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1 | /* |
2 | * kernel API |
3 | * |
4 | * |
5 | * Copyright (C) 2005-2009 Rodolfo Giometti <giometti@linux.it> |
6 | * |
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. |
11 | * |
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. |
16 | * |
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. |
20 | */ |
21 | |
22 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
23 | |
24 | #include <linux/kernel.h> |
25 | #include <linux/module.h> |
26 | #include <linux/init.h> |
27 | #include <linux/sched.h> |
28 | #include <linux/time.h> |
29 | #include <linux/timex.h> |
30 | #include <linux/spinlock.h> |
31 | #include <linux/fs.h> |
32 | #include <linux/pps_kernel.h> |
33 | #include <linux/slab.h> |
34 | |
35 | #include "kc.h" |
36 | |
37 | /* |
38 | * Local functions |
39 | */ |
40 | |
41 | static void pps_add_offset(struct pps_ktime *ts, struct pps_ktime *offset) |
42 | { |
43 | ts->nsec += offset->nsec; |
44 | while (ts->nsec >= NSEC_PER_SEC) { |
45 | ts->nsec -= NSEC_PER_SEC; |
46 | ts->sec++; |
47 | } |
48 | while (ts->nsec < 0) { |
49 | ts->nsec += NSEC_PER_SEC; |
50 | ts->sec--; |
51 | } |
52 | ts->sec += offset->sec; |
53 | } |
54 | |
55 | static void pps_echo_client_default(struct pps_device *pps, int event, |
56 | void *data) |
57 | { |
58 | dev_info(pps->dev, "echo %s %s\n", |
59 | event & PPS_CAPTUREASSERT ? "assert" : "", |
60 | event & PPS_CAPTURECLEAR ? "clear" : ""); |
61 | } |
62 | |
63 | /* |
64 | * Exported functions |
65 | */ |
66 | |
67 | /* pps_register_source - add a PPS source in the system |
68 | * @info: the PPS info struct |
69 | * @default_params: the default PPS parameters of the new source |
70 | * |
71 | * This function is used to add a new PPS source in the system. The new |
72 | * source is described by info's fields and it will have, as default PPS |
73 | * parameters, the ones specified into default_params. |
74 | * |
75 | * The function returns, in case of success, the PPS device. Otherwise NULL. |
76 | */ |
77 | |
78 | struct pps_device *pps_register_source(struct pps_source_info *info, |
79 | int default_params) |
80 | { |
81 | struct pps_device *pps; |
82 | int err; |
83 | |
84 | /* Sanity checks */ |
85 | if ((info->mode & default_params) != default_params) { |
86 | pr_err("%s: unsupported default parameters\n", |
87 | info->name); |
88 | err = -EINVAL; |
89 | goto pps_register_source_exit; |
90 | } |
91 | if ((info->mode & (PPS_TSFMT_TSPEC | PPS_TSFMT_NTPFP)) == 0) { |
92 | pr_err("%s: unspecified time format\n", |
93 | info->name); |
94 | err = -EINVAL; |
95 | goto pps_register_source_exit; |
96 | } |
97 | |
98 | /* Allocate memory for the new PPS source struct */ |
99 | pps = kzalloc(sizeof(struct pps_device), GFP_KERNEL); |
100 | if (pps == NULL) { |
101 | err = -ENOMEM; |
102 | goto pps_register_source_exit; |
103 | } |
104 | |
105 | /* These initializations must be done before calling idr_get_new() |
106 | * in order to avoid reces into pps_event(). |
107 | */ |
108 | pps->params.api_version = PPS_API_VERS; |
109 | pps->params.mode = default_params; |
110 | pps->info = *info; |
111 | |
112 | /* check for default echo function */ |
113 | if ((pps->info.mode & (PPS_ECHOASSERT | PPS_ECHOCLEAR)) && |
114 | pps->info.echo == NULL) |
115 | pps->info.echo = pps_echo_client_default; |
116 | |
117 | init_waitqueue_head(&pps->queue); |
118 | spin_lock_init(&pps->lock); |
119 | |
120 | /* Create the char device */ |
121 | err = pps_register_cdev(pps); |
122 | if (err < 0) { |
123 | pr_err("%s: unable to create char device\n", |
124 | info->name); |
