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cdf7545a | 1 | // SPDX-License-Identifier: GPL-2.0 |
0c86edc0 AZ |
2 | /* |
3 | * RTC subsystem, base class | |
4 | * | |
5 | * Copyright (C) 2005 Tower Technologies | |
6 | * Author: Alessandro Zummo <a.zummo@towertech.it> | |
7 | * | |
8 | * class skeleton from drivers/hwmon/hwmon.c | |
cdf7545a | 9 | */ |
0c86edc0 | 10 | |
c100a5e0 JH |
11 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
12 | ||
0c86edc0 | 13 | #include <linux/module.h> |
9d2b7e53 | 14 | #include <linux/of.h> |
0c86edc0 AZ |
15 | #include <linux/rtc.h> |
16 | #include <linux/kdev_t.h> | |
17 | #include <linux/idr.h> | |
5a0e3ad6 | 18 | #include <linux/slab.h> |
6610e089 | 19 | #include <linux/workqueue.h> |
0c86edc0 | 20 | |
5726fb20 DB |
21 | #include "rtc-core.h" |
22 | ||
6d03d06d | 23 | static DEFINE_IDA(rtc_ida); |
0c86edc0 AZ |
24 | struct class *rtc_class; |
25 | ||
cd966209 | 26 | static void rtc_device_release(struct device *dev) |
0c86edc0 | 27 | { |
cd966209 | 28 | struct rtc_device *rtc = to_rtc_device(dev); |
606cc43c | 29 | |
6d03d06d | 30 | ida_simple_remove(&rtc_ida, rtc->id); |
0d6d7a39 | 31 | mutex_destroy(&rtc->ops_lock); |
0c86edc0 AZ |
32 | kfree(rtc); |
33 | } | |
34 | ||
4c24e29e DF |
35 | #ifdef CONFIG_RTC_HCTOSYS_DEVICE |
36 | /* Result of the last RTC to system clock attempt. */ | |
37 | int rtc_hctosys_ret = -ENODEV; | |
f9b2a4d6 SM |
38 | |
39 | /* IMPORTANT: the RTC only stores whole seconds. It is arbitrary | |
40 | * whether it stores the most close value or the value with partial | |
41 | * seconds truncated. However, it is important that we use it to store | |
42 | * the truncated value. This is because otherwise it is necessary, | |
43 | * in an rtc sync function, to read both xtime.tv_sec and | |
44 | * xtime.tv_nsec. On some processors (i.e. ARM), an atomic read | |
45 | * of >32bits is not possible. So storing the most close value would | |
46 | * slow down the sync API. So here we have the truncated value and | |
47 | * the best guess is to add 0.5s. | |
48 | */ | |
49 | ||
5614a4a3 | 50 | static void rtc_hctosys(struct rtc_device *rtc) |
f9b2a4d6 | 51 | { |
3edf29d9 | 52 | int err; |
f9b2a4d6 SM |
53 | struct rtc_time tm; |
54 | struct timespec64 tv64 = { | |
55 | .tv_nsec = NSEC_PER_SEC >> 1, | |
56 | }; | |
f9b2a4d6 SM |
57 | |
58 | err = rtc_read_time(rtc, &tm); | |
59 | if (err) { | |
60 | dev_err(rtc->dev.parent, | |
61 | "hctosys: unable to read the hardware clock\n"); | |
62 | goto err_read; | |
63 | } | |
64 | ||
65 | tv64.tv_sec = rtc_tm_to_time64(&tm); | |
66 | ||
67 | #if BITS_PER_LONG == 32 | |
68 | if (tv64.tv_sec > INT_MAX) { | |
69 | err = -ERANGE; | |
70 | goto err_read; | |
71 | } | |
72 | #endif | |
73 | ||
74 | err = do_settimeofday64(&tv64); | |
75 | ||
76 | dev_info(rtc->dev.parent, "setting system clock to %ptR UTC (%lld)\n", | |
77 | &tm, (long long)tv64.tv_sec); | |
78 | ||
79 | err_read: | |
f9b2a4d6 | 80 | rtc_hctosys_ret = err; |
f9b2a4d6 | 81 | } |
4c24e29e | 82 | #endif |
7ca1d488 | 83 | |
