1 // SPDX-License-Identifier: GPL-2.0-only
3  * NXP LPC18xx Watchdog Timer (WDT)
8  * -----
9  * The Watchdog consists of a fixed divide-by-4 clock pre-scaler and a 24-bit
18 #include <linux/watchdog.h>
35 /* Clock pre-scaler */
43 MODULE_PARM_DESC(heartbeat, "Watchdog heartbeats in seconds (default="
48 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
57 	struct timer_list	timer;  member
70 	spin_lock_irqsave(&lpc18xx_wdt->lock, flags);  in lpc18xx_wdt_feed()
71 	writel(LPC18XX_WDT_FEED_MAGIC1, lpc18xx_wdt->base + LPC18XX_WDT_FEED);  in lpc18xx_wdt_feed()
72 	writel(LPC18XX_WDT_FEED_MAGIC2, lpc18xx_wdt->base + LPC18XX_WDT_FEED);  in lpc18xx_wdt_feed()
73 	spin_unlock_irqrestore(&lpc18xx_wdt->lock, flags);  in lpc18xx_wdt_feed()
80 	struct lpc18xx_wdt_dev *lpc18xx_wdt = from_timer(lpc18xx_wdt, t, timer);  in lpc18xx_wdt_timer_feed()
81 	struct watchdog_device *wdt_dev = &lpc18xx_wdt->wdt_dev;  in lpc18xx_wdt_timer_feed()
86 	mod_timer(&lpc18xx_wdt->timer, jiffies +  in lpc18xx_wdt_timer_feed()
87 		  msecs_to_jiffies((wdt_dev->timeout * MSEC_PER_SEC) / 2));  in lpc18xx_wdt_timer_feed()
91  * Since LPC18xx Watchdog cannot be disabled in hardware, we must keep feeding
92  * it with a timer until userspace watchdog software takes over.
98 	lpc18xx_wdt_timer_feed(&lpc18xx_wdt->timer);  in lpc18xx_wdt_stop()
107 	val = DIV_ROUND_UP(lpc18xx_wdt->wdt_dev.timeout * lpc18xx_wdt->clk_rate,  in __lpc18xx_wdt_set_timeout()
109 	writel(val, lpc18xx_wdt->base + LPC18XX_WDT_TC);  in __lpc18xx_wdt_set_timeout()
117 	lpc18xx_wdt->wdt_dev.timeout = new_timeout;  in lpc18xx_wdt_set_timeout()
128 	val = readl(lpc18xx_wdt->base + LPC18XX_WDT_TV);  in lpc18xx_wdt_get_timeleft()
129 	return (val * LPC18XX_WDT_CLK_DIV) / lpc18xx_wdt->clk_rate;  in lpc18xx_wdt_get_timeleft()
137 	if (timer_pending(&lpc18xx_wdt->timer))  in lpc18xx_wdt_start()
138 		del_timer(&lpc18xx_wdt->timer);  in lpc18xx_wdt_start()
140 	val = readl(lpc18xx_wdt->base + LPC18XX_WDT_MOD);  in lpc18xx_wdt_start()
143 	writel(val, lpc18xx_wdt->base + LPC18XX_WDT_MOD);  in lpc18xx_wdt_start()
147 	 * enable the Watchdog. A valid feed sequence must be completed after  in lpc18xx_wdt_start()
148 	 * setting WDEN before the Watchdog is capable of generating a reset.  in lpc18xx_wdt_start()
163 	 * Incorrect feed sequence causes immediate watchdog reset if enabled.  in lpc18xx_wdt_restart()
165 	spin_lock_irqsave(&lpc18xx_wdt->lock, flags);  in lpc18xx_wdt_restart()
167 	val = readl(lpc18xx_wdt->base + LPC18XX_WDT_MOD);  in lpc18xx_wdt_restart()
170 	writel(val, lpc18xx_wdt->base + LPC18XX_WDT_MOD);  in lpc18xx_wdt_restart()
172 	writel(LPC18XX_WDT_FEED_MAGIC1, lpc18xx_wdt->base + LPC18XX_WDT_FEED);  in lpc18xx_wdt_restart()
173 	writel(LPC18XX_WDT_FEED_MAGIC2, lpc18xx_wdt->base + LPC18XX_WDT_FEED);  in lpc18xx_wdt_restart()
175 	writel(LPC18XX_WDT_FEED_MAGIC1, lpc18xx_wdt->base + LPC18XX_WDT_FEED);  in lpc18xx_wdt_restart()
176 	writel(LPC18XX_WDT_FEED_MAGIC1, lpc18xx_wdt->base + LPC18XX_WDT_FEED);  in lpc18xx_wdt_restart()
