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>
32 #include "ptp_private.h"
34 #define PTP_MAX_ALARMS 4
35 #define PTP_PPS_DEFAULTS (PPS_CAPTUREASSERT | PPS_OFFSETASSERT)
36 #define PTP_PPS_EVENT PPS_CAPTUREASSERT
37 #define PTP_PPS_MODE (PTP_PPS_DEFAULTS | PPS_CANWAIT | PPS_TSFMT_TSPEC)
41 static dev_t ptp_devt;
42 static struct class *ptp_class;
44 static DEFINE_IDA(ptp_clocks_map);
46 /* time stamp event queue operations */
48 static inline int queue_free(struct timestamp_event_queue *q)
50 return PTP_MAX_TIMESTAMPS - queue_cnt(q) - 1;
53 static void enqueue_external_timestamp(struct timestamp_event_queue *queue,
54 struct ptp_clock_event *src)
56 struct ptp_extts_event *dst;
61 seconds = div_u64_rem(src->timestamp, 1000000000, &remainder);
63 spin_lock_irqsave(&queue->lock, flags);
65 dst = &queue->buf[queue->tail];
66 dst->index = src->index;
68 dst->t.nsec = remainder;
70 if (!queue_free(queue))
71 queue->head = (queue->head + 1) % PTP_MAX_TIMESTAMPS;
73 queue->tail = (queue->tail + 1) % PTP_MAX_TIMESTAMPS;
75 spin_unlock_irqrestore(&queue->lock, flags);
78 static s32 scaled_ppm_to_ppb(long ppm)
81 * The 'freq' field in the 'struct timex' is in parts per
82 * million, but with a 16 bit binary fractional field.
84 * We want to calculate
86 * ppb = scaled_ppm * 1000 / 2^16
90 * ppb = scaled_ppm * 125 / 2^13
98 /* posix clock implementation */
100 static int ptp_clock_getres(struct posix_clock *pc, struct timespec *tp)
107 static int ptp_clock_settime(struct posix_clock *pc, const struct timespec *tp)
109 struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
110 struct timespec64 ts = timespec_to_timespec64(*tp);
112 return ptp->info->settime64(ptp->info, &ts);
115 static int ptp_clock_gettime(struct posix_clock *pc, struct timespec *tp)
117 struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
118 struct timespec64 ts;
121 err = ptp->info->gettime64(ptp->info, &ts);
123 *tp = timespec64_to_timespec(ts);
127 static int ptp_clock_adjtime(struct posix_clock *pc, struct timex *tx)
129 struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
130 struct ptp_clock_info *ops;
131 int err = -EOPNOTSUPP;
135 if (tx->modes & ADJ_SETOFFSET) {
140 ts.tv_sec = tx->time.tv_sec;
141 ts.tv_nsec = tx->time.tv_usec;
143 if (!(tx->modes & ADJ_NANO))
146 if ((unsigned long) ts.tv_nsec >= NSEC_PER_SEC)
149 kt = timespec_to_ktime(ts);
150 delta = ktime_to_ns(kt);
151 err = ops->adjtime(ops, delta);
152 } else if (tx->modes & ADJ_FREQUENCY) {
153 s32 ppb = scaled_ppm_to_ppb(tx->freq);
154 if (ppb > ops->max_adj || ppb < -ops->max_adj)
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 /* public interface */
190 struct ptp_clock *ptp_clock_register(struct ptp_clock_info *info,
191 struct device *parent)
193 struct ptp_clock *ptp;
194 int err = 0, index, major = MAJOR(ptp_devt);
196 if (info->n_alarm > PTP_MAX_ALARMS)
197 return ERR_PTR(-EINVAL);
199 /* Initialize a clock structure. */
201 ptp = kzalloc(sizeof(struct ptp_clock), GFP_KERNEL);
205 index = ida_simple_get(&ptp_clocks_map, 0, MINORMASK + 1, GFP_KERNEL);
211 ptp->clock.ops = ptp_clock_ops;
212 ptp->clock.release = delete_ptp_clock;
214 ptp->devid = MKDEV(major, index);
