xref: /openbmc/linux/drivers/watchdog/da9063_wdt.c (revision b830f94f)
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 
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  * Return 0 if watchdog is disabled, else non zero.
50  */
51 static unsigned int da9063_wdt_is_running(struct da9063 *da9063)
52 {
53 	unsigned int val;
54 
55 	regmap_read(da9063->regmap, DA9063_REG_CONTROL_D, &val);
56 
57 	return val & DA9063_TWDSCALE_MASK;
58 }
59 
60 static int da9063_wdt_disable_timer(struct da9063 *da9063)
61 {
62 	return regmap_update_bits(da9063->regmap, DA9063_REG_CONTROL_D,
63 				  DA9063_TWDSCALE_MASK,
64 				  DA9063_TWDSCALE_DISABLE);
65 }
66 
67 static int
68 da9063_wdt_update_timeout(struct da9063 *da9063, unsigned int timeout)
69 {
70 	unsigned int regval;
71 	int ret;
72 
73 	/*
74 	 * The watchdog triggers a reboot if a timeout value is already
75 	 * programmed because the timeout value combines two functions
76 	 * in one: indicating the counter limit and starting the watchdog.
77 	 * The watchdog must be disabled to be able to change the timeout
78 	 * value if the watchdog is already running. Then we can set the
79 	 * new timeout value which enables the watchdog again.
80 	 */
81 	ret = da9063_wdt_disable_timer(da9063);
82 	if (ret)
83 		return ret;
84 
85 	usleep_range(150, 300);
86 	regval = da9063_wdt_timeout_to_sel(timeout);
87 
88 	return regmap_update_bits(da9063->regmap, DA9063_REG_CONTROL_D,
89 				  DA9063_TWDSCALE_MASK, regval);
90 }
91 
92 static int da9063_wdt_start(struct watchdog_device *wdd)
93 {
94 	struct da9063 *da9063 = watchdog_get_drvdata(wdd);
95 	int ret;
96 
97 	ret = da9063_wdt_update_timeout(da9063, wdd->timeout);
98 	if (ret)
99 		dev_err(da9063->dev, "Watchdog failed to start (err = %d)\n",
100 			ret);
101 
102 	return ret;
103 }
104 
105 static int da9063_wdt_stop(struct watchdog_device *wdd)
106 {
107 	struct da9063 *da9063 = watchdog_get_drvdata(wdd);
108 	int ret;
109 
110 	ret = da9063_wdt_disable_timer(da9063);
111 	if (ret)
112 		dev_alert(da9063->dev, "Watchdog failed to stop (err = %d)\n",
113 			  ret);
114 
115 	return ret;
116 }
117 
118 static int da9063_wdt_ping(struct watchdog_device *wdd)
119 {
120 	struct da9063 *da9063 = watchdog_get_drvdata(wdd);
121 	int ret;
122 
123 	ret = regmap_write(da9063->regmap, DA9063_REG_CONTROL_F,
124 			   DA9063_WATCHDOG);
125 	if (ret)
126 		dev_alert(da9063->dev, "Failed to ping the watchdog (err = %d)\n",
127 			  ret);
128 
129 	return ret;
130 }
131 
132 static int da9063_wdt_set_timeout(struct watchdog_device *wdd,
133 				  unsigned int timeout)
134 {
135 	struct da9063 *da9063 = watchdog_get_drvdata(wdd);
136 	int ret = 0;
137 
138 	/*
139 	 * There are two cases when a set_timeout() will be called:
140 	 * 1. The watchdog is off and someone wants to set the timeout for the
141 	 *    further use.
142 	 * 2. The watchdog is already running and a new timeout value should be
143 	 *    set.
144 	 *
145 	 * The watchdog can't store a timeout value not equal zero without
146 	 * enabling the watchdog, so the timeout must be buffered by the driver.
