xref: /linux/drivers/watchdog/da9063_wdt.c (revision 42d52acfb10cfc53139a1139e1c401a52c3f924c)
1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * Watchdog driver for DA9063 PMICs.
4  *
5  * Copyright(c) 2012 Dialog Semiconductor Ltd.
6  *
7  * Author: Mariusz Wojtasik <mariusz.wojtasik@diasemi.com>
8  *
9  */
10 
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/property.h>
22 #include <linux/regmap.h>
23 
24 /*
25  * Watchdog selector to timeout in seconds.
26  *   0: WDT disabled;
27  *   others: timeout = 2048 ms * 2^(TWDSCALE-1).
28  */
29 static const unsigned int wdt_timeout[] = { 0, 2, 4, 8, 16, 32, 65, 131 };
30 
31 #define DA9063_TWDSCALE_DISABLE		0
32 #define DA9063_TWDSCALE_MIN		1
33 #define DA9063_TWDSCALE_MAX		(ARRAY_SIZE(wdt_timeout) - 1)
34 #define DA9063_WDT_MIN_TIMEOUT		wdt_timeout[DA9063_TWDSCALE_MIN]
35 #define DA9063_WDT_MAX_TIMEOUT		wdt_timeout[DA9063_TWDSCALE_MAX]
36 #define DA9063_WDG_TIMEOUT		wdt_timeout[3]
37 #define DA9063_RESET_PROTECTION_MS	256
38 
da9063_wdt_timeout_to_sel(unsigned int secs)39 static unsigned int da9063_wdt_timeout_to_sel(unsigned int secs)
40 {
41 	unsigned int i;
42 
43 	for (i = DA9063_TWDSCALE_MIN; i <= DA9063_TWDSCALE_MAX; i++) {
44 		if (wdt_timeout[i] >= secs)
45 			return i;
46 	}
47 
48 	return DA9063_TWDSCALE_MAX;
49 }
50 
51 /*
52  * Read the currently active timeout.
53  * Zero means the watchdog is disabled.
54  */
da9063_wdt_read_timeout(struct da9063 * da9063)55 static unsigned int da9063_wdt_read_timeout(struct da9063 *da9063)
56 {
57 	unsigned int val;
58 
59 	regmap_read(da9063->regmap, DA9063_REG_CONTROL_D, &val);
60 
61 	return wdt_timeout[val & DA9063_TWDSCALE_MASK];
62 }
63 
da9063_wdt_disable_timer(struct da9063 * da9063)64 static int da9063_wdt_disable_timer(struct da9063 *da9063)
65 {
66 	return regmap_update_bits(da9063->regmap, DA9063_REG_CONTROL_D,
67 				  DA9063_TWDSCALE_MASK,
68 				  DA9063_TWDSCALE_DISABLE);
69 }
70 
71 static int
da9063_wdt_update_timeout(struct da9063 * da9063,unsigned int timeout)72 da9063_wdt_update_timeout(struct da9063 *da9063, unsigned int timeout)
73 {
74 	unsigned int regval;
75 	int ret;
76 
77 	/*
78 	 * The watchdog triggers a reboot if a timeout value is already
79 	 * programmed because the timeout value combines two functions
80 	 * in one: indicating the counter limit and starting the watchdog.
81 	 * The watchdog must be disabled to be able to change the timeout
82 	 * value if the watchdog is already running. Then we can set the
83 	 * new timeout value which enables the watchdog again.
