// SPDX-License-Identifier: GPL-2.0
/*
 * Power off through MediaTek PMIC
 *
 * Copyright (C) 2018 MediaTek Inc.
 *
 * Author: Sean Wang <sean.wang@mediatek.com>
 *
 */

#include <linux/err.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/mfd/mt6397/core.h>
#include <linux/mfd/mt6397/rtc.h>
#include <linux/reboot.h>

struct mt6323_pwrc {
        struct device *dev;
        struct regmap *regmap;
        u32 base;
};

static int mt6323_do_pwroff(struct sys_off_data *data)
{
        struct mt6323_pwrc *pwrc = data->cb_data;
        unsigned int val;
        int ret;

        regmap_write(pwrc->regmap, pwrc->base + RTC_BBPU, RTC_BBPU_KEY);
        regmap_write(pwrc->regmap, pwrc->base + RTC_WRTGR_MT6323, 1);

        ret = regmap_read_poll_timeout(pwrc->regmap,
                                        pwrc->base + RTC_BBPU, val,
                                        !(val & RTC_BBPU_CBUSY),
                                        MTK_RTC_POLL_DELAY_US,
                                        MTK_RTC_POLL_TIMEOUT);
        if (ret)
                dev_err(pwrc->dev, "failed to write BBPU: %d\n", ret);

        /* Wait some time until system down, otherwise, notice with a warn */
        mdelay(1000);

        WARN_ONCE(1, "Unable to power off system\n");

        return NOTIFY_DONE;
}

static int mt6323_pwrc_probe(struct platform_device *pdev)
{
        struct mt6397_chip *mt6397_chip = dev_get_drvdata(pdev->dev.parent);
        struct mt6323_pwrc *pwrc;
        struct resource *res;
        int ret;

        pwrc = devm_kzalloc(&pdev->dev, sizeof(*pwrc), GFP_KERNEL);
        if (!pwrc)
                return -ENOMEM;

        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
        if (!res)
                return -EINVAL;

        pwrc->base = res->start;
        pwrc->regmap = mt6397_chip->regmap;
        pwrc->dev = &pdev->dev;

        ret = devm_register_sys_off_handler(pwrc->dev,
                                            SYS_OFF_MODE_POWER_OFF,
                                            SYS_OFF_PRIO_DEFAULT,
                                            mt6323_do_pwroff,
                                            pwrc);
        if (ret)
                return dev_err_probe(pwrc->dev, ret, "failed to register power-off handler\n");

        return 0;
}

static const struct of_device_id mt6323_pwrc_dt_match[] = {
        { .compatible = "mediatek,mt6323-pwrc" },
        {},
};
MODULE_DEVICE_TABLE(of, mt6323_pwrc_dt_match);

static struct platform_driver mt6323_pwrc_driver = {
        .probe          = mt6323_pwrc_probe,
        .driver         = {
                .name   = "mt6323-pwrc",
                .of_match_table = mt6323_pwrc_dt_match,
        },
};

module_platform_driver(mt6323_pwrc_driver);

MODULE_DESCRIPTION("Poweroff driver for MT6323 PMIC");
MODULE_AUTHOR("Sean Wang <sean.wang@mediatek.com>");