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c5c3e192 AZ |
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 | ||
ab6a2d70 DB |
15 | #include "rtc-core.h" |
16 | ||
17 | ||
c5c3e192 AZ |
18 | /* device attributes */ |
19 | ||
8a0bdfd7 DB |
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 | ||
cd966209 DB |
27 | static ssize_t |
28 | rtc_sysfs_show_name(struct device *dev, struct device_attribute *attr, | |
29 | char *buf) | |
c5c3e192 AZ |
30 | { |
31 | return sprintf(buf, "%s\n", to_rtc_device(dev)->name); | |
32 | } | |
c5c3e192 | 33 | |
cd966209 DB |
34 | static ssize_t |
35 | rtc_sysfs_show_date(struct device *dev, struct device_attribute *attr, | |
36 | char *buf) | |
c5c3e192 AZ |
37 | { |
38 | ssize_t retval; | |
39 | struct rtc_time tm; | |
40 | ||
ab6a2d70 | 41 | retval = rtc_read_time(to_rtc_device(dev), &tm); |
c5c3e192 AZ |
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 | } | |
c5c3e192 | 49 | |
cd966209 DB |
50 | static ssize_t |
51 | rtc_sysfs_show_time(struct device *dev, struct device_attribute *attr, | |
52 | char *buf) | |
c5c3e192 AZ |
53 | { |
54 | ssize_t retval; | |
55 | struct rtc_time tm; | |
56 | ||
ab6a2d70 | 57 | retval = rtc_read_time(to_rtc_device(dev), &tm); |
c5c3e192 AZ |
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 | } | |
c5c3e192 | 65 | |
cd966209 DB |
66 | static ssize_t |
67 | rtc_sysfs_show_since_epoch(struct device *dev, struct device_attribute *attr, | |
68 | char *buf) | |
c5c3e192 AZ |
69 | { |
70 | ssize_t retval; | |
71 | struct rtc_time tm; | |
72 | ||
ab6a2d70 | 73 | retval = rtc_read_time(to_rtc_device(dev), &tm); |
c5c3e192 AZ |
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 | } | |
c5c3e192 | 82 | |
06c65eb4 BK |
83 | static ssize_t |
84 | rtc_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 | ||
90 | static ssize_t | |
91 | rtc_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 | ||
cd966209 | 105 | static struct device_attribute rtc_attrs[] = { |
446ecbd9 DB |
106 | __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), | |
06c65eb4 BK |
110 | __ATTR(max_user_freq, S_IRUGO | S_IWUSR, rtc_sysfs_show_max_user_freq, |
111 | rtc_sysfs_set_max_user_freq), | |
446ecbd9 | 112 | { }, |
c5c3e192 AZ |
113 | }; |
114 | ||
3925a5ce | 115 | static ssize_t |
cd966209 DB |
116 | rtc_sysfs_show_wakealarm(struct device *dev, struct device_attribute *attr, |
117 | char *buf) | |
3925a5ce DB |
118 | { |
119 | ssize_t retval; | |
120 | unsigned long alarm; | |
121 | struct rtc_wkalrm alm; | |
122 | ||
8a0bdfd7 DB |
123 | /* 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. | |
3925a5ce | 126 | * |
8a0bdfd7 DB |
127 | * 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. | |
3925a5ce | 130 | */ |
ab6a2d70 | 131 | retval = rtc_read_alarm(to_rtc_device(dev), &alm); |
3925a5ce DB |
132 | 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 | ||
140 | static ssize_t | |
cd966209 DB |
141 | rtc_sysfs_set_wakealarm(struct device *dev, struct device_attribute *attr, |
142 | const char *buf, size_t n) | |
3925a5ce DB |
143 | { |
144 | ssize_t retval; | |
145 | unsigned long now, alarm; | |
146 | struct rtc_wkalrm alm; | |
ab6a2d70 | 147 | struct rtc_device *rtc = to_rtc_device(dev); |
3925a5ce DB |
148 | |
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 | */ | |
ab6a2d70 | 152 | retval = rtc_read_time(rtc, &alm.time); |
3925a5ce DB |
153 | 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 | */ | |
ab6a2d70 | 163 | retval = rtc_read_alarm(rtc, &alm); |
3925a5ce DB |
164 | 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 | ||
ab6a2d70 | 180 | retval = rtc_set_alarm(rtc, &alm); |
3925a5ce DB |
181 | return (retval < 0) ? retval : n; |
182 | } | |
cd966209 | 183 | static DEVICE_ATTR(wakealarm, S_IRUGO | S_IWUSR, |
3925a5ce DB |
184 | 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 | */ | |
446ecbd9 | 192 | static inline int rtc_does_wakealarm(struct rtc_device *rtc) |
3925a5ce | 193 | { |
cd966209 | 194 | if (!device_can_wakeup(rtc->dev.parent)) |
3925a5ce | 195 | return 0; |
3925a5ce DB |
196 | return rtc->ops->set_alarm != NULL; |
197 | } | |
198 | ||
199 | ||
446ecbd9 | 200 | void rtc_sysfs_add_device(struct