84 	 */
85 	ret = da9063_wdt_disable_timer(da9063);
86 	if (ret)
87 		return ret;
88 
89 	usleep_range(150, 300);
90 	regval = da9063_wdt_timeout_to_sel(timeout);
91 
92 	return regmap_update_bits(da9063->regmap, DA9063_REG_CONTROL_D,
93 				  DA9063_TWDSCALE_MASK, regval);
94 }
95 
da9063_wdt_start(struct watchdog_device * wdd)96 static int da9063_wdt_start(struct watchdog_device *wdd)
97 {
98 	struct da9063 *da9063 = watchdog_get_drvdata(wdd);
99 	int ret;
100 
101 	ret = da9063_wdt_update_timeout(da9063, wdd->timeout);
102 	if (ret)
103 		dev_err(da9063->dev, "Watchdog failed to start (err = %d)\n",
104 			ret);
105 
106 	return ret;
107 }
108 
da9063_wdt_stop(struct watchdog_device * wdd)109 static int da9063_wdt_stop(struct watchdog_device *wdd)
110 {
111 	struct da9063 *da9063 = watchdog_get_drvdata(wdd);
112 	int ret;
113 
114 	ret = da9063_wdt_disable_timer(da9063);
115 	if (ret)
116 		dev_alert(da9063->dev, "Watchdog failed to stop (err = %d)\n",
117 			  ret);
118 
119 	return ret;
120 }
121 
da9063_wdt_ping(struct watchdog_device * wdd)122 static int da9063_wdt_ping(struct watchdog_device *wdd)
123 {
124 	struct da9063 *da9063 = watchdog_get_drvdata(wdd);
125 	int ret;
126 
127 	/*
128 	 * Prevent pings from occurring late in system poweroff/reboot sequence
129 	 * and possibly locking out restart handler from accessing i2c bus.
130 	 */
131 	if (system_state > SYSTEM_RUNNING)
132 		return 0;
133 
134 	ret = regmap_write(da9063->regmap, DA9063_REG_CONTROL_F,
135 			   DA9063_WATCHDOG);
136 	if (ret)
137 		dev_alert(da9063->dev, "Failed to ping the watchdog (err = %d)\n",
138 			  ret);
139 
140 	return ret;
141 }
142 
da9063_wdt_set_timeout(struct watchdog_device * wdd,unsigned int timeout)143 static int da9063_wdt_set_timeout(struct watchdog_device *wdd,
144 				  unsigned int timeout)
145 {
146 	struct da9063 *da9063 = watchdog_get_drvdata(wdd);
147 	int ret = 0;
148 
149 	/*
150 	 * There are two cases when a set_timeout() will be called:
151 	 * 1. The watchdog is off and someone wants to set the timeout for the
152 	 *    further use.
153 	 * 2. The watchdog is already running and a new timeout value should be
154 	 *    set.
155 	 *
156 	 * The watchdog can't store a timeout value not equal zero without
157 	 * enabling the watchdog, so the timeout must be buffered by the driver.
158 	 */
159 	if (watchdog_active(wdd))
160 		ret = da9063_wdt_update_timeout(da9063, timeout);
161 
162 	if (ret)
163 		dev_err(da9063->dev, "Failed to set watchdog timeout (err = %d)\n",
164 			ret);
165 	else
166 		wdd->timeout = wdt_timeout[da9063_wdt_timeout_to_sel(timeout)];
167 
168 	return ret;
169 }
170 
da9063_wdt_restart(struct watchdog_device * wdd,unsigned long action,void * data)171 static int da9063_wdt_restart(struct watchdog_device *wdd, unsigned long action,
172 			      void *data)
173 {
174 	struct da9063 *da9063 = watchdog_get_drvdata(wdd);
175 	struct i2c_client *client = to_i2c_client(da9063->dev);
176 	union i2c_smbus_data msg;
177 	int ret;
178 
179 	/*
180 	 * Don't use regmap because it is not atomic safe. Additionally, use
181 	 * unlocked flavor of i2c_smbus_xfer to avoid scenario where i2c bus
182 	 * might previously be locked by some process unable to release the
183 	 * lock due to interrupts already being disabled at this late stage.
