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lkundrakWim Van Sebroeck
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Wim Van Sebroeck
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watchdog: Add Broadcom BCM2835 watchdog timer driver
This adds a driver for watchdog timer hardware present on Broadcom BCM2835 SoC, used in Raspberry Pi and Roku 2 devices. Signed-off-by: Lubomir Rintel <[email protected]> Tested-by: Stephen Warren <[email protected]> Reviewed-by: Guenter Roeck <[email protected]> Signed-off-by: Wim Van Sebroeck <[email protected]> Cc: [email protected] Cc: [email protected] Cc: [email protected]
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Documentation/devicetree/bindings/watchdog/brcm,bcm2835-pm-wdog.txt

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@@ -5,9 +5,14 @@ Required properties:
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- compatible : should be "brcm,bcm2835-pm-wdt"
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- reg : Specifies base physical address and size of the registers.
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Optional properties:
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- timeout-sec : Contains the watchdog timeout in seconds
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Example:
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watchdog {
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compatible = "brcm,bcm2835-pm-wdt";
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reg = <0x7e100000 0x28>;
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timeout-sec = <10>;
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};

drivers/watchdog/Kconfig

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@@ -1100,6 +1100,17 @@ config BCM63XX_WDT
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To compile this driver as a loadable module, choose M here.
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The module will be called bcm63xx_wdt.
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config BCM2835_WDT
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tristate "Broadcom BCM2835 hardware watchdog"
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depends on ARCH_BCM2835
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select WATCHDOG_CORE
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help
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Watchdog driver for the built in watchdog hardware in Broadcom
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BCM2835 SoC.
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To compile this driver as a loadable module, choose M here.
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The module will be called bcm2835_wdt.
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config LANTIQ_WDT
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tristate "Lantiq SoC watchdog"
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depends on LANTIQ

drivers/watchdog/Makefile

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@@ -53,6 +53,7 @@ obj-$(CONFIG_TS72XX_WATCHDOG) += ts72xx_wdt.o
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obj-$(CONFIG_IMX2_WDT) += imx2_wdt.o
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obj-$(CONFIG_UX500_WATCHDOG) += ux500_wdt.o
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obj-$(CONFIG_RETU_WATCHDOG) += retu_wdt.o
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obj-$(CONFIG_BCM2835_WDT) += bcm2835_wdt.o
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# AVR32 Architecture
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obj-$(CONFIG_AT32AP700X_WDT) += at32ap700x_wdt.o