92e7f04a | 84 | #if defined(CONFIG_PM_SLEEP) && defined(CONFIG_RTC_HCTOSYS_DEVICE) |
7ca1d488 DB |
85 | /* |
86 | * On suspend(), measure the delta between one RTC and the | |
87 | * system's wall clock; restore it on resume(). | |
88 | */ | |
89 | ||
d4bda8f8 | 90 | static struct timespec64 old_rtc, old_system, old_delta; |
3dcad5ff | 91 | |
92e7f04a | 92 | static int rtc_suspend(struct device *dev) |
7ca1d488 DB |
93 | { |
94 | struct rtc_device *rtc = to_rtc_device(dev); | |
95 | struct rtc_time tm; | |
d4bda8f8 | 96 | struct timespec64 delta, delta_delta; |
e1d60093 | 97 | int err; |
9ecf37eb | 98 | |
0fa88cb4 | 99 | if (timekeeping_rtc_skipsuspend()) |
9ecf37eb FT |
100 | return 0; |
101 | ||
d4afc76c | 102 | if (strcmp(dev_name(&rtc->dev), CONFIG_RTC_HCTOSYS_DEVICE) != 0) |
7ca1d488 DB |
103 | return 0; |
104 | ||
3dcad5ff | 105 | /* snapshot the current RTC and system time at suspend*/ |
e1d60093 HG |
106 | err = rtc_read_time(rtc, &tm); |
107 | if (err < 0) { | |
108 | pr_debug("%s: fail to read rtc time\n", dev_name(&rtc->dev)); | |
109 | return 0; | |
110 | } | |
111 | ||
5089ea15 | 112 | ktime_get_real_ts64(&old_system); |
d4bda8f8 | 113 | old_rtc.tv_sec = rtc_tm_to_time64(&tm); |
3dcad5ff | 114 | |
3dcad5ff JS |
115 | /* |
116 | * To avoid drift caused by repeated suspend/resumes, | |
117 | * which each can add ~1 second drift error, | |
118 | * try to compensate so the difference in system time | |
119 | * and rtc time stays close to constant. | |
120 | */ | |
d4bda8f8 JS |
121 | delta = timespec64_sub(old_system, old_rtc); |
122 | delta_delta = timespec64_sub(delta, old_delta); | |
6a8943d9 | 123 | if (delta_delta.tv_sec < -2 || delta_delta.tv_sec >= 2) { |
3dcad5ff JS |
124 | /* |
125 | * if delta_delta is too large, assume time correction | |
606cc43c | 126 | * has occurred and set old_delta to the current delta. |
3dcad5ff JS |
127 | */ |
128 | old_delta = delta; | |
129 | } else { | |
130 | /* Otherwise try to adjust old_system to compensate */ | |
d4bda8f8 | 131 | old_system = timespec64_sub(old_system, delta_delta); |
3dcad5ff | 132 | } |
7ca1d488 | 133 | |
7ca1d488 DB |
134 | return 0; |
135 | } | |
136 | ||
137 | static int rtc_resume(struct device *dev) | |
138 | { | |
139 | struct rtc_device *rtc = to_rtc_device(dev); | |
140 | struct rtc_time tm; | |
d4bda8f8 JS |
141 | struct timespec64 new_system, new_rtc; |
142 | struct timespec64 sleep_time; | |
e1d60093 | 143 | int err; |
7ca1d488 | 144 | |
0fa88cb4 | 145 | if (timekeeping_rtc_skipresume()) |
9ecf37eb FT |
146 | return 0; |
147 | ||
4c24e29e | 148 | rtc_hctosys_ret = -ENODEV; |
d4afc76c | 149 | if (strcmp(dev_name(&rtc->dev), CONFIG_RTC_HCTOSYS_DEVICE) != 0) |
7ca1d488 DB |
150 | return 0; |
151 | ||
3dcad5ff | 152 | /* snapshot the current rtc and system time at resume */ |
5089ea15 | 153 | ktime_get_real_ts64(&new_system); |
e1d60093 HG |
154 | err = rtc_read_time(rtc, &tm); |
155 | if (err < 0) { | |
156 | pr_debug("%s: fail to read rtc time\n", dev_name(&rtc->dev)); | |
157 | return 0; | |
