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Alessandro Zummoc5c3e192006-03-27 01:16:39 -08001/*
2 * RTC subsystem, sysfs interface
3 *
4 * Copyright (C) 2005 Tower Technologies
5 * Author: Alessandro Zummo <a.zummo@towertech.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 version 2 as
9 * published by the Free Software Foundation.
10*/
11
12#include <linux/module.h>
13#include <linux/rtc.h>
14
David Brownellab6a2d72007-05-08 00:33:30 -070015#include "rtc-core.h"
16
17
Alessandro Zummoc5c3e192006-03-27 01:16:39 -080018/* device attributes */
19
David Brownell8a0bdfd2008-02-06 01:38:45 -080020/*
21 * NOTE: RTC times displayed in sysfs use the RTC's timezone. That's
22 * ideally UTC. However, PCs that also boot to MS-Windows normally use
23 * the local time and change to match daylight savings time. That affects
24 * attributes including date, time, since_epoch, and wakealarm.
25 */
26
David Brownellcd966202007-05-08 00:33:40 -070027static ssize_t
28rtc_sysfs_show_name(struct device *dev, struct device_attribute *attr,
29 char *buf)
Alessandro Zummoc5c3e192006-03-27 01:16:39 -080030{
31 return sprintf(buf, "%s\n", to_rtc_device(dev)->name);
32}
Alessandro Zummoc5c3e192006-03-27 01:16:39 -080033
David Brownellcd966202007-05-08 00:33:40 -070034static ssize_t
35rtc_sysfs_show_date(struct device *dev, struct device_attribute *attr,
36 char *buf)
Alessandro Zummoc5c3e192006-03-27 01:16:39 -080037{
38 ssize_t retval;
39 struct rtc_time tm;
40
David Brownellab6a2d72007-05-08 00:33:30 -070041 retval = rtc_read_time(to_rtc_device(dev), &tm);
Alessandro Zummoc5c3e192006-03-27 01:16:39 -080042 if (retval == 0) {
43 retval = sprintf(buf, "%04d-%02d-%02d\n",
44 tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday);
45 }
46
47 return retval;
48}
Alessandro Zummoc5c3e192006-03-27 01:16:39 -080049
David Brownellcd966202007-05-08 00:33:40 -070050static ssize_t
51rtc_sysfs_show_time(struct device *dev, struct device_attribute *attr,
52 char *buf)
Alessandro Zummoc5c3e192006-03-27 01:16:39 -080053{
54 ssize_t retval;
55 struct rtc_time tm;
56
David Brownellab6a2d72007-05-08 00:33:30 -070057 retval = rtc_read_time(to_rtc_device(dev), &tm);
Alessandro Zummoc5c3e192006-03-27 01:16:39 -080058 if (retval == 0) {
59 retval = sprintf(buf, "%02d:%02d:%02d\n",
60 tm.tm_hour, tm.tm_min, tm.tm_sec);
61 }
62
63 return retval;
64}
Alessandro Zummoc5c3e192006-03-27 01:16:39 -080065
David Brownellcd966202007-05-08 00:33:40 -070066static ssize_t
67rtc_sysfs_show_since_epoch(struct device *dev, struct device_attribute *attr,
68 char *buf)
Alessandro Zummoc5c3e192006-03-27 01:16:39 -080069{
70 ssize_t retval;
71 struct rtc_time tm;
72
David Brownellab6a2d72007-05-08 00:33:30 -070073 retval = rtc_read_time(to_rtc_device(dev), &tm);
Alessandro Zummoc5c3e192006-03-27 01:16:39 -080074 if (retval == 0) {
75 unsigned long time;
76 rtc_tm_to_time(&tm, &time);
77 retval = sprintf(buf, "%lu\n", time);
78 }
79
80 return retval;
81}
Alessandro Zummoc5c3e192006-03-27 01:16:39 -080082
Bryan Kadzban06c65eb2007-10-16 01:28:22 -070083static ssize_t
84rtc_sysfs_show_max_user_freq(struct device *dev, struct device_attribute *attr,
85 char *buf)
86{
87 return sprintf(buf, "%d\n", to_rtc_device(dev)->max_user_freq);
