1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * Watchdog device driver for DA9062 and DA9061 PMICs
4  * Copyright (C) 2015  Dialog Semiconductor Ltd.
5  *
6  */
7 
8 #include <linux/kernel.h>
9 #include <linux/module.h>
10 #include <linux/watchdog.h>
11 #include <linux/platform_device.h>
12 #include <linux/uaccess.h>
13 #include <linux/slab.h>
14 #include <linux/i2c.h>
15 #include <linux/delay.h>
16 #include <linux/jiffies.h>
17 #include <linux/mfd/da9062/registers.h>
18 #include <linux/mfd/da9062/core.h>
19 #include <linux/property.h>
20 #include <linux/regmap.h>
21 #include <linux/of.h>
22 
23 static const unsigned int wdt_timeout[] = { 0, 2, 4, 8, 16, 32, 65, 131 };
24 #define DA9062_TWDSCALE_DISABLE		0
25 #define DA9062_TWDSCALE_MIN		1
26 #define DA9062_TWDSCALE_MAX		(ARRAY_SIZE(wdt_timeout) - 1)
27 #define DA9062_WDT_MIN_TIMEOUT		wdt_timeout[DA9062_TWDSCALE_MIN]
28 #define DA9062_WDT_MAX_TIMEOUT		wdt_timeout[DA9062_TWDSCALE_MAX]
29 #define DA9062_WDG_DEFAULT_TIMEOUT	wdt_timeout[DA9062_TWDSCALE_MAX-1]
30 #define DA9062_RESET_PROTECTION_MS	300
31 
32 struct da9062_watchdog {
33 	struct da9062 *hw;
34 	struct watchdog_device wdtdev;
35 	bool use_sw_pm;
36 };
37 
da9062_wdt_read_timeout(struct da9062_watchdog * wdt)38 static unsigned int da9062_wdt_read_timeout(struct da9062_watchdog *wdt)
39 {
40 	unsigned int val;
41 
42 	regmap_read(wdt->hw->regmap, DA9062AA_CONTROL_D, &val);
43 
44 	return wdt_timeout[val & DA9062AA_TWDSCALE_MASK];
45 }
46 
da9062_wdt_timeout_to_sel(unsigned int secs)47 static unsigned int da9062_wdt_timeout_to_sel(unsigned int secs)
48 {
49 	unsigned int i;
50 
51 	for (i = DA9062_TWDSCALE_MIN; i <= DA9062_TWDSCALE_MAX; i++) {
52 		if (wdt_timeout[i] >= secs)
53 			return i;
54 	}
55 
56 	return DA9062_TWDSCALE_MAX;
57 }
58 
da9062_reset_watchdog_timer(struct da9062_watchdog * wdt)59 static int da9062_reset_watchdog_timer(struct da9062_watchdog *wdt)
60 {
61 	return regmap_update_bits(wdt->hw->regmap, DA9062AA_CONTROL_F,
62 				  DA9062AA_WATCHDOG_MASK,
63 				  DA9062AA_WATCHDOG_MASK);
64 }
65 
da9062_wdt_update_timeout_register(struct da9062_watchdog * wdt,unsigned int regval)66 static int da9062_wdt_update_timeout_register(struct da9062_watchdog *wdt,
67 					      unsigned int regval)
68 {
69 	struct da9062 *chip = wdt->hw;
70 
71 	regmap_update_bits(chip->regmap,
72 				  DA9062AA_CONTROL_D,
73 				  DA9062AA_TWDSCALE_MASK,
74 				  DA9062_TWDSCALE_DISABLE);
75 
76 	usleep_range(150, 300);
77 
78 	return regmap_update_bits(chip->regmap,
79 				  DA9062AA_CONTROL_D,
80 				  DA9062AA_TWDSCALE_MASK,
81 				  regval);
82 }
83 
da9062_wdt_start(struct watchdog_device * wdd)84 static int da9062_wdt_start(struct watchdog_device *wdd)
85 {
86 	struct da9062_watchdog *wdt = watchdog_get_drvdata(wdd);
87 	unsigned int selector;
88 	int ret;
89 
90 	selector = da9062_wdt_timeout_to_sel(wdt->wdtdev.timeout);
91 	ret = da9062_wdt_update_timeout_register(wdt, selector);
92 	if (ret)
93 		dev_err(wdt->hw->dev, "Watchdog failed to start (err = %d)\n",
94 			ret);
95 
96 	return ret;
97 }
98 
da9062_wdt_stop(struct watchdog_device * wdd)99 static int da9062_wdt_stop(struct watchdog_device *wdd)
100 {
101 	struct da9062_watchdog *wdt = watchdog_get_drvdata(wdd);
102 	int ret;
103 
104 	ret = regmap_update_bits(wdt->hw->regmap,
105 				 DA9062AA_CONTROL_D,
106 				 DA9062AA_TWDSCALE_MASK,
107 				 DA9062_TWDSCALE_DISABLE);
108 	if (ret)
109 		dev_err(wdt->hw->dev, "Watchdog failed to stop (err = %d)\n",
110 			ret);
111 
112 	return ret;
113 }
114 
da9062_wdt_ping(struct watchdog_device * wdd)115 static int da9062_wdt_ping(struct watchdog_device *wdd)
116 {
117 	struct da9062_watchdog *wdt = watchdog_get_drvdata(wdd);
118 	int ret;
119 
120 	/*
121 	 * Prevent pings from occurring late in system poweroff/reboot sequence
122 	 * and possibly locking out restart handler from accessing i2c bus.