178 	spin_unlock_irqrestore(&lpc18xx_wdt->lock, flags);  in lpc18xx_wdt_restart()
184 	.identity	= "NXP LPC18xx Watchdog",
208 	struct device *dev = &pdev->dev;  in lpc18xx_wdt_probe()
213 		return -ENOMEM;  in lpc18xx_wdt_probe()
215 	lpc18xx_wdt->base = devm_platform_ioremap_resource(pdev, 0);  in lpc18xx_wdt_probe()
216 	if (IS_ERR(lpc18xx_wdt->base))  in lpc18xx_wdt_probe()
217 		return PTR_ERR(lpc18xx_wdt->base);  in lpc18xx_wdt_probe()
219 	lpc18xx_wdt->reg_clk = devm_clk_get(dev, "reg");  in lpc18xx_wdt_probe()
220 	if (IS_ERR(lpc18xx_wdt->reg_clk)) {  in lpc18xx_wdt_probe()
222 		return PTR_ERR(lpc18xx_wdt->reg_clk);  in lpc18xx_wdt_probe()
225 	lpc18xx_wdt->wdt_clk = devm_clk_get(dev, "wdtclk");  in lpc18xx_wdt_probe()
226 	if (IS_ERR(lpc18xx_wdt->wdt_clk)) {  in lpc18xx_wdt_probe()
228 		return PTR_ERR(lpc18xx_wdt->wdt_clk);  in lpc18xx_wdt_probe()
231 	ret = clk_prepare_enable(lpc18xx_wdt->reg_clk);  in lpc18xx_wdt_probe()
237 				       lpc18xx_wdt->reg_clk);  in lpc18xx_wdt_probe()
241 	ret = clk_prepare_enable(lpc18xx_wdt->wdt_clk);  in lpc18xx_wdt_probe()
247 				       lpc18xx_wdt->wdt_clk);  in lpc18xx_wdt_probe()
252 	lpc18xx_wdt->clk_rate = clk_get_rate(lpc18xx_wdt->wdt_clk);  in lpc18xx_wdt_probe()
253 	if (lpc18xx_wdt->clk_rate == 0) {  in lpc18xx_wdt_probe()
255 		return -EINVAL;  in lpc18xx_wdt_probe()
258 	lpc18xx_wdt->wdt_dev.info = &lpc18xx_wdt_info;  in lpc18xx_wdt_probe()
259 	lpc18xx_wdt->wdt_dev.ops = &lpc18xx_wdt_ops;  in lpc18xx_wdt_probe()
261 	lpc18xx_wdt->wdt_dev.min_timeout = DIV_ROUND_UP(LPC18XX_WDT_TC_MIN *  in lpc18xx_wdt_probe()
262 				LPC18XX_WDT_CLK_DIV, lpc18xx_wdt->clk_rate);  in lpc18xx_wdt_probe()
264 	lpc18xx_wdt->wdt_dev.max_timeout = (LPC18XX_WDT_TC_MAX *  in lpc18xx_wdt_probe()
265 				LPC18XX_WDT_CLK_DIV) / lpc18xx_wdt->clk_rate;  in lpc18xx_wdt_probe()
267 	lpc18xx_wdt->wdt_dev.timeout = min(lpc18xx_wdt->wdt_dev.max_timeout,  in lpc18xx_wdt_probe()
270 	spin_lock_init(&lpc18xx_wdt->lock);  in lpc18xx_wdt_probe()
272 	lpc18xx_wdt->wdt_dev.parent = dev;  in lpc18xx_wdt_probe()
273 	watchdog_set_drvdata(&lpc18xx_wdt->wdt_dev, lpc18xx_wdt);  in lpc18xx_wdt_probe()
275 	watchdog_init_timeout(&lpc18xx_wdt->wdt_dev, heartbeat, dev);  in lpc18xx_wdt_probe()
279 	timer_setup(&lpc18xx_wdt->timer, lpc18xx_wdt_timer_feed, 0);  in lpc18xx_wdt_probe()
281 	watchdog_set_nowayout(&lpc18xx_wdt->wdt_dev, nowayout);  in lpc18xx_wdt_probe()
282 	watchdog_set_restart_priority(&lpc18xx_wdt->wdt_dev, 128);  in lpc18xx_wdt_probe()
286 	watchdog_stop_on_reboot(&lpc18xx_wdt->wdt_dev);  in lpc18xx_wdt_probe()
287 	return devm_watchdog_register_device(dev, &lpc18xx_wdt->wdt_dev);  in lpc18xx_wdt_probe()
294 	dev_warn(&pdev->dev, "I quit now, hardware will probably reboot!\n");  in lpc18xx_wdt_remove()
295 	del_timer_sync(&lpc18xx_wdt->timer);  in lpc18xx_wdt_remove()
301 	{ .compatible = "nxp,lpc1850-wwdt" },
308 		.name = "lpc18xx-wdt",
317 MODULE_DESCRIPTION("NXP LPC18xx Watchdog Timer Driver");