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 | |
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 | */ |
56 | static unsigned int da9063_wdt_read_timeout(struct da9063 *da9063) |
57 | { |
58 | unsigned int val; |
59 | |
60 | regmap_read(map: da9063->regmap, DA9063_REG_CONTROL_D, val: &val); |
61 | |
62 | return wdt_timeout[val & DA9063_TWDSCALE_MASK]; |
63 | } |
64 | |
65 | static int da9063_wdt_disable_timer(struct da9063 *da9063) |
66 | { |
67 | return regmap_update_bits(map: da9063->regmap, DA9063_REG_CONTROL_D, |
68 | DA9063_TWDSCALE_MASK, |
69 | DA9063_TWDSCALE_DISABLE); |
70 | } |
71 | |
72 | static int |
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(min: 150, max: 300); |
91 | regval = da9063_wdt_timeout_to_sel(secs: timeout); |
92 | |
93 | return regmap_update_bits(map: da9063->regmap, DA9063_REG_CONTROL_D, |
94 | DA9063_TWDSCALE_MASK, val: regval); |
95 | } |
96 | |
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, timeout: 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 | |
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 | |
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(map: 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 | |
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(secs: timeout)]; |
168 | |
169 | return ret; |
170 | } |
171 | |
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 | union i2c_smbus_data msg; |
178 | int ret; |
179 | |
180 | /* |
181 | * Don't use regmap because it is not atomic safe. Additionally, use |
182 | * unlocked flavor of i2c_smbus_xfer to avoid scenario where i2c bus |
183 | * might previously be locked by some process unable to release the |
184 | * lock due to interrupts already being disabled at this late stage. |
185 | */ |
186 | msg.byte = DA9063_SHUTDOWN; |
187 | ret = __i2c_smbus_xfer(adapter: client->adapter, addr: client->addr, flags: client->flags, |
188 | I2C_SMBUS_WRITE, DA9063_REG_CONTROL_F, |
189 | I2C_SMBUS_BYTE_DATA, data: &msg); |
190 | |
191 | if (ret < 0) |
192 | dev_alert(da9063->dev, "Failed to shutdown (err = %d)\n" , |
193 | ret); |
194 | |
195 | /* wait for reset to assert... */ |
196 | mdelay(500); |
197 | |
198 | return ret; |
199 | } |
200 | |
201 | static const struct watchdog_info da9063_watchdog_info = { |
202 | .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING, |
203 | .identity = "DA9063 Watchdog" , |
204 | }; |
205 | |
206 | static const struct watchdog_ops da9063_watchdog_ops = { |
207 | .owner = THIS_MODULE, |
208 | .start = da9063_wdt_start, |
209 | .stop = da9063_wdt_stop, |
210 | .ping = da9063_wdt_ping, |
211 | .set_timeout = da9063_wdt_set_timeout, |
212 | .restart = da9063_wdt_restart, |
213 | }; |
214 | |
215 | static int da9063_wdt_probe(struct platform_device *pdev) |
216 | { |
217 | struct device *dev = &pdev->dev; |
218 | struct da9063 *da9063; |
219 | struct watchdog_device *wdd; |
220 | unsigned int timeout; |
221 | |
222 | if (!dev->parent) |
223 | return -EINVAL; |
224 | |
225 | da9063 = dev_get_drvdata(dev: dev->parent); |
226 | if (!da9063) |
227 | return -EINVAL; |
228 | |
229 | wdd = devm_kzalloc(dev, size: sizeof(*wdd), GFP_KERNEL); |
230 | if (!wdd) |
231 | return -ENOMEM; |
232 | |
233 | use_sw_pm = device_property_present(dev, propname: "dlg,use-sw-pm" ); |
234 | |
235 | wdd->info = &da9063_watchdog_info; |
236 | wdd->ops = &da9063_watchdog_ops; |
237 | wdd->min_timeout = DA9063_WDT_MIN_TIMEOUT; |
238 | wdd->max_timeout = DA9063_WDT_MAX_TIMEOUT; |
239 | wdd->min_hw_heartbeat_ms = DA9063_RESET_PROTECTION_MS; |
240 | wdd->parent = dev; |
241 | wdd->status = WATCHDOG_NOWAYOUT_INIT_STATUS; |
242 | |
243 | watchdog_set_restart_priority(wdd, priority: 128); |
244 | watchdog_set_drvdata(wdd, data: da9063); |
245 | dev_set_drvdata(dev, data: wdd); |
246 | |
247 | wdd->timeout = DA9063_WDG_TIMEOUT; |
248 | |
249 | /* Use pre-configured timeout if watchdog is already running. */ |
250 | timeout = da9063_wdt_read_timeout(da9063); |
251 | if (timeout) |
252 | wdd->timeout = timeout; |
253 | |
254 | /* Set timeout, maybe override it with DT value, scale it */ |
255 | watchdog_init_timeout(wdd, timeout_parm: 0, dev); |
256 | da9063_wdt_set_timeout(wdd, timeout: wdd->timeout); |
257 | |
258 | /* Update timeout if the watchdog is already running. */ |
259 | if (timeout) { |
260 | da9063_wdt_update_timeout(da9063, timeout: wdd->timeout); |
261 | set_bit(WDOG_HW_RUNNING, addr: &wdd->status); |
262 | } |
263 | |
264 | return devm_watchdog_register_device(dev, wdd); |
265 | } |
266 | |
267 | static int __maybe_unused da9063_wdt_suspend(struct device *dev) |
268 | { |
269 | struct watchdog_device *wdd = dev_get_drvdata(dev); |
270 | |
271 | if (!use_sw_pm) |
272 | return 0; |
273 | |
274 | if (watchdog_active(wdd)) |
275 | return da9063_wdt_stop(wdd); |
276 | |
277 | return 0; |
278 | } |
279 | |
280 | static int __maybe_unused da9063_wdt_resume(struct device *dev) |
281 | { |
282 | struct watchdog_device *wdd = dev_get_drvdata(dev); |
283 | |
284 | if (!use_sw_pm) |
285 | return 0; |
286 | |
287 | if (watchdog_active(wdd)) |
288 | return da9063_wdt_start(wdd); |
289 | |
290 | return 0; |
291 | } |
292 | |
293 | static SIMPLE_DEV_PM_OPS(da9063_wdt_pm_ops, |
294 | da9063_wdt_suspend, da9063_wdt_resume); |
295 | |
296 | static struct platform_driver da9063_wdt_driver = { |
297 | .probe = da9063_wdt_probe, |
298 | .driver = { |
299 | .name = DA9063_DRVNAME_WATCHDOG, |
300 | .pm = &da9063_wdt_pm_ops, |
301 | }, |
302 | }; |
303 | module_platform_driver(da9063_wdt_driver); |
304 | |
305 | MODULE_AUTHOR("Mariusz Wojtasik <mariusz.wojtasik@diasemi.com>" ); |
306 | MODULE_DESCRIPTION("Watchdog driver for Dialog DA9063" ); |
307 | MODULE_LICENSE("GPL" ); |
308 | MODULE_ALIAS("platform:" DA9063_DRVNAME_WATCHDOG); |
309 | |