xref: /linux/drivers/ptp/ptp_clock.c (revision 07fdad3a93756b872da7b53647715c48d0f4a2d0) 
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * PTP 1588 clock support
4  *
5  * Copyright (C) 2010 OMICRON electronics GmbH
6  */
7 #include <linux/device.h>
8 #include <linux/err.h>
9 #include <linux/init.h>
10 #include <linux/kernel.h>
11 #include <linux/module.h>
12 #include <linux/posix-clock.h>
13 #include <linux/pps_kernel.h>
14 #include <linux/property.h>
15 #include <linux/slab.h>
16 #include <linux/syscalls.h>
17 #include <linux/uaccess.h>
18 #include <linux/debugfs.h>
19 #include <linux/xarray.h>
20 #include <uapi/linux/sched/types.h>
21 
22 #include "ptp_private.h"
23 
24 #define PTP_MAX_ALARMS 4
25 #define PTP_PPS_DEFAULTS (PPS_CAPTUREASSERT | PPS_OFFSETASSERT)
26 #define PTP_PPS_EVENT PPS_CAPTUREASSERT
27 #define PTP_PPS_MODE (PTP_PPS_DEFAULTS | PPS_CANWAIT | PPS_TSFMT_TSPEC)
28 
29 const struct class ptp_class = {
30 	.name = "ptp",
31 	.dev_groups = ptp_groups
32 };
33 
34 /* private globals */
35 
36 static dev_t ptp_devt;
37 
38 static DEFINE_XARRAY_ALLOC(ptp_clocks_map);
39 
40 /* time stamp event queue operations */
41 
42 static inline int queue_free(struct timestamp_event_queue *q)
43 {
44 	return PTP_MAX_TIMESTAMPS - queue_cnt(q) - 1;
45 }
46 
47 static void enqueue_external_timestamp(struct timestamp_event_queue *queue,
48 				       struct ptp_clock_event *src)
49 {
50 	struct ptp_extts_event *dst;
51 	struct timespec64 offset_ts;
52 	unsigned long flags;
53 	s64 seconds;
54 	u32 remainder;
55 
56 	if (src->type == PTP_CLOCK_EXTTS) {
57 		seconds = div_u64_rem(src->timestamp, 1000000000, &remainder);
58 	} else if (src->type == PTP_CLOCK_EXTOFF) {
59 		offset_ts = ns_to_timespec64(src->offset);
60 		seconds = offset_ts.tv_sec;
61 		remainder = offset_ts.tv_nsec;
62 	} else {
63 		WARN(1, "%s: unknown type %d\n", __func__, src->type);
64 		return;
65 	}
66 
67 	spin_lock_irqsave(&queue->lock, flags);
68 
69 	dst = &queue->buf[queue->tail];
70 	dst->index = src->index;
71 	dst->flags = PTP_EXTTS_EVENT_VALID;
72 	dst->t.sec = seconds;
73 	dst->t.nsec = remainder;
74 	if (src->type == PTP_CLOCK_EXTOFF)
75 		dst->flags |= PTP_EXT_OFFSET;
76 
77 	/* Both WRITE_ONCE() are paired with READ_ONCE() in queue_cnt() */
78 	if (!queue_free(queue))
79 		WRITE_ONCE(queue->head, (queue->head + 1) % PTP_MAX_TIMESTAMPS);
80 
81 	WRITE_ONCE(queue->tail, (queue->tail + 1) % PTP_MAX_TIMESTAMPS);
82 
83 	spin_unlock_irqrestore(&queue->lock, flags);
84 }
85 
86 /* posix clock implementation */
87 
88 static int ptp_clock_getres(struct posix_clock *pc, struct timespec64 *tp)
89 {
90 	tp->tv_sec = 0;
91 	tp->tv_nsec = 1;
92 	return 0;
93 }
94 
95 static int ptp_clock_settime(struct posix_clock *pc, const struct timespec64 *tp)
96 {
97 	struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
98 
99 	if (ptp_clock_freerun(ptp)) {