88}
89
90static ssize_t
91rtc_sysfs_set_max_user_freq(struct device *dev, struct device_attribute *attr,
92 const char *buf, size_t n)
93{
94 struct rtc_device *rtc = to_rtc_device(dev);
95 unsigned long val = simple_strtoul(buf, NULL, 0);
96
97 if (val >= 4096 || val == 0)
98 return -EINVAL;
99
100 rtc->max_user_freq = (int)val;
101
102 return n;
103}
104
David Brownellcd966202007-05-08 00:33:40 -0700105static struct device_attribute rtc_attrs[] = {
David Brownell446ecbd2007-05-08 00:33:33 -0700106 __ATTR(name, S_IRUGO, rtc_sysfs_show_name, NULL),
107 __ATTR(date, S_IRUGO, rtc_sysfs_show_date, NULL),
108 __ATTR(time, S_IRUGO, rtc_sysfs_show_time, NULL),
109 __ATTR(since_epoch, S_IRUGO, rtc_sysfs_show_since_epoch, NULL),
Bryan Kadzban06c65eb2007-10-16 01:28:22 -0700110 __ATTR(max_user_freq, S_IRUGO | S_IWUSR, rtc_sysfs_show_max_user_freq,
111 rtc_sysfs_set_max_user_freq),
David Brownell446ecbd2007-05-08 00:33:33 -0700112 { },
Alessandro Zummoc5c3e192006-03-27 01:16:39 -0800113};
114
David Brownell3925a5c2007-02-12 00:52:47 -0800115static ssize_t
David Brownellcd966202007-05-08 00:33:40 -0700116rtc_sysfs_show_wakealarm(struct device *dev, struct device_attribute *attr,
117 char *buf)
David Brownell3925a5c2007-02-12 00:52:47 -0800118{
119 ssize_t retval;
120 unsigned long alarm;
121 struct rtc_wkalrm alm;
122
David Brownell8a0bdfd2008-02-06 01:38:45 -0800123 /* Don't show disabled alarms. For uniformity, RTC alarms are
124 * conceptually one-shot, even though some common RTCs (on PCs)
125 * don't actually work that way.
David Brownell3925a5c2007-02-12 00:52:47 -0800126 *
David Brownell8a0bdfd2008-02-06 01:38:45 -0800127 * NOTE: RTC implementations where the alarm doesn't match an
128 * exact YYYY-MM-DD HH:MM[:SS] date *must* disable their RTC
129 * alarms after they trigger, to ensure one-shot semantics.
David Brownell3925a5c2007-02-12 00:52:47 -0800130 */
David Brownellab6a2d72007-05-08 00:33:30 -0700131 retval = rtc_read_alarm(to_rtc_device(dev), &alm);
David Brownell3925a5c2007-02-12 00:52:47 -0800132 if (retval == 0 && alm.enabled) {
133 rtc_tm_to_time(&alm.time, &alarm);
134 retval = sprintf(buf, "%lu\n", alarm);
135 }
136
137 return retval;
138}
139
140static ssize_t
David Brownellcd966202007-05-08 00:33:40 -0700141rtc_sysfs_set_wakealarm(struct device *dev, struct device_attribute *attr,
142 const char *buf, size_t n)
David Brownell3925a5c2007-02-12 00:52:47 -0800143{
144 ssize_t retval;
145 unsigned long now, alarm;
146 struct rtc_wkalrm alm;
David Brownellab6a2d72007-05-08 00:33:30 -0700147 struct rtc_device *rtc = to_rtc_device(dev);
David Brownell3925a5c2007-02-12 00:52:47 -0800148
149 /* Only request alarms that trigger in the future. Disable them
150 * by writing another time, e.g. 0 meaning Jan 1 1970 UTC.
151 */
David Brownellab6a2d72007-05-08 00:33:30 -0700152 retval = rtc_read_time(rtc, &alm.time);
David Brownell3925a5c2007-02-12 00:52:47 -0800153 if (retval < 0)
154 return retval;
155 rtc_tm_to_time(&alm.time, &now);
156
157 alarm = simple_strtoul(buf, NULL, 0);
158 if (alarm > now) {
159 /* Avoid accidentally clobbering active alarms; we can't
160 * entirely prevent that here, without even the minimal
161 * locking from the /dev/rtcN api.
