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1/*
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
15#include "rtc-core.h"
16
17
18/* device attributes */
19
20/*
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
27static ssize_t
28rtc_sysfs_show_name(struct device *dev, struct device_attribute *attr,
29 char *buf)
30{
31 return sprintf(buf, "%s\n", to_rtc_device(dev)->name);
32}
33
34static ssize_t
35rtc_sysfs_show_date(struct device *dev, struct device_attribute *attr,
36 char *buf)
37{
38 ssize_t retval;
39 struct rtc_time tm;
40
41 retval = rtc_read_time(to_rtc_device(dev), &tm);
42 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}
49
50static ssize_t
51rtc_sysfs_show_time(struct device *dev, struct device_attribute *attr,
52 char *buf)
53{
54 ssize_t retval;
55 struct rtc_time tm;
56
57 retval = rtc_read_time(to_rtc_device(dev), &tm);
58 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}
65
66static ssize_t
67rtc_sysfs_show_since_epoch(struct device *dev, struct device_attribute *attr,
68 char *buf)
69{
70 ssize_t retval;
71 struct rtc_time tm;
72
73 retval = rtc_read_time(to_rtc_device(dev), &tm);
74 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}
82
83static 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
105static ssize_t
106rtc_sysfs_show_hctosys(struct device *dev, struct device_attribute *attr,
107 char *buf)
108{
109#ifdef CONFIG_RTC_HCTOSYS_DEVICE
110 if (rtc_hctosys_ret == 0 &&
111 strcmp(dev_name(&to_rtc_device(dev)->dev),
112 CONFIG_RTC_HCTOSYS_DEVICE) == 0)
113 return sprintf(buf, "1\n");
114 else
115#endif
116 return sprintf(buf, "0\n");
117}
118
119static struct device_attribute rtc_attrs[] = {
120 __ATTR(name, S_IRUGO, rtc_sysfs_show_name, NULL),
121 __ATTR(date, S_IRUGO, rtc_sysfs_show_date, NULL),
122 __ATTR(time, S_IRUGO, rtc_sysfs_show_time, NULL),
123 __ATTR(since_epoch, S_IRUGO, rtc_sysfs_show_since_epoch, NULL),
124 __ATTR(max_user_freq, S_IRUGO | S_IWUSR, rtc_sysfs_show_max_user_freq,
125 rtc_sysfs_set_max_user_freq),
126 __ATTR(hctosys, S_IRUGO, rtc_sysfs_show_hctosys, NULL),
127 { },
128};
129
130static ssize_t
131rtc_sysfs_show_wakealarm(struct device *dev, struct device_attribute *attr,
132 char *buf)
133{
134 ssize_t retval;
135 unsigned long alarm;
136 struct rtc_wkalrm alm;
137
138 /* Don't show disabled alarms. For uniformity, RTC alarms are
139 * conceptually one-shot, even though some common RTCs (on PCs)
140 * don't actually work that way.
141 *
142 * NOTE: RTC implementations where the alarm doesn't match an
143 * exact YYYY-MM-DD HH:MM[:SS] date *must* disable their RTC
144 * alarms after they trigger, to ensure one-shot semantics.
145 */
146 retval = rtc_read_alarm(to_rtc_device(dev), &alm);
147 if (retval == 0 && alm.enabled) {
148 rtc_tm_to_time(&alm.time, &alarm);
149 retval = sprintf(buf, "%lu\n", alarm);
150 }
151
152 return retval;
153}
154
155static ssize_t
156rtc_sysfs_set_wakealarm(struct device *dev, struct device_attribute *attr,
157 const char *buf, size_t n)
158{
159 ssize_t retval;
160 unsigned long now, alarm;
161 struct rtc_wkalrm alm;
162 struct rtc_device *rtc = to_rtc_device(dev);
163 char *buf_ptr;
164 int adjust = 0;
165
166 /* Only request alarms that trigger in the future. Disable them
167 * by writing another time, e.g. 0 meaning Jan 1 1970 UTC.
168 */
169 retval = rtc_read_time(rtc, &alm.time);
170 if (retval < 0)
171 return retval;
172 rtc_tm_to_time(&alm.time, &now);
173
174 buf_ptr = (char *)buf;
175 if (*buf_ptr == '+') {
176 buf_ptr++;
177 adjust = 1;
178 }
179 alarm = simple_strtoul(buf_ptr, NULL, 0);
180 if (adjust) {
181 alarm += now;
182 }
183 if (alarm > now) {
184 /* Avoid accidentally clobbering active alarms; we can't
185 * entirely prevent that here, without even the minimal
186 * locking from the /dev/rtcN api.
187 */
188 retval = rtc_read_alarm(rtc, &alm);
189 if (retval < 0)
190 return retval;
191 if (alm.enabled)
192 return -EBUSY;
193
194 alm.enabled = 1;
195 } else {
196 alm.enabled = 0;
197
198 /* Provide a valid future alarm time. Linux isn't EFI,
199 * this time won't be ignored when disabling the alarm.
