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git.proxmox.com Git - mirror_ubuntu-artful-kernel.git/blob - drivers/pps/kapi.c
5 * Copyright (C) 2005-2009 Rodolfo Giometti <giometti@linux.it>
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 2 of the License, or
10 * (at your option) any later version.
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
17 * You should have received a copy of the GNU General Public License
18 * along with this program; if not, write to the Free Software
19 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
23 #include <linux/kernel.h>
24 #include <linux/module.h>
25 #include <linux/init.h>
26 #include <linux/sched.h>
27 #include <linux/time.h>
28 #include <linux/spinlock.h>
29 #include <linux/idr.h>
31 #include <linux/pps_kernel.h>
37 DEFINE_SPINLOCK(pps_idr_lock
);
44 static void pps_add_offset(struct pps_ktime
*ts
, struct pps_ktime
*offset
)
46 ts
->nsec
+= offset
->nsec
;
47 while (ts
->nsec
>= NSEC_PER_SEC
) {
48 ts
->nsec
-= NSEC_PER_SEC
;
51 while (ts
->nsec
< 0) {
52 ts
->nsec
+= NSEC_PER_SEC
;
55 ts
->sec
+= offset
->sec
;
62 /* pps_get_source - find a PPS source
63 * @source: the PPS source ID.
65 * This function is used to find an already registered PPS source into the
68 * The function returns NULL if found nothing, otherwise it returns a pointer
69 * to the PPS source data struct (the refcounter is incremented by 1).
72 struct pps_device
*pps_get_source(int source
)
74 struct pps_device
*pps
;
77 spin_lock_irqsave(&pps_idr_lock
, flags
);
79 pps
= idr_find(&pps_idr
, source
);
81 atomic_inc(&pps
->usage
);
83 spin_unlock_irqrestore(&pps_idr_lock
, flags
);
88 /* pps_put_source - free the PPS source data
89 * @pps: a pointer to the PPS source.
91 * This function is used to free a PPS data struct if its refcount is 0.
94 void pps_put_source(struct pps_device
*pps
)
98 spin_lock_irqsave(&pps_idr_lock
, flags
);
99 BUG_ON(atomic_read(&pps
->usage
) == 0);
101 if (!atomic_dec_and_test(&pps
->usage
)) {
106 /* No more reference to the PPS source. We can safely remove the
109 idr_remove(&pps_idr
, pps
->id
);
112 spin_unlock_irqrestore(&pps_idr_lock
, flags
);
116 /* pps_register_source - add a PPS source in the system
117 * @info: the PPS info struct
118 * @default_params: the default PPS parameters of the new source
120 * This function is used to add a new PPS source in the system. The new
121 * source is described by info's fields and it will have, as default PPS
122 * parameters, the ones specified into default_params.
124 * The function returns, in case of success, the PPS source ID.
127 int pps_register_source(struct pps_source_info
*info
, int default_params
)
129 struct pps_device
*pps
;
134 if ((info
->mode
& default_params
) != default_params
) {
135 printk(KERN_ERR
"pps: %s: unsupported default parameters\n",
138 goto pps_register_source_exit
;
140 if ((info
->mode
& (PPS_ECHOASSERT
| PPS_ECHOCLEAR
)) != 0 &&
141 info
->echo
== NULL
) {
142 printk(KERN_ERR
"pps: %s: echo function is not defined\n",
145 goto pps_register_source_exit
;
147 if ((info
->mode
& (PPS_TSFMT_TSPEC
| PPS_TSFMT_NTPFP
)) == 0) {
148 printk(KERN_ERR
"pps: %s: unspecified time format\n",
151 goto pps_register_source_exit
;
154 /* Allocate memory for the new PPS source struct */
155 pps
= kzalloc(sizeof(struct pps_device
), GFP_KERNEL
);
158 goto pps_register_source_exit
;
161 /* These initializations must be done before calling idr_get_new()
162 * in order to avoid reces into pps_event().
164 pps
->params
.api_version
= PPS_API_VERS
;
165 pps
->params
.mode
= default_params
;
168 init_waitqueue_head(&pps
->queue
);
169 spin_lock_init(&pps
->lock
);
170 atomic_set(&pps
->usage
, 1);
172 /* Get new ID for the new PPS source */
173 if (idr_pre_get(&pps_idr
, GFP_KERNEL
) == 0) {
178 spin_lock_irq(&pps_idr_lock
);
180 /* Now really allocate the PPS source.
