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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); |
0c86edc0 AZ |
31 | kfree(rtc); |
32 | } | |
33 | ||
4c24e29e DF |
34 | #ifdef CONFIG_RTC_HCTOSYS_DEVICE |
35 | /* Result of the last RTC to system clock attempt. */ | |
36 | int rtc_hctosys_ret = -ENODEV; | |
f9b2a4d6 SM |
37 | |
38 | /* IMPORTANT: the RTC only stores whole seconds. It is arbitrary | |
39 | * whether it stores the most close value or the value with partial | |
40 | * seconds truncated. However, it is important that we use it to store | |
41 | * the truncated value. This is because otherwise it is necessary, | |
42 | * in an rtc sync function, to read both xtime.tv_sec and | |
43 | * xtime.tv_nsec. On some processors (i.e. ARM), an atomic read | |
44 | * of >32bits is not possible. So storing the most close value would | |
45 | * slow down the sync API. So here we have the truncated value and | |
46 | * the best guess is to add 0.5s. | |
47 | */ | |
48 | ||
5614a4a3 | 49 | static void rtc_hctosys(struct rtc_device *rtc) |
f9b2a4d6 | 50 | { |
3edf29d9 | 51 | int err; |
f9b2a4d6 SM |
52 | struct rtc_time tm; |
53 | struct timespec64 tv64 = { | |
54 | .tv_nsec = NSEC_PER_SEC >> 1, | |
55 | }; | |
f9b2a4d6 SM |
56 | |
57 | err = rtc_read_time(rtc, &tm); | |
58 | if (err) { | |
59 | dev_err(rtc->dev.parent, | |
60 | "hctosys: unable to read the hardware clock\n"); | |
61 | goto err_read; | |
62 | } | |
63 | ||
64 | tv64.tv_sec = rtc_tm_to_time64(&tm); | |
65 | ||
66 | #if BITS_PER_LONG == 32 | |
67 | if (tv64.tv_sec > INT_MAX) { | |
68 | err = -ERANGE; | |
69 | goto err_read; | |
70 | } | |
71 | #endif | |
72 | ||
73 | err = do_settimeofday64(&tv64); | |
74 | ||
75 | dev_info(rtc->dev.parent, "setting system clock to %ptR UTC (%lld)\n", | |
76 | &tm, (long long)tv64.tv_sec); | |
77 | ||
78 | err_read: | |
f9b2a4d6 | 79 | rtc_hctosys_ret = err; |
f9b2a4d6 | 80 | } |
4c24e29e | 81 | #endif |
7ca1d488 | 82 | |
92e7f04a | 83 | #if defined(CONFIG_PM_SLEEP) && defined(CONFIG_RTC_HCTOSYS_DEVICE) |
7ca1d488 DB |
84 | /* |
85 | * On suspend(), measure the delta between one RTC and the | |
86 | * system's wall clock; restore it on resume(). | |
87 | */ | |
88 | ||
d4bda8f8 | 89 | static struct timespec64 old_rtc, old_system, old_delta; |
3dcad5ff | 90 | |
92e7f04a | 91 | static int rtc_suspend(struct device *dev) |
7ca1d488 DB |
92 | { |
93 | struct rtc_device *rtc = to_rtc_device(dev); | |
94 | struct rtc_time tm; | |
d4bda8f8 | 95 | struct timespec64 delta, delta_delta; |
e1d60093 | 96 | int err; |
9ecf37eb | 97 | |
0fa88cb4 | 98 | if (timekeeping_rtc_skipsuspend()) |
9ecf37eb FT |
99 | return 0; |
100 | ||
d4afc76c | 101 | if (strcmp(dev_name(&rtc->dev), CONFIG_RTC_HCTOSYS_DEVICE) != 0) |
7ca1d488 DB |
102 | return 0; |
103 | ||
3dcad5ff | 104 | /* snapshot the current RTC and system time at suspend*/ |
e1d60093 HG |
105 | err = rtc_read_time(rtc, &tm); |
106 | if (err < 0) { | |
107 | pr_debug("%s: fail to read rtc time\n", dev_name(&rtc->dev)); | |
108 | return 0; | |
109 | } | |
110 | ||
5089ea15 | 111 | ktime_get_real_ts64(&old_system); |
d4bda8f8 | 112 | old_rtc.tv_sec = rtc_tm_to_time64(&tm); |
3dcad5ff | 113 | |
3dcad5ff JS |
114 | /* |
115 | * To avoid drift caused by repeated suspend/resumes, | |
116 | * which each can add ~1 second drift error, | |
117 | * try to compensate so the difference in system time | |