216 spin_lock_init(&ptp->tsevq.lock);
217 mutex_init(&ptp->tsevq_mux);
218 mutex_init(&ptp->pincfg_mux);
219 init_waitqueue_head(&ptp->tsev_wq);
221 /* Create a new device in our class. */
222 ptp->dev = device_create(ptp_class, parent, ptp->devid, ptp,
223 "ptp%d", ptp->index);
224 if (IS_ERR(ptp->dev))
227 dev_set_drvdata(ptp->dev, ptp);
229 err = ptp_populate_sysfs(ptp);
233 /* Register a new PPS source. */
235 struct pps_source_info pps;
236 memset(&pps, 0, sizeof(pps));
237 snprintf(pps.name, PPS_MAX_NAME_LEN, "ptp%d", index);
238 pps.mode = PTP_PPS_MODE;
239 pps.owner = info->owner;
240 ptp->pps_source = pps_register_source(&pps, PTP_PPS_DEFAULTS);
241 if (!ptp->pps_source) {
242 pr_err("failed to register pps source\n");
247 /* Create a posix clock. */
248 err = posix_clock_register(&ptp->clock, ptp->devid);
250 pr_err("failed to create posix clock\n");
258 pps_unregister_source(ptp->pps_source);
260 ptp_cleanup_sysfs(ptp);
262 device_destroy(ptp_class, ptp->devid);
264 mutex_destroy(&ptp->tsevq_mux);
265 mutex_destroy(&ptp->pincfg_mux);
271 EXPORT_SYMBOL(ptp_clock_register);
273 int ptp_clock_unregister(struct ptp_clock *ptp)
276 wake_up_interruptible(&ptp->tsev_wq);
278 /* Release the clock's resources. */
280 pps_unregister_source(ptp->pps_source);
281 ptp_cleanup_sysfs(ptp);
282 device_destroy(ptp_class, ptp->devid);
284 posix_clock_unregister(&ptp->clock);
287 EXPORT_SYMBOL(ptp_clock_unregister);
289 void ptp_clock_event(struct ptp_clock *ptp, struct ptp_clock_event *event)
291 struct pps_event_time evt;
293 switch (event->type) {
295 case PTP_CLOCK_ALARM:
298 case PTP_CLOCK_EXTTS:
299 enqueue_external_timestamp(&ptp->tsevq, event);
300 wake_up_interruptible(&ptp->tsev_wq);
305 pps_event(ptp->pps_source, &evt, PTP_PPS_EVENT, NULL);
308 case PTP_CLOCK_PPSUSR:
309 pps_event(ptp->pps_source, &event->pps_times,
310 PTP_PPS_EVENT, NULL);
314 EXPORT_SYMBOL(ptp_clock_event);
316 int ptp_clock_index(struct ptp_clock *ptp)
320 EXPORT_SYMBOL(ptp_clock_index);
322 int ptp_find_pin(struct ptp_clock *ptp,
323 enum ptp_pin_function func, unsigned int chan)
325 struct ptp_pin_desc *pin = NULL;
328 mutex_lock(&ptp->pincfg_mux);
329 for (i = 0; i < ptp->info->n_pins; i++) {
330 if (ptp->info->pin_config[i].func == func &&
331 ptp->info->pin_config[i].chan == chan) {
332 pin = &ptp->info->pin_config[i];
336 mutex_unlock(&ptp->pincfg_mux);
340 EXPORT_SYMBOL(ptp_find_pin);
342 /* module operations */
344 static void __exit ptp_exit(void)
346 class_destroy(ptp_class);
347 unregister_chrdev_region(ptp_devt, MINORMASK + 1);
348 ida_destroy(&ptp_clocks_map);
351 static int __init ptp_init(void)
355 ptp_class = class_create(THIS_MODULE, "ptp");
356 if (IS_ERR(ptp_class)) {
357 pr_err("ptp: failed to allocate class\n");
358 return PTR_ERR(ptp_class);
361 err = alloc_chrdev_region(&ptp_devt, 0, MINORMASK + 1, "ptp");
363 pr_err("ptp: failed to allocate device region\n");
367 ptp_class->dev_groups = ptp_groups;
368 pr_info("PTP clock support registered\n");
372 class_destroy(ptp_class);
376 subsys_initcall(ptp_init);
377 module_exit(ptp_exit);
379 MODULE_AUTHOR("Richard Cochran <richardcochran@gmail.com>");
380 MODULE_DESCRIPTION("PTP clocks support");
381 MODULE_LICENSE("GPL");