252 lines
6.2 KiB
C
252 lines
6.2 KiB
C
/*
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* Mediatek Watchdog Driver
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*
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* Copyright (C) 2014 Matthias Brugger
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*
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* Matthias Brugger <matthias.bgg@gmail.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* Based on sunxi_wdt.c
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*/
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#include <linux/err.h>
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#include <linux/init.h>
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#include <linux/io.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/moduleparam.h>
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#include <linux/of.h>
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#include <linux/platform_device.h>
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#include <linux/types.h>
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#include <linux/watchdog.h>
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#include <linux/notifier.h>
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#include <linux/reboot.h>
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#include <linux/delay.h>
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#define WDT_MAX_TIMEOUT 31
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#define WDT_MIN_TIMEOUT 1
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#define WDT_LENGTH_TIMEOUT(n) ((n) << 5)
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#define WDT_LENGTH 0x04
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#define WDT_LENGTH_KEY 0x8
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#define WDT_RST 0x08
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#define WDT_RST_RELOAD 0x1971
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#define WDT_MODE 0x00
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#define WDT_MODE_EN (1 << 0)
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#define WDT_MODE_EXT_POL_LOW (0 << 1)
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#define WDT_MODE_EXT_POL_HIGH (1 << 1)
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#define WDT_MODE_EXRST_EN (1 << 2)
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#define WDT_MODE_IRQ_EN (1 << 3)
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#define WDT_MODE_AUTO_START (1 << 4)
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#define WDT_MODE_DUAL_EN (1 << 6)
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#define WDT_MODE_KEY 0x22000000
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#define WDT_SWRST 0x14
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#define WDT_SWRST_KEY 0x1209
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#define DRV_NAME "mtk-wdt"
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#define DRV_VERSION "1.0"
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static bool nowayout = WATCHDOG_NOWAYOUT;
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static unsigned int timeout = WDT_MAX_TIMEOUT;
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struct mtk_wdt_dev {
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struct watchdog_device wdt_dev;
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void __iomem *wdt_base;
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struct notifier_block restart_handler;
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};
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static int mtk_reset_handler(struct notifier_block *this, unsigned long mode,
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void *cmd)
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{
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struct mtk_wdt_dev *mtk_wdt;
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void __iomem *wdt_base;
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mtk_wdt = container_of(this, struct mtk_wdt_dev, restart_handler);
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wdt_base = mtk_wdt->wdt_base;
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while (1) {
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writel(WDT_SWRST_KEY, wdt_base + WDT_SWRST);
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mdelay(5);
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}
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return NOTIFY_DONE;
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}
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static int mtk_wdt_ping(struct watchdog_device *wdt_dev)
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{
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struct mtk_wdt_dev *mtk_wdt = watchdog_get_drvdata(wdt_dev);
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void __iomem *wdt_base = mtk_wdt->wdt_base;
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iowrite32(WDT_RST_RELOAD, wdt_base + WDT_RST);
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return 0;
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}
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static int mtk_wdt_set_timeout(struct watchdog_device *wdt_dev,
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unsigned int timeout)
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{
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struct mtk_wdt_dev *mtk_wdt = watchdog_get_drvdata(wdt_dev);
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void __iomem *wdt_base = mtk_wdt->wdt_base;
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u32 reg;
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wdt_dev->timeout = timeout;
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/*
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* One bit is the value of 512 ticks
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* The clock has 32 KHz
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*/
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reg = WDT_LENGTH_TIMEOUT(timeout << 6) | WDT_LENGTH_KEY;
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iowrite32(reg, wdt_base + WDT_LENGTH);
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mtk_wdt_ping(wdt_dev);
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return 0;
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}
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static int mtk_wdt_stop(struct watchdog_device *wdt_dev)
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{
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struct mtk_wdt_dev *mtk_wdt = watchdog_get_drvdata(wdt_dev);
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void __iomem *wdt_base = mtk_wdt->wdt_base;
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u32 reg;
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reg = readl(wdt_base + WDT_MODE);
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reg &= ~WDT_MODE_EN;
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iowrite32(reg, wdt_base + WDT_MODE);
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return 0;
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}
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static int mtk_wdt_start(struct watchdog_device *wdt_dev)
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{
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u32 reg;
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struct mtk_wdt_dev *mtk_wdt = watchdog_get_drvdata(wdt_dev);
