1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
|
/*
* RTC subsystem, sysfs interface
*
* Copyright (C) 2005 Tower Technologies
* Author: Alessandro Zummo <a.zummo@towertech.it>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/module.h>
#include <linux/rtc.h>
#include "rtc-core.h"
/* device attributes */
static ssize_t rtc_sysfs_show_name(struct class_device *dev, char *buf)
{
return sprintf(buf, "%s\n", to_rtc_device(dev)->name);
}
static CLASS_DEVICE_ATTR(name, S_IRUGO, rtc_sysfs_show_name, NULL);
static ssize_t rtc_sysfs_show_date(struct class_device *dev, char *buf)
{
ssize_t retval;
struct rtc_time tm;
retval = rtc_read_time(to_rtc_device(dev), &tm);
if (retval == 0) {
retval = sprintf(buf, "%04d-%02d-%02d\n",
tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday);
}
return retval;
}
static CLASS_DEVICE_ATTR(date, S_IRUGO, rtc_sysfs_show_date, NULL);
static ssize_t rtc_sysfs_show_time(struct class_device *dev, char *buf)
{
ssize_t retval;
struct rtc_time tm;
retval = rtc_read_time(to_rtc_device(dev), &tm);
if (retval == 0) {
retval = sprintf(buf, "%02d:%02d:%02d\n",
tm.tm_hour, tm.tm_min, tm.tm_sec);
}
return retval;
}
static CLASS_DEVICE_ATTR(time, S_IRUGO, rtc_sysfs_show_time, NULL);
static ssize_t rtc_sysfs_show_since_epoch(struct class_device *dev, char *buf)
{
ssize_t retval;
struct rtc_time tm;
retval = rtc_read_time(to_rtc_device(dev), &tm);
if (retval == 0) {
unsigned long time;
rtc_tm_to_time(&tm, &time);
retval = sprintf(buf, "%lu\n", time);
}
return retval;
}
static CLASS_DEVICE_ATTR(since_epoch, S_IRUGO, rtc_sysfs_show_since_epoch, NULL);
static struct attribute *rtc_attrs[] = {
&class_device_attr_name.attr,
&class_device_attr_date.attr,
&class_device_attr_time.attr,
&class_device_attr_since_epoch.attr,
NULL,
};
static struct attribute_group rtc_attr_group = {
.attrs = rtc_attrs,
};
static ssize_t
rtc_sysfs_show_wakealarm(struct class_device *dev, char *buf)
{
ssize_t retval;
unsigned long alarm;
struct rtc_wkalrm alm;
/* Don't show disabled alarms; but the RTC could leave the
* alarm enabled after it's already triggered. Alarms are
* conceptually one-shot, even though some common hardware
* (PCs) doesn't actually work that way.
*
* REVISIT maybe we should require RTC implementations to
* disable the RTC alarm after it triggers, for uniformity.
*/
retval = rtc_read_alarm(to_rtc_device(dev), &alm);
if (retval == 0 && alm.enabled) {
rtc_tm_to_time(&alm.time, &alarm);
retval = sprintf(buf, "%lu\n", alarm);
}
return retval;
}
static ssize_t
rtc_sysfs_set_wakealarm(struct class_device *dev, const char *buf, size_t n)
{
ssize_t retval;
unsigned long now, alarm;
struct rtc_wkalrm alm;
struct rtc_device *rtc = to_rtc_device(dev);
/* Only request alarms that trigger in the future. Disable them
* by writing another time, e.g. 0 meaning Jan 1 1970 UTC.
*/
retval = rtc_read_time(rtc, &alm.time);
if (retval < 0)
return retval;
rtc_tm_to_time(&alm.time, &now);
alarm = simple_strtoul(buf, NULL, 0);
if (alarm > now) {
/* Avoid accidentally clobbering active alarms; we can't
* entirely prevent that here, without even the minimal
* locking from the /dev/rtcN api.
*/
retval = rtc_read_alarm(rtc, &alm);
if (retval < 0)
return retval;
if (alm.enabled)
return -EBUSY;
alm.enabled = 1;
} else {
alm.enabled = 0;
/* Provide a valid future alarm time. Linux isn't EFI,
* this time won't be ignored when disabling the alarm.
*/
alarm = now + 300;
}
rtc_time_to_tm(alarm, &alm.time);
retval = rtc_set_alarm(rtc, &alm);
return (retval < 0) ? retval : n;
}
static const CLASS_DEVICE_ATTR(wakealarm, S_IRUGO | S_IWUSR,
rtc_sysfs_show_wakealarm, rtc_sysfs_set_wakealarm);
/* The reason to trigger an alarm with no process watching it (via sysfs)
* is its side effect: waking from a system state like suspend-to-RAM or
* suspend-to-disk. So: no attribute unless that side effect is possible.
* (Userspace may disable that mechanism later.)
*/
static inline int rtc_does_wakealarm(struct class_device *class_dev)
{
struct rtc_device *rtc;
if (!device_can_wakeup(class_dev->dev))
return 0;
rtc = to_rtc_device(class_dev);
return rtc->ops->set_alarm != NULL;
}
static int rtc_sysfs_add_device(struct class_device *class_dev,
struct class_interface *class_intf)
{
int err;
dev_dbg(class_dev->dev, "rtc intf: sysfs\n");
err = sysfs_create_group(&class_dev->kobj, &rtc_attr_group);
if (err)
dev_err(class_dev->dev, "failed to create %s\n",
"sysfs attributes");
else if (rtc_does_wakealarm(class_dev)) {
/* not all RTCs support both alarms and wakeup */
err = class_device_create_file(class_dev,
&class_device_attr_wakealarm);
if (err) {
dev_err(class_dev->dev, "failed to create %s\n",
"alarm attribute");
sysfs_remove_group(&class_dev->kobj, &rtc_attr_group);
}
}
return err;
}
static void rtc_sysfs_remove_device(struct class_device *class_dev,
struct class_interface *class_intf)
{
if (rtc_does_wakealarm(class_dev))
class_device_remove_file(class_dev,
&class_device_attr_wakealarm);
sysfs_remove_group(&class_dev->kobj, &rtc_attr_group);
}
/* interface registration */
static struct class_interface rtc_sysfs_interface = {
.add = &rtc_sysfs_add_device,
.remove = &rtc_sysfs_remove_device,
};
static int __init rtc_sysfs_init(void)
{
return rtc_interface_register(&rtc_sysfs_interface);
}
static void __exit rtc_sysfs_exit(void)
{
class_interface_unregister(&rtc_sysfs_interface);
}
subsys_initcall(rtc_sysfs_init);
module_exit(rtc_sysfs_exit);
MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>");
MODULE_DESCRIPTION("RTC class sysfs interface");
MODULE_LICENSE("GPL");
|