100 		pr_err_ratelimited("ptp: physical clock is free running\n");
101 		return -EBUSY;
102 	}
103 
104 	if (!timespec64_valid_settod(tp))
105 		return -EINVAL;
106 
107 	return  ptp->info->settime64(ptp->info, tp);
108 }
109 
110 static int ptp_clock_gettime(struct posix_clock *pc, struct timespec64 *tp)
111 {
112 	struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
113 	int err;
114 
115 	if (ptp->info->gettimex64)
116 		err = ptp->info->gettimex64(ptp->info, tp, NULL);
117 	else
118 		err = ptp->info->gettime64(ptp->info, tp);
119 	return err;
120 }
121 
122 static int ptp_clock_adjtime(struct posix_clock *pc, struct __kernel_timex *tx)
123 {
124 	struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
125 	struct ptp_clock_info *ops;
126 	int err = -EOPNOTSUPP;
127 
128 	if (tx->modes & (ADJ_SETOFFSET | ADJ_FREQUENCY | ADJ_OFFSET) &&
129 	    ptp_clock_freerun(ptp)) {
130 		pr_err("ptp: physical clock is free running\n");
131 		return -EBUSY;
132 	}
133 
134 	ops = ptp->info;
135 
136 	if (tx->modes & ADJ_SETOFFSET) {
137 		struct timespec64 ts, ts2;
138 		ktime_t kt;
139 		s64 delta;
140 
141 		ts.tv_sec  = tx->time.tv_sec;
142 		ts.tv_nsec = tx->time.tv_usec;
143 
144 		if (!(tx->modes & ADJ_NANO))
145 			ts.tv_nsec *= 1000;
146 
147 		if ((unsigned long) ts.tv_nsec >= NSEC_PER_SEC)
148 			return -EINVAL;
149 
150 		/* Make sure the offset is valid */
151 		err = ptp_clock_gettime(pc, &ts2);
152 		if (err)
153 			return err;
154 		ts2 = timespec64_add(ts2, ts);
155 		if (!timespec64_valid_settod(&ts2))
156 			return -EINVAL;
157 
158 		kt = timespec64_to_ktime(ts);
159 		delta = ktime_to_ns(kt);
160 		err = ops->adjtime(ops, delta);
161 	} else if (tx->modes & ADJ_FREQUENCY) {
162 		long ppb = scaled_ppm_to_ppb(tx->freq);
163 		if (ppb > ops->max_adj || ppb < -ops->max_adj)
164 			return -ERANGE;
165 		err = ops->adjfine(ops, tx->freq);
166 		if (!err)
167 			ptp->dialed_frequency = tx->freq;
168 	} else if (tx->modes & ADJ_OFFSET) {
169 		if (ops->adjphase) {
170 			s32 max_phase_adj = ops->getmaxphase(ops);
171 			s32 offset = tx->offset;
172 
173 			if (!(tx->modes & ADJ_NANO))
174 				offset *= NSEC_PER_USEC;
175 
176 			if (offset > max_phase_adj || offset < -max_phase_adj)
177 				return -ERANGE;
178 
179 			err = ops->adjphase(ops, offset);
180 		}
181 	} else if (tx->modes == 0) {
182 		tx->freq = ptp->dialed_frequency;
183 		err = 0;
184 	}
185 
186 	return err;
187 }
188 
189 static struct posix_clock_operations ptp_clock_ops = {
190 	.owner		= THIS_MODULE,
191 	.clock_adjtime	= ptp_clock_adjtime,
192 	.clock_gettime	= ptp_clock_gettime,
193 	.clock_getres	= ptp_clock_getres,
194 	.clock_settime	= ptp_clock_settime,
195 	.ioctl		= ptp_ioctl,
196 	.open		= ptp_open,
197 	.release	= ptp_release,
198 	.poll		= ptp_poll,
199 	.read		= ptp_read,
200 };
201 
