1 // SPDX-License-Identifier: GPL-2.0+
3 * Watchdog driver for DA9063 PMICs.
5 * Copyright(c) 2012 Dialog Semiconductor Ltd.
7 * Author: Mariusz Wojtasik <mariusz.wojtasik@diasemi.com>
11 #include <linux/kernel.h>
12 #include <linux/module.h>
13 #include <linux/watchdog.h>
14 #include <linux/platform_device.h>
15 #include <linux/uaccess.h>
16 #include <linux/slab.h>
17 #include <linux/i2c.h>
18 #include <linux/delay.h>
19 #include <linux/mfd/da9063/registers.h>
20 #include <linux/mfd/da9063/core.h>
21 #include <linux/regmap.h>
24 * Watchdog selector to timeout in seconds.
26 * others: timeout = 2048 ms * 2^(TWDSCALE-1).
28 static const unsigned int wdt_timeout[] = { 0, 2, 4, 8, 16, 32, 65, 131 };
29 #define DA9063_TWDSCALE_DISABLE 0
30 #define DA9063_TWDSCALE_MIN 1
31 #define DA9063_TWDSCALE_MAX (ARRAY_SIZE(wdt_timeout) - 1)
32 #define DA9063_WDT_MIN_TIMEOUT wdt_timeout[DA9063_TWDSCALE_MIN]
33 #define DA9063_WDT_MAX_TIMEOUT wdt_timeout[DA9063_TWDSCALE_MAX]
34 #define DA9063_WDG_TIMEOUT wdt_timeout[3]
35 #define DA9063_RESET_PROTECTION_MS 256
37 static unsigned int da9063_wdt_timeout_to_sel(unsigned int secs)
41 for (i = DA9063_TWDSCALE_MIN; i <= DA9063_TWDSCALE_MAX; i++) {
42 if (wdt_timeout[i] >= secs)
46 return DA9063_TWDSCALE_MAX;
50 * Read the currently active timeout.
51 * Zero means the watchdog is disabled.
53 static unsigned int da9063_wdt_read_timeout(struct da9063 *da9063)
57 regmap_read(da9063->regmap, DA9063_REG_CONTROL_D, &val);
59 return wdt_timeout[val & DA9063_TWDSCALE_MASK];
62 static int da9063_wdt_disable_timer(struct da9063 *da9063)
64 return regmap_update_bits(da9063->regmap, DA9063_REG_CONTROL_D,
66 DA9063_TWDSCALE_DISABLE);
70 da9063_wdt_update_timeout(struct da9063 *da9063, unsigned int timeout)
76 * The watchdog triggers a reboot if a timeout value is already
77 * programmed because the timeout value combines two functions
78 * in one: indicating the counter limit and starting the watchdog.
79 * The watchdog must be disabled to be able to change the timeout
80 * value if the watchdog is already running. Then we can set the
81 * new timeout value which enables the watchdog again.
83 ret = da9063_wdt_disable_timer(da9063);
87 usleep_range(150, 300);
88 regval = da9063_wdt_timeout_to_sel(timeout);
90 return regmap_update_bits(da9063->regmap, DA9063_REG_CONTROL_D,
91 DA9063_TWDSCALE_MASK, regval);
94 static int da9063_wdt_start(struct watchdog_device *wdd)
96 struct da9063 *da9063 = watchdog_get_drvdata(wdd);
99 ret = da9063_wdt_update_timeout(da9063, wdd->timeout);
101 dev_err(da9063->dev, "Watchdog failed to start (err = %d)\n",
107 static int da9063_wdt_stop(struct watchdog_device *wdd)
109 struct da9063 *da9063 = watchdog_get_drvdata(wdd);
112 ret = da9063_wdt_disable_timer(da9063);
114 dev_alert(da9063->dev, "Watchdog failed to stop (err = %d)\n",
120 static int da9063_wdt_ping(struct watchdog_device *wdd)
122 struct da9063 *da9063 = watchdog_get_drvdata(wdd);
126 * Prevent pings from occurring late in system poweroff/reboot sequence
127 * and possibly locking out restart handler from accessing i2c bus.