158 | } | |
159 | ||
d4bda8f8 | 160 | new_rtc.tv_sec = rtc_tm_to_time64(&tm); |
3dcad5ff JS |
161 | new_rtc.tv_nsec = 0; |
162 | ||
6a8943d9 AH |
163 | if (new_rtc.tv_sec < old_rtc.tv_sec) { |
164 | pr_debug("%s: time travel!\n", dev_name(&rtc->dev)); | |
7ca1d488 DB |
165 | return 0; |
166 | } | |
167 | ||
3dcad5ff | 168 | /* calculate the RTC time delta (sleep time)*/ |
d4bda8f8 | 169 | sleep_time = timespec64_sub(new_rtc, old_rtc); |
3dcad5ff JS |
170 | |
171 | /* | |
172 | * Since these RTC suspend/resume handlers are not called | |
173 | * at the very end of suspend or the start of resume, | |
174 | * some run-time may pass on either sides of the sleep time | |
175 | * so subtract kernel run-time between rtc_suspend to rtc_resume | |
176 | * to keep things accurate. | |
177 | */ | |
d4bda8f8 | 178 | sleep_time = timespec64_sub(sleep_time, |
606cc43c | 179 | timespec64_sub(new_system, old_system)); |
7ca1d488 | 180 | |
6a8943d9 | 181 | if (sleep_time.tv_sec >= 0) |
d4bda8f8 | 182 | timekeeping_inject_sleeptime64(&sleep_time); |
4c24e29e | 183 | rtc_hctosys_ret = 0; |
7ca1d488 DB |
184 | return 0; |
185 | } | |
186 | ||
92e7f04a SK |
187 | static SIMPLE_DEV_PM_OPS(rtc_class_dev_pm_ops, rtc_suspend, rtc_resume); |
188 | #define RTC_CLASS_DEV_PM_OPS (&rtc_class_dev_pm_ops) | |
7ca1d488 | 189 | #else |
92e7f04a | 190 | #define RTC_CLASS_DEV_PM_OPS NULL |
7ca1d488 DB |
191 | #endif |
192 | ||
3068a254 | 193 | /* Ensure the caller will set the id before releasing the device */ |
d1bec20f AB |
194 | static struct rtc_device *rtc_allocate_device(void) |
195 | { | |
196 | struct rtc_device *rtc; | |
197 | ||
198 | rtc = kzalloc(sizeof(*rtc), GFP_KERNEL); | |
199 | if (!rtc) | |
200 | return NULL; | |
201 | ||
202 | device_initialize(&rtc->dev); | |
203 | ||
69eca258 TG |
204 | /* |
205 | * Drivers can revise this default after allocating the device. | |
206 | * The default is what most RTCs do: Increment seconds exactly one | |
207 | * second after the write happened. This adds a default transport | |
208 | * time of 5ms which is at least halfways close to reality. | |
209 | */ | |
210 | rtc->set_offset_nsec = NSEC_PER_SEC + 5 * NSEC_PER_MSEC; | |
0f295b06 | 211 | |
d1bec20f AB |
212 | rtc->irq_freq = 1; |
213 | rtc->max_user_freq = 64; | |
214 | rtc->dev.class = rtc_class; | |
215 | rtc->dev.groups = rtc_get_dev_attribute_groups(); | |
216 | rtc->dev.release = rtc_device_release; | |
217 | ||
218 | mutex_init(&rtc->ops_lock); | |
219 | spin_lock_init(&rtc->irq_lock); | |
d1bec20f AB |
220 | init_waitqueue_head(&rtc->irq_queue); |
221 | ||
222 | /* Init timerqueue */ | |
223 | timerqueue_init_head(&rtc->timerqueue); | |
224 | INIT_WORK(&rtc->irqwork, rtc_timer_do_work); | |
225 | /* Init aie timer */ | |
9a032011 | 226 | rtc_timer_init(&rtc->aie_timer, rtc_aie_update_irq, rtc); |
d1bec20f | 227 | /* Init uie timer */ |
9a032011 | 228 | rtc_timer_init(&rtc->uie_rtctimer, rtc_uie_update_irq, rtc); |
d1bec20f AB |
229 | /* Init pie timer */ |
230 | hrtimer_init(&rtc->pie_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); | |