202 static void ptp_clock_release(struct device *dev)
203 {
204 	struct ptp_clock *ptp = container_of(dev, struct ptp_clock, dev);
205 	struct timestamp_event_queue *tsevq;
206 	unsigned long flags;
207 
208 	ptp_cleanup_pin_groups(ptp);
209 	kfree(ptp->vclock_index);
210 	mutex_destroy(&ptp->pincfg_mux);
211 	mutex_destroy(&ptp->n_vclocks_mux);
212 	/* Delete first entry */
213 	spin_lock_irqsave(&ptp->tsevqs_lock, flags);
214 	tsevq = list_first_entry(&ptp->tsevqs, struct timestamp_event_queue,
215 				 qlist);
216 	list_del(&tsevq->qlist);
217 	spin_unlock_irqrestore(&ptp->tsevqs_lock, flags);
218 	bitmap_free(tsevq->mask);
219 	kfree(tsevq);
220 	debugfs_remove(ptp->debugfs_root);
221 	xa_erase(&ptp_clocks_map, ptp->index);
222 	kfree(ptp);
223 }
224 
225 static int ptp_getcycles64(struct ptp_clock_info *info, struct timespec64 *ts)
226 {
227 	if (info->getcyclesx64)
228 		return info->getcyclesx64(info, ts, NULL);
229 	else
230 		return info->gettime64(info, ts);
231 }
232 
233 static int ptp_enable(struct ptp_clock_info *ptp, struct ptp_clock_request *request, int on)
234 {
235 	return -EOPNOTSUPP;
236 }
237 
238 static void ptp_aux_kworker(struct kthread_work *work)
239 {
240 	struct ptp_clock *ptp = container_of(work, struct ptp_clock,
241 					     aux_work.work);
242 	struct ptp_clock_info *info = ptp->info;
243 	long delay;
244 
245 	delay = info->do_aux_work(info);
246 
247 	if (delay >= 0)
248 		kthread_queue_delayed_work(ptp->kworker, &ptp->aux_work, delay);
249 }
250 
251 static ssize_t ptp_n_perout_loopback_read(struct file *filep,
252 					  char __user *buffer,
253 					  size_t count, loff_t *pos)
254 {
255 	struct ptp_clock *ptp = filep->private_data;
256 	char buf[12] = {};
257 
258 	snprintf(buf, sizeof(buf), "%d\n", ptp->info->n_per_lp);
259 
260 	return simple_read_from_buffer(buffer, count, pos, buf, strlen(buf));
261 }
262 
263 static const struct file_operations ptp_n_perout_loopback_fops = {
264 	.owner	= THIS_MODULE,
265 	.open	= simple_open,
266 	.read	= ptp_n_perout_loopback_read,
267 };
268 
269 static ssize_t ptp_perout_loopback_write(struct file *filep,
270 					 const char __user *buffer,
271 					 size_t count, loff_t *ppos)
272 {
273 	struct ptp_clock *ptp = filep->private_data;
274 	struct ptp_clock_info *ops = ptp->info;
275 	unsigned int index, enable;
276 	int len, cnt, err;
277 	char buf[32] = {};
278 
279 	if (*ppos || !count)
280 		return -EINVAL;
281 
282 	if (count >= sizeof(buf))
283 		return -ENOSPC;
284 
285 	len = simple_write_to_buffer(buf, sizeof(buf) - 1,
286 				     ppos, buffer, count);
287 	if (len < 0)
288 		return len;
289 
290 	buf[len] = '\0';
291 	cnt = sscanf(buf, "%u %u", &index, &enable);
292 	if (cnt != 2)
293 		return -EINVAL;
294 
295 	if (index >= ops->n_per_lp)
296 		return -EINVAL;
297 
298 	if (enable != 0 && enable != 1)
299 		return -EINVAL;
300 