147 	 */
148 	if (watchdog_active(wdd))
149 		ret = da9063_wdt_update_timeout(da9063, timeout);
150 
151 	if (ret)
152 		dev_err(da9063->dev, "Failed to set watchdog timeout (err = %d)\n",
153 			ret);
154 	else
155 		wdd->timeout = wdt_timeout[da9063_wdt_timeout_to_sel(timeout)];
156 
157 	return ret;
158 }
159 
160 static int da9063_wdt_restart(struct watchdog_device *wdd, unsigned long action,
161 			      void *data)
162 {
163 	struct da9063 *da9063 = watchdog_get_drvdata(wdd);
164 	int ret;
165 
166 	ret = regmap_write(da9063->regmap, DA9063_REG_CONTROL_F,
167 			   DA9063_SHUTDOWN);
168 	if (ret)
169 		dev_alert(da9063->dev, "Failed to shutdown (err = %d)\n",
170 			  ret);
171 
172 	return ret;
173 }
174 
175 static const struct watchdog_info da9063_watchdog_info = {
176 	.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
177 	.identity = "DA9063 Watchdog",
178 };
179 
180 static const struct watchdog_ops da9063_watchdog_ops = {
181 	.owner = THIS_MODULE,
182 	.start = da9063_wdt_start,
183 	.stop = da9063_wdt_stop,
184 	.ping = da9063_wdt_ping,
185 	.set_timeout = da9063_wdt_set_timeout,
186 	.restart = da9063_wdt_restart,
187 };
188 
189 static int da9063_wdt_probe(struct platform_device *pdev)
190 {
191 	struct device *dev = &pdev->dev;
192 	struct da9063 *da9063;
193 	struct watchdog_device *wdd;
194 
195 	if (!dev->parent)
196 		return -EINVAL;
197 
198 	da9063 = dev_get_drvdata(dev->parent);
199 	if (!da9063)
200 		return -EINVAL;
201 
202 	wdd = devm_kzalloc(dev, sizeof(*wdd), GFP_KERNEL);
203 	if (!wdd)
204 		return -ENOMEM;
205 
206 	wdd->info = &da9063_watchdog_info;
207 	wdd->ops = &da9063_watchdog_ops;
208 	wdd->min_timeout = DA9063_WDT_MIN_TIMEOUT;
209 	wdd->max_timeout = DA9063_WDT_MAX_TIMEOUT;
210 	wdd->min_hw_heartbeat_ms = DA9063_RESET_PROTECTION_MS;
211 	wdd->parent = dev;
212 	wdd->status = WATCHDOG_NOWAYOUT_INIT_STATUS;
213 
214 	watchdog_set_restart_priority(wdd, 128);
215 	watchdog_set_drvdata(wdd, da9063);
216 
217 	/* Set default timeout, maybe override it with DT value, scale it */
218 	wdd->timeout = DA9063_WDG_TIMEOUT;
219 	watchdog_init_timeout(wdd, 0, dev);
220 	da9063_wdt_set_timeout(wdd, wdd->timeout);
221 
222 	/* Change the timeout to the default value if the watchdog is running */
223 	if (da9063_wdt_is_running(da9063)) {
224 		da9063_wdt_update_timeout(da9063, wdd->timeout);
225 		set_bit(WDOG_HW_RUNNING, &wdd->status);
226 	}
227 
228 	return devm_watchdog_register_device(dev, wdd);
229 }
230 
231 static struct platform_driver da9063_wdt_driver = {
232 	.probe = da9063_wdt_probe,
233 	.driver = {
234 		.name = DA9063_DRVNAME_WATCHDOG,
235 	},
236 };
237 module_platform_driver(da9063_wdt_driver);
238 
239 MODULE_AUTHOR("Mariusz Wojtasik <mariusz.wojtasik@diasemi.com>");
240 MODULE_DESCRIPTION("Watchdog driver for Dialog DA9063");
241 MODULE_LICENSE("GPL");
242 MODULE_ALIAS("platform:" DA9063_DRVNAME_WATCHDOG);
243