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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 %s\n", dev_driver_string(dev->parent),
31 dev_name(dev->parent));
32}
33static DEVICE_ATTR_RO(name);
34
35static ssize_t
36date_show(struct device *dev, struct device_attribute *attr, 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}
49static DEVICE_ATTR_RO(date);
50
51static ssize_t
52time_show(struct device *dev, struct device_attribute *attr, 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}
65static DEVICE_ATTR_RO(time);
66
67static ssize_t
68since_epoch_show(struct device *dev, struct device_attribute *attr, 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 time64_t time;
76
77 time = rtc_tm_to_time64(&tm);
78 retval = sprintf(buf, "%lld\n", time);
79 }
80
81 return retval;
82}
83static DEVICE_ATTR_RO(since_epoch);
84
85static ssize_t
86max_user_freq_show(struct device *dev, struct device_attribute *attr, char *buf)
87{
88 return sprintf(buf, "%d\n", to_rtc_device(dev)->max_user_freq);
89}
90
91static ssize_t
92max_user_freq_store(struct device *dev, struct device_attribute *attr,
93 const char *buf, size_t n)
94{
95 struct rtc_device *rtc = to_rtc_device(dev);
96 unsigned long val;
97 int err;
98
99 err = kstrtoul(buf, 0, &val);
100 if (err)
101 return err;
102
103 if (val >= 4096 || val == 0)
104 return -EINVAL;
105
106 rtc->max_user_freq = (int)val;
107
108 return n;
109}
110static DEVICE_ATTR_RW(max_user_freq);
111
112/**
113 * rtc_sysfs_show_hctosys - indicate if the given RTC set the system time
114 *
115 * Returns 1 if the system clock was set by this RTC at the last
116 * boot or resume event.
117 */
118static ssize_t
119hctosys_show(struct device *dev, struct device_attribute *attr, char *buf)
120{
121#ifdef CONFIG_RTC_HCTOSYS_DEVICE
122 if (rtc_hctosys_ret == 0 &&
123 strcmp(dev_name(&to_rtc_device(dev)->dev),
124 CONFIG_RTC_HCTOSYS_DEVICE) == 0)
125 return sprintf(buf, "1\n");
126 else
127#endif
128 return sprintf(buf, "0\n");
129}
130static DEVICE_ATTR_RO(hctosys);
131
132static ssize_t
133wakealarm_show(struct device *dev, struct device_attribute *attr, char *buf)
134{
135 ssize_t retval;
136 time64_t alarm;
137 struct rtc_wkalrm alm;
138
139 /* Don't show disabled alarms. For uniformity, RTC alarms are
140 * conceptually one-shot, even though some common RTCs (on PCs)
141 * don't actually work that way.
142 *
143 * NOTE: RTC implementations where the alarm doesn't match an
144 * exact YYYY-MM-DD HH:MM[:SS] date *must* disable their RTC
145 * alarms after they trigger, to ensure one-shot semantics.
146 */
147 retval = rtc_read_alarm(to_rtc_device(dev), &alm);
148 if (retval == 0 && alm.enabled) {
149 alarm = rtc_tm_to_time64(&alm.time);
150 retval = sprintf(buf, "%lld\n", alarm);
151 }
152
153 return retval;
154}
155
156static ssize_t
157wakealarm_store(struct device *dev, struct device_attribute *attr,
158 const char *buf, size_t n)
159{
160 ssize_t retval;
161 time64_t now, alarm;
162 time64_t push = 0;
163 struct rtc_wkalrm alm;
164 struct rtc_device *rtc = to_rtc_device(dev);
165 const char *buf_ptr;
166 int adjust = 0;
167
168 /* Only request alarms that trigger in the future. Disable them
169 * by writing another time, e.g. 0 meaning Jan 1 1970 UTC.
170 */
171 retval = rtc_read_time(rtc, &alm.time);
172 if (retval < 0)
173 return retval;
174 now = rtc_tm_to_time64(&alm.time);
175
176 buf_ptr = buf;
177 if (*buf_ptr == '+') {
178 buf_ptr++;
179 if (*buf_ptr == '=') {
180 buf_ptr++;
181 push = 1;
182 } else
183 adjust = 1;
184 }
185 retval = kstrtos64(buf_ptr, 0, &alarm);
186 if (retval)
187 return retval;
188 if (adjust) {
189 alarm += now;
190 }
191 if (alarm > now || push) {
192 /* Avoid accidentally clobbering active alarms; we can't
193 * entirely prevent that here, without even the minimal
194 * locking from the /dev/rtcN api.
