xref: /openbmc/linux/drivers/pps/clients/pps-ktimer.c (revision 4800cd83)
1 /*
2  * pps-ktimer.c -- kernel timer test client
3  *
4  *
5  * Copyright (C) 2005-2006   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/time.h>
28 #include <linux/timer.h>
29 #include <linux/pps_kernel.h>
30 
31 /*
32  * Global variables
33  */
34 
35 static struct pps_device *pps;
36 static struct timer_list ktimer;
37 
38 /*
39  * The kernel timer
40  */
41 
42 static void pps_ktimer_event(unsigned long ptr)
43 {
44 	struct pps_event_time ts;
45 
46 	/* First of all we get the time stamp... */
47 	pps_get_ts(&ts);
48 
49 	pps_event(pps, &ts, PPS_CAPTUREASSERT, NULL);
50 
51 	mod_timer(&ktimer, jiffies + HZ);
52 }
53 
54 /*
55  * The echo function
56  */
57 
58 static void pps_ktimer_echo(struct pps_device *pps, int event, void *data)
59 {
60 	dev_info(pps->dev, "echo %s %s\n",
61 		event & PPS_CAPTUREASSERT ? "assert" : "",
62 		event & PPS_CAPTURECLEAR ? "clear" : "");
63 }
64 
65 /*
66  * The PPS info struct
67  */
68 
69 static struct pps_source_info pps_ktimer_info = {
70 	.name		= "ktimer",
71 	.path		= "",
72 	.mode		= PPS_CAPTUREASSERT | PPS_OFFSETASSERT |
73 			  PPS_ECHOASSERT |
74 			  PPS_CANWAIT | PPS_TSFMT_TSPEC,
75 	.echo		= pps_ktimer_echo,
76 	.owner		= THIS_MODULE,
77 };
78 
79 /*
80  * Module staff
81  */
82 
83 static void __exit pps_ktimer_exit(void)
84 {
85 	dev_info(pps->dev, "ktimer PPS source unregistered\n");
86 
87 	del_timer_sync(&ktimer);
88 	pps_unregister_source(pps);
89 }
90 
91 static int __init pps_ktimer_init(void)
92 {
93 	pps = pps_register_source(&pps_ktimer_info,
94 				PPS_CAPTUREASSERT | PPS_OFFSETASSERT);
95 	if (pps == NULL) {
96 		pr_err("cannot register PPS source\n");
97 		return -ENOMEM;
98 	}
99 
100 	setup_timer(&ktimer, pps_ktimer_event, 0);
101 	mod_timer(&ktimer, jiffies + HZ);
102 
103 	dev_info(pps->dev, "ktimer PPS source registered\n");
104 
105 	return 0;
106 }
107 
108 module_init(pps_ktimer_init);
109 module_exit(pps_ktimer_exit);
110 
111 MODULE_AUTHOR("Rodolfo Giometti <giometti@linux.it>");
112 MODULE_DESCRIPTION("dummy PPS source by using a kernel timer (just for debug)");
113 MODULE_LICENSE("GPL");
114