// SPDX-License-Identifier: GPL-2.0+
/*
 * Watchdog driver for the wm8350
 *
 * Copyright (C) 2007, 2008 Wolfson Microelectronics <linux@wolfsonmicro.com>
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/platform_device.h>
#include <linux/watchdog.h>
#include <linux/uaccess.h>
#include <linux/mfd/wm8350/core.h>

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 DEFINE_MUTEX(wdt_mutex);

static struct {
        unsigned int time;  /* Seconds */
        u16 val;            /* To be set in WM8350_SYSTEM_CONTROL_2 */
} wm8350_wdt_cfgs[] = {
        { 1, 0x02 },
        { 2, 0x04 },
        { 4, 0x05 },
};

static int wm8350_wdt_set_timeout(struct watchdog_device *wdt_dev,
                                  unsigned int timeout)
{
        struct wm8350 *wm8350 = watchdog_get_drvdata(wdt_dev);
        int ret, i;
        u16 reg;

        for (i = 0; i < ARRAY_SIZE(wm8350_wdt_cfgs); i++)
                if (wm8350_wdt_cfgs[i].time == timeout)
                        break;
        if (i == ARRAY_SIZE(wm8350_wdt_cfgs))
                return -EINVAL;

        mutex_lock(&wdt_mutex);
        wm8350_reg_unlock(wm8350);

        reg = wm8350_reg_read(wm8350, WM8350_SYSTEM_CONTROL_2);
        reg &= ~WM8350_WDOG_TO_MASK;
        reg |= wm8350_wdt_cfgs[i].val;
        ret = wm8350_reg_write(wm8350, WM8350_SYSTEM_CONTROL_2, reg);

        wm8350_reg_lock(wm8350);
        mutex_unlock(&wdt_mutex);

        wdt_dev->timeout = timeout;
        return ret;
}

static int wm8350_wdt_start(struct watchdog_device *wdt_dev)
{
        struct wm8350 *wm8350 = watchdog_get_drvdata(wdt_dev);
        int ret;
        u16 reg;

        mutex_lock(&wdt_mutex);
        wm8350_reg_unlock(wm8350);

        reg = wm8350_reg_read(wm8350, WM8350_SYSTEM_CONTROL_2);
        reg &= ~WM8350_WDOG_MODE_MASK;
        reg |= 0x20;
        ret = wm8350_reg_write(wm8350, WM8350_SYSTEM_CONTROL_2, reg);

        wm8350_reg_lock(wm8350);
        mutex_unlock(&wdt_mutex);

        return ret;
}

static int wm8350_wdt_stop(struct watchdog_device *wdt_dev)
{
        struct wm8350 *wm8350 = watchdog_get_drvdata(wdt_dev);
        int ret;
        u16 reg;

        mutex_lock(&wdt_mutex);
        wm8350_reg_unlock(wm8350);

        reg = wm8350_reg_read(wm8350, WM8350_SYSTEM_CONTROL_2);
        reg &= ~WM8350_WDOG_MODE_MASK;
        ret = wm8350_reg_write(wm8350, WM8350_SYSTEM_CONTROL_2, reg);

        wm8350_reg_lock(wm8350);
        mutex_unlock(&wdt_mutex);

        return ret;
}

static int wm8350_wdt_ping(struct watchdog_device *wdt_dev)
{
        struct wm8350 *wm8350 = watchdog_get_drvdata(wdt_dev);
        int ret;
        u16 reg;

        mutex_lock(&wdt_mutex);

        reg = wm8350_reg_read(wm8350, WM8350_SYSTEM_CONTROL_2);
        ret = wm8350_reg_write(wm8350, WM8350_SYSTEM_CONTROL_2, reg);

        mutex_unlock(&wdt_mutex);

        return ret;
}

static const struct watchdog_info wm8350_wdt_info = {
        .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
        .identity = "WM8350 Watchdog",
};

static const struct watchdog_ops wm8350_wdt_ops = {
        .owner = THIS_MODULE,
        .start = wm8350_wdt_start,
        .stop = wm8350_wdt_stop,
        .ping = wm8350_wdt_ping,
        .set_timeout = wm8350_wdt_set_timeout,
};

static struct watchdog_device wm8350_wdt = {
        .info = &wm8350_wdt_info,
        .ops = &wm8350_wdt_ops,
        .timeout = 4,
        .min_timeout = 1,
        .max_timeout = 4,
};

static int wm8350_wdt_probe(struct platform_device *pdev)
{
        struct wm8350 *wm8350 = platform_get_drvdata(pdev);

        if (!wm8350) {
                pr_err("No driver data supplied\n");
                return -ENODEV;
        }

        watchdog_set_nowayout(&wm8350_wdt, nowayout);
        watchdog_set_drvdata(&wm8350_wdt, wm8350);
        wm8350_wdt.parent = &pdev->dev;

        /* Default to 4s timeout */
        wm8350_wdt_set_timeout(&wm8350_wdt, 4);

        return devm_watchdog_register_device(&pdev->dev, &wm8350_wdt);
}

static struct platform_driver wm8350_wdt_driver = {
        .probe = wm8350_wdt_probe,
        .driver = {
                .name = "wm8350-wdt",
        },
};

module_platform_driver(wm8350_wdt_driver);

MODULE_AUTHOR("Mark Brown");
MODULE_DESCRIPTION("WM8350 Watchdog");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:wm8350-wdt");