195 */
196 retval = rtc_read_alarm(rtc, &alm);
197 if (retval < 0)
198 return retval;
199 if (alm.enabled) {
200 if (push) {
201 push = rtc_tm_to_time64(&alm.time);
202 alarm += push;
203 } else
204 return -EBUSY;
205 } else if (push)
206 return -EINVAL;
207 alm.enabled = 1;
208 } else {
209 alm.enabled = 0;
210
211 /* Provide a valid future alarm time. Linux isn't EFI,
212 * this time won't be ignored when disabling the alarm.
213 */
214 alarm = now + 300;
215 }
216 rtc_time64_to_tm(alarm, &alm.time);
217
218 retval = rtc_set_alarm(rtc, &alm);
219 return (retval < 0) ? retval : n;
220}
221static DEVICE_ATTR_RW(wakealarm);
222
223static ssize_t
224offset_show(struct device *dev, struct device_attribute *attr, char *buf)
225{
226 ssize_t retval;
227 long offset;
228
229 retval = rtc_read_offset(to_rtc_device(dev), &offset);
230 if (retval == 0)
231 retval = sprintf(buf, "%ld\n", offset);
232
233 return retval;
234}
235
236static ssize_t
237offset_store(struct device *dev, struct device_attribute *attr,
238 const char *buf, size_t n)
239{
240 ssize_t retval;
241 long offset;
242
243 retval = kstrtol(buf, 10, &offset);
244 if (retval == 0)
245 retval = rtc_set_offset(to_rtc_device(dev), offset);
246
247 return (retval < 0) ? retval : n;
248}
249static DEVICE_ATTR_RW(offset);
250
251static ssize_t
252range_show(struct device *dev, struct device_attribute *attr, char *buf)
253{
254 return sprintf(buf, "[%lld,%llu]\n", to_rtc_device(dev)->range_min,
255 to_rtc_device(dev)->range_max);
256}
257static DEVICE_ATTR_RO(range);
258
259static struct attribute *rtc_attrs[] = {
260 &dev_attr_name.attr,
261 &dev_attr_date.attr,
262 &dev_attr_time.attr,
263 &dev_attr_since_epoch.attr,
264 &dev_attr_max_user_freq.attr,
265 &dev_attr_hctosys.attr,
266 &dev_attr_wakealarm.attr,
267 &dev_attr_offset.attr,
268 &dev_attr_range.attr,
269 NULL,
270};
271
272/* The reason to trigger an alarm with no process watching it (via sysfs)
273 * is its side effect: waking from a system state like suspend-to-RAM or
274 * suspend-to-disk. So: no attribute unless that side effect is possible.
275 * (Userspace may disable that mechanism later.)
276 */
277static bool rtc_does_wakealarm(struct rtc_device *rtc)
278{
279 if (!device_can_wakeup(rtc->dev.parent))
280 return false;
281
282 return rtc->ops->set_alarm != NULL;
283}
284
285static umode_t rtc_attr_is_visible(struct kobject *kobj,
286 struct attribute *attr, int n)
287{
288 struct device *dev = container_of(kobj, struct device, kobj);
289 struct rtc_device *rtc = to_rtc_device(dev);
290 umode_t mode = attr->mode;
291
292 if (attr == &dev_attr_wakealarm.attr) {
293 if (!rtc_does_wakealarm(rtc))
294 mode = 0;
295 } else if (attr == &dev_attr_offset.attr) {
296 if (!rtc->ops->set_offset)
297 mode = 0;
298 } else if (attr == &dev_attr_range.attr) {
299 if (!(rtc->range_max - rtc->range_min))
300 mode = 0;
301 }
302
303 return mode;
304}
305
306static struct attribute_group rtc_attr_group = {
307 .is_visible = rtc_attr_is_visible,
308 .attrs = rtc_attrs,
309};
310
311static const struct attribute_group *rtc_attr_groups[] = {
312 &rtc_attr_group,
313 NULL
314};
315
316const struct attribute_group **rtc_get_dev_attribute_groups(void)
317{
318 return rtc_attr_groups;
319}
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}