200 */
201 alarm = now + 300;
202 }
203 rtc_time_to_tm(alarm, &alm.time);
204
205 retval = rtc_set_alarm(rtc, &alm);
206 return (retval < 0) ? retval : n;
207}
208static DEVICE_ATTR(wakealarm, S_IRUGO | S_IWUSR,
209 rtc_sysfs_show_wakealarm, rtc_sysfs_set_wakealarm);
210
211
212/* The reason to trigger an alarm with no process watching it (via sysfs)
213 * is its side effect: waking from a system state like suspend-to-RAM or
214 * suspend-to-disk. So: no attribute unless that side effect is possible.
215 * (Userspace may disable that mechanism later.)
216 */
217static inline int rtc_does_wakealarm(struct rtc_device *rtc)
218{
219 if (!device_can_wakeup(rtc->dev.parent))
220 return 0;
221 return rtc->ops->set_alarm != NULL;
222}
223
224
225void rtc_sysfs_add_device(struct rtc_device *rtc)
226{
227 int err;
228
229 /* not all RTCs support both alarms and wakeup */
230 if (!rtc_does_wakealarm(rtc))
231 return;
232
233 err = device_create_file(&rtc->dev, &dev_attr_wakealarm);
234 if (err)
235 dev_err(rtc->dev.parent,
236 "failed to create alarm attribute, %d\n", err);
237}
238
239void rtc_sysfs_del_device(struct rtc_device *rtc)
240{
241 /* REVISIT did we add it successfully? */
242 if (rtc_does_wakealarm(rtc))
243 device_remove_file(&rtc->dev, &dev_attr_wakealarm);
244}
245
246void __init rtc_sysfs_init(struct class *rtc_class)
247{
248 rtc_class->dev_attrs = rtc_attrs;
249}
1/*
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
15#include "rtc-core.h"
16
17
18/* device attributes */
19
20/*
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
27static ssize_t
28name_show(struct device *dev, struct device_attribute *attr, char *buf)
29{
30 return sprintf(buf, "%s\n", to_rtc_device(dev)->name);
31}
32static DEVICE_ATTR_RO(name);
33
34static ssize_t
35date_show(struct device *dev, struct device_attribute *attr, char *buf)
36{
37 ssize_t retval;
38 struct rtc_time tm;
39
40 retval = rtc_read_time(to_rtc_device(dev), &tm);
41 if (retval == 0) {
42 retval = sprintf(buf, "%04d-%02d-%02d\n",
43 tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday);
44 }
45
46 return retval;
47}
48static DEVICE_ATTR_RO(date);
49
50static ssize_t
51time_show(struct device *dev, struct device_attribute *attr, char *buf)
52{
53 ssize_t retval;
54 struct rtc_time tm;
55
56 retval = rtc_read_time(to_rtc_device(dev), &tm);
57 if (retval == 0) {
58 retval = sprintf(buf, "%02d:%02d:%02d\n",
59 tm.tm_hour, tm.tm_min, tm.tm_sec);
60 }
61
62 return retval;
63}
64static DEVICE_ATTR_RO(time);
65
66static ssize_t
67since_epoch_show(struct device *dev, struct device_attribute *attr, char *buf)
68{
69 ssize_t retval;
70 struct rtc_time tm;
71
72 retval = rtc_read_time(to_rtc_device(dev), &tm);
73 if (retval == 0) {
74 unsigned long time;
75 rtc_tm_to_time(&tm, &time);
76 retval = sprintf(buf, "%lu\n", time);
77 }
78
79 return retval;
80}
81static DEVICE_ATTR_RO(since_epoch);
82
83static ssize_t
84max_user_freq_show(struct device *dev, struct device_attribute *attr, char *buf)
85{
86 return sprintf(buf, "%d\n", to_rtc_device(dev)->max_user_freq);
87}
88
89static ssize_t
90max_user_freq_store(struct device *dev, struct device_attribute *attr,
91 const char *buf, size_t n)
92{
93 struct rtc_device *rtc = to_rtc_device(dev);
94 unsigned long val = simple_strtoul(buf, NULL, 0);
95
96 if (val >= 4096 || val == 0)
97 return -EINVAL;
98
99 rtc->max_user_freq = (int)val;
100
101 return n;
102}
103static DEVICE_ATTR_RW(max_user_freq);
104
105/**
106 * rtc_sysfs_show_hctosys - indicate if the given RTC set the system time
107 *
108 * Returns 1 if the system clock was set by this RTC at the last
109 * boot or resume event.