301 	err = ops->perout_loopback(ops, index, enable);
302 	if (err)
303 		return err;
304 
305 	return count;
306 }
307 
308 static const struct file_operations ptp_perout_loopback_ops = {
309 	.owner   = THIS_MODULE,
310 	.open    = simple_open,
311 	.write	 = ptp_perout_loopback_write,
312 };
313 
314 /* public interface */
315 
316 struct ptp_clock *ptp_clock_register(struct ptp_clock_info *info,
317 				     struct device *parent)
318 {
319 	struct ptp_clock *ptp;
320 	struct timestamp_event_queue *queue = NULL;
321 	int err, index, major = MAJOR(ptp_devt);
322 	char debugfsname[16];
323 	size_t size;
324 
325 	if (info->n_alarm > PTP_MAX_ALARMS)
326 		return ERR_PTR(-EINVAL);
327 
328 	/* Initialize a clock structure. */
329 	ptp = kzalloc(sizeof(struct ptp_clock), GFP_KERNEL);
330 	if (!ptp) {
331 		err = -ENOMEM;
332 		goto no_memory;
333 	}
334 
335 	err = xa_alloc(&ptp_clocks_map, &index, ptp, xa_limit_31b,
336 		       GFP_KERNEL);
337 	if (err)
338 		goto no_slot;
339 
340 	ptp->clock.ops = ptp_clock_ops;
341 	ptp->info = info;
342 	ptp->devid = MKDEV(major, index);
343 	ptp->index = index;
344 	INIT_LIST_HEAD(&ptp->tsevqs);
345 	queue = kzalloc(sizeof(*queue), GFP_KERNEL);
346 	if (!queue) {
347 		err = -ENOMEM;
348 		goto no_memory_queue;
349 	}
350 	list_add_tail(&queue->qlist, &ptp->tsevqs);
351 	spin_lock_init(&ptp->tsevqs_lock);
352 	queue->mask = bitmap_alloc(PTP_MAX_CHANNELS, GFP_KERNEL);
353 	if (!queue->mask) {
354 		err = -ENOMEM;
355 		goto no_memory_bitmap;
356 	}
357 	bitmap_set(queue->mask, 0, PTP_MAX_CHANNELS);
358 	spin_lock_init(&queue->lock);
359 	mutex_init(&ptp->pincfg_mux);
360 	mutex_init(&ptp->n_vclocks_mux);
361 	init_waitqueue_head(&ptp->tsev_wq);
362 
363 	if (ptp->info->getcycles64 || ptp->info->getcyclesx64) {
364 		ptp->has_cycles = true;
365 		if (!ptp->info->getcycles64 && ptp->info->getcyclesx64)
366 			ptp->info->getcycles64 = ptp_getcycles64;
367 	} else {
368 		/* Free running cycle counter not supported, use time. */
369 		ptp->info->getcycles64 = ptp_getcycles64;
370 
371 		if (ptp->info->gettimex64)
372 			ptp->info->getcyclesx64 = ptp->info->gettimex64;
373 
374 		if (ptp->info->getcrosststamp)
375 			ptp->info->getcrosscycles = ptp->info->getcrosststamp;
376 	}
377 
378 	if (!ptp->info->enable)
379 		ptp->info->enable = ptp_enable;
380 
381 	if (ptp->info->do_aux_work) {
382 		kthread_init_delayed_work(&ptp->aux_work, ptp_aux_kworker);
383 		ptp->kworker = kthread_run_worker(0, "ptp%d", ptp->index);
384 		if (IS_ERR(ptp->kworker)) {
385 			err = PTR_ERR(ptp->kworker);
386 			pr_err("failed to create ptp aux_worker %d\n", err);
387 			goto kworker_err;
388 		}
389 	}
390 
391 	/* PTP virtual clock is being registered under physical clock */
392 	if (parent && parent->class && parent->class->name &&
393 	    strcmp(parent->class->name, "ptp") == 0)
394 		ptp->is_virtual_clock = true;