162 */
David Brownellab6a2d72007-05-08 00:33:30 -0700163 retval = rtc_read_alarm(rtc, &alm);
David Brownell3925a5c2007-02-12 00:52:47 -0800164 if (retval < 0)
165 return retval;
166 if (alm.enabled)
167 return -EBUSY;
168
169 alm.enabled = 1;
170 } else {
171 alm.enabled = 0;
172
173 /* Provide a valid future alarm time. Linux isn't EFI,
174 * this time won't be ignored when disabling the alarm.
175 */
176 alarm = now + 300;
177 }
178 rtc_time_to_tm(alarm, &alm.time);
179
David Brownellab6a2d72007-05-08 00:33:30 -0700180 retval = rtc_set_alarm(rtc, &alm);
David Brownell3925a5c2007-02-12 00:52:47 -0800181 return (retval < 0) ? retval : n;
182}
David Brownellcd966202007-05-08 00:33:40 -0700183static DEVICE_ATTR(wakealarm, S_IRUGO | S_IWUSR,
David Brownell3925a5c2007-02-12 00:52:47 -0800184 rtc_sysfs_show_wakealarm, rtc_sysfs_set_wakealarm);
185
186
187/* The reason to trigger an alarm with no process watching it (via sysfs)
188 * is its side effect: waking from a system state like suspend-to-RAM or
189 * suspend-to-disk. So: no attribute unless that side effect is possible.
190 * (Userspace may disable that mechanism later.)
191 */
David Brownell446ecbd2007-05-08 00:33:33 -0700192static inline int rtc_does_wakealarm(struct rtc_device *rtc)
David Brownell3925a5c2007-02-12 00:52:47 -0800193{
David Brownellcd966202007-05-08 00:33:40 -0700194 if (!device_can_wakeup(rtc->dev.parent))
David Brownell3925a5c2007-02-12 00:52:47 -0800195 return 0;
David Brownell3925a5c2007-02-12 00:52:47 -0800196 return rtc->ops->set_alarm != NULL;
197}
198
199
David Brownell446ecbd2007-05-08 00:33:33 -0700200void rtc_sysfs_add_device(struct rtc_device *rtc)
Alessandro Zummoc5c3e192006-03-27 01:16:39 -0800201{
202 int err;
203
David Brownell446ecbd2007-05-08 00:33:33 -0700204 /* not all RTCs support both alarms and wakeup */
205 if (!rtc_does_wakealarm(rtc))
206 return;
Alessandro Zummoc5c3e192006-03-27 01:16:39 -0800207
David Brownellcd966202007-05-08 00:33:40 -0700208 err = device_create_file(&rtc->dev, &dev_attr_wakealarm);
David Brownell446ecbd2007-05-08 00:33:33 -0700209 if (err)
Joe Perches898eb712007-10-18 03:06:30 -0700210 dev_err(rtc->dev.parent,
211 "failed to create alarm attribute, %d\n", err);
Alessandro Zummoc5c3e192006-03-27 01:16:39 -0800212}
213
David Brownell446ecbd2007-05-08 00:33:33 -0700214void rtc_sysfs_del_device(struct rtc_device *rtc)
Alessandro Zummoc5c3e192006-03-27 01:16:39 -0800215{
David Brownell446ecbd2007-05-08 00:33:33 -0700216 /* REVISIT did we add it successfully? */
217 if (rtc_does_wakealarm(rtc))
David Brownellcd966202007-05-08 00:33:40 -0700218 device_remove_file(&rtc->dev, &dev_attr_wakealarm);
Alessandro Zummoc5c3e192006-03-27 01:16:39 -0800219}
220
David Brownell446ecbd2007-05-08 00:33:33 -0700221void __init rtc_sysfs_init(struct class *rtc_class)
Alessandro Zummoc5c3e192006-03-27 01:16:39 -0800222{
David Brownellcd966202007-05-08 00:33:40 -0700223 rtc_class->dev_attrs = rtc_attrs;
Alessandro Zummoc5c3e192006-03-27 01:16:39 -0800224}