2 * PTP 1588 clock support
4 * Copyright (C) 2010 OMICRON electronics GmbH
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
20 #include <linux/idr.h>
21 #include <linux/device.h>
22 #include <linux/err.h>
23 #include <linux/init.h>
24 #include <linux/kernel.h>
25 #include <linux/module.h>
26 #include <linux/posix-clock.h>
27 #include <linux/pps_kernel.h>
28 #include <linux/slab.h>
29 #include <linux/syscalls.h>
30 #include <linux/uaccess.h>
31 #include <uapi/linux/sched/types.h>
33 #include "ptp_private.h"
35 #define PTP_MAX_ALARMS 4
36 #define PTP_PPS_DEFAULTS (PPS_CAPTUREASSERT | PPS_OFFSETASSERT)
37 #define PTP_PPS_EVENT PPS_CAPTUREASSERT
38 #define PTP_PPS_MODE (PTP_PPS_DEFAULTS | PPS_CANWAIT | PPS_TSFMT_TSPEC)
42 static dev_t ptp_devt;
43 static struct class *ptp_class;
45 static DEFINE_IDA(ptp_clocks_map);
47 /* time stamp event queue operations */
49 static inline int queue_free(struct timestamp_event_queue *q)
51 return PTP_MAX_TIMESTAMPS - queue_cnt(q) - 1;
54 static void enqueue_external_timestamp(struct timestamp_event_queue *queue,
55 struct ptp_clock_event *src)
57 struct ptp_extts_event *dst;
62 seconds = div_u64_rem(src->timestamp, 1000000000, &remainder);
64 spin_lock_irqsave(&queue->lock, flags);
66 dst = &queue->buf[queue->tail];
67 dst->index = src->index;
69 dst->t.nsec = remainder;
71 if (!queue_free(queue))
72 queue->head = (queue->head + 1) % PTP_MAX_TIMESTAMPS;
74 queue->tail = (queue->tail + 1) % PTP_MAX_TIMESTAMPS;
76 spin_unlock_irqrestore(&queue->lock, flags);
79 static s32 scaled_ppm_to_ppb(long ppm)
82 * The 'freq' field in the 'struct timex' is in parts per
83 * million, but with a 16 bit binary fractional field.
85 * We want to calculate
87 * ppb = scaled_ppm * 1000 / 2^16
91 * ppb = scaled_ppm * 125 / 2^13
99 /* posix clock implementation */
101 static int ptp_clock_getres(struct posix_clock *pc, struct timespec64 *tp)
108 static int ptp_clock_settime(struct posix_clock *pc, const struct timespec64 *tp)
110 struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
112 return ptp->info->settime64(ptp->info, tp);
115 static int ptp_clock_gettime(struct posix_clock *pc, struct timespec64 *tp)
117 struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
120 err = ptp->info->gettime64(ptp->info, tp);
124 static int ptp_clock_adjtime(struct posix_clock *pc, struct timex *tx)
126 struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
127 struct ptp_clock_info *ops;
128 int err = -EOPNOTSUPP;
132 if (tx->modes & ADJ_SETOFFSET) {
133 struct timespec64 ts;
137 ts.tv_sec = tx->time.tv_sec;
138 ts.tv_nsec = tx->time.tv_usec;
140 if (!(tx->modes & ADJ_NANO))
143 if ((unsigned long) ts.tv_nsec >= NSEC_PER_SEC)
146 kt = timespec64_to_ktime(ts);
147 delta = ktime_to_ns(kt);
148 err = ops->adjtime(ops, delta);
149 } else if (tx->modes & ADJ_FREQUENCY) {
150 s32 ppb = scaled_ppm_to_ppb(tx->freq);
151 if (ppb > ops->max_adj || ppb < -ops->max_adj)
154 err = ops->adjfine(ops, tx->freq);
156 err = ops->adjfreq(ops, ppb);
157 ptp->dialed_frequency = tx->freq;
158 } else if (tx->modes == 0) {
159 tx->freq = ptp->dialed_frequency;
166 static struct posix_clock_operations ptp_clock_ops = {
167 .owner = THIS_MODULE,
168 .clock_adjtime = ptp_clock_adjtime,
169 .clock_gettime = ptp_clock_gettime,
170 .clock_getres = ptp_clock_getres,
171 .clock_settime = ptp_clock_settime,
178 static void delete_ptp_clock(struct posix_clock *pc)
180 struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
182 mutex_destroy(&ptp->tsevq_mux);
183 mutex_destroy(&ptp->pincfg_mux);
184 ida_simple_remove(&ptp_clocks_map, ptp->index);
188 static void ptp_aux_kworker(struct kthread_work *work)
190 struct ptp_clock *ptp = container_of(work, struct ptp_clock,
192 struct ptp_clock_info *info = ptp->info;
195 delay = info->do_aux_work(info);
198 kthread_queue_delayed_work(ptp->kworker, &ptp->aux_work, delay);
201 /* public interface */
203 struct ptp_clock *ptp_clock_register(struct ptp_clock_info *info,
204 struct device *parent)
206 struct ptp_clock *ptp;
207 int err = 0, index, major = MAJOR(ptp_devt);
209 if (info->n_alarm > PTP_MAX_ALARMS)
210 return ERR_PTR(-EINVAL);
212 /* Initialize a clock structure. */
