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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
Greg Kroah-Hartmanf21e6832013-07-24 15:05:22 -070028name_show(struct device *dev, struct device_attribute *attr, char *buf)
Alessandro Zummoc5c3e192006-03-27 01:16:39 -080029{
30 return sprintf(buf, "%s\n", to_rtc_device(dev)->name);
31}
Greg Kroah-Hartmanf21e6832013-07-24 15:05:22 -070032static DEVICE_ATTR_RO(name);
Alessandro Zummoc5c3e192006-03-27 01:16:39 -080033
David Brownellcd966202007-05-08 00:33:40 -070034static ssize_t
Greg Kroah-Hartmanf21e6832013-07-24 15:05:22 -070035date_show(struct device *dev, struct device_attribute *attr, char *buf)
Alessandro Zummoc5c3e192006-03-27 01:16:39 -080036{
37 ssize_t retval;
38 struct rtc_time tm;
39
David Brownellab6a2d72007-05-08 00:33:30 -070040 retval = rtc_read_time(to_rtc_device(dev), &tm);
Alessandro Zummoc5c3e192006-03-27 01:16:39 -080041 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}
Greg Kroah-Hartmanf21e6832013-07-24 15:05:22 -070048static DEVICE_ATTR_RO(date);
Alessandro Zummoc5c3e192006-03-27 01:16:39 -080049
David Brownellcd966202007-05-08 00:33:40 -070050static ssize_t
Greg Kroah-Hartmanf21e6832013-07-24 15:05:22 -070051time_show(struct device *dev, struct device_attribute *attr, char *buf)
Alessandro Zummoc5c3e192006-03-27 01:16:39 -080052{
53 ssize_t retval;
54 struct rtc_time tm;
55
David Brownellab6a2d72007-05-08 00:33:30 -070056 retval = rtc_read_time(to_rtc_device(dev), &tm);
Alessandro Zummoc5c3e192006-03-27 01:16:39 -080057 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}
Greg Kroah-Hartmanf21e6832013-07-24 15:05:22 -070064static DEVICE_ATTR_RO(time);
Alessandro Zummoc5c3e192006-03-27 01:16:39 -080065
David Brownellcd966202007-05-08 00:33:40 -070066static ssize_t
Greg Kroah-Hartmanf21e6832013-07-24 15:05:22 -070067since_epoch_show(struct device *dev, struct device_attribute *attr, char *buf)
Alessandro Zummoc5c3e192006-03-27 01:16:39 -080068{
69 ssize_t retval;
70 struct rtc_time tm;
71
David Brownellab6a2d72007-05-08 00:33:30 -070072 retval = rtc_read_time(to_rtc_device(dev), &tm);
Alessandro Zummoc5c3e192006-03-27 01:16:39 -080073 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}
Greg Kroah-Hartmanf21e6832013-07-24 15:05:22 -070081static DEVICE_ATTR_RO(since_epoch);
Alessandro Zummoc5c3e192006-03-27 01:16:39 -080082
Bryan Kadzban06c65eb2007-10-16 01:28:22 -070083static ssize_t
Greg Kroah-Hartmanf21e6832013-07-24 15:05:22 -070084max_user_freq_show(struct device *dev, struct device_attribute *attr, char *buf)
Bryan Kadzban06c65eb2007-10-16 01:28:22 -070085{
86 return sprintf(buf, "%d\n", to_rtc_device(dev)->max_user_freq);
87}
88
89static ssize_t
Greg Kroah-Hartmanf21e6832013-07-24 15:05:22 -070090max_user_freq_store(struct device *dev, struct device_attribute *attr,
Bryan Kadzban06c65eb2007-10-16 01:28:22 -070091 const char *buf, size_t n)
92{
93 struct rtc_device *rtc = to_rtc_device(dev);
LABBE Corentinf5712872015-12-17 14:11:04 +010094 unsigned long val;
95 int err;
96
97 err = kstrtoul(buf, 0, &val);
98 if (err)
99 return err;
Bryan Kadzban06c65eb2007-10-16 01:28:22 -0700100
101 if (val >= 4096 || val == 0)
102 return -EINVAL;
103
104 rtc->max_user_freq = (int)val;
105
106 return n;
107}
