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/delay.h>
18 #include <linux/mfd/da9063/registers.h>
19 #include <linux/mfd/da9063/core.h>
20 #include <linux/regmap.h>
21
22 /*
23 * Watchdog selector to timeout in seconds.
24 * 0: WDT disabled;
25 * others: timeout = 2048 ms * 2^(TWDSCALE-1).
26 */
27 static const unsigned int wdt_timeout[] = { 0, 2, 4, 8, 16, 32, 65, 131 };
28 #define DA9063_TWDSCALE_DISABLE 0
29 #define DA9063_TWDSCALE_MIN 1
30 #define DA9063_TWDSCALE_MAX (ARRAY_SIZE(wdt_timeout) - 1)
31 #define DA9063_WDT_MIN_TIMEOUT wdt_timeout[DA9063_TWDSCALE_MIN]
32 #define DA9063_WDT_MAX_TIMEOUT wdt_timeout[DA9063_TWDSCALE_MAX]
33 #define DA9063_WDG_TIMEOUT wdt_timeout[3]
34 #define DA9063_RESET_PROTECTION_MS 256
35
da9063_wdt_timeout_to_sel(unsigned int secs)36 static unsigned int da9063_wdt_timeout_to_sel(unsigned int secs)
37 {
38 unsigned int i;
39
40 for (i = DA9063_TWDSCALE_MIN; i <= DA9063_TWDSCALE_MAX; i++) {
41 if (wdt_timeout[i] >= secs)
42 return i;
43 }
44
45 return DA9063_TWDSCALE_MAX;
46 }
47
48 /*
49 * Read the currently active timeout.
50 * Zero means the watchdog is disabled.
51 */
da9063_wdt_read_timeout(struct da9063 * da9063)52 static unsigned int da9063_wdt_read_timeout(struct da9063 *da9063)
53 {
54 unsigned int val;
55
56 regmap_read(da9063->regmap, DA9063_REG_CONTROL_D, &val);
57
58 return wdt_timeout[val & DA9063_TWDSCALE_MASK];
59 }
60
da9063_wdt_disable_timer(struct da9063 * da9063)61 static int da9063_wdt_disable_timer(struct da9063 *da9063)
62 {
63 return regmap_update_bits(da9063->regmap, DA9063_REG_CONTROL_D,
64 DA9063_TWDSCALE_MASK,
65 DA9063_TWDSCALE_DISABLE);
66 }
67
68 static int
da9063_wdt_update_timeout(struct da9063 * da9063,unsigned int timeout)69 da9063_wdt_update_timeout(struct da9063 *da9063, unsigned int timeout)
70 {
71 unsigned int regval;
72 int ret;
73
74 /*
75 * The watchdog triggers a reboot if a timeout value is already
76 * programmed because the timeout value combines two functions
77 * in one: indicating the counter limit and starting the watchdog.
78 * The watchdog must be disabled to be able to change the timeout
79 * value if the watchdog is already running. Then we can set the
80 * new timeout value which enables the watchdog again.
81 */
82 ret = da9063_wdt_disable_timer(da9063);
83 if (ret)
84 return ret;
85
86 usleep_range(150, 300);
87 regval = da9063_wdt_timeout_to_sel(timeout);
88
89 return regmap_update_bits(da9063->regmap, DA9063_REG_CONTROL_D,
90 DA9063_TWDSCALE_MASK, regval);
91 }
92
da9063_wdt_start(struct watchdog_device * wdd)93 static int da9063_wdt_start(struct watchdog_device *wdd)
94 {
95 struct da9063 *da9063 = watchdog_get_drvdata(wdd);
96 int ret;
97
98 ret = da9063_wdt_update_timeout(da9063, wdd->timeout);
99 if (ret)
100 dev_err(da9063->dev, "Watchdog failed to start (err = %d)\n",
101 ret);
102
103 return ret;
104 }
105
da9063_wdt_stop(struct watchdog_device * wdd)106 static int da9063_wdt_stop(struct watchdog_device *wdd)
107 {
108 struct da9063 *da9063 = watchdog_get_drvdata(wdd);
109 int ret;
110
111 ret = da9063_wdt_disable_timer(da9063);
112 if (ret)
113 dev_alert(da9063->dev, "Watchdog failed to stop (err = %d)\n",
114 ret);
115
116 return ret;
117 }
118
da9063_wdt_ping(struct watchdog_device * wdd)119 static int da9063_wdt_ping(struct watchdog_device *wdd)
120 {
121 struct da9063 *da9063 = watchdog_get_drvdata(wdd);
122 int ret;
123
124 /*
125 * Prevent pings from occurring late in system poweroff/reboot sequence
126 * and possibly locking out restart handler from accessing i2c bus.
