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 static bool use_sw_pm;
31
32 #define DA9063_TWDSCALE_DISABLE 0
33 #define DA9063_TWDSCALE_MIN 1
34 #define DA9063_TWDSCALE_MAX (ARRAY_SIZE(wdt_timeout) - 1)
35 #define DA9063_WDT_MIN_TIMEOUT wdt_timeout[DA9063_TWDSCALE_MIN]
36 #define DA9063_WDT_MAX_TIMEOUT wdt_timeout[DA9063_TWDSCALE_MAX]
37 #define DA9063_WDG_TIMEOUT wdt_timeout[3]
38 #define DA9063_RESET_PROTECTION_MS 256
39
da9063_wdt_timeout_to_sel(unsigned int secs)40 static unsigned int da9063_wdt_timeout_to_sel(unsigned int secs)
41 {
42 unsigned int i;
43
44 for (i = DA9063_TWDSCALE_MIN; i <= DA9063_TWDSCALE_MAX; i++) {
45 if (wdt_timeout[i] >= secs)
46 return i;
47 }
48
49 return DA9063_TWDSCALE_MAX;
50 }
51
52 /*
53 * Read the currently active timeout.
54 * Zero means the watchdog is disabled.
55 */
da9063_wdt_read_timeout(struct da9063 * da9063)56 static unsigned int da9063_wdt_read_timeout(struct da9063 *da9063)
57 {
58 unsigned int val;
59
60 regmap_read(da9063->regmap, DA9063_REG_CONTROL_D, &val);
61
62 return wdt_timeout[val & DA9063_TWDSCALE_MASK];
63 }
64
da9063_wdt_disable_timer(struct da9063 * da9063)65 static int da9063_wdt_disable_timer(struct da9063 *da9063)
66 {
67 return regmap_update_bits(da9063->regmap, DA9063_REG_CONTROL_D,
68 DA9063_TWDSCALE_MASK,
69 DA9063_TWDSCALE_DISABLE);
70 }
71
72 static int
da9063_wdt_update_timeout(struct da9063 * da9063,unsigned int timeout)73 da9063_wdt_update_timeout(struct da9063 *da9063, unsigned int timeout)
74 {
75 unsigned int regval;
76 int ret;
77
78 /*
79 * The watchdog triggers a reboot if a timeout value is already
80 * programmed because the timeout value combines two functions
81 * in one: indicating the counter limit and starting the watchdog.
82 * The watchdog must be disabled to be able to change the timeout
83 * value if the watchdog is already running. Then we can set the
84 * new timeout value which enables the watchdog again.
85 */
86 ret = da9063_wdt_disable_timer(da9063);
87 if (ret)
88 return ret;
89
90 usleep_range(150, 300);
91 regval = da9063_wdt_timeout_to_sel(timeout);
92
93 return regmap_update_bits(da9063->regmap, DA9063_REG_CONTROL_D,
94 DA9063_TWDSCALE_MASK, regval);
95 }
96
da9063_wdt_start(struct watchdog_device * wdd)97 static int da9063_wdt_start(struct watchdog_device *wdd)
98 {
99 struct da9063 *da9063 = watchdog_get_drvdata(wdd);
100 int ret;
101
102 ret = da9063_wdt_update_timeout(da9063, wdd->timeout);
103 if (ret)
104 dev_err(da9063->dev, "Watchdog failed to start (err = %d)\n",
105 ret);
106
107 return ret;
108 }
109
da9063_wdt_stop(struct watchdog_device * wdd)110 static int da9063_wdt_stop(struct watchdog_device *wdd)
111 {
112 struct da9063 *da9063 = watchdog_get_drvdata(wdd);
113 int ret;
114
115 ret = da9063_wdt_disable_timer(da9063);
116 if (ret)
117 dev_alert(da9063->dev, "Watchdog failed to stop (err = %d)\n",
118 ret);
119
120 return ret;
121 }
122
da9063_wdt_ping(struct watchdog_device * wdd)123 static int da9063_wdt_ping(struct watchdog_device *wdd)
124 {
125 struct da9063 *da9063 = watchdog_get_drvdata(wdd);
126 int ret;
127
128 /*
129 * Prevent pings from occurring late in system poweroff/reboot sequence
130 * and possibly locking out restart handler from accessing i2c bus.
131 */
132 if (system_state > SYSTEM_RUNNING)
133 return 0;
134
135 ret = regmap_write(da9063->regmap, DA9063_REG_CONTROL_F,
136 DA9063_WATCHDOG);
137 if (ret)
138 dev_alert(da9063->dev, "Failed to ping the watchdog (err = %d)\n",
139 ret);
140
141 return ret;
142 }
143
da9063_wdt_set_timeout(struct watchdog_device * wdd,unsigned int timeout)144 static int da9063_wdt_set_timeout(struct watchdog_device *wdd,
145 unsigned int timeout)
146 {
147 struct da9063 *da9063 = watchdog_get_drvdata(wdd);
148 int ret = 0;
149
150 /*
151 * There are two cases when a set_timeout() will be called:
152 * 1. The watchdog is off and someone wants to set the timeout for the
153 * further use.
154 * 2. The watchdog is already running and a new timeout value should be
155 * set.
156 *
157 * The watchdog can't store a timeout value not equal zero without
158 * enabling the watchdog, so the timeout must be buffered by the driver.