118 | * and rtc time stays close to constant. | |
119 | */ | |
d4bda8f8 JS |
120 | delta = timespec64_sub(old_system, old_rtc); |
121 | delta_delta = timespec64_sub(delta, old_delta); | |
6a8943d9 | 122 | if (delta_delta.tv_sec < -2 || delta_delta.tv_sec >= 2) { |
3dcad5ff JS |
123 | /* |
124 | * if delta_delta is too large, assume time correction | |
606cc43c | 125 | * has occurred and set old_delta to the current delta. |
3dcad5ff JS |
126 | */ |
127 | old_delta = delta; | |
128 | } else { | |
129 | /* Otherwise try to adjust old_system to compensate */ | |
d4bda8f8 | 130 | old_system = timespec64_sub(old_system, delta_delta); |
3dcad5ff | 131 | } |
7ca1d488 | 132 | |
7ca1d488 DB |
133 | return 0; |
134 | } | |
135 | ||
136 | static int rtc_resume(struct device *dev) | |
137 | { | |
138 | struct rtc_device *rtc = to_rtc_device(dev); | |
139 | struct rtc_time tm; | |
d4bda8f8 JS |
140 | struct timespec64 new_system, new_rtc; |
141 | struct timespec64 sleep_time; | |
e1d60093 | 142 | int err; |
7ca1d488 | 143 | |
0fa88cb4 | 144 | if (timekeeping_rtc_skipresume()) |
9ecf37eb FT |
145 | return 0; |
146 | ||
4c24e29e | 147 | rtc_hctosys_ret = -ENODEV; |
d4afc76c | 148 | if (strcmp(dev_name(&rtc->dev), CONFIG_RTC_HCTOSYS_DEVICE) != 0) |
7ca1d488 DB |
149 | return 0; |
150 | ||
3dcad5ff | 151 | /* snapshot the current rtc and system time at resume */ |
5089ea15 | 152 | ktime_get_real_ts64(&new_system); |
e1d60093 HG |
153 | err = rtc_read_time(rtc, &tm); |
154 | if (err < 0) { | |
155 | pr_debug("%s: fail to read rtc time\n", dev_name(&rtc->dev)); | |
156 | return 0; | |
157 | } | |
158 | ||
d4bda8f8 | 159 | new_rtc.tv_sec = rtc_tm_to_time64(&tm); |
3dcad5ff JS |
160 | new_rtc.tv_nsec = 0; |
161 | ||
6a8943d9 AH |
162 | if (new_rtc.tv_sec < old_rtc.tv_sec) { |
163 | pr_debug("%s: time travel!\n", dev_name(&rtc->dev)); | |
7ca1d488 DB |
164 | return 0; |
165 | } | |
166 | ||
3dcad5ff | 167 | /* calculate the RTC time delta (sleep time)*/ |
d4bda8f8 | 168 | sleep_time = timespec64_sub(new_rtc, old_rtc); |
3dcad5ff JS |
169 | |
170 | /* | |
171 | * Since these RTC suspend/resume handlers are not called | |
172 | * at the very end of suspend or the start of resume, | |
173 | * some run-time may pass on either sides of the sleep time | |
174 | * so subtract kernel run-time between rtc_suspend to rtc_resume | |
175 | * to keep things accurate. | |
176 | */ | |
d4bda8f8 | 177 | sleep_time = timespec64_sub(sleep_time, |
606cc43c | 178 | timespec64_sub(new_system, old_system)); |
7ca1d488 | 179 | |
6a8943d9 | 180 | if (sleep_time.tv_sec >= 0) |
d4bda8f8 | 181 | timekeeping_inject_sleeptime64(&sleep_time); |
4c24e29e | 182 | rtc_hctosys_ret = 0; |
7ca1d488 DB |
183 | return 0; |
184 | } | |
185 | ||
92e7f04a SK |
186 | static SIMPLE_DEV_PM_OPS(rtc_class_dev_pm_ops, rtc_suspend, rtc_resume); |
187 | #define RTC_CLASS_DEV_PM_OPS (&rtc_class_dev_pm_ops) | |
7ca1d488 | 188 | #else |
92e7f04a | 189 | #define RTC_CLASS_DEV_PM_OPS NULL |
7ca1d488 DB |
190 | #endif |
191 | ||
3068a254 | 192 | /* Ensure the caller will set the id before releasing the device */ |
d1bec20f AB |
193 | static struct rtc_device *rtc_allocate_device(void) |
194 | { | |
195 | struct rtc_device *rtc; | |
196 | ||
197 | rtc = kzalloc(sizeof(*rtc), GFP_KERNEL); | |
198 | if (!rtc) | |
199 | return NULL; | |
200 | ||
201 | device_initialize(&rtc->dev); | |
202 | ||
0f295b06 JG |
