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235 lines
5.5 KiB
235 lines
5.5 KiB
// SPDX-License-Identifier: GPL-2.0+ |
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/* |
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* Copyright (C) 2015 Broadcom Corporation |
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* |
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*/ |
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#include <linux/clk.h> |
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#include <linux/init.h> |
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#include <linux/io.h> |
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#include <linux/module.h> |
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#include <linux/of.h> |
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#include <linux/platform_device.h> |
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#include <linux/pm.h> |
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#include <linux/watchdog.h> |
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#define WDT_START_1 0xff00 |
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#define WDT_START_2 0x00ff |
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#define WDT_STOP_1 0xee00 |
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#define WDT_STOP_2 0x00ee |
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#define WDT_TIMEOUT_REG 0x0 |
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#define WDT_CMD_REG 0x4 |
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#define WDT_MIN_TIMEOUT 1 /* seconds */ |
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#define WDT_DEFAULT_TIMEOUT 30 /* seconds */ |
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#define WDT_DEFAULT_RATE 27000000 |
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struct bcm7038_watchdog { |
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void __iomem *base; |
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struct watchdog_device wdd; |
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u32 rate; |
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struct clk *clk; |
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}; |
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static bool nowayout = WATCHDOG_NOWAYOUT; |
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static inline void bcm7038_wdt_write(u32 value, void __iomem *addr) |
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{ |
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/* MIPS chips strapped for BE will automagically configure the |
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* peripheral registers for CPU-native byte order. |
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*/ |
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if (IS_ENABLED(CONFIG_MIPS) && IS_ENABLED(CONFIG_CPU_BIG_ENDIAN)) |
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__raw_writel(value, addr); |
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else |
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writel_relaxed(value, addr); |
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} |
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static inline u32 bcm7038_wdt_read(void __iomem *addr) |
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{ |
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if (IS_ENABLED(CONFIG_MIPS) && IS_ENABLED(CONFIG_CPU_BIG_ENDIAN)) |
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return __raw_readl(addr); |
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else |
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return readl_relaxed(addr); |
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} |
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static void bcm7038_wdt_set_timeout_reg(struct watchdog_device *wdog) |
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{ |
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struct bcm7038_watchdog *wdt = watchdog_get_drvdata(wdog); |
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u32 timeout; |
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timeout = wdt->rate * wdog->timeout; |
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bcm7038_wdt_write(timeout, wdt->base + WDT_TIMEOUT_REG); |
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} |
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static int bcm7038_wdt_ping(struct watchdog_device *wdog) |
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{ |
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struct bcm7038_watchdog *wdt = watchdog_get_drvdata(wdog); |
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bcm7038_wdt_write(WDT_START_1, wdt->base + WDT_CMD_REG); |
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bcm7038_wdt_write(WDT_START_2, wdt->base + WDT_CMD_REG); |
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return 0; |
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} |
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static int bcm7038_wdt_start(struct watchdog_device *wdog) |
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{ |
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bcm7038_wdt_set_timeout_reg(wdog); |
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bcm7038_wdt_ping(wdog); |
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return 0; |
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} |
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static int bcm7038_wdt_stop(struct watchdog_device *wdog) |
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{ |
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struct bcm7038_watchdog *wdt = watchdog_get_drvdata(wdog); |
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bcm7038_wdt_write(WDT_STOP_1, wdt->base + WDT_CMD_REG); |
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bcm7038_wdt_write(WDT_STOP_2, wdt->base + WDT_CMD_REG); |
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return 0; |
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} |
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static int bcm7038_wdt_set_timeout(struct watchdog_device *wdog, |
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unsigned int t) |
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{ |
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/* Can't modify timeout value if watchdog timer is running */ |
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bcm7038_wdt_stop(wdog); |
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wdog->timeout = t; |
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bcm7038_wdt_start(wdog); |
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return 0; |
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} |
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static unsigned int bcm7038_wdt_get_timeleft(struct watchdog_device *wdog) |
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{ |
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struct bcm7038_watchdog *wdt = watchdog_get_drvdata(wdog); |
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u32 time_left; |
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time_left = bcm7038_wdt_read(wdt->base + WDT_CMD_REG); |
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return time_left / wdt->rate; |
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} |
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static const struct watchdog_info bcm7038_wdt_info = { |
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.identity = "Broadcom BCM7038 Watchdog Timer", |
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.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | |
