2 * Watchdog driver for Conexant Digicolor
4 * Copyright (C) 2015 Paradox Innovation Ltd.
6 * This program is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License as published by the
8 * Free Software Foundation; either version 2 of the License, or (at your
9 * option) any later version.
12 #include <linux/types.h>
13 #include <linux/module.h>
15 #include <linux/delay.h>
16 #include <linux/clk.h>
17 #include <linux/watchdog.h>
18 #include <linux/platform_device.h>
19 #include <linux/of_address.h>
21 #define TIMER_A_CONTROL 0
22 #define TIMER_A_COUNT 4
24 #define TIMER_A_ENABLE_COUNT BIT(0)
25 #define TIMER_A_ENABLE_WATCHDOG BIT(1)
33 static unsigned timeout;
34 module_param(timeout, uint, 0);
35 MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds");
37 static void dc_wdt_set(struct dc_wdt *wdt, u32 ticks)
41 spin_lock_irqsave(&wdt->lock, flags);
43 writel_relaxed(0, wdt->base + TIMER_A_CONTROL);
44 writel_relaxed(ticks, wdt->base + TIMER_A_COUNT);
45 writel_relaxed(TIMER_A_ENABLE_COUNT | TIMER_A_ENABLE_WATCHDOG,
46 wdt->base + TIMER_A_CONTROL);
48 spin_unlock_irqrestore(&wdt->lock, flags);
51 static int dc_wdt_restart(struct watchdog_device *wdog)
53 struct dc_wdt *wdt = watchdog_get_drvdata(wdog);
56 /* wait for reset to assert... */
62 static int dc_wdt_start(struct watchdog_device *wdog)
64 struct dc_wdt *wdt = watchdog_get_drvdata(wdog);
66 dc_wdt_set(wdt, wdog->timeout * clk_get_rate(wdt->clk));
71 static int dc_wdt_stop(struct watchdog_device *wdog)
73 struct dc_wdt *wdt = watchdog_get_drvdata(wdog);
75 writel_relaxed(0, wdt->base + TIMER_A_CONTROL);
80 static int dc_wdt_set_timeout(struct watchdog_device *wdog, unsigned int t)
82 struct dc_wdt *wdt = watchdog_get_drvdata(wdog);
84 dc_wdt_set(wdt, t * clk_get_rate(wdt->clk));
90 static unsigned int dc_wdt_get_timeleft(struct watchdog_device *wdog)
92 struct dc_wdt *wdt = watchdog_get_drvdata(wdog);
93 uint32_t count = readl_relaxed(wdt->base + TIMER_A_COUNT);
95 return count / clk_get_rate(wdt->clk);
98 static struct watchdog_ops dc_wdt_ops = {
100 .start = dc_wdt_start,
102 .set_timeout = dc_wdt_set_timeout,
103 .get_timeleft = dc_wdt_get_timeleft,
104 .restart = dc_wdt_restart,
107 static struct watchdog_info dc_wdt_info = {
108 .options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE
109 | WDIOF_KEEPALIVEPING,
110 .identity = "Conexant Digicolor Watchdog",
113 static struct watchdog_device dc_wdt_wdd = {
114 .info = &dc_wdt_info,
119 static int dc_wdt_probe(struct platform_device *pdev)
121 struct device *dev = &pdev->dev;
122 struct device_node *np = dev->of_node;
126 wdt = devm_kzalloc(dev, sizeof(struct dc_wdt), GFP_KERNEL);
129 platform_set_drvdata(pdev, wdt);
131 wdt->base = of_iomap(np, 0);
133 dev_err(dev, "Failed to remap watchdog regs");
137 wdt->clk = devm_clk_get(&pdev->dev, NULL);
138 if (IS_ERR(wdt->clk)) {
139 ret = PTR_ERR(wdt->clk);
142 dc_wdt_wdd.max_timeout = U32_MAX / clk_get_rate(wdt->clk);
143 dc_wdt_wdd.timeout = dc_wdt_wdd.max_timeout;
144 dc_wdt_wdd.parent = &pdev->dev;
146 spin_lock_init(&wdt->lock);
148 watchdog_set_drvdata(&dc_wdt_wdd, wdt);
149 watchdog_set_restart_priority(&dc_wdt_wdd, 128);
150 watchdog_init_timeout(&dc_wdt_wdd, timeout, dev);
151 ret = watchdog_register_device(&dc_wdt_wdd);
153 dev_err(dev, "Failed to register watchdog device");
164 static int dc_wdt_remove(struct platform_device *pdev)
166 struct dc_wdt *wdt = platform_get_drvdata(pdev);
168 watchdog_unregister_device(&dc_wdt_wdd);
174 static void dc_wdt_shutdown(struct platform_device *pdev)
176 dc_wdt_stop(&dc_wdt_wdd);
179 static const struct of_device_id dc_wdt_of_match[] = {
180 { .compatible = "cnxt,cx92755-wdt", },
183 MODULE_DEVICE_TABLE(of, dc_wdt_of_match);
185 static struct platform_driver dc_wdt_driver = {
186 .probe = dc_wdt_probe,
187 .remove = dc_wdt_remove,
188 .shutdown = dc_wdt_shutdown,
190 .name = "digicolor-wdt",
191 .of_match_table = dc_wdt_of_match,
194 module_platform_driver(dc_wdt_driver);
196 MODULE_AUTHOR("Baruch Siach <baruch@tkos.co.il>");
197 MODULE_DESCRIPTION("Driver for Conexant Digicolor watchdog timer");
198 MODULE_LICENSE("GPL");