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