Greg Kroah-Hartmanf21e6832013-07-24 15:05:22 -0700108static DEVICE_ATTR_RW(max_user_freq);
Bryan Kadzban06c65eb2007-10-16 01:28:22 -0700109
David Fries4c24e292012-10-04 17:14:12 -0700110/**
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 */
Matthew Garrettd8c1acb2009-09-22 16:46:32 -0700116static ssize_t
Greg Kroah-Hartmanf21e6832013-07-24 15:05:22 -0700117hctosys_show(struct device *dev, struct device_attribute *attr, char *buf)
Matthew Garrettd8c1acb2009-09-22 16:46:32 -0700118{
119#ifdef CONFIG_RTC_HCTOSYS_DEVICE
Uwe Kleine-Königd0ab4a42010-03-10 15:20:35 -0800120 if (rtc_hctosys_ret == 0 &&
121 strcmp(dev_name(&to_rtc_device(dev)->dev),
122 CONFIG_RTC_HCTOSYS_DEVICE) == 0)
Matthew Garrettd8c1acb2009-09-22 16:46:32 -0700123 return sprintf(buf, "1\n");
124 else
125#endif
126 return sprintf(buf, "0\n");
127}
Greg Kroah-Hartmanf21e6832013-07-24 15:05:22 -0700128static DEVICE_ATTR_RO(hctosys);
Matthew Garrettd8c1acb2009-09-22 16:46:32 -0700129
David Brownell3925a5c2007-02-12 00:52:47 -0800130static ssize_t
Dmitry Torokhova17ccd12015-07-23 16:01:07 -0700131wakealarm_show(struct device *dev, struct device_attribute *attr, char *buf)
David Brownell3925a5c2007-02-12 00:52:47 -0800132{
133 ssize_t retval;
134 unsigned long alarm;
135 struct rtc_wkalrm alm;
136
David Brownell8a0bdfd2008-02-06 01:38:45 -0800137 /* 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.
David Brownell3925a5c2007-02-12 00:52:47 -0800140 *
David Brownell8a0bdfd2008-02-06 01:38:45 -0800141 * 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.
David Brownell3925a5c2007-02-12 00:52:47 -0800144 */
David Brownellab6a2d72007-05-08 00:33:30 -0700145 retval = rtc_read_alarm(to_rtc_device(dev), &alm);
David Brownell3925a5c2007-02-12 00:52:47 -0800146 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
Dmitry Torokhova17ccd12015-07-23 16:01:07 -0700155wakealarm_store(struct device *dev, struct device_attribute *attr,
David Brownellcd966202007-05-08 00:33:40 -0700156 const char *buf, size_t n)
David Brownell3925a5c2007-02-12 00:52:47 -0800157{
158 ssize_t retval;
159 unsigned long now, alarm;
Bernie Thompson1df0a472013-07-03 15:07:03 -0700160 unsigned long push = 0;
David Brownell3925a5c2007-02-12 00:52:47 -0800161 struct rtc_wkalrm alm;
David Brownellab6a2d72007-05-08 00:33:30 -0700162 struct rtc_device *rtc = to_rtc_device(dev);
LABBE Corentin84281c22016-08-12 14:46:14 +0200163 const char *buf_ptr;
Zhao Yakuic116bc22008-04-28 02:11:58 -0700164 int adjust = 0;
David Brownell3925a5c2007-02-12 00:52:47 -0800165
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 */
David Brownellab6a2d72007-05-08 00:33:30 -0700169 retval = rtc_read_time(rtc, &alm.time);
David Brownell3925a5c2007-02-12 00:52:47 -0800170 if (retval < 0)
171 return retval;
172 rtc_tm_to_time(&alm.time, &now);
173
LABBE Corentin84281c22016-08-12 14:46:14 +0200174 buf_ptr = buf;
Zhao Yakuic116bc22008-04-28 02:11:58 -0700175 if (*buf_ptr == '+') {
176 buf_ptr++;
Bernie Thompson1df0a472013-07-03 15:07:03 -0700177 if (*buf_ptr == '=') {
178 buf_ptr++;
179 push = 1;
180 } else
181 adjust = 1;
Zhao Yakuic116bc22008-04-28 02:11:58 -0700182 }
LABBE Corentinf5712872015-12-17 14:11:04 +0100183 retval = kstrtoul(buf_ptr, 0, &alarm);
184 if (retval)
185 return retval;
