long id)
{
        int ret;
        struct a10sr_reset *a10r = to_a10sr_rst(rcdev);
        int offset = a10sr_reset_shift(id);
        u8 mask = ALTR_A10SR_REG_BIT_MASK(offset);
        int index = ALTR_A10SR_HPS_RST_REG + ALTR_A10SR_REG_OFFSET(offset);
        unsigned int value;

        ret = regmap_read(a10r->regmap, index, &value);
        if (ret < 0)
                return ret;

        return !!(value & mask);
}

static const struct reset_control_ops a10sr_reset_ops = {
        .assert         = a10sr_reset_assert,
        .deassert       = a10sr_reset_deassert,
        .status         = a10sr_reset_status,
};

static int a10sr_reset_probe(struct platform_device *pdev)
{
        struct altr_a10sr *a10sr = dev_get_drvdata(pdev->dev.parent);
        struct a10sr_reset *a10r;

        a10r = devm_kzalloc(&pdev->dev, sizeof(struct a10sr_reset),
                            GFP_KERNEL);
        if (!a10r)
                return -ENOMEM;

        a10r->rcdev.owner = THIS_MODULE;
        a10r->rcdev.nr_resets = A10SR_RESET_NUM;
        a10r->rcdev.ops = &a10sr_reset_ops;
        a10r->rcdev.of_node = pdev->dev.of_node;
        a10r->regmap = a10sr->regmap;

        platform_set_drvdata(pdev, a10r);

        return devm_reset_controller_register(&pdev->dev, &a10r->rcdev);
}

static const struct of_device_id a10sr_reset_of_match[] = {
        { .compatible = "altr,a10sr-reset" },
        { },
};
MODULE_DEVICE_TABLE(of, a10sr_reset_of_match);

static struct platform_driver a10sr_reset_driver = {
        .probe  = a10sr_reset_probe,
        .driver = {
                .name           = "altr_a10sr_reset",
                .of_match_table = a10sr_reset_of_match,
        },
};
module_platform_driver(a10sr_reset_driver);

MODULE_AUTHOR("Thor Thayer <thor.thayer@linux.intel.com>");
MODULE_DESCRIPTION("Altera Arria10 System Resource Reset Controller Driver");
MODULE_LICENSE("GPL v2");