214 ptp = kzalloc(sizeof(struct ptp_clock), GFP_KERNEL);
218 index = ida_simple_get(&ptp_clocks_map, 0, MINORMASK + 1, GFP_KERNEL);
224 ptp->clock.ops = ptp_clock_ops;
225 ptp->clock.release = delete_ptp_clock;
227 ptp->devid = MKDEV(major, index);
229 spin_lock_init(&ptp->tsevq.lock);
230 mutex_init(&ptp->tsevq_mux);
231 mutex_init(&ptp->pincfg_mux);
232 init_waitqueue_head(&ptp->tsev_wq);
234 if (ptp->info->do_aux_work) {
235 kthread_init_delayed_work(&ptp->aux_work, ptp_aux_kworker);
236 ptp->kworker = kthread_create_worker(0, "ptp%d", ptp->index);
237 if (IS_ERR(ptp->kworker)) {
238 err = PTR_ERR(ptp->kworker);
239 pr_err("failed to create ptp aux_worker %d\n", err);
244 err = ptp_populate_pin_groups(ptp);
248 /* Create a new device in our class. */
249 ptp->dev = device_create_with_groups(ptp_class, parent, ptp->devid,
250 ptp, ptp->pin_attr_groups,
251 "ptp%d", ptp->index);
252 if (IS_ERR(ptp->dev))
255 /* Register a new PPS source. */
257 struct pps_source_info pps;
258 memset(&pps, 0, sizeof(pps));
259 snprintf(pps.name, PPS_MAX_NAME_LEN, "ptp%d", index);
260 pps.mode = PTP_PPS_MODE;
261 pps.owner = info->owner;
262 ptp->pps_source = pps_register_source(&pps, PTP_PPS_DEFAULTS);
263 if (!ptp->pps_source) {
264 pr_err("failed to register pps source\n");
269 /* Create a posix clock. */
270 err = posix_clock_register(&ptp->clock, ptp->devid);
272 pr_err("failed to create posix clock\n");
280 pps_unregister_source(ptp->pps_source);
282 device_destroy(ptp_class, ptp->devid);
284 ptp_cleanup_pin_groups(ptp);
287 kthread_destroy_worker(ptp->kworker);
289 mutex_destroy(&ptp->tsevq_mux);
290 mutex_destroy(&ptp->pincfg_mux);
291 ida_simple_remove(&ptp_clocks_map, index);
297 EXPORT_SYMBOL(ptp_clock_register);
299 int ptp_clock_unregister(struct ptp_clock *ptp)
302 wake_up_interruptible(&ptp->tsev_wq);
305 kthread_cancel_delayed_work_sync(&ptp->aux_work);
306 kthread_destroy_worker(ptp->kworker);
309 /* Release the clock's resources. */
311 pps_unregister_source(ptp->pps_source);
313 device_destroy(ptp_class, ptp->devid);
314 ptp_cleanup_pin_groups(ptp);
316 posix_clock_unregister(&ptp->clock);
319 EXPORT_SYMBOL(ptp_clock_unregister);
321 void ptp_clock_event(struct ptp_clock *ptp, struct ptp_clock_event *event)
323 struct pps_event_time evt;
325 switch (event->type) {
327 case PTP_CLOCK_ALARM:
330 case PTP_CLOCK_EXTTS:
331 enqueue_external_timestamp(&ptp->tsevq, event);
332 wake_up_interruptible(&ptp->tsev_wq);
337 pps_event(ptp->pps_source, &evt, PTP_PPS_EVENT, NULL);
340 case PTP_CLOCK_PPSUSR:
341 pps_event(ptp->pps_source, &event->pps_times,
342 PTP_PPS_EVENT, NULL);
346 EXPORT_SYMBOL(ptp_clock_event);
348 int ptp_clock_index(struct ptp_clock *ptp)
352 EXPORT_SYMBOL(ptp_clock_index);
354 int ptp_find_pin(struct ptp_clock *ptp,
355 enum ptp_pin_function func, unsigned int chan)
357 struct ptp_pin_desc *pin = NULL;
360 mutex_lock(&ptp->pincfg_mux);
361 for (i = 0; i < ptp->info->n_pins; i++) {
362 if (ptp->info->pin_config[i].func == func &&
363 ptp->info->pin_config[i].chan == chan) {
364 pin = &ptp->info->pin_config[i];
368 mutex_unlock(&ptp->pincfg_mux);
372 EXPORT_SYMBOL(ptp_find_pin);
374 int ptp_schedule_worker(struct ptp_clock *ptp, unsigned long delay)
376 return kthread_mod_delayed_work(ptp->kworker, &ptp->aux_work, delay);
378 EXPORT_SYMBOL(ptp_schedule_worker);
380 /* module operations */
382 static void __exit ptp_exit(void)
384 class_destroy(ptp_class);
385 unregister_chrdev_region(ptp_devt, MINORMASK + 1);
386 ida_destroy(&ptp_clocks_map);
389 static int __init ptp_init(void)
393 ptp_class = class_create(THIS_MODULE, "ptp");
394 if (IS_ERR(ptp_class)) {
395 pr_err("ptp: failed to allocate class\n");
396 return PTR_ERR(ptp_class);
399 err = alloc_chrdev_region(&ptp_devt, 0, MINORMASK + 1, "ptp");
401 pr_err("ptp: failed to allocate device region\n");
405 ptp_class->dev_groups = ptp_groups;
406 pr_info("PTP clock support registered\n");
410 class_destroy(ptp_class);
414 subsys_initcall(ptp_init);
415 module_exit(ptp_exit);
417 MODULE_AUTHOR("Richard Cochran <richardcochran@gmail.com>");
418 MODULE_DESCRIPTION("PTP clocks support");
419 MODULE_LICENSE("GPL");