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void __iomem *wdt_base = mtk_wdt->wdt_base;
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int ret;
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ret = mtk_wdt_set_timeout(wdt_dev, wdt_dev->timeout);
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if (ret < 0)
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return ret;
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reg = ioread32(wdt_base + WDT_MODE);
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reg &= ~(WDT_MODE_IRQ_EN | WDT_MODE_DUAL_EN);
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reg |= (WDT_MODE_EN | WDT_MODE_KEY);
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iowrite32(reg, wdt_base + WDT_MODE);
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return 0;
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}
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static const struct watchdog_info mtk_wdt_info = {
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.identity = DRV_NAME,
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.options = WDIOF_SETTIMEOUT |
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WDIOF_KEEPALIVEPING |
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WDIOF_MAGICCLOSE,
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};
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static const struct watchdog_ops mtk_wdt_ops = {
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.owner = THIS_MODULE,
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.start = mtk_wdt_start,
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.stop = mtk_wdt_stop,
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.ping = mtk_wdt_ping,
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.set_timeout = mtk_wdt_set_timeout,
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};
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static int mtk_wdt_probe(struct platform_device *pdev)
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{
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struct mtk_wdt_dev *mtk_wdt;
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struct resource *res;
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int err;
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mtk_wdt = devm_kzalloc(&pdev->dev, sizeof(*mtk_wdt), GFP_KERNEL);
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if (!mtk_wdt)
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return -ENOMEM;
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platform_set_drvdata(pdev, mtk_wdt);
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res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
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mtk_wdt->wdt_base = devm_ioremap_resource(&pdev->dev, res);
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if (IS_ERR(mtk_wdt->wdt_base))
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return PTR_ERR(mtk_wdt->wdt_base);
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mtk_wdt->wdt_dev.info = &mtk_wdt_info;
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mtk_wdt->wdt_dev.ops = &mtk_wdt_ops;
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mtk_wdt->wdt_dev.timeout = WDT_MAX_TIMEOUT;
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mtk_wdt->wdt_dev.max_timeout = WDT_MAX_TIMEOUT;
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mtk_wdt->wdt_dev.min_timeout = WDT_MIN_TIMEOUT;
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mtk_wdt->wdt_dev.parent = &pdev->dev;
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watchdog_init_timeout(&mtk_wdt->wdt_dev, timeout, &pdev->dev);
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watchdog_set_nowayout(&mtk_wdt->wdt_dev, nowayout);
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watchdog_set_drvdata(&mtk_wdt->wdt_dev, mtk_wdt);
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mtk_wdt_stop(&mtk_wdt->wdt_dev);
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err = watchdog_register_device(&mtk_wdt->wdt_dev);
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if (unlikely(err))
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return err;
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mtk_wdt->restart_handler.notifier_call = mtk_reset_handler;
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mtk_wdt->restart_handler.priority = 128;
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err = register_restart_handler(&mtk_wdt->restart_handler);
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if (err)
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dev_warn(&pdev->dev,
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"cannot register restart handler (err=%d)\n", err);
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dev_info(&pdev->dev, "Watchdog enabled (timeout=%d sec, nowayout=%d)\n",
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mtk_wdt->wdt_dev.timeout, nowayout);
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return 0;
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}
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static int mtk_wdt_remove(struct platform_device *pdev)
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{
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struct mtk_wdt_dev *mtk_wdt = platform_get_drvdata(pdev);
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unregister_restart_handler(&mtk_wdt->restart_handler);
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watchdog_unregister_device(&mtk_wdt->wdt_dev);
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return 0;
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}
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static const struct of_device_id mtk_wdt_dt_ids[] = {
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{ .compatible = "mediatek,mt6589-wdt" },
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{ /* sentinel */ }
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};
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MODULE_DEVICE_TABLE(of, mtk_wdt_dt_ids);
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static struct platform_driver mtk_wdt_driver = {
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.probe = mtk_wdt_probe,
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.remove = mtk_wdt_remove,
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.driver = {
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.name = DRV_NAME,
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.of_match_table = mtk_wdt_dt_ids,
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},
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};
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module_platform_driver(mtk_wdt_driver);
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module_param(timeout, uint, 0);
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MODULE_PARM_DESC(timeout, "Watchdog heartbeat in seconds");
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module_param(nowayout, bool, 0);
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MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
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__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("Matthias Brugger <matthias.bgg@gmail.com>");
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MODULE_DESCRIPTION("Mediatek WatchDog Timer Driver");
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MODULE_VERSION(DRV_VERSION);
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