395 
396 	if (!ptp->is_virtual_clock) {
397 		ptp->max_vclocks = PTP_DEFAULT_MAX_VCLOCKS;
398 
399 		size = sizeof(int) * ptp->max_vclocks;
400 		ptp->vclock_index = kzalloc(size, GFP_KERNEL);
401 		if (!ptp->vclock_index) {
402 			err = -ENOMEM;
403 			goto no_mem_for_vclocks;
404 		}
405 	}
406 
407 	err = ptp_populate_pin_groups(ptp);
408 	if (err)
409 		goto no_pin_groups;
410 
411 	/* Register a new PPS source. */
412 	if (info->pps) {
413 		struct pps_source_info pps;
414 		memset(&pps, 0, sizeof(pps));
415 		snprintf(pps.name, PPS_MAX_NAME_LEN, "ptp%d", index);
416 		pps.mode = PTP_PPS_MODE;
417 		pps.owner = info->owner;
418 		ptp->pps_source = pps_register_source(&pps, PTP_PPS_DEFAULTS);
419 		if (IS_ERR(ptp->pps_source)) {
420 			err = PTR_ERR(ptp->pps_source);
421 			pr_err("failed to register pps source\n");
422 			goto no_pps;
423 		}
424 		ptp->pps_source->lookup_cookie = ptp;
425 	}
426 
427 	/* Initialize a new device of our class in our clock structure. */
428 	device_initialize(&ptp->dev);
429 	ptp->dev.devt = ptp->devid;
430 	ptp->dev.class = &ptp_class;
431 	ptp->dev.parent = parent;
432 	ptp->dev.groups = ptp->pin_attr_groups;
433 	ptp->dev.release = ptp_clock_release;
434 	dev_set_drvdata(&ptp->dev, ptp);
435 	dev_set_name(&ptp->dev, "ptp%d", ptp->index);
436 
437 	/* Create a posix clock and link it to the device. */
438 	err = posix_clock_register(&ptp->clock, &ptp->dev);
439 	if (err) {
440 		if (ptp->pps_source)
441 			pps_unregister_source(ptp->pps_source);
442 
443 		if (ptp->kworker)
444 			kthread_destroy_worker(ptp->kworker);
445 
446 		put_device(&ptp->dev);
447 
448 		pr_err("failed to create posix clock\n");
449 		return ERR_PTR(err);
450 	}
451 
452 	/* Debugfs initialization */
453 	snprintf(debugfsname, sizeof(debugfsname), "ptp%d", ptp->index);
454 	ptp->debugfs_root = debugfs_create_dir(debugfsname, NULL);
455 	if (info->n_per_lp > 0 && info->perout_loopback) {
456 		debugfs_create_file("n_perout_loopback", 0400, ptp->debugfs_root,
457 				    ptp, &ptp_n_perout_loopback_fops);
458 		debugfs_create_file("perout_loopback", 0200, ptp->debugfs_root,
459 				    ptp, &ptp_perout_loopback_ops);
460 	}
461 
462 	return ptp;
463 
464 no_pps:
465 	ptp_cleanup_pin_groups(ptp);
466 no_pin_groups:
467 	kfree(ptp->vclock_index);
468 no_mem_for_vclocks:
469 	if (ptp->kworker)
470 		kthread_destroy_worker(ptp->kworker);
471 kworker_err:
472 	mutex_destroy(&ptp->pincfg_mux);
473 	mutex_destroy(&ptp->n_vclocks_mux);
474 	bitmap_free(queue->mask);
475 no_memory_bitmap:
476 	list_del(&queue->qlist);
477 	kfree(queue);
478 no_memory_queue:
479 	xa_erase(&ptp_clocks_map, index);
480 no_slot:
481 	kfree(ptp);
482 no_memory:
483 	return ERR_PTR(err);
484 }
485 EXPORT_SYMBOL(ptp_clock_register);
486 
487 static int unregister_vclock(struct device *dev, void *data)
488 {
489 	struct ptp_clock *ptp = dev_get_drvdata(dev);