drivers/watchdog/bcm2835_wdt.c

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/*
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* Watchdog driver for Broadcom BCM2835
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*
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* "bcm2708_wdog" driver written by Luke Diamand that was obtained from
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* branch "rpi-3.6.y" of git://github.com/raspberrypi/linux.git was used
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* as a hardware reference for the Broadcom BCM2835 watchdog timer.
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*
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* Copyright (C) 2013 Lubomir Rintel <[email protected]>
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the
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* Free Software Foundation; either version 2 of the License, or (at your
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* option) any later version.
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*/
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#include <linux/types.h>
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#include <linux/module.h>
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#include <linux/io.h>
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#include <linux/watchdog.h>
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#include <linux/platform_device.h>
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#include <linux/of_address.h>
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#include <linux/miscdevice.h>
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#define PM_RSTC 0x1c
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#define PM_WDOG 0x24
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#define PM_PASSWORD 0x5a000000
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#define PM_WDOG_TIME_SET 0x000fffff
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#define PM_RSTC_WRCFG_CLR 0xffffffcf
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#define PM_RSTC_WRCFG_SET 0x00000030
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#define PM_RSTC_WRCFG_FULL_RESET 0x00000020
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#define PM_RSTC_RESET 0x00000102
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#define SECS_TO_WDOG_TICKS(x) ((x) << 16)
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#define WDOG_TICKS_TO_SECS(x) ((x) >> 16)
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struct bcm2835_wdt {
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void __iomem *base;
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spinlock_t lock;
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};
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static unsigned int heartbeat;
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static bool nowayout = WATCHDOG_NOWAYOUT;
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static int bcm2835_wdt_start(struct watchdog_device *wdog)
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{
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struct bcm2835_wdt *wdt = watchdog_get_drvdata(wdog);
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uint32_t cur;
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unsigned long flags;
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spin_lock_irqsave(&wdt->lock, flags);
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writel_relaxed(PM_PASSWORD | (SECS_TO_WDOG_TICKS(wdog->timeout) &
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PM_WDOG_TIME_SET), wdt->base + PM_WDOG);
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cur = readl_relaxed(wdt->base + PM_RSTC);
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writel_relaxed(PM_PASSWORD | (cur & PM_RSTC_WRCFG_CLR) |
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PM_RSTC_WRCFG_FULL_RESET, wdt->base + PM_RSTC);
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spin_unlock_irqrestore(&wdt->lock, flags);
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return 0;
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}
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static int bcm2835_wdt_stop(struct watchdog_device *wdog)
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{
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struct bcm2835_wdt *wdt = watchdog_get_drvdata(wdog);
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writel_relaxed(PM_PASSWORD | PM_RSTC_RESET, wdt->base + PM_RSTC);
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dev_info(wdog->dev, "Watchdog timer stopped");
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return 0;
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}
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static int bcm2835_wdt_set_timeout(struct watchdog_device *wdog, unsigned int t)
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{
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wdog->timeout = t;
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return 0;
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}
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static unsigned int bcm2835_wdt_get_timeleft(struct watchdog_device *wdog)
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{
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struct bcm2835_wdt *wdt = watchdog_get_drvdata(wdog);
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uint32_t ret = readl_relaxed(wdt->base + PM_WDOG);
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return WDOG_TICKS_TO_SECS(ret & PM_WDOG_TIME_SET);
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}
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static struct watchdog_ops bcm2835_wdt_ops = {
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.owner = THIS_MODULE,
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.start = bcm2835_wdt_start,
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.stop = bcm2835_wdt_stop,
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.set_timeout = bcm2835_wdt_set_timeout,
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.get_timeleft = bcm2835_wdt_get_timeleft,
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};
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static struct watchdog_info bcm2835_wdt_info = {
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.options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE |
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WDIOF_KEEPALIVEPING,
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.identity = "Broadcom BCM2835 Watchdog timer",
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};
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static struct watchdog_device bcm2835_wdt_wdd = {
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.info = &bcm2835_wdt_info,
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.ops = &bcm2835_wdt_ops,
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.min_timeout = 1,
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.max_timeout = WDOG_TICKS_TO_SECS(PM_WDOG_TIME_SET),
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.timeout = WDOG_TICKS_TO_SECS(PM_WDOG_TIME_SET),
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};
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static int bcm2835_wdt_probe(struct platform_device *pdev)
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{
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struct device *dev = &pdev->dev;
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struct device_node *np = dev->of_node;
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struct bcm2835_wdt *wdt;
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int err;
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wdt = devm_kzalloc(dev, sizeof(struct bcm2835_wdt), GFP_KERNEL);
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if (!wdt) {
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dev_err(dev, "Failed to allocate memory for watchdog device");
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return -ENOMEM;
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}
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platform_set_drvdata(pdev, wdt);
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spin_lock_init(&wdt->lock);
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wdt->base = of_iomap(np, 0);
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if (!wdt->base) {
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dev_err(dev, "Failed to remap watchdog regs");
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return -ENODEV;
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}
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watchdog_set_drvdata(&bcm2835_wdt_wdd, wdt);
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watchdog_init_timeout(&bcm2835_wdt_wdd, heartbeat, dev);
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watchdog_set_nowayout(&bcm2835_wdt_wdd, nowayout);
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err = watchdog_register_device(&bcm2835_wdt_wdd);
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if (err) {
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dev_err(dev, "Failed to register watchdog device");
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iounmap(wdt->base);
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return err;
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}
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dev_info(dev, "Broadcom BCM2835 watchdog timer");
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return 0;
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}
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static int bcm2835_wdt_remove(struct platform_device *pdev)
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{
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struct bcm2835_wdt *wdt = platform_get_drvdata(pdev);
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watchdog_unregister_device(&bcm2835_wdt_wdd);
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iounmap(wdt->base);
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return 0;
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}
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static void bcm2835_wdt_shutdown(struct platform_device *pdev)
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{
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bcm2835_wdt_stop(&bcm2835_wdt_wdd);
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}
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static const struct of_device_id bcm2835_wdt_of_match[] = {
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{ .compatible = "brcm,bcm2835-pm-wdt", },
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{},
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};
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MODULE_DEVICE_TABLE(of, bcm2835_wdt_of_match);
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static struct platform_driver bcm2835_wdt_driver = {
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.probe = bcm2835_wdt_probe,
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.remove = bcm2835_wdt_remove,
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.shutdown = bcm2835_wdt_shutdown,
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.driver = {
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.name = "bcm2835-wdt",
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.owner = THIS_MODULE,
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.of_match_table = bcm2835_wdt_of_match,
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},
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};
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module_platform_driver(bcm2835_wdt_driver);
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module_param(heartbeat, uint, 0);
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MODULE_PARM_DESC(heartbeat, "Initial 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_AUTHOR("Lubomir Rintel <[email protected]>");
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MODULE_DESCRIPTION("Driver for Broadcom BCM2835 watchdog timer");
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MODULE_LICENSE("GPL");
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MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);

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