123 	 */
124 	if (system_state > SYSTEM_RUNNING)
125 		return 0;
126 
127 	ret = da9062_reset_watchdog_timer(wdt);
128 	if (ret)
129 		dev_err(wdt->hw->dev, "Failed to ping the watchdog (err = %d)\n",
130 			ret);
131 
132 	return ret;
133 }
134 
da9062_wdt_set_timeout(struct watchdog_device * wdd,unsigned int timeout)135 static int da9062_wdt_set_timeout(struct watchdog_device *wdd,
136 				  unsigned int timeout)
137 {
138 	struct da9062_watchdog *wdt = watchdog_get_drvdata(wdd);
139 	unsigned int selector;
140 	int ret;
141 
142 	selector = da9062_wdt_timeout_to_sel(timeout);
143 	ret = da9062_wdt_update_timeout_register(wdt, selector);
144 	if (ret)
145 		dev_err(wdt->hw->dev, "Failed to set watchdog timeout (err = %d)\n",
146 			ret);
147 	else
148 		wdd->timeout = wdt_timeout[selector];
149 
150 	return ret;
151 }
152 
da9062_wdt_restart(struct watchdog_device * wdd,unsigned long action,void * data)153 static int da9062_wdt_restart(struct watchdog_device *wdd, unsigned long action,
154 			      void *data)
155 {
156 	struct da9062_watchdog *wdt = watchdog_get_drvdata(wdd);
157 	struct i2c_client *client = to_i2c_client(wdt->hw->dev);
158 	union i2c_smbus_data msg;
159 	int ret;
160 
161 	/*
162 	 * Don't use regmap because it is not atomic safe. Additionally, use
163 	 * unlocked flavor of i2c_smbus_xfer to avoid scenario where i2c bus
164 	 * might be previously locked by some process unable to release the
165 	 * lock due to interrupts already being disabled at this late stage.