184 	 */
185 	msg.byte = DA9063_SHUTDOWN;
186 	ret = __i2c_smbus_xfer(client->adapter, client->addr, client->flags,
187 			I2C_SMBUS_WRITE, DA9063_REG_CONTROL_F,
188 			I2C_SMBUS_BYTE_DATA, &msg);
189 
190 	if (ret < 0)
191 		dev_alert(da9063->dev, "Failed to shutdown (err = %d)\n",
192 			  ret);
193 
194 	/* wait for reset to assert... */
195 	mdelay(500);
196 
197 	return ret;
198 }
199 
200 static const struct watchdog_info da9063_watchdog_info = {
201 	.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
202 	.identity = "DA9063 Watchdog",
203 };
204 
205 static const struct watchdog_ops da9063_watchdog_ops = {
206 	.owner = THIS_MODULE,
207 	.start = da9063_wdt_start,
208 	.stop = da9063_wdt_stop,
209 	.ping = da9063_wdt_ping,
210 	.set_timeout = da9063_wdt_set_timeout,
211 	.restart = da9063_wdt_restart,
212 };
213 
da9063_wdt_probe(struct platform_device * pdev)214 static int da9063_wdt_probe(struct platform_device *pdev)
215 {
216 	struct device *dev = &pdev->dev;
217 	struct da9063 *da9063;
218 	struct watchdog_device *wdd;
219 	unsigned int timeout;
220 
221 	if (!dev->parent)
222 		return -EINVAL;
223 
224 	da9063 = dev_get_drvdata(dev->parent);
225 	if (!da9063)
226 		return -EINVAL;
227 
228 	wdd = devm_kzalloc(dev, sizeof(*wdd), GFP_KERNEL);
229 	if (!wdd)
230 		return -ENOMEM;
231 
232 	da9063->use_sw_pm = device_property_present(dev, "dlg,use-sw-pm");
233 
234 	wdd->info = &da9063_watchdog_info;
235 	wdd->ops = &da9063_watchdog_ops;
236 	wdd->min_timeout = DA9063_WDT_MIN_TIMEOUT;
237 	wdd->max_timeout = DA9063_WDT_MAX_TIMEOUT;
238 	wdd->min_hw_heartbeat_ms = DA9063_RESET_PROTECTION_MS;
239 	wdd->parent = dev;
240 	wdd->status = WATCHDOG_NOWAYOUT_INIT_STATUS;
241 
242 	watchdog_set_restart_priority(wdd, 128);
243 	watchdog_set_drvdata(wdd, da9063);
244 	dev_set_drvdata(dev, wdd);
245 
246 	wdd->timeout = DA9063_WDG_TIMEOUT;
247 
248 	/* Use pre-configured timeout if watchdog is already running. */
249 	timeout = da9063_wdt_read_timeout(da9063);
250 	if (timeout)
251 		wdd->timeout = timeout;
252 
253 	/* Set timeout, maybe override it with DT value, scale it */
254 	watchdog_init_timeout(wdd, 0, dev);
255 	da9063_wdt_set_timeout(wdd, wdd->timeout);
256 
257 	/* Update timeout if the watchdog is already running. */
258 	if (timeout) {
259 		da9063_wdt_update_timeout(da9063, wdd->timeout);
260 		set_bit(WDOG_HW_RUNNING, &wdd->status);
261 	}
262 
263 	return devm_watchdog_register_device(dev, wdd);
264 }
265 
da9063_wdt_suspend(struct device * dev)266 static int da9063_wdt_suspend(struct device *dev)
267 {
268 	struct watchdog_device *wdd = dev_get_drvdata(dev);
269 	struct da9063 *da9063 = watchdog_get_drvdata(wdd);
270 
271 	if (!da9063->use_sw_pm)
272 		return 0;
273 
274 	if (watchdog_active(wdd))
275 		return da9063_wdt_stop(wdd);
276 
277 	return 0;
278 }
279 
da9063_wdt_resume(struct device * dev)280 static int da9063_wdt_resume(struct device *dev)
281 {
282 	struct watchdog_device *wdd = dev_get_drvdata(dev);
283 	struct da9063 *da9063 = watchdog_get_drvdata(wdd);
284 
285 	if (!da9063->use_sw_pm)
286 		return 0;
287 
288 	if (watchdog_active(wdd))
289 		return da9063_wdt_start(wdd);
290 
291 	return 0;
292 }
293 
294 static DEFINE_SIMPLE_DEV_PM_OPS(da9063_wdt_pm_ops, da9063_wdt_suspend,
295 				da9063_wdt_resume);
296 
297 static struct platform_driver da9063_wdt_driver = {
298 	.probe = da9063_wdt_probe,
299 	.driver = {
300 		.name = DA9063_DRVNAME_WATCHDOG,
301 		.pm = pm_sleep_ptr(&da9063_wdt_pm_ops),
302 	},
303 };
304 module_platform_driver(da9063_wdt_driver);
305 
306 MODULE_AUTHOR("Mariusz Wojtasik <mariusz.wojtasik@diasemi.com>");
307 MODULE_DESCRIPTION("Watchdog driver for Dialog DA9063");
308 MODULE_LICENSE("GPL");
309 MODULE_ALIAS("platform:" DA9063_DRVNAME_WATCHDOG);
310