127 */
128 if (system_state > SYSTEM_RUNNING)
129 return 0;
130
131 ret = regmap_write(da9063->regmap, DA9063_REG_CONTROL_F,
132 DA9063_WATCHDOG);
133 if (ret)
134 dev_alert(da9063->dev, "Failed to ping the watchdog (err = %d)\n",
135 ret);
136
137 return ret;
138 }
139
da9063_wdt_set_timeout(struct watchdog_device * wdd,unsigned int timeout)140 static int da9063_wdt_set_timeout(struct watchdog_device *wdd,
141 unsigned int timeout)
142 {
143 struct da9063 *da9063 = watchdog_get_drvdata(wdd);
144 int ret = 0;
145
146 /*
147 * There are two cases when a set_timeout() will be called:
148 * 1. The watchdog is off and someone wants to set the timeout for the
149 * further use.
150 * 2. The watchdog is already running and a new timeout value should be
151 * set.
152 *
153 * The watchdog can't store a timeout value not equal zero without
154 * enabling the watchdog, so the timeout must be buffered by the driver.
155 */
156 if (watchdog_active(wdd))
157 ret = da9063_wdt_update_timeout(da9063, timeout);
158
159 if (ret)
160 dev_err(da9063->dev, "Failed to set watchdog timeout (err = %d)\n",
161 ret);
162 else
163 wdd->timeout = wdt_timeout[da9063_wdt_timeout_to_sel(timeout)];
164
165 return ret;
166 }
167
da9063_wdt_restart(struct watchdog_device * wdd,unsigned long action,void * data)168 static int da9063_wdt_restart(struct watchdog_device *wdd, unsigned long action,
169 void *data)
170 {
171 struct da9063 *da9063 = watchdog_get_drvdata(wdd);
172 int ret;
173
174 ret = regmap_write(da9063->regmap, DA9063_REG_CONTROL_F,
175 DA9063_SHUTDOWN);
176 if (ret)
177 dev_alert(da9063->dev, "Failed to shutdown (err = %d)\n",
178 ret);
179
180 return ret;
181 }
182
183 static const struct watchdog_info da9063_watchdog_info = {
184 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
185 .identity = "DA9063 Watchdog",
186 };
187
188 static const struct watchdog_ops da9063_watchdog_ops = {
189 .owner = THIS_MODULE,
190 .start = da9063_wdt_start,
191 .stop = da9063_wdt_stop,
192 .ping = da9063_wdt_ping,
193 .set_timeout = da9063_wdt_set_timeout,
194 .restart = da9063_wdt_restart,
195 };
196
da9063_wdt_probe(struct platform_device * pdev)197 static int da9063_wdt_probe(struct platform_device *pdev)
198 {
199 struct device *dev = &pdev->dev;
200 struct da9063 *da9063;
201 struct watchdog_device *wdd;
202 unsigned int timeout;
203
204 if (!dev->parent)
205 return -EINVAL;
206
207 da9063 = dev_get_drvdata(dev->parent);
208 if (!da9063)
209 return -EINVAL;
210
211 wdd = devm_kzalloc(dev, sizeof(*wdd), GFP_KERNEL);
212 if (!wdd)
213 return -ENOMEM;
214
215 wdd->info = &da9063_watchdog_info;
216 wdd->ops = &da9063_watchdog_ops;
217 wdd->min_timeout = DA9063_WDT_MIN_TIMEOUT;
218 wdd->max_timeout = DA9063_WDT_MAX_TIMEOUT;
219 wdd->min_hw_heartbeat_ms = DA9063_RESET_PROTECTION_MS;
220 wdd->parent = dev;
221 wdd->status = WATCHDOG_NOWAYOUT_INIT_STATUS;
222
223 watchdog_set_restart_priority(wdd, 128);
224 watchdog_set_drvdata(wdd, da9063);
225
226 wdd->timeout = DA9063_WDG_TIMEOUT;
227
228 /* Use pre-configured timeout if watchdog is already running. */
229 timeout = da9063_wdt_read_timeout(da9063);
230 if (timeout)
231 wdd->timeout = timeout;
232
233 /* Set timeout, maybe override it with DT value, scale it */
234 watchdog_init_timeout(wdd, 0, dev);
235 da9063_wdt_set_timeout(wdd, wdd->timeout);
236
237 /* Update timeout if the watchdog is already running. */
238 if (timeout) {
239 da9063_wdt_update_timeout(da9063, wdd->timeout);
240 set_bit(WDOG_HW_RUNNING, &wdd->status);
241 }
242
243 return devm_watchdog_register_device(dev, wdd);
244 }
245
246 static struct platform_driver da9063_wdt_driver = {
247 .probe = da9063_wdt_probe,
248 .driver = {
249 .name = DA9063_DRVNAME_WATCHDOG,
250 },
251 };
252 module_platform_driver(da9063_wdt_driver);
253
254 MODULE_AUTHOR("Mariusz Wojtasik <mariusz.wojtasik@diasemi.com>");
255 MODULE_DESCRIPTION("Watchdog driver for Dialog DA9063");
256 MODULE_LICENSE("GPL");
257 MODULE_ALIAS("platform:" DA9063_DRVNAME_WATCHDOG);
258