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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
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;
95 int err;
96
97 err = kstrtoul(buf, 0, &val);
98 if (err)
99 return err;
100
101 if (val >= 4096 || val == 0)
102 return -EINVAL;
103
104 rtc->max_user_freq = (int)val;
105
106 return n;
107}
108static DEVICE_ATTR_RW(max_user_freq);
109
110/**
111 * rtc_sysfs_show_hctosys - indicate if the given RTC set the system time
112 *
113 * Returns 1 if the system clock was set by this RTC at the last
114 * boot or resume event.
115 */
116static ssize_t
117hctosys_show(struct device *dev, struct device_attribute *attr, char *buf)
118{
119#ifdef CONFIG_RTC_HCTOSYS_DEVICE
120 if (rtc_hctosys_ret == 0 &&
121 strcmp(dev_name(&to_rtc_device(dev)->dev),
122 CONFIG_RTC_HCTOSYS_DEVICE) == 0)
123 return sprintf(buf, "1\n");
124 else
125#endif
126 return sprintf(buf, "0\n");
127}
128static DEVICE_ATTR_RO(hctosys);
129
130static ssize_t
131wakealarm_show(struct device *dev, struct device_attribute *attr, char *buf)
132{
133 ssize_t retval;
134 unsigned long alarm;
135 struct rtc_wkalrm alm;
136
137 /* Don't show disabled alarms. For uniformity, RTC alarms are
138 * conceptually one-shot, even though some common RTCs (on PCs)
139 * don't actually work that way.
140 *
141 * NOTE: RTC implementations where the alarm doesn't match an
142 * exact YYYY-MM-DD HH:MM[:SS] date *must* disable their RTC
143 * alarms after they trigger, to ensure one-shot semantics.
144 */
145 retval = rtc_read_alarm(to_rtc_device(dev), &alm);
146 if (retval == 0 && alm.enabled) {
147 rtc_tm_to_time(&alm.time, &alarm);
148 retval = sprintf(buf, "%lu\n", alarm);
149 }
150
151 return retval;
152}
153
154static ssize_t
155wakealarm_store(struct device *dev, struct device_attribute *attr,
156 const char *buf, size_t n)
157{
158 ssize_t retval;
159 unsigned long now, alarm;
160 unsigned long push = 0;
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 if (*buf_ptr == '=') {
178 buf_ptr++;
179 push = 1;
180 } else
181 adjust = 1;
182 }
183 retval = kstrtoul(buf_ptr, 0, &alarm);
184 if (retval)
185 return retval;
186 if (adjust) {
187 alarm += now;
188 }
189 if (alarm > now || push) {
190 /* Avoid accidentally clobbering active alarms; we can't
191 * entirely prevent that here, without even the minimal
192 * locking from the /dev/rtcN api.
193 */
194 retval = rtc_read_alarm(rtc, &alm);
195 if (retval < 0)
196 return retval;
197 if (alm.enabled) {
198 if (push) {
199 rtc_tm_to_time(&alm.time, &push);
200 alarm += push;
201 } else
202 return -EBUSY;
203 } else if (push)
204 return -EINVAL;
205 alm.enabled = 1;
206 } else {
207 alm.enabled = 0;
208
209 /* Provide a valid future alarm time. Linux isn't EFI,
210 * this time won't be ignored when disabling the alarm.
211 */
212 alarm = now + 300;
213 }
214 rtc_time_to_tm(alarm, &alm.time);
215
216 retval = rtc_set_alarm(rtc, &alm);
217 return (retval < 0) ? retval : n;
218}
219static DEVICE_ATTR_RW(wakealarm);
220
221static ssize_t
222offset_show(struct device *dev, struct device_attribute *attr, char *buf)
223{
224 ssize_t retval;
225 long offset;
226
227 retval = rtc_read_offset(to_rtc_device(dev), &offset);
228 if (retval == 0)
229 retval = sprintf(buf, "%ld\n", offset);
230
231 return retval;
232}
233
234static ssize_t
235offset_store(struct device *dev, struct device_attribute *attr,
236 const char *buf, size_t n)
237{
238 ssize_t retval;
239 long offset;
240
241 retval = kstrtol(buf, 10, &offset);
242 if (retval == 0)
243 retval = rtc_set_offset(to_rtc_device(dev), offset);
244
245 return (retval < 0) ? retval : n;
246}
247static DEVICE_ATTR_RW(offset);
248
249static struct attribute *rtc_attrs[] = {
250 &dev_attr_name.attr,
251 &dev_attr_date.attr,
252 &dev_attr_time.attr,
253 &dev_attr_since_epoch.attr,
254 &dev_attr_max_user_freq.attr,
255 &dev_attr_hctosys.attr,
256 &dev_attr_wakealarm.attr,
257 &dev_attr_offset.attr,
258 NULL,
259};
260
261/* The reason to trigger an alarm with no process watching it (via sysfs)
262 * is its side effect: waking from a system state like suspend-to-RAM or
263 * suspend-to-disk. So: no attribute unless that side effect is possible.
264 * (Userspace may disable that mechanism later.)
265 */
266static bool rtc_does_wakealarm(struct rtc_device *rtc)
267{
268 if (!device_can_wakeup(rtc->dev.parent))
269 return false;
270
271 return rtc->ops->set_alarm != NULL;
272}
273
274static umode_t rtc_attr_is_visible(struct kobject *kobj,
275 struct attribute *attr, int n)
276{
277 struct device *dev = container_of(kobj, struct device, kobj);
278 struct rtc_device *rtc = to_rtc_device(dev);
279 umode_t mode = attr->mode;
280
281 if (attr == &dev_attr_wakealarm.attr) {
282 if (!rtc_does_wakealarm(rtc))
283 mode = 0;
284 } else if (attr == &dev_attr_offset.attr) {
285 if (!rtc->ops->set_offset)
286 mode = 0;
287 }
288
289 return mode;
290}
291
292static struct attribute_group rtc_attr_group = {
293 .is_visible = rtc_attr_is_visible,
294 .attrs = rtc_attrs,
295};
296
297static const struct attribute_group *rtc_attr_groups[] = {
298 &rtc_attr_group,
299 NULL
300};
301
302const struct attribute_group **rtc_get_dev_attribute_groups(void)
303{
304 return rtc_attr_groups;
305}
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}