490 
491 	ptp_vclock_unregister(info_to_vclock(ptp->info));
492 	return 0;
493 }
494 
495 int ptp_clock_unregister(struct ptp_clock *ptp)
496 {
497 	if (ptp_vclock_in_use(ptp)) {
498 		device_for_each_child(&ptp->dev, NULL, unregister_vclock);
499 	}
500 
501 	/* Get the device to stop posix_clock_unregister() doing the last put
502 	 * and freeing the structure(s)
503 	 */
504 	get_device(&ptp->dev);
505 
506 	/* Wake up any userspace waiting for an event. */
507 	ptp->defunct = 1;
508 	wake_up_interruptible(&ptp->tsev_wq);
509 
510 	/* Tear down the POSIX clock, which removes the user interface. */
511 	posix_clock_unregister(&ptp->clock);
512 
513 	/* Disable all sources of event generation. */
514 	ptp_disable_all_events(ptp);
515 
516 	if (ptp->kworker) {
517 		kthread_cancel_delayed_work_sync(&ptp->aux_work);
518 		kthread_destroy_worker(ptp->kworker);
519 	}
520 
521 	/* Release the clock's resources. */
522 	if (ptp->pps_source)
523 		pps_unregister_source(ptp->pps_source);
524 
525 	/* The final put, normally here, will invoke ptp_clock_release(). */
526 	put_device(&ptp->dev);
527 
528 	return 0;
529 }
530 EXPORT_SYMBOL(ptp_clock_unregister);
531 
532 void ptp_clock_event(struct ptp_clock *ptp, struct ptp_clock_event *event)
533 {
534 	struct timestamp_event_queue *tsevq;
535 	struct pps_event_time evt;
536 	unsigned long flags;
537 
538 	switch (event->type) {
539 
540 	case PTP_CLOCK_ALARM:
541 		break;
542 
543 	case PTP_CLOCK_EXTTS:
544 	case PTP_CLOCK_EXTOFF:
545 		/* Enqueue timestamp on selected queues */
546 		spin_lock_irqsave(&ptp->tsevqs_lock, flags);
547 		list_for_each_entry(tsevq, &ptp->tsevqs, qlist) {
548 			if (test_bit((unsigned int)event->index, tsevq->mask))
549 				enqueue_external_timestamp(tsevq, event);
550 		}
551 		spin_unlock_irqrestore(&ptp->tsevqs_lock, flags);
552 		wake_up_interruptible(&ptp->tsev_wq);
553 		break;
554 
555 	case PTP_CLOCK_PPS:
556 		pps_get_ts(&evt);
557 		pps_event(ptp->pps_source, &evt, PTP_PPS_EVENT, NULL);
558 		break;
559 
560 	case PTP_CLOCK_PPSUSR:
561 		pps_event(ptp->pps_source, &event->pps_times,
562 			  PTP_PPS_EVENT, NULL);
563 		break;
564 	}
565 }
566 EXPORT_SYMBOL(ptp_clock_event);
567 
568 int ptp_clock_index(struct ptp_clock *ptp)
569 {
570 	return ptp->index;
571 }
572 EXPORT_SYMBOL(ptp_clock_index);
573 
574 static int ptp_clock_of_node_match(struct device *dev, const void *data)
575 {
576 	const struct device_node *parent_np = data;
577 
578 	return (dev->parent && dev_of_node(dev->parent) == parent_np);
579 }
580 
581 int ptp_clock_index_by_of_node(struct device_node *np)
582 {
583 	struct ptp_clock *ptp;
584 	struct device *dev;
585 	int phc_index;
586 
587 	dev = class_find_device(&ptp_class, NULL, np,
588 				ptp_clock_of_node_match);
589 	if (!dev)
590 		return -1;
591 
592 	ptp = dev_get_drvdata(dev);