231 | rtc->pie_timer.function = rtc_pie_update_irq; | |
232 | rtc->pie_enabled = 0; | |
233 | ||
7ae41220 AB |
234 | set_bit(RTC_FEATURE_ALARM, rtc->features); |
235 | ||
d1bec20f AB |
236 | return rtc; |
237 | } | |
7ca1d488 | 238 | |
b91336df AB |
239 | static int rtc_device_get_id(struct device *dev) |
240 | { | |
241 | int of_id = -1, id = -1; | |
242 | ||
243 | if (dev->of_node) | |
244 | of_id = of_alias_get_id(dev->of_node, "rtc"); | |
245 | else if (dev->parent && dev->parent->of_node) | |
246 | of_id = of_alias_get_id(dev->parent->of_node, "rtc"); | |
247 | ||
248 | if (of_id >= 0) { | |
249 | id = ida_simple_get(&rtc_ida, of_id, of_id + 1, GFP_KERNEL); | |
250 | if (id < 0) | |
251 | dev_warn(dev, "/aliases ID %d not available\n", of_id); | |
252 | } | |
253 | ||
254 | if (id < 0) | |
255 | id = ida_simple_get(&rtc_ida, 0, 0, GFP_KERNEL); | |
256 | ||
257 | return id; | |
258 | } | |
259 | ||
98951564 BW |
260 | static void rtc_device_get_offset(struct rtc_device *rtc) |
261 | { | |
262 | time64_t range_secs; | |
263 | u32 start_year; | |
264 | int ret; | |
265 | ||
266 | /* | |
267 | * If RTC driver did not implement the range of RTC hardware device, | |
268 | * then we can not expand the RTC range by adding or subtracting one | |
269 | * offset. | |
270 | */ | |
271 | if (rtc->range_min == rtc->range_max) | |
272 | return; | |
273 | ||
274 | ret = device_property_read_u32(rtc->dev.parent, "start-year", | |
275 | &start_year); | |
276 | if (!ret) { | |
277 | rtc->start_secs = mktime64(start_year, 1, 1, 0, 0, 0); | |
278 | rtc->set_start_time = true; | |
279 | } | |
280 | ||
281 | /* | |
282 | * If user did not implement the start time for RTC driver, then no | |
283 | * need to expand the RTC range. | |
284 | */ | |
285 | if (!rtc->set_start_time) | |
286 | return; | |
287 | ||
288 | range_secs = rtc->range_max - rtc->range_min + 1; | |
289 | ||
290 | /* | |
291 | * If the start_secs is larger than the maximum seconds (rtc->range_max) | |
292 | * supported by RTC hardware or the maximum seconds of new expanded | |
293 | * range (start_secs + rtc->range_max - rtc->range_min) is less than | |
294 | * rtc->range_min, which means the minimum seconds (rtc->range_min) of | |
295 | * RTC hardware will be mapped to start_secs by adding one offset, so | |
296 | * the offset seconds calculation formula should be: | |
297 | * rtc->offset_secs = rtc->start_secs - rtc->range_min; | |
298 | * | |
299 | * If the start_secs is larger than the minimum seconds (rtc->range_min) | |
300 | * supported by RTC hardware, then there is one region is overlapped | |
301 | * between the original RTC hardware range and the new expanded range, | |
302 | * and this overlapped region do not need to be mapped into the new | |
303 | * expanded range due to it is valid for RTC device. So the minimum | |
304 | * seconds of RTC hardware (rtc->range_min) should be mapped to | |
305 | * rtc->range_max + 1, then the offset seconds formula should be: | |
