1 // SPDX-License-Identifier: GPL-2.0+
3  * Cadence WDT driver - Used by Xilinx Zynq
5  * Copyright (C) 2010 - 2014 Xilinx, Inc.
18 #include <linux/watchdog.h>
21 /* Supports 1 - 516 sec */
54 		 "Watchdog time in seconds. (default="
59 		 "Watchdog cannot be stopped once started (default="
63  * struct cdns_wdt - Watchdog device structure
70  * @cdns_wdt_device: watchdog device structure
72  * Structure containing parameters specific to cadence watchdog.
87 	writel_relaxed(val, wdt->regs + offset);  in cdns_wdt_writereg()
99  * Zero Mode Register - This register controls how the time out is indicated
102 #define CDNS_WDT_ZMR_WDEN_MASK	0x00000001 /* Enable the WDT */
103 #define CDNS_WDT_ZMR_RSTEN_MASK	0x00000002 /* Enable the reset output */
104 #define CDNS_WDT_ZMR_IRQEN_MASK	0x00000004 /* Enable IRQ output */
108  * Counter Control register - This register controls how fast the timer runs
115  * cdns_wdt_stop - Stop the watchdog.
117  * @wdd: watchdog device
128 	spin_lock(&wdt->io_lock);  in cdns_wdt_stop()
131 	spin_unlock(&wdt->io_lock);  in cdns_wdt_stop()
137  * cdns_wdt_reload - Reload the watchdog timer (i.e. pat the watchdog).
139  * @wdd: watchdog device
149 	spin_lock(&wdt->io_lock);  in cdns_wdt_reload()
152 	spin_unlock(&wdt->io_lock);  in cdns_wdt_reload()
158  * cdns_wdt_start - Enable and start the watchdog.
160  * @wdd: watchdog device
180 	unsigned long clock_f = clk_get_rate(wdt->clk);  in cdns_wdt_start()
186 	count = (wdd->timeout * (clock_f / wdt->prescaler)) /  in cdns_wdt_start()
192 	spin_lock(&wdt->io_lock);  in cdns_wdt_start()
199 	data = count | CDNS_WDT_REGISTER_ACCESS_KEY | wdt->ctrl_clksel;  in cdns_wdt_start()
205 	if (wdt->rst) {  in cdns_wdt_start()
215 	spin_unlock(&wdt->io_lock);  in cdns_wdt_start()
221  * cdns_wdt_settimeout - Set a new timeout value for the watchdog device.
223  * @wdd: watchdog device
233 	wdd->timeout = new_time;  in cdns_wdt_settimeout()
239  * cdns_wdt_irq_handler - Notifies of watchdog timeout.
245  * The handler is invoked when the watchdog times out and a
252 	dev_info(&pdev->dev,  in cdns_wdt_irq_handler()
253 		 "Watchdog timed out. Internal reset not enabled\n");  in cdns_wdt_irq_handler()
260  * to the upper layers. This is defined in watchdog.h header file.
263 	.identity	= "cdns_wdt watchdog",
268 /* Watchdog Core Ops */
279  * cdns_wdt_probe - Probe call for the device.
288 	struct device *dev = &pdev->dev;  in cdns_wdt_probe()
296 		return -ENOMEM;  in cdns_wdt_probe()
298 	cdns_wdt_device = &wdt->cdns_wdt_device;  in cdns_wdt_probe()
299 	cdns_wdt_device->info = &cdns_wdt_info;  in cdns_wdt_probe()
300 	cdns_wdt_device->ops = &cdns_wdt_ops;  in cdns_wdt_probe()
301 	cdns_wdt_device->timeout = CDNS_WDT_DEFAULT_TIMEOUT;  in cdns_wdt_probe()
302 	cdns_wdt_device->min_timeout = CDNS_WDT_MIN_TIMEOUT;  in cdns_wdt_probe()
303 	cdns_wdt_device->max_timeout = CDNS_WDT_MAX_TIMEOUT;  in cdns_wdt_probe()
305 	wdt->regs = devm_platform_ioremap_resource(pdev, 0);  in cdns_wdt_probe()
306 	if (IS_ERR(wdt->regs))  in cdns_wdt_probe()
307 		return PTR_ERR(wdt->regs);  in cdns_wdt_probe()
310 	wdt->rst = of_property_read_bool(dev->of_node, "reset-on-timeout");  in cdns_wdt_probe()
312 	if (!wdt->rst && irq >= 0) {  in cdns_wdt_probe()
314 				       pdev->name, pdev);  in cdns_wdt_probe()
324 	cdns_wdt_device->parent = dev;  in cdns_wdt_probe()
331 	wdt->clk = devm_clk_get_enabled(dev, NULL);  in cdns_wdt_probe()
332 	if (IS_ERR(wdt->clk))  in cdns_wdt_probe()
333 		return dev_err_probe(dev, PTR_ERR(wdt->clk),  in cdns_wdt_probe()
336 	clock_f = clk_get_rate(wdt->clk);  in cdns_wdt_probe()
338 		wdt->prescaler = CDNS_WDT_PRESCALE_512;  in cdns_wdt_probe()
339 		wdt->ctrl_clksel = CDNS_WDT_PRESCALE_SELECT_512;  in cdns_wdt_probe()
341 		wdt->prescaler = CDNS_WDT_PRESCALE_4096;  in cdns_wdt_probe()
342 		wdt->ctrl_clksel = CDNS_WDT_PRESCALE_SELECT_4096;  in cdns_wdt_probe()
345 	spin_lock_init(&wdt->io_lock);  in cdns_wdt_probe()
354 	dev_info(dev, "Xilinx Watchdog Timer with timeout %ds%s\n",  in cdns_wdt_probe()
355 		 cdns_wdt_device->timeout, nowayout ? ", nowayout" : "");  in cdns_wdt_probe()
361  * cdns_wdt_suspend - Stop the device.
370 	if (watchdog_active(&wdt->cdns_wdt_device)) {  in cdns_wdt_suspend()
371 		cdns_wdt_stop(&wdt->cdns_wdt_device);  in cdns_wdt_suspend()
372 		clk_disable_unprepare(wdt->clk);  in cdns_wdt_suspend()
379  * cdns_wdt_resume - Resume the device.
389 	if (watchdog_active(&wdt->cdns_wdt_device)) {  in cdns_wdt_resume()
390 		ret = clk_prepare_enable(wdt->clk);  in cdns_wdt_resume()
392 			dev_err(dev, "unable to enable clock\n");  in cdns_wdt_resume()
395 		cdns_wdt_start(&wdt->cdns_wdt_device);  in cdns_wdt_resume()
404 	{ .compatible = "cdns,wdt-r1p2", },
413 		.name	= "cdns-wdt",
422 MODULE_DESCRIPTION("Watchdog driver for Cadence WDT");