159 */
160 if (watchdog_active(wdd))
161 ret = da9063_wdt_update_timeout(da9063, timeout);
162
163 if (ret)
164 dev_err(da9063->dev, "Failed to set watchdog timeout (err = %d)\n",
165 ret);
166 else
167 wdd->timeout = wdt_timeout[da9063_wdt_timeout_to_sel(timeout)];
168
169 return ret;
170 }
171
da9063_wdt_restart(struct watchdog_device * wdd,unsigned long action,void * data)172 static int da9063_wdt_restart(struct watchdog_device *wdd, unsigned long action,
173 void *data)
174 {
175 struct da9063 *da9063 = watchdog_get_drvdata(wdd);
176 struct i2c_client *client = to_i2c_client(da9063->dev);
177 int ret;
178
179 /* Don't use regmap because it is not atomic safe */
180 ret = i2c_smbus_write_byte_data(client, DA9063_REG_CONTROL_F,
181 DA9063_SHUTDOWN);
182 if (ret < 0)
183 dev_alert(da9063->dev, "Failed to shutdown (err = %d)\n",
184 ret);
185
186 /* wait for reset to assert... */
187 mdelay(500);
188
189 return ret;
190 }
191
192 static const struct watchdog_info da9063_watchdog_info = {
193 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
194 .identity = "DA9063 Watchdog",
195 };
196
197 static const struct watchdog_ops da9063_watchdog_ops = {
198 .owner = THIS_MODULE,
199 .start = da9063_wdt_start,
200 .stop = da9063_wdt_stop,
201 .ping = da9063_wdt_ping,
202 .set_timeout = da9063_wdt_set_timeout,
203 .restart = da9063_wdt_restart,
204 };
205
da9063_wdt_probe(struct platform_device * pdev)206 static int da9063_wdt_probe(struct platform_device *pdev)
207 {
208 struct device *dev = &pdev->dev;
209 struct da9063 *da9063;
210 struct watchdog_device *wdd;
211 unsigned int timeout;
212
213 if (!dev->parent)
214 return -EINVAL;
215
216 da9063 = dev_get_drvdata(dev->parent);
217 if (!da9063)
218 return -EINVAL;
219
220 wdd = devm_kzalloc(dev, sizeof(*wdd), GFP_KERNEL);
221 if (!wdd)
222 return -ENOMEM;
223
224 use_sw_pm = device_property_present(dev, "dlg,use-sw-pm");
225
226 wdd->info = &da9063_watchdog_info;
227 wdd->ops = &da9063_watchdog_ops;
228 wdd->min_timeout = DA9063_WDT_MIN_TIMEOUT;
229 wdd->max_timeout = DA9063_WDT_MAX_TIMEOUT;
230 wdd->min_hw_heartbeat_ms = DA9063_RESET_PROTECTION_MS;
231 wdd->parent = dev;
232 wdd->status = WATCHDOG_NOWAYOUT_INIT_STATUS;
233
234 watchdog_set_restart_priority(wdd, 128);
235 watchdog_set_drvdata(wdd, da9063);
236 dev_set_drvdata(dev, wdd);
237
238 wdd->timeout = DA9063_WDG_TIMEOUT;
239
240 /* Use pre-configured timeout if watchdog is already running. */
241 timeout = da9063_wdt_read_timeout(da9063);
242 if (timeout)
243 wdd->timeout = timeout;
244
245 /* Set timeout, maybe override it with DT value, scale it */
246 watchdog_init_timeout(wdd, 0, dev);
247 da9063_wdt_set_timeout(wdd, wdd->timeout);
248
249 /* Update timeout if the watchdog is already running. */
250 if (timeout) {
251 da9063_wdt_update_timeout(da9063, wdd->timeout);
252 set_bit(WDOG_HW_RUNNING, &wdd->status);
253 }
254
255 return devm_watchdog_register_device(dev, wdd);
256 }
257
da9063_wdt_suspend(struct device * dev)258 static int __maybe_unused da9063_wdt_suspend(struct device *dev)
259 {
260 struct watchdog_device *wdd = dev_get_drvdata(dev);
261
262 if (!use_sw_pm)
263 return 0;
264
265 if (watchdog_active(wdd))
266 return da9063_wdt_stop(wdd);
267
268 return 0;
269 }
270
da9063_wdt_resume(struct device * dev)271 static int __maybe_unused da9063_wdt_resume(struct device *dev)
272 {
273 struct watchdog_device *wdd = dev_get_drvdata(dev);
274
275 if (!use_sw_pm)
276 return 0;
277
278 if (watchdog_active(wdd))
279 return da9063_wdt_start(wdd);
280
281 return 0;
282 }
283
284 static SIMPLE_DEV_PM_OPS(da9063_wdt_pm_ops,
285 da9063_wdt_suspend, da9063_wdt_resume);
286
287 static struct platform_driver da9063_wdt_driver = {
288 .probe = da9063_wdt_probe,
289 .driver = {
290 .name = DA9063_DRVNAME_WATCHDOG,
291 .pm = &da9063_wdt_pm_ops,
292 },
293 };
294 module_platform_driver(da9063_wdt_driver);
295
296 MODULE_AUTHOR("Mariusz Wojtasik <mariusz.wojtasik@diasemi.com>");
297 MODULE_DESCRIPTION("Watchdog driver for Dialog DA9063");
298 MODULE_LICENSE("GPL");
299 MODULE_ALIAS("platform:" DA9063_DRVNAME_WATCHDOG);
300