166 	 */
167 	msg.byte = DA9062AA_SHUTDOWN_MASK;
168 	ret = __i2c_smbus_xfer(client->adapter, client->addr, client->flags,
169 			       I2C_SMBUS_WRITE, DA9062AA_CONTROL_F,
170 			       I2C_SMBUS_BYTE_DATA, &msg);
171 
172 	if (ret < 0)
173 		dev_alert(wdt->hw->dev, "Failed to shutdown (err = %d)\n",
174 			  ret);
175 
176 	/* wait for reset to assert... */
177 	mdelay(500);
178 
179 	return ret;
180 }
181 
182 static const struct watchdog_info da9062_watchdog_info = {
183 	.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
184 	.identity = "DA9062 WDT",
185 };
186 
187 static const struct watchdog_ops da9062_watchdog_ops = {
188 	.owner = THIS_MODULE,
189 	.start = da9062_wdt_start,
190 	.stop = da9062_wdt_stop,
191 	.ping = da9062_wdt_ping,
192 	.set_timeout = da9062_wdt_set_timeout,
193 	.restart = da9062_wdt_restart,
194 };
195 
196 static const struct of_device_id da9062_compatible_id_table[] = {
197 	{ .compatible = "dlg,da9062-watchdog", },
198 	{ },
199 };
200 
201 MODULE_DEVICE_TABLE(of, da9062_compatible_id_table);
202 
da9062_wdt_probe(struct platform_device * pdev)203 static int da9062_wdt_probe(struct platform_device *pdev)
204 {
205 	struct device *dev = &pdev->dev;
206 	unsigned int timeout;
207 	struct da9062 *chip;
208 	struct da9062_watchdog *wdt;
209 
210 	chip = dev_get_drvdata(dev->parent);
211 	if (!chip)
212 		return -EINVAL;
213 
214 	wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL);
215 	if (!wdt)
216 		return -ENOMEM;
217 
218 	wdt->use_sw_pm = device_property_present(dev, "dlg,use-sw-pm");
219 
220 	wdt->hw = chip;
221 
222 	wdt->wdtdev.info = &da9062_watchdog_info;
223 	wdt->wdtdev.ops = &da9062_watchdog_ops;
224 	wdt->wdtdev.min_timeout = DA9062_WDT_MIN_TIMEOUT;
225 	wdt->wdtdev.max_timeout = DA9062_WDT_MAX_TIMEOUT;
226 	wdt->wdtdev.min_hw_heartbeat_ms = DA9062_RESET_PROTECTION_MS;
227 	wdt->wdtdev.timeout = DA9062_WDG_DEFAULT_TIMEOUT;
228 	wdt->wdtdev.status = WATCHDOG_NOWAYOUT_INIT_STATUS;
229 	wdt->wdtdev.parent = dev;
230 
231 	watchdog_set_restart_priority(&wdt->wdtdev, 128);
232 
233 	watchdog_set_drvdata(&wdt->wdtdev, wdt);
234 	dev_set_drvdata(dev, &wdt->wdtdev);
235 
236 	timeout = da9062_wdt_read_timeout(wdt);
237 	if (timeout)
238 		wdt->wdtdev.timeout = timeout;
239 
240 	/* Set timeout from DT value if available */
241 	watchdog_init_timeout(&wdt->wdtdev, 0, dev);
242 
243 	if (timeout) {
244 		da9062_wdt_set_timeout(&wdt->wdtdev, wdt->wdtdev.timeout);
245 		set_bit(WDOG_HW_RUNNING, &wdt->wdtdev.status);
246 	}
247 
248 	return devm_watchdog_register_device(dev, &wdt->wdtdev);
249 }
250 
da9062_wdt_suspend(struct device * dev)251 static int __maybe_unused da9062_wdt_suspend(struct device *dev)
252 {
253 	struct watchdog_device *wdd = dev_get_drvdata(dev);
254 	struct da9062_watchdog *wdt = watchdog_get_drvdata(wdd);
255 
256 	if (!wdt->use_sw_pm)
257 		return 0;
258 
259 	if (watchdog_active(wdd))
260 		return da9062_wdt_stop(wdd);
261 
262 	return 0;
263 }
264 
da9062_wdt_resume(struct device * dev)265 static int __maybe_unused da9062_wdt_resume(struct device *dev)
266 {
267 	struct watchdog_device *wdd = dev_get_drvdata(dev);
268 	struct da9062_watchdog *wdt = watchdog_get_drvdata(wdd);
269 
270 	if (!wdt->use_sw_pm)
271 		return 0;
272 
273 	if (watchdog_active(wdd))
274 		return da9062_wdt_start(wdd);
275 
276 	return 0;
277 }
278 
279 static SIMPLE_DEV_PM_OPS(da9062_wdt_pm_ops,
280 			 da9062_wdt_suspend, da9062_wdt_resume);
281 
282 static struct platform_driver da9062_wdt_driver = {
283 	.probe = da9062_wdt_probe,
284 	.driver = {
285 		.name = "da9062-watchdog",
286 		.pm = &da9062_wdt_pm_ops,
287 		.of_match_table = da9062_compatible_id_table,
288 	},
289 };
290 module_platform_driver(da9062_wdt_driver);
291 
292 MODULE_AUTHOR("S Twiss <stwiss.opensource@diasemi.com>");
293 MODULE_DESCRIPTION("WDT device driver for Dialog DA9062 and DA9061");
294 MODULE_LICENSE("GPL");
295 MODULE_ALIAS("platform:da9062-watchdog");
296