// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Generic Syscon Poweroff Driver
 *
 * Copyright (c) 2015, National Instruments Corp.
 * Author: Moritz Fischer <moritz.fischer@ettus.com>
 */

#include <linux/delay.h>
#include <linux/io.h>
#include <linux/notifier.h>
#include <linux/mfd/syscon.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/pm.h>
#include <linux/reboot.h>
#include <linux/regmap.h>

struct syscon_poweroff_data {
        struct regmap *map;
        u32 offset;
        u32 value;
        u32 mask;
};

static int syscon_poweroff(struct sys_off_data *off_data)
{
        struct syscon_poweroff_data *data = off_data->cb_data;

        /* Issue the poweroff */
        regmap_update_bits(data->map, data->offset, data->mask, data->value);

        mdelay(1000);

        pr_emerg("Unable to poweroff system\n");

        return NOTIFY_DONE;
}

static int syscon_poweroff_probe(struct platform_device *pdev)
{
        struct device *dev = &pdev->dev;
        struct syscon_poweroff_data *data;
        int mask_err, value_err;

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

        data->map = syscon_regmap_lookup_by_phandle(dev->of_node, "regmap");
        if (IS_ERR(data->map)) {
                data->map = syscon_node_to_regmap(dev->parent->of_node);
                if (IS_ERR(data->map)) {
                        dev_err(dev, "unable to get syscon");
                        return PTR_ERR(data->map);
                }
        }

        if (of_property_read_u32(dev->of_node, "offset", &data->offset)) {
                dev_err(dev, "unable to read 'offset'");
                return -EINVAL;
        }

        value_err = of_property_read_u32(dev->of_node, "value", &data->value);
        mask_err = of_property_read_u32(dev->of_node, "mask", &data->mask);
        if (value_err && mask_err) {
                dev_err(dev, "unable to read 'value' and 'mask'");
                return -EINVAL;
        }

        if (value_err) {
                /* support old binding */
                data->value = data->mask;
                data->mask = 0xFFFFFFFF;
        } else if (mask_err) {
                /* support value without mask*/
                data->mask = 0xFFFFFFFF;
        }

        return devm_register_sys_off_handler(&pdev->dev,
                                             SYS_OFF_MODE_POWER_OFF,
                                             SYS_OFF_PRIO_DEFAULT,
                                             syscon_poweroff, data);
}

static const struct of_device_id syscon_poweroff_of_match[] = {
        { .compatible = "syscon-poweroff" },
        {}
};

static struct platform_driver syscon_poweroff_driver = {
        .probe = syscon_poweroff_probe,
        .driver = {
                .name = "syscon-poweroff",
                .of_match_table = syscon_poweroff_of_match,
        },
};
builtin_platform_driver(syscon_poweroff_driver);