110 */
111static ssize_t
112hctosys_show(struct device *dev, struct device_attribute *attr, char *buf)
113{
114#ifdef CONFIG_RTC_HCTOSYS_DEVICE
115 if (rtc_hctosys_ret == 0 &&
116 strcmp(dev_name(&to_rtc_device(dev)->dev),
117 CONFIG_RTC_HCTOSYS_DEVICE) == 0)
118 return sprintf(buf, "1\n");
119 else
120#endif
121 return sprintf(buf, "0\n");
122}
123static DEVICE_ATTR_RO(hctosys);
124
125static struct attribute *rtc_attrs[] = {
126 &dev_attr_name.attr,
127 &dev_attr_date.attr,
128 &dev_attr_time.attr,
129 &dev_attr_since_epoch.attr,
130 &dev_attr_max_user_freq.attr,
131 &dev_attr_hctosys.attr,
132 NULL,
133};
134ATTRIBUTE_GROUPS(rtc);
135
136static ssize_t
137rtc_sysfs_show_wakealarm(struct device *dev, struct device_attribute *attr,
138 char *buf)
139{
140 ssize_t retval;
141 unsigned long alarm;
142 struct rtc_wkalrm alm;
143
144 /* Don't show disabled alarms. For uniformity, RTC alarms are
145 * conceptually one-shot, even though some common RTCs (on PCs)
146 * don't actually work that way.
147 *
148 * NOTE: RTC implementations where the alarm doesn't match an
149 * exact YYYY-MM-DD HH:MM[:SS] date *must* disable their RTC
150 * alarms after they trigger, to ensure one-shot semantics.
151 */
152 retval = rtc_read_alarm(to_rtc_device(dev), &alm);
153 if (retval == 0 && alm.enabled) {
154 rtc_tm_to_time(&alm.time, &alarm);
155 retval = sprintf(buf, "%lu\n", alarm);
156 }
157
158 return retval;
159}
160
161static ssize_t
162rtc_sysfs_set_wakealarm(struct device *dev, struct device_attribute *attr,
163 const char *buf, size_t n)
164{
165 ssize_t retval;
166 unsigned long now, alarm;
167 unsigned long push = 0;
168 struct rtc_wkalrm alm;
169 struct rtc_device *rtc = to_rtc_device(dev);
170 char *buf_ptr;
171 int adjust = 0;
172
173 /* Only request alarms that trigger in the future. Disable them
174 * by writing another time, e.g. 0 meaning Jan 1 1970 UTC.
175 */
176 retval = rtc_read_time(rtc, &alm.time);
177 if (retval < 0)
178 return retval;
179 rtc_tm_to_time(&alm.time, &now);
180
181 buf_ptr = (char *)buf;
182 if (*buf_ptr == '+') {
183 buf_ptr++;
184 if (*buf_ptr == '=') {
185 buf_ptr++;
186 push = 1;
187 } else
188 adjust = 1;
189 }
190 alarm = simple_strtoul(buf_ptr, NULL, 0);
191 if (adjust) {
192 alarm += now;
193 }
194 if (alarm > now || push) {
195 /* Avoid accidentally clobbering active alarms; we can't
196 * entirely prevent that here, without even the minimal
197 * locking from the /dev/rtcN api.
198 */
199 retval = rtc_read_alarm(rtc, &alm);
200 if (retval < 0)
201 return retval;
202 if (alm.enabled) {
203 if (push) {
204 rtc_tm_to_time(&alm.time, &push);
205 alarm += push;
206 } else
207 return -EBUSY;
208 } else if (push)
209 return -EINVAL;
210 alm.enabled = 1;
211 } else {
212 alm.enabled = 0;
213
214 /* Provide a valid future alarm time. Linux isn't EFI,
215 * this time won't be ignored when disabling the alarm.
216 */
217 alarm = now + 300;
218 }
219 rtc_time_to_tm(alarm, &alm.time);
220
221 retval = rtc_set_alarm(rtc, &alm);
222 return (retval < 0) ? retval : n;
223}
224static DEVICE_ATTR(wakealarm, S_IRUGO | S_IWUSR,
225 rtc_sysfs_show_wakealarm, rtc_sysfs_set_wakealarm);
226
227
228/* The reason to trigger an alarm with no process watching it (via sysfs)
229 * is its side effect: waking from a system state like suspend-to-RAM or
230 * suspend-to-disk. So: no attribute unless that side effect is possible.
231 * (Userspace may disable that mechanism later.)
232 */
233static inline int rtc_does_wakealarm(struct rtc_device *rtc)
234{
235 if (!device_can_wakeup(rtc->dev.parent))
236 return 0;
237 return rtc->ops->set_alarm != NULL;
238}
239
240
241void rtc_sysfs_add_device(struct rtc_device *rtc)
242{
243 int err;
244
245 /* not all RTCs support both alarms and wakeup */
246 if (!rtc_does_wakealarm(rtc))
247 return;
248
249 err = device_create_file(&rtc->dev, &dev_attr_wakealarm);
250 if (err)
251 dev_err(rtc->dev.parent,
252 "failed to create alarm attribute, %d\n", err);
253}
254
255void rtc_sysfs_del_device(struct rtc_device *rtc)
256{
257 /* REVISIT did we add it successfully? */
258 if (rtc_does_wakealarm(rtc))
259 device_remove_file(&rtc->dev, &dev_attr_wakealarm);
260}
261
262void __init rtc_sysfs_init(struct class *rtc_class)
263{
264 rtc_class->dev_groups = rtc_groups;
265}