181 * After idr_get_new() calling the new source will be freely available
184 err
= idr_get_new(&pps_idr
, pps
, &id
);
186 spin_unlock_irq(&pps_idr_lock
);
190 id
= id
& MAX_ID_MASK
;
191 if (id
>= PPS_MAX_SOURCES
) {
192 spin_unlock_irq(&pps_idr_lock
);
194 printk(KERN_ERR
"pps: %s: too many PPS sources in the system\n",
201 spin_unlock_irq(&pps_idr_lock
);
203 /* Create the char device */
204 err
= pps_register_cdev(pps
);
206 printk(KERN_ERR
"pps: %s: unable to create char device\n",
211 pr_info("new PPS source %s at ID %d\n", info
->name
, id
);
216 spin_lock_irq(&pps_idr_lock
);
217 idr_remove(&pps_idr
, id
);
218 spin_unlock_irq(&pps_idr_lock
);
223 pps_register_source_exit
:
224 printk(KERN_ERR
"pps: %s: unable to register source\n", info
->name
);
228 EXPORT_SYMBOL(pps_register_source
);
230 /* pps_unregister_source - remove a PPS source from the system
231 * @source: the PPS source ID
233 * This function is used to remove a previously registered PPS source from
237 void pps_unregister_source(int source
)
239 struct pps_device
*pps
;
241 spin_lock_irq(&pps_idr_lock
);
242 pps
= idr_find(&pps_idr
, source
);
246 spin_unlock_irq(&pps_idr_lock
);
249 spin_unlock_irq(&pps_idr_lock
);
251 pps_unregister_cdev(pps
);
254 EXPORT_SYMBOL(pps_unregister_source
);
256 /* pps_event - register a PPS event into the system
257 * @source: the PPS source ID
258 * @ts: the event timestamp
259 * @event: the event type
260 * @data: userdef pointer
262 * This function is used by each PPS client in order to register a new
263 * PPS event into the system (it's usually called inside an IRQ handler).
265 * If an echo function is associated with the PPS source it will be called
267 * pps->info.echo(source, event, data);
270 void pps_event(int source
, struct pps_ktime
*ts
, int event
, void *data
)
272 struct pps_device
*pps
;
275 if ((event
& (PPS_CAPTUREASSERT
| PPS_CAPTURECLEAR
)) == 0) {
276 printk(KERN_ERR
"pps: unknown event (%x) for source %d\n",
281 pps
= pps_get_source(source
);
285 pr_debug("PPS event on source %d at %llu.%06u\n",
286 pps
->id
, (unsigned long long) ts
->sec
, ts
->nsec
);
288 spin_lock_irqsave(&pps
->lock
, flags
);
290 /* Must call the echo function? */
291 if ((pps
->params
.mode
& (PPS_ECHOASSERT
| PPS_ECHOCLEAR
)))
292 pps
->info
.echo(source
, event
, data
);
294 /* Check the event */
295 pps
->current_mode
= pps
->params
.mode
;
296 if (event
& PPS_CAPTUREASSERT
) {
297 /* We have to add an offset? */
298 if (pps
->params
.mode
& PPS_OFFSETASSERT
)
299 pps_add_offset(ts
, &pps
->params
.assert_off_tu
);
301 /* Save the time stamp */
302 pps
->assert_tu
= *ts
;
303 pps
->assert_sequence
++;
304 pr_debug("capture assert seq #%u for source %d\n",
305 pps
->assert_sequence
, source
);
307 if (event
& PPS_CAPTURECLEAR
) {
308 /* We have to add an offset? */
309 if (pps
->params
.mode
& PPS_OFFSETCLEAR
)
310 pps_add_offset(ts
, &pps
->params
.clear_off_tu
);
312 /* Save the time stamp */
314 pps
->clear_sequence
++;
315 pr_debug("capture clear seq #%u for source %d\n",
316 pps
->clear_sequence
, source
);
320 wake_up_interruptible(&pps
->queue
);
322 kill_fasync(&pps
->async_queue
, SIGIO
, POLL_IN
);
324 spin_unlock_irqrestore(&pps
->lock
, flags
);
326 /* Now we can release the PPS source for (possible) deregistration */
329 EXPORT_SYMBOL(pps_event
);