203 | /* Drivers can revise this default after allocating the device. */ |
204 | rtc->set_offset_nsec = NSEC_PER_SEC / 2; | |
205 | ||
d1bec20f AB |
206 | rtc->irq_freq = 1; |
207 | rtc->max_user_freq = 64; | |
208 | rtc->dev.class = rtc_class; | |
209 | rtc->dev.groups = rtc_get_dev_attribute_groups(); | |
210 | rtc->dev.release = rtc_device_release; | |
211 | ||
212 | mutex_init(&rtc->ops_lock); | |
213 | spin_lock_init(&rtc->irq_lock); | |
d1bec20f AB |
214 | init_waitqueue_head(&rtc->irq_queue); |
215 | ||
216 | /* Init timerqueue */ | |
217 | timerqueue_init_head(&rtc->timerqueue); | |
218 | INIT_WORK(&rtc->irqwork, rtc_timer_do_work); | |
219 | /* Init aie timer */ | |
9a032011 | 220 | rtc_timer_init(&rtc->aie_timer, rtc_aie_update_irq, rtc); |
d1bec20f | 221 | /* Init uie timer */ |
9a032011 | 222 | rtc_timer_init(&rtc->uie_rtctimer, rtc_uie_update_irq, rtc); |
d1bec20f AB |
223 | /* Init pie timer */ |
224 | hrtimer_init(&rtc->pie_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); | |
225 | rtc->pie_timer.function = rtc_pie_update_irq; | |
226 | rtc->pie_enabled = 0; | |
227 | ||
228 | return rtc; | |
229 | } | |
7ca1d488 | 230 | |
b91336df AB |
231 | static int rtc_device_get_id(struct device *dev) |
232 | { | |
233 | int of_id = -1, id = -1; | |
234 | ||
235 | if (dev->of_node) | |
236 | of_id = of_alias_get_id(dev->of_node, "rtc"); | |
237 | else if (dev->parent && dev->parent->of_node) | |
238 | of_id = of_alias_get_id(dev->parent->of_node, "rtc"); | |
239 | ||
240 | if (of_id >= 0) { | |
241 | id = ida_simple_get(&rtc_ida, of_id, of_id + 1, GFP_KERNEL); | |
242 | if (id < 0) | |
243 | dev_warn(dev, "/aliases ID %d not available\n", of_id); | |
244 | } | |
245 | ||
246 | if (id < 0) | |
247 | id = ida_simple_get(&rtc_ida, 0, 0, GFP_KERNEL); | |
248 | ||
249 | return id; | |
250 | } | |
251 | ||
98951564 BW |
252 | static void rtc_device_get_offset(struct rtc_device *rtc) |
253 | { | |
254 | time64_t range_secs; | |
255 | u32 start_year; | |
256 | int ret; | |
257 | ||
258 | /* | |
259 | * If RTC driver did not implement the range of RTC hardware device, | |
260 | * then we can not expand the RTC range by adding or subtracting one | |
261 | * offset. | |
262 | */ | |
263 | if (rtc->range_min == rtc->range_max) | |
264 | return; | |
265 | ||
266 | ret = device_property_read_u32(rtc->dev.parent, "start-year", | |
267 | &start_year); | |
268 | if (!ret) { | |
269 | rtc->start_secs = mktime64(start_year, 1, 1, 0, 0, 0); | |
270 | rtc->set_start_time = true; | |
271 | } | |
272 | ||
273 | /* | |
274 | * If user did not implement the start time for RTC driver, then no | |
275 | * need to expand the RTC range. | |
276 | */ | |
277 | if (!rtc->set_start_time) | |
278 | return; | |
279 | ||
280 | range_secs = rtc->range_max - rtc->range_min + 1; | |
281 | ||
282 | /* | |
283 | * If the start_secs is larger than the maximum seconds (rtc->range_max) | |
284 | * supported by RTC hardware or the maximum seconds of new expanded | |
285 | * range (start_secs + rtc->range_max - rtc->range_min) is less than | |
286 | * rtc->range_min, which means the minimum seconds (rtc->range_min) of | |
287 | * RTC hardware will be mapped to start_secs by adding one offset, so | |
288 | * the offset seconds calculation formula should be: | |
289 | * rtc->offset_secs = rtc->start_secs - rtc->range_min; | |
290 | * | |