593 	phc_index = ptp_clock_index(ptp);
594 	put_device(dev);
595 
596 	return phc_index;
597 }
598 EXPORT_SYMBOL_GPL(ptp_clock_index_by_of_node);
599 
600 static int ptp_clock_dev_match(struct device *dev, const void *data)
601 {
602 	const struct device *parent = data;
603 
604 	return dev->parent == parent;
605 }
606 
607 int ptp_clock_index_by_dev(struct device *parent)
608 {
609 	struct ptp_clock *ptp;
610 	struct device *dev;
611 	int phc_index;
612 
613 	dev = class_find_device(&ptp_class, NULL, parent,
614 				ptp_clock_dev_match);
615 	if (!dev)
616 		return -1;
617 
618 	ptp = dev_get_drvdata(dev);
619 	phc_index = ptp_clock_index(ptp);
620 	put_device(dev);
621 
622 	return phc_index;
623 }
624 EXPORT_SYMBOL_GPL(ptp_clock_index_by_dev);
625 
626 int ptp_find_pin(struct ptp_clock *ptp,
627 		 enum ptp_pin_function func, unsigned int chan)
628 {
629 	struct ptp_pin_desc *pin = NULL;
630 	int i;
631 
632 	for (i = 0; i < ptp->info->n_pins; i++) {
633 		if (ptp->info->pin_config[i].func == func &&
634 		    ptp->info->pin_config[i].chan == chan) {
635 			pin = &ptp->info->pin_config[i];
636 			break;
637 		}
638 	}
639 
640 	return pin ? i : -1;
641 }
642 EXPORT_SYMBOL(ptp_find_pin);
643 
644 int ptp_find_pin_unlocked(struct ptp_clock *ptp,
645 			  enum ptp_pin_function func, unsigned int chan)
646 {
647 	int result;
648 
649 	mutex_lock(&ptp->pincfg_mux);
650 
651 	result = ptp_find_pin(ptp, func, chan);
652 
653 	mutex_unlock(&ptp->pincfg_mux);
654 
655 	return result;
656 }
657 EXPORT_SYMBOL(ptp_find_pin_unlocked);
658 
659 int ptp_schedule_worker(struct ptp_clock *ptp, unsigned long delay)
660 {
661 	return kthread_mod_delayed_work(ptp->kworker, &ptp->aux_work, delay);
662 }
663 EXPORT_SYMBOL(ptp_schedule_worker);
664 
665 void ptp_cancel_worker_sync(struct ptp_clock *ptp)
666 {
667 	kthread_cancel_delayed_work_sync(&ptp->aux_work);
668 }
669 EXPORT_SYMBOL(ptp_cancel_worker_sync);
670 
671 /* module operations */
672 
673 static void __exit ptp_exit(void)
674 {
675 	class_unregister(&ptp_class);
676 	unregister_chrdev_region(ptp_devt, MINORMASK + 1);
677 	xa_destroy(&ptp_clocks_map);
678 }
679 
680 static int __init ptp_init(void)
681 {
682 	int err;
683 
684 	err = class_register(&ptp_class);
685 	if (err) {
686 		pr_err("ptp: failed to allocate class\n");
687 		return err;
688 	}
689 
690 	err = alloc_chrdev_region(&ptp_devt, 0, MINORMASK + 1, "ptp");
691 	if (err < 0) {
692 		pr_err("ptp: failed to allocate device region\n");
693 		goto no_region;
694 	}
695 
696 	pr_info("PTP clock support registered\n");
697 	return 0;
698 
699 no_region:
700 	class_unregister(&ptp_class);
701 	return err;
702 }
703 
704 subsys_initcall(ptp_init);
705 module_exit(ptp_exit);
706 
707 MODULE_AUTHOR("Richard Cochran <richardcochran@gmail.com>");
708 MODULE_DESCRIPTION("PTP clocks support");
709 MODULE_LICENSE("GPL");
710