125 | goto kfree_pps; |
126 | } |
127 | |
128 | dev_info(pps->dev, "new PPS source %s\n", info->name); |
129 | |
130 | return pps; |
131 | |
132 | kfree_pps: |
133 | kfree(pps); |
134 | |
135 | pps_register_source_exit: |
136 | pr_err("%s: unable to register source\n", info->name); |
137 | |
138 | return NULL; |
139 | } |
140 | EXPORT_SYMBOL(pps_register_source); |
141 | |
142 | /* pps_unregister_source - remove a PPS source from the system |
143 | * @pps: the PPS source |
144 | * |
145 | * This function is used to remove a previously registered PPS source from |
146 | * the system. |
147 | */ |
148 | |
149 | void pps_unregister_source(struct pps_device *pps) |
150 | { |
151 | pps_kc_remove(pps); |
152 | pps_unregister_cdev(pps); |
153 | |
154 | /* don't have to kfree(pps) here because it will be done on |
155 | * device destruction */ |
156 | } |
157 | EXPORT_SYMBOL(pps_unregister_source); |
158 | |
159 | /* pps_event - register a PPS event into the system |
160 | * @pps: the PPS device |
161 | * @ts: the event timestamp |
162 | * @event: the event type |
163 | * @data: userdef pointer |
164 | * |
165 | * This function is used by each PPS client in order to register a new |
166 | * PPS event into the system (it's usually called inside an IRQ handler). |
167 | * |
168 | * If an echo function is associated with the PPS device it will be called |
169 | * as: |
170 | * pps->info.echo(pps, event, data); |
171 | */ |
172 | void pps_event(struct pps_device *pps, struct pps_event_time *ts, int event, |
173 | void *data) |
174 | { |
175 | unsigned long flags; |
176 | int captured = 0; |
177 | struct pps_ktime ts_real = { .sec = 0, .nsec = 0, .flags = 0 }; |
178 | |
179 | /* check event type */ |
180 | BUG_ON((event & (PPS_CAPTUREASSERT | PPS_CAPTURECLEAR)) == 0); |
181 | |
182 | dev_dbg(pps->dev, "PPS event at %ld.%09ld\n", |
183 | ts->ts_real.tv_sec, ts->ts_real.tv_nsec); |
184 | |
185 | timespec_to_pps_ktime(&ts_real, ts->ts_real); |
186 | |
187 | spin_lock_irqsave(&pps->lock, flags); |
188 | |
189 | /* Must call the echo function? */ |
190 | if ((pps->params.mode & (PPS_ECHOASSERT | PPS_ECHOCLEAR))) |
191 | pps->info.echo(pps, event, data); |
192 | |
193 | /* Check the event */ |
194 | pps->current_mode = pps->params.mode; |
195 | if (event & pps->params.mode & PPS_CAPTUREASSERT) { |
196 | /* We have to add an offset? */ |
197 | if (pps->params.mode & PPS_OFFSETASSERT) |
198 | pps_add_offset(&ts_real, |
199 | &pps->params.assert_off_tu); |
200 | |
201 | /* Save the time stamp */ |
202 | pps->assert_tu = ts_real; |
203 | pps->assert_sequence++; |
204 | dev_dbg(pps->dev, "capture assert seq #%u\n", |
205 | pps->assert_sequence); |
206 | |
207 | captured = ~0; |
208 | } |
209 | if (event & pps->params.mode & PPS_CAPTURECLEAR) { |
210 | /* We have to add an offset? */ |
211 | if (pps->params.mode & PPS_OFFSETCLEAR) |
212 | pps_add_offset(&ts_real, |
213 | &pps->params.clear_off_tu); |
214 | |
215 | /* Save the time stamp */ |
216 | pps->clear_tu = ts_real; |
217 | pps->clear_sequence++; |
218 | dev_dbg(pps->dev, "capture clear seq #%u\n", |
219 | pps->clear_sequence); |
220 | |
221 | captured = ~0; |
222 | } |
223 | |
224 | pps_kc_event(pps, ts, event); |
225 | |
226 | /* Wake up if captured something */ |
227 | if (captured) { |
228 | pps->last_ev++; |
229 | wake_up_interruptible_all(&pps->queue); |
230 | |
231 | kill_fasync(&pps->async_queue, SIGIO, POLL_IN); |
232 | } |
233 | |
234 | spin_unlock_irqrestore(&pps->lock, flags); |
235 | } |
236 | EXPORT_SYMBOL(pps_event); |
237 |
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