291 | * If the start_secs is larger than the minimum seconds (rtc->range_min) | |
292 | * supported by RTC hardware, then there is one region is overlapped | |
293 | * between the original RTC hardware range and the new expanded range, | |
294 | * and this overlapped region do not need to be mapped into the new | |
295 | * expanded range due to it is valid for RTC device. So the minimum | |
296 | * seconds of RTC hardware (rtc->range_min) should be mapped to | |
297 | * rtc->range_max + 1, then the offset seconds formula should be: | |
298 | * rtc->offset_secs = rtc->range_max - rtc->range_min + 1; | |
299 | * | |
300 | * If the start_secs is less than the minimum seconds (rtc->range_min), | |
301 | * which is similar to case 2. So the start_secs should be mapped to | |
302 | * start_secs + rtc->range_max - rtc->range_min + 1, then the | |
303 | * offset seconds formula should be: | |
304 | * rtc->offset_secs = -(rtc->range_max - rtc->range_min + 1); | |
305 | * | |
306 | * Otherwise the offset seconds should be 0. | |
307 | */ | |
308 | if (rtc->start_secs > rtc->range_max || | |
309 | rtc->start_secs + range_secs - 1 < rtc->range_min) | |
310 | rtc->offset_secs = rtc->start_secs - rtc->range_min; | |
311 | else if (rtc->start_secs > rtc->range_min) | |
312 | rtc->offset_secs = range_secs; | |
313 | else if (rtc->start_secs < rtc->range_min) | |
314 | rtc->offset_secs = -range_secs; | |
315 | else | |
316 | rtc->offset_secs = 0; | |
317 | } | |
318 | ||
0c86edc0 AZ |
319 | /** |
320 | * rtc_device_unregister - removes the previously registered RTC class device | |
321 | * | |
322 | * @rtc: the RTC class device to destroy | |
323 | */ | |
1e479c61 | 324 | static void rtc_device_unregister(struct rtc_device *rtc) |
0c86edc0 | 325 | { |
c3b399a4 DT |
326 | mutex_lock(&rtc->ops_lock); |
327 | /* | |
328 | * Remove innards of this RTC, then disable it, before | |
329 | * letting any rtc_class_open() users access it again | |
330 | */ | |
c3b399a4 | 331 | rtc_proc_del_device(rtc); |
d5ed9177 | 332 | cdev_device_del(&rtc->char_dev, &rtc->dev); |
c3b399a4 DT |
333 | rtc->ops = NULL; |
334 | mutex_unlock(&rtc->ops_lock); | |
335 | put_device(&rtc->dev); | |
0c86edc0 | 336 | } |
0c86edc0 | 337 | |
3068a254 AB |
338 | static void devm_rtc_release_device(struct device *dev, void *res) |
339 | { | |
340 | struct rtc_device *rtc = *(struct rtc_device **)res; | |
341 | ||
ac75779b AB |
342 | rtc_nvmem_unregister(rtc); |
343 | ||
3068a254 AB |
344 | if (rtc->registered) |
345 | rtc_device_unregister(rtc); | |
346 | else | |
347 | put_device(&rtc->dev); | |
348 | } | |
349 | ||
350 | struct rtc_device *devm_rtc_allocate_device(struct device *dev) | |
351 | { | |
352 | struct rtc_device **ptr, *rtc; | |
353 | int id, err; | |
354 | ||
355 | id = rtc_device_get_id(dev); | |
356 | if (id < 0) | |
357 | return ERR_PTR(id); | |
358 | ||
359 | ptr = devres_alloc(devm_rtc_release_device, sizeof(*ptr), GFP_KERNEL); | |
360 | if (!ptr) { | |
361 | err = -ENOMEM; | |
362 | goto exit_ida; | |
363 | } | |
364 | ||
365 | rtc = rtc_allocate_device(); | |
366 | if (!rtc) { | |
367 | err = -ENOMEM; | |
368 | goto exit_devres; | |
369 | } | |
370 | ||
371 | *ptr = rtc; | |
372 | devres_add(dev, ptr); | |
373 | ||
374 | rtc->id = id; | |
375 | rtc->dev.parent = dev; | |
376 | dev_set_name(&rtc->dev, "rtc%d", id); | |
377 | ||
378 | return rtc; | |
379 | ||
380 | exit_devres: | |
