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drivers/watchdog/bcm7038_wdt.c
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7a3629fe9 watchdog: Watchdo... |
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/* * Copyright (C) 2015 Broadcom Corporation * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation; either version 2 * of the License, or (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. */ #include <linux/clk.h> #include <linux/init.h> #include <linux/io.h> #include <linux/module.h> #include <linux/of.h> #include <linux/platform_device.h> #include <linux/pm.h> #include <linux/watchdog.h> #define WDT_START_1 0xff00 #define WDT_START_2 0x00ff #define WDT_STOP_1 0xee00 #define WDT_STOP_2 0x00ee #define WDT_TIMEOUT_REG 0x0 #define WDT_CMD_REG 0x4 #define WDT_MIN_TIMEOUT 1 /* seconds */ #define WDT_DEFAULT_TIMEOUT 30 /* seconds */ #define WDT_DEFAULT_RATE 27000000 struct bcm7038_watchdog { void __iomem *base; struct watchdog_device wdd; u32 rate; struct clk *clk; }; static bool nowayout = WATCHDOG_NOWAYOUT; static void bcm7038_wdt_set_timeout_reg(struct watchdog_device *wdog) { struct bcm7038_watchdog *wdt = watchdog_get_drvdata(wdog); u32 timeout; timeout = wdt->rate * wdog->timeout; writel(timeout, wdt->base + WDT_TIMEOUT_REG); } static int bcm7038_wdt_ping(struct watchdog_device *wdog) { struct bcm7038_watchdog *wdt = watchdog_get_drvdata(wdog); writel(WDT_START_1, wdt->base + WDT_CMD_REG); writel(WDT_START_2, wdt->base + WDT_CMD_REG); return 0; } static int bcm7038_wdt_start(struct watchdog_device *wdog) { bcm7038_wdt_set_timeout_reg(wdog); bcm7038_wdt_ping(wdog); return 0; } static int bcm7038_wdt_stop(struct watchdog_device *wdog) { struct bcm7038_watchdog *wdt = watchdog_get_drvdata(wdog); writel(WDT_STOP_1, wdt->base + WDT_CMD_REG); writel(WDT_STOP_2, wdt->base + WDT_CMD_REG); return 0; } static int bcm7038_wdt_set_timeout(struct watchdog_device *wdog, unsigned int t) { /* Can't modify timeout value if watchdog timer is running */ bcm7038_wdt_stop(wdog); wdog->timeout = t; bcm7038_wdt_start(wdog); return 0; } static unsigned int bcm7038_wdt_get_timeleft(struct watchdog_device *wdog) { struct bcm7038_watchdog *wdt = watchdog_get_drvdata(wdog); u32 time_left; time_left = readl(wdt->base + WDT_CMD_REG); return time_left / wdt->rate; } static struct watchdog_info bcm7038_wdt_info = { .identity = "Broadcom BCM7038 Watchdog Timer", .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE }; |
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static const struct watchdog_ops bcm7038_wdt_ops = { |
7a3629fe9 watchdog: Watchdo... |
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.owner = THIS_MODULE, .start = bcm7038_wdt_start, .stop = bcm7038_wdt_stop, .set_timeout = bcm7038_wdt_set_timeout, .get_timeleft = bcm7038_wdt_get_timeleft, }; static int bcm7038_wdt_probe(struct platform_device *pdev) { struct device *dev = &pdev->dev; struct bcm7038_watchdog *wdt; struct resource *res; int err; wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL); if (!wdt) return -ENOMEM; platform_set_drvdata(pdev, wdt); res = platform_get_resource(pdev, IORESOURCE_MEM, 0); wdt->base = devm_ioremap_resource(dev, res); if (IS_ERR(wdt->base)) return PTR_ERR(wdt->base); wdt->clk = devm_clk_get(dev, NULL); /* If unable to get clock, use default frequency */ if (!IS_ERR(wdt->clk)) { clk_prepare_enable(wdt->clk); wdt->rate = clk_get_rate(wdt->clk); /* Prevent divide-by-zero exception */ if (!wdt->rate) wdt->rate = WDT_DEFAULT_RATE; } else { wdt->rate = WDT_DEFAULT_RATE; wdt->clk = NULL; } wdt->wdd.info = &bcm7038_wdt_info; wdt->wdd.ops = &bcm7038_wdt_ops; wdt->wdd.min_timeout = WDT_MIN_TIMEOUT; wdt->wdd.timeout = WDT_DEFAULT_TIMEOUT; wdt->wdd.max_timeout = 0xffffffff / wdt->rate; wdt->wdd.parent = dev; watchdog_set_drvdata(&wdt->wdd, wdt); err = watchdog_register_device(&wdt->wdd); if (err) { dev_err(dev, "Failed to register watchdog device "); clk_disable_unprepare(wdt->clk); return err; } dev_info(dev, "Registered BCM7038 Watchdog "); return 0; } static int bcm7038_wdt_remove(struct platform_device *pdev) { struct bcm7038_watchdog *wdt = platform_get_drvdata(pdev); if (!nowayout) bcm7038_wdt_stop(&wdt->wdd); watchdog_unregister_device(&wdt->wdd); clk_disable_unprepare(wdt->clk); return 0; } #ifdef CONFIG_PM_SLEEP static int bcm7038_wdt_suspend(struct device *dev) { struct bcm7038_watchdog *wdt = dev_get_drvdata(dev); if (watchdog_active(&wdt->wdd)) return bcm7038_wdt_stop(&wdt->wdd); return 0; } static int bcm7038_wdt_resume(struct device *dev) { struct bcm7038_watchdog *wdt = dev_get_drvdata(dev); if (watchdog_active(&wdt->wdd)) return bcm7038_wdt_start(&wdt->wdd); return 0; } #endif static SIMPLE_DEV_PM_OPS(bcm7038_wdt_pm_ops, bcm7038_wdt_suspend, bcm7038_wdt_resume); static void bcm7038_wdt_shutdown(struct platform_device *pdev) { struct bcm7038_watchdog *wdt = platform_get_drvdata(pdev); if (watchdog_active(&wdt->wdd)) bcm7038_wdt_stop(&wdt->wdd); } static const struct of_device_id bcm7038_wdt_match[] = { { .compatible = "brcm,bcm7038-wdt" }, {}, }; static struct platform_driver bcm7038_wdt_driver = { .probe = bcm7038_wdt_probe, .remove = bcm7038_wdt_remove, .shutdown = bcm7038_wdt_shutdown, .driver = { .name = "bcm7038-wdt", .of_match_table = bcm7038_wdt_match, .pm = &bcm7038_wdt_pm_ops, } }; module_platform_driver(bcm7038_wdt_driver); module_param(nowayout, bool, 0); MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); MODULE_LICENSE("GPL v2"); MODULE_DESCRIPTION("Driver for Broadcom 7038 SoCs Watchdog"); MODULE_AUTHOR("Justin Chen"); |