306 | * rtc->offset_secs = rtc->range_max - rtc->range_min + 1; | |
307 | * | |
308 | * If the start_secs is less than the minimum seconds (rtc->range_min), | |
309 | * which is similar to case 2. So the start_secs should be mapped to | |
310 | * start_secs + rtc->range_max - rtc->range_min + 1, then the | |
311 | * offset seconds formula should be: | |
312 | * rtc->offset_secs = -(rtc->range_max - rtc->range_min + 1); | |
313 | * | |
314 | * Otherwise the offset seconds should be 0. | |
315 | */ | |
316 | if (rtc->start_secs > rtc->range_max || | |
317 | rtc->start_secs + range_secs - 1 < rtc->range_min) | |
318 | rtc->offset_secs = rtc->start_secs - rtc->range_min; | |
319 | else if (rtc->start_secs > rtc->range_min) | |
320 | rtc->offset_secs = range_secs; | |
321 | else if (rtc->start_secs < rtc->range_min) | |
322 | rtc->offset_secs = -range_secs; | |
323 | else | |
324 | rtc->offset_secs = 0; | |
325 | } | |
326 | ||
fdcfd854 | 327 | static void devm_rtc_unregister_device(void *data) |
0c86edc0 | 328 | { |
fdcfd854 BG |
329 | struct rtc_device *rtc = data; |
330 | ||
c3b399a4 DT |
331 | mutex_lock(&rtc->ops_lock); |
332 | /* | |
333 | * Remove innards of this RTC, then disable it, before | |
334 | * letting any rtc_class_open() users access it again | |
335 | */ | |
c3b399a4 | 336 | rtc_proc_del_device(rtc); |
d5ed9177 | 337 | cdev_device_del(&rtc->char_dev, &rtc->dev); |
c3b399a4 DT |
338 | rtc->ops = NULL; |
339 | mutex_unlock(&rtc->ops_lock); | |
0c86edc0 | 340 | } |
0c86edc0 | 341 | |
1bfc485b | 342 | static void devm_rtc_release_device(void *res) |
3068a254 | 343 | { |
1bfc485b | 344 | struct rtc_device *rtc = res; |
3068a254 | 345 | |
fdcfd854 | 346 | put_device(&rtc->dev); |
3068a254 AB |
347 | } |
348 | ||
349 | struct rtc_device *devm_rtc_allocate_device(struct device *dev) | |
350 | { | |
1bfc485b | 351 | struct rtc_device *rtc; |
3068a254 AB |
352 | int id, err; |
353 | ||
354 | id = rtc_device_get_id(dev); | |
355 | if (id < 0) | |
356 | return ERR_PTR(id); | |
357 | ||
3068a254 AB |
358 | rtc = rtc_allocate_device(); |
359 | if (!rtc) { | |
1bfc485b BG |
360 | ida_simple_remove(&rtc_ida, id); |
361 | return ERR_PTR(-ENOMEM); | |
3068a254 AB |
362 | } |
363 | ||
3068a254 AB |
364 | rtc->id = id; |
365 | rtc->dev.parent = dev; | |
366 | dev_set_name(&rtc->dev, "rtc%d", id); | |
367 | ||
1bfc485b BG |
368 | err = devm_add_action_or_reset(dev, devm_rtc_release_device, rtc); |
369 | if (err) | |
370 | return ERR_PTR(err); | |
3068a254 | 371 | |
1bfc485b | 372 | return rtc; |
3068a254 AB |
373 | } |
374 | EXPORT_SYMBOL_GPL(devm_rtc_allocate_device); | |
375 | ||
fdcfd854 | 376 | int __devm_rtc_register_device(struct module *owner, struct rtc_device *rtc) |
3068a254 AB |
377 | { |
378 | struct rtc_wkalrm alrm; | |
379 | int err; | |
380 | ||
924068e5 AB |
381 | if (!rtc->ops) { |
382 | dev_dbg(&rtc->dev, "no ops set\n"); | |
3068a254 | 383 | return -EINVAL; |
924068e5 | 384 | } |
3068a254 | 385 | |
7ae41220 AB |
386 | if (!rtc->ops->set_alarm) |
387 | clear_bit(RTC_FEATURE_ALARM, rtc->features); | |