381 | devres_free(ptr); | |
382 | exit_ida: | |
383 | ida_simple_remove(&rtc_ida, id); | |
384 | return ERR_PTR(err); | |
385 | } | |
386 | EXPORT_SYMBOL_GPL(devm_rtc_allocate_device); | |
387 | ||
388 | int __rtc_register_device(struct module *owner, struct rtc_device *rtc) | |
389 | { | |
390 | struct rtc_wkalrm alrm; | |
391 | int err; | |
392 | ||
924068e5 AB |
393 | if (!rtc->ops) { |
394 | dev_dbg(&rtc->dev, "no ops set\n"); | |
3068a254 | 395 | return -EINVAL; |
924068e5 | 396 | } |
3068a254 AB |
397 | |
398 | rtc->owner = owner; | |
98951564 | 399 | rtc_device_get_offset(rtc); |
3068a254 AB |
400 | |
401 | /* Check to see if there is an ALARM already set in hw */ | |
402 | err = __rtc_read_alarm(rtc, &alrm); | |
403 | if (!err && !rtc_valid_tm(&alrm.time)) | |
404 | rtc_initialize_alarm(rtc, &alrm); | |
405 | ||
406 | rtc_dev_prepare(rtc); | |
407 | ||
408 | err = cdev_device_add(&rtc->char_dev, &rtc->dev); | |
409 | if (err) | |
410 | dev_warn(rtc->dev.parent, "failed to add char device %d:%d\n", | |
411 | MAJOR(rtc->dev.devt), rtc->id); | |
412 | else | |
413 | dev_dbg(rtc->dev.parent, "char device (%d:%d)\n", | |
414 | MAJOR(rtc->dev.devt), rtc->id); | |
415 | ||
416 | rtc_proc_add_device(rtc); | |
417 | ||
418 | rtc->registered = true; | |
419 | dev_info(rtc->dev.parent, "registered as %s\n", | |
420 | dev_name(&rtc->dev)); | |
421 | ||
f9b2a4d6 SM |
422 | #ifdef CONFIG_RTC_HCTOSYS_DEVICE |
423 | if (!strcmp(dev_name(&rtc->dev), CONFIG_RTC_HCTOSYS_DEVICE)) | |
5614a4a3 | 424 | rtc_hctosys(rtc); |
f9b2a4d6 SM |
425 | #endif |
426 | ||
3068a254 AB |
427 | return 0; |
428 | } | |
429 | EXPORT_SYMBOL_GPL(__rtc_register_device); | |
430 | ||
a2694414 AB |
431 | /** |
432 | * devm_rtc_device_register - resource managed rtc_device_register() | |
433 | * @dev: the device to register | |
434 | * @name: the name of the device (unused) | |
435 | * @ops: the rtc operations structure | |
436 | * @owner: the module owner | |
437 | * | |
438 | * @return a struct rtc on success, or an ERR_PTR on error | |
439 | * | |
440 | * Managed rtc_device_register(). The rtc_device returned from this function | |
441 | * are automatically freed on driver detach. | |
442 | * This function is deprecated, use devm_rtc_allocate_device and | |
443 | * rtc_register_device instead | |
444 | */ | |
445 | struct rtc_device *devm_rtc_device_register(struct device *dev, | |
606cc43c AB |
446 | const char *name, |
447 | const struct rtc_class_ops *ops, | |
448 | struct module *owner) | |
a2694414 AB |
449 | { |
450 | struct rtc_device *rtc; | |
451 | int err; | |
452 | ||
453 | rtc = devm_rtc_allocate_device(dev); | |
454 | if (IS_ERR(rtc)) | |
455 | return rtc; | |
456 | ||
457 | rtc->ops = ops; | |
458 | ||
459 | err = __rtc_register_device(owner, rtc); | |
460 | if (err) | |
461 | return ERR_PTR(err); | |
462 | ||
463 | return rtc; | |
464 | } | |
465 | EXPORT_SYMBOL_GPL(devm_rtc_device_register); | |
466 | ||
0c86edc0 AZ |
467 | static int __init rtc_init(void) |
468 | { | |
469 | rtc_class = class_create(THIS_MODULE, "rtc"); | |
470 | if (IS_ERR(rtc_class)) { | |
c100a5e0 | 471 | pr_err("couldn't create class\n"); |
0c86edc0 AZ |
472 | return PTR_ERR(rtc_class); |
473 | } | |
92e7f04a | 474 | rtc_class->pm = RTC_CLASS_DEV_PM_OPS; |
5726fb20 | 475 | rtc_dev_init(); |
0c86edc0 AZ |
476 | return 0; |
477 | } | |
818a8674 | 478 | subsys_initcall(rtc_init); |