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WDIOF_MAGICCLOSE |
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}; |
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static const struct watchdog_ops bcm7038_wdt_ops = { |
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.owner = THIS_MODULE, |
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.start = bcm7038_wdt_start, |
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.stop = bcm7038_wdt_stop, |
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.set_timeout = bcm7038_wdt_set_timeout, |
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.get_timeleft = bcm7038_wdt_get_timeleft, |
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}; |
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static void bcm7038_clk_disable_unprepare(void *data) |
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{ |
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clk_disable_unprepare(data); |
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} |
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static int bcm7038_wdt_probe(struct platform_device *pdev) |
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{ |
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struct device *dev = &pdev->dev; |
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struct bcm7038_watchdog *wdt; |
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int err; |
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wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL); |
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if (!wdt) |
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return -ENOMEM; |
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platform_set_drvdata(pdev, wdt); |
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wdt->base = devm_platform_ioremap_resource(pdev, 0); |
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if (IS_ERR(wdt->base)) |
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return PTR_ERR(wdt->base); |
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wdt->clk = devm_clk_get(dev, NULL); |
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/* If unable to get clock, use default frequency */ |
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if (!IS_ERR(wdt->clk)) { |
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err = clk_prepare_enable(wdt->clk); |
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if (err) |
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return err; |
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err = devm_add_action_or_reset(dev, |
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bcm7038_clk_disable_unprepare, |
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wdt->clk); |
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if (err) |
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return err; |
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wdt->rate = clk_get_rate(wdt->clk); |
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/* Prevent divide-by-zero exception */ |
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if (!wdt->rate) |
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wdt->rate = WDT_DEFAULT_RATE; |
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} else { |
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wdt->rate = WDT_DEFAULT_RATE; |
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wdt->clk = NULL; |
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} |
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wdt->wdd.info = &bcm7038_wdt_info; |
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wdt->wdd.ops = &bcm7038_wdt_ops; |
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wdt->wdd.min_timeout = WDT_MIN_TIMEOUT; |
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wdt->wdd.timeout = WDT_DEFAULT_TIMEOUT; |
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wdt->wdd.max_timeout = 0xffffffff / wdt->rate; |
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wdt->wdd.parent = dev; |
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watchdog_set_drvdata(&wdt->wdd, wdt); |
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watchdog_stop_on_reboot(&wdt->wdd); |
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watchdog_stop_on_unregister(&wdt->wdd); |
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err = devm_watchdog_register_device(dev, &wdt->wdd); |
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if (err) |
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return err; |
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dev_info(dev, "Registered BCM7038 Watchdog\n"); |
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return 0; |
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} |
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#ifdef CONFIG_PM_SLEEP |
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static int bcm7038_wdt_suspend(struct device *dev) |
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{ |
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struct bcm7038_watchdog *wdt = dev_get_drvdata(dev); |
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if (watchdog_active(&wdt->wdd)) |
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return bcm7038_wdt_stop(&wdt->wdd); |
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return 0; |
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} |
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static int bcm7038_wdt_resume(struct device *dev) |
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{ |
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struct bcm7038_watchdog *wdt = dev_get_drvdata(dev); |
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if (watchdog_active(&wdt->wdd)) |
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return bcm7038_wdt_start(&wdt->wdd); |
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return 0; |
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} |
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#endif |
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static SIMPLE_DEV_PM_OPS(bcm7038_wdt_pm_ops, bcm7038_wdt_suspend, |
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bcm7038_wdt_resume); |
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static const struct of_device_id bcm7038_wdt_match[] = { |
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{ .compatible = "brcm,bcm7038-wdt" }, |
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{}, |
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}; |
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MODULE_DEVICE_TABLE(of, bcm7038_wdt_match); |
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static struct platform_driver bcm7038_wdt_driver = { |
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.probe = bcm7038_wdt_probe, |
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.driver = { |
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.name = "bcm7038-wdt", |
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.of_match_table = bcm7038_wdt_match, |
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.pm = &bcm7038_wdt_pm_ops, |
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} |
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}; |
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module_platform_driver(bcm7038_wdt_driver); |
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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_DESCRIPTION("Driver for Broadcom 7038 SoCs Watchdog"); |
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MODULE_AUTHOR("Justin Chen");
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