// SPDX-License-Identifier: GPL-2.0-only
/*
 * Pistachio SoC Reset Controller driver
 *
 * Copyright (C) 2015 Imagination Technologies Ltd.
 *
 * Author: Damien Horsley <Damien.Horsley@imgtec.com>
 */

#include <linux/init.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/regmap.h>
#include <linux/reset-controller.h>
#include <linux/slab.h>
#include <linux/mfd/syscon.h>

#include <dt-bindings/reset/pistachio-resets.h>

#define PISTACHIO_SOFT_RESET            0

struct pistachio_reset_data {
        struct reset_controller_dev     rcdev;
        struct regmap                   *periph_regs;
};

static inline int pistachio_reset_shift(unsigned long id)
{
        switch (id) {
        case PISTACHIO_RESET_I2C0:
        case PISTACHIO_RESET_I2C1:
        case PISTACHIO_RESET_I2C2:
        case PISTACHIO_RESET_I2C3:
        case PISTACHIO_RESET_I2S_IN:
        case PISTACHIO_RESET_PRL_OUT:
        case PISTACHIO_RESET_SPDIF_OUT:
        case PISTACHIO_RESET_SPI:
        case PISTACHIO_RESET_PWM_PDM:
        case PISTACHIO_RESET_UART0:
        case PISTACHIO_RESET_UART1:
        case PISTACHIO_RESET_QSPI:
        case PISTACHIO_RESET_MDC:
        case PISTACHIO_RESET_SDHOST:
        case PISTACHIO_RESET_ETHERNET:
        case PISTACHIO_RESET_IR:
        case PISTACHIO_RESET_HASH:
        case PISTACHIO_RESET_TIMER:
                return id;
        case PISTACHIO_RESET_I2S_OUT:
        case PISTACHIO_RESET_SPDIF_IN:
        case PISTACHIO_RESET_EVT:
                return id + 6;
        case PISTACHIO_RESET_USB_H:
        case PISTACHIO_RESET_USB_PR:
        case PISTACHIO_RESET_USB_PHY_PR:
        case PISTACHIO_RESET_USB_PHY_PON:
                return id + 7;
        default:
                return -EINVAL;
        }
}

static int pistachio_reset_assert(struct reset_controller_dev *rcdev,
                                  unsigned long id)
{
        struct pistachio_reset_data *rd;
        u32 mask;
        int shift;

        rd = container_of(rcdev, struct pistachio_reset_data, rcdev);
        shift = pistachio_reset_shift(id);
        if (shift < 0)
                return shift;
        mask = BIT(shift);

        return regmap_update_bits(rd->periph_regs, PISTACHIO_SOFT_RESET,
                                  mask, mask);
}

static int pistachio_reset_deassert(struct reset_controller_dev *rcdev,
                                    unsigned long id)
{
        struct pistachio_reset_data *rd;
        u32 mask;
        int shift;

        rd = container_of(rcdev, struct pistachio_reset_data, rcdev);
        shift = pistachio_reset_shift(id);
        if (shift < 0)
                return shift;
        mask = BIT(shift);

        return regmap_update_bits(rd->periph_regs, PISTACHIO_SOFT_RESET,
                                  mask, 0);
}

static const struct reset_control_ops pistachio_reset_ops = {
        .assert         = pistachio_reset_assert,
        .deassert       = pistachio_reset_deassert,
};

static int pistachio_reset_probe(struct platform_device *pdev)
{
        struct pistachio_reset_data *rd;
        struct device *dev = &pdev->dev;
        struct device_node *np = pdev->dev.of_node;

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

        rd->periph_regs = syscon_node_to_regmap(np->parent);
        if (IS_ERR(rd->periph_regs))
                return PTR_ERR(rd->periph_regs);

        rd->rcdev.owner = THIS_MODULE;
        rd->rcdev.nr_resets = PISTACHIO_RESET_MAX + 1;
        rd->rcdev.ops = &pistachio_reset_ops;
        rd->rcdev.of_node = np;

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

static const struct of_device_id pistachio_reset_dt_ids[] = {
         { .compatible = "img,pistachio-reset", },
         { /* sentinel */ },
};

static struct platform_driver pistachio_reset_driver = {
        .probe  = pistachio_reset_probe,
        .driver = {
                .name           = "pistachio-reset",
                .of_match_table = pistachio_reset_dt_ids,
        },
};
builtin_platform_driver(pistachio_reset_driver);