// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Copyright (C) Nokia Corporation
 *
 * Written by Timo Kokkonen <timo.t.kokkonen at nokia.com>
 */

#include <linux/module.h>
#include <linux/types.h>
#include <linux/slab.h>
#include <linux/kernel.h>
#include <linux/mod_devicetable.h>
#include <linux/watchdog.h>
#include <linux/platform_device.h>
#include <linux/mfd/twl.h>

#define TWL4030_WATCHDOG_CFG_REG_OFFS   0x3

static bool nowayout = WATCHDOG_NOWAYOUT;
module_param(nowayout, bool, 0);
MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started "
        "(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");

static int twl4030_wdt_write(unsigned char val)
{
        return twl_i2c_write_u8(TWL_MODULE_PM_RECEIVER, val,
                                        TWL4030_WATCHDOG_CFG_REG_OFFS);
}

static int twl4030_wdt_start(struct watchdog_device *wdt)
{
        return twl4030_wdt_write(wdt->timeout + 1);
}

static int twl4030_wdt_stop(struct watchdog_device *wdt)
{
        return twl4030_wdt_write(0);
}

static int twl4030_wdt_set_timeout(struct watchdog_device *wdt,
                                   unsigned int timeout)
{
        wdt->timeout = timeout;
        return 0;
}

static const struct watchdog_info twl4030_wdt_info = {
        .options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING,
        .identity = "TWL4030 Watchdog",
};

static const struct watchdog_ops twl4030_wdt_ops = {
        .owner          = THIS_MODULE,
        .start          = twl4030_wdt_start,
        .stop           = twl4030_wdt_stop,
        .set_timeout    = twl4030_wdt_set_timeout,
};

static int twl4030_wdt_probe(struct platform_device *pdev)
{
        struct device *dev = &pdev->dev;
        struct watchdog_device *wdt;

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

        wdt->info               = &twl4030_wdt_info;
        wdt->ops                = &twl4030_wdt_ops;
        wdt->status             = 0;
        wdt->timeout            = 30;
        wdt->min_timeout        = 1;
        wdt->max_timeout        = 30;
        wdt->parent = dev;

        watchdog_set_nowayout(wdt, nowayout);
        platform_set_drvdata(pdev, wdt);

        twl4030_wdt_stop(wdt);

        return devm_watchdog_register_device(dev, wdt);
}

static int twl4030_wdt_suspend(struct platform_device *pdev, pm_message_t state)
{
        struct watchdog_device *wdt = platform_get_drvdata(pdev);
        if (watchdog_active(wdt))
                return twl4030_wdt_stop(wdt);

        return 0;
}

static int twl4030_wdt_resume(struct platform_device *pdev)
{
        struct watchdog_device *wdt = platform_get_drvdata(pdev);
        if (watchdog_active(wdt))
                return twl4030_wdt_start(wdt);

        return 0;
}

static const struct of_device_id twl_wdt_of_match[] = {
        { .compatible = "ti,twl4030-wdt", },
        { },
};
MODULE_DEVICE_TABLE(of, twl_wdt_of_match);

static struct platform_driver twl4030_wdt_driver = {
        .probe          = twl4030_wdt_probe,
        .suspend        = pm_ptr(twl4030_wdt_suspend),
        .resume         = pm_ptr(twl4030_wdt_resume),
        .driver         = {
                .name           = "twl4030_wdt",
                .of_match_table = twl_wdt_of_match,
        },
};

module_platform_driver(twl4030_wdt_driver);

MODULE_AUTHOR("Nokia Corporation");
MODULE_DESCRIPTION("TWL4030 Watchdog");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:twl4030_wdt");