Zhao Yakuic116bc22008-04-28 02:11:58 -0700186 if (adjust) {
187 alarm += now;
188 }
Bernie Thompson1df0a472013-07-03 15:07:03 -0700189 if (alarm > now || push) {
David Brownell3925a5c2007-02-12 00:52:47 -0800190 /* 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 */
David Brownellab6a2d72007-05-08 00:33:30 -0700194 retval = rtc_read_alarm(rtc, &alm);
David Brownell3925a5c2007-02-12 00:52:47 -0800195 if (retval < 0)
196 return retval;
Bernie Thompson1df0a472013-07-03 15:07:03 -0700197 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;
David Brownell3925a5c2007-02-12 00:52:47 -0800205 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
David Brownellab6a2d72007-05-08 00:33:30 -0700216 retval = rtc_set_alarm(rtc, &alm);
David Brownell3925a5c2007-02-12 00:52:47 -0800217 return (retval < 0) ? retval : n;
218}
Dmitry Torokhova17ccd12015-07-23 16:01:07 -0700219static DEVICE_ATTR_RW(wakealarm);
David Brownell3925a5c2007-02-12 00:52:47 -0800220
Joshua Clayton5495a412016-02-05 12:41:12 -0800221static 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
Dmitry Torokhov3ee2c402015-07-23 16:01:08 -0700249static 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,
Joshua Clayton5495a412016-02-05 12:41:12 -0800257 &dev_attr_offset.attr,
Dmitry Torokhov3ee2c402015-07-23 16:01:08 -0700258 NULL,
259};
David Brownell3925a5c2007-02-12 00:52:47 -0800260
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 */
Dmitry Torokhovdf100c02015-07-23 16:01:06 -0700266static bool rtc_does_wakealarm(struct rtc_device *rtc)
David Brownell3925a5c2007-02-12 00:52:47 -0800267{
David Brownellcd966202007-05-08 00:33:40 -0700268 if (!device_can_wakeup(rtc->dev.parent))
Dmitry Torokhovdf100c02015-07-23 16:01:06 -0700269 return false;
270
David Brownell3925a5c2007-02-12 00:52:47 -0800271 return rtc->ops->set_alarm != NULL;
272}
273
Dmitry Torokhov3ee2c402015-07-23 16:01:08 -0700274static umode_t rtc_attr_is_visible(struct kobject *kobj,
275 struct attribute *attr, int n)
Alessandro Zummoc5c3e192006-03-27 01:16:39 -0800276{
Dmitry Torokhov3ee2c402015-07-23 16:01:08 -0700277 struct device *dev = container_of(kobj, struct device, kobj);
278 struct rtc_device *rtc = to_rtc_device(dev);
279 umode_t mode = attr->mode;
Alessandro Zummoc5c3e192006-03-27 01:16:39 -0800280
Joshua Clayton5495a412016-02-05 12:41:12 -0800281 if (attr == &dev_attr_wakealarm.attr) {
Dmitry Torokhov3ee2c402015-07-23 16:01:08 -0700282 if (!rtc_does_wakealarm(rtc))
283 mode = 0;
Joshua Clayton5495a412016-02-05 12:41:12 -0800284 } else if (attr == &dev_attr_offset.attr) {
285 if (!rtc->ops->set_offset)
286 mode = 0;
287 }
Alessandro Zummoc5c3e192006-03-27 01:16:39 -0800288
Dmitry Torokhov3ee2c402015-07-23 16:01:08 -0700289 return mode;
Alessandro Zummoc5c3e192006-03-27 01:16:39 -0800290}
291
Dmitry Torokhov3ee2c402015-07-23 16:01:08 -0700292static struct attribute_group rtc_attr_group = {
293 .is_visible = rtc_attr_is_visible,
294 .attrs = rtc_attrs,
295};
Alessandro Zummoc5c3e192006-03-27 01:16:39 -0800296
Dmitry Torokhov3ee2c402015-07-23 16:01:08 -0700297static 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)
Alessandro Zummoc5c3e192006-03-27 01:16:39 -0800303{
Dmitry Torokhov3ee2c402015-07-23 16:01:08 -0700304 return rtc_attr_groups;
Alessandro Zummoc5c3e192006-03-27 01:16:39 -0800305}