129 if (system_state > SYSTEM_RUNNING)
132 ret = regmap_write(da9063->regmap, DA9063_REG_CONTROL_F,
135 dev_alert(da9063->dev, "Failed to ping the watchdog (err = %d)\n",
141 static int da9063_wdt_set_timeout(struct watchdog_device *wdd,
142 unsigned int timeout)
144 struct da9063 *da9063 = watchdog_get_drvdata(wdd);
148 * There are two cases when a set_timeout() will be called:
149 * 1. The watchdog is off and someone wants to set the timeout for the
151 * 2. The watchdog is already running and a new timeout value should be
154 * The watchdog can't store a timeout value not equal zero without
155 * enabling the watchdog, so the timeout must be buffered by the driver.
157 if (watchdog_active(wdd))
158 ret = da9063_wdt_update_timeout(da9063, timeout);
161 dev_err(da9063->dev, "Failed to set watchdog timeout (err = %d)\n",
164 wdd->timeout = wdt_timeout[da9063_wdt_timeout_to_sel(timeout)];
169 static int da9063_wdt_restart(struct watchdog_device *wdd, unsigned long action,
172 struct da9063 *da9063 = watchdog_get_drvdata(wdd);
173 struct i2c_client *client = to_i2c_client(da9063->dev);
176 /* Don't use regmap because it is not atomic safe */
177 ret = i2c_smbus_write_byte_data(client, DA9063_REG_CONTROL_F,
180 dev_alert(da9063->dev, "Failed to shutdown (err = %d)\n",
183 /* wait for reset to assert... */
189 static const struct watchdog_info da9063_watchdog_info = {
190 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
191 .identity = "DA9063 Watchdog",
194 static const struct watchdog_ops da9063_watchdog_ops = {
195 .owner = THIS_MODULE,
196 .start = da9063_wdt_start,
197 .stop = da9063_wdt_stop,
198 .ping = da9063_wdt_ping,
199 .set_timeout = da9063_wdt_set_timeout,
200 .restart = da9063_wdt_restart,
203 static int da9063_wdt_probe(struct platform_device *pdev)
205 struct device *dev = &pdev->dev;
206 struct da9063 *da9063;
207 struct watchdog_device *wdd;
208 unsigned int timeout;
213 da9063 = dev_get_drvdata(dev->parent);
217 wdd = devm_kzalloc(dev, sizeof(*wdd), GFP_KERNEL);
221 wdd->info = &da9063_watchdog_info;
222 wdd->ops = &da9063_watchdog_ops;
223 wdd->min_timeout = DA9063_WDT_MIN_TIMEOUT;
224 wdd->max_timeout = DA9063_WDT_MAX_TIMEOUT;
225 wdd->min_hw_heartbeat_ms = DA9063_RESET_PROTECTION_MS;
227 wdd->status = WATCHDOG_NOWAYOUT_INIT_STATUS;
229 watchdog_set_restart_priority(wdd, 128);
230 watchdog_set_drvdata(wdd, da9063);
232 wdd->timeout = DA9063_WDG_TIMEOUT;
234 /* Use pre-configured timeout if watchdog is already running. */
235 timeout = da9063_wdt_read_timeout(da9063);
237 wdd->timeout = timeout;
239 /* Set timeout, maybe override it with DT value, scale it */
240 watchdog_init_timeout(wdd, 0, dev);
241 da9063_wdt_set_timeout(wdd, wdd->timeout);
243 /* Update timeout if the watchdog is already running. */
245 da9063_wdt_update_timeout(da9063, wdd->timeout);
246 set_bit(WDOG_HW_RUNNING, &wdd->status);
249 return devm_watchdog_register_device(dev, wdd);
252 static struct platform_driver da9063_wdt_driver = {
253 .probe = da9063_wdt_probe,
255 .name = DA9063_DRVNAME_WATCHDOG,
258 module_platform_driver(da9063_wdt_driver);
260 MODULE_AUTHOR("Mariusz Wojtasik <mariusz.wojtasik@diasemi.com>");
261 MODULE_DESCRIPTION("Watchdog driver for Dialog DA9063");
262 MODULE_LICENSE("GPL");
263 MODULE_ALIAS("platform:" DA9063_DRVNAME_WATCHDOG);