388 | ||
3068a254 | 389 | rtc->owner = owner; |
98951564 | 390 | rtc_device_get_offset(rtc); |
3068a254 AB |
391 | |
392 | /* Check to see if there is an ALARM already set in hw */ | |
393 | err = __rtc_read_alarm(rtc, &alrm); | |
394 | if (!err && !rtc_valid_tm(&alrm.time)) | |
395 | rtc_initialize_alarm(rtc, &alrm); | |
396 | ||
397 | rtc_dev_prepare(rtc); | |
398 | ||
399 | err = cdev_device_add(&rtc->char_dev, &rtc->dev); | |
400 | if (err) | |
401 | dev_warn(rtc->dev.parent, "failed to add char device %d:%d\n", | |
402 | MAJOR(rtc->dev.devt), rtc->id); | |
403 | else | |
404 | dev_dbg(rtc->dev.parent, "char device (%d:%d)\n", | |
405 | MAJOR(rtc->dev.devt), rtc->id); | |
406 | ||
407 | rtc_proc_add_device(rtc); | |
408 | ||
3068a254 AB |
409 | dev_info(rtc->dev.parent, "registered as %s\n", |
410 | dev_name(&rtc->dev)); | |
411 | ||
f9b2a4d6 SM |
412 | #ifdef CONFIG_RTC_HCTOSYS_DEVICE |
413 | if (!strcmp(dev_name(&rtc->dev), CONFIG_RTC_HCTOSYS_DEVICE)) | |
5614a4a3 | 414 | rtc_hctosys(rtc); |
f9b2a4d6 SM |
415 | #endif |
416 | ||
fdcfd854 BG |
417 | return devm_add_action_or_reset(rtc->dev.parent, |
418 | devm_rtc_unregister_device, rtc); | |
3068a254 | 419 | } |
fdcfd854 | 420 | EXPORT_SYMBOL_GPL(__devm_rtc_register_device); |
3068a254 | 421 | |
a2694414 AB |
422 | /** |
423 | * devm_rtc_device_register - resource managed rtc_device_register() | |
424 | * @dev: the device to register | |
425 | * @name: the name of the device (unused) | |
426 | * @ops: the rtc operations structure | |
427 | * @owner: the module owner | |
428 | * | |
429 | * @return a struct rtc on success, or an ERR_PTR on error | |
430 | * | |
431 | * Managed rtc_device_register(). The rtc_device returned from this function | |
432 | * are automatically freed on driver detach. | |
433 | * This function is deprecated, use devm_rtc_allocate_device and | |
434 | * rtc_register_device instead | |
435 | */ | |
436 | struct rtc_device *devm_rtc_device_register(struct device *dev, | |
606cc43c AB |
437 | const char *name, |
438 | const struct rtc_class_ops *ops, | |
439 | struct module *owner) | |
a2694414 AB |
440 | { |
441 | struct rtc_device *rtc; | |
442 | int err; | |
443 | ||
444 | rtc = devm_rtc_allocate_device(dev); | |
445 | if (IS_ERR(rtc)) | |
446 | return rtc; | |
447 | ||
448 | rtc->ops = ops; | |
449 | ||
fdcfd854 | 450 | err = __devm_rtc_register_device(owner, rtc); |
a2694414 AB |
451 | if (err) |
452 | return ERR_PTR(err); | |
453 | ||
454 | return rtc; | |
455 | } | |
456 | EXPORT_SYMBOL_GPL(devm_rtc_device_register); | |
457 | ||
0c86edc0 AZ |
458 | static int __init rtc_init(void) |
459 | { | |
460 | rtc_class = class_create(THIS_MODULE, "rtc"); | |
461 | if (IS_ERR(rtc_class)) { | |
c100a5e0 | 462 | pr_err("couldn't create class\n"); |
0c86edc0 AZ |
463 | return PTR_ERR(rtc_class); |
464 | } | |
92e7f04a | 465 | rtc_class->pm = RTC_CLASS_DEV_PM_OPS; |
5726fb20 | 466 | rtc_dev_init(); |
0c86edc0 AZ |
467 | return 0; |
468 | } | |
818a8674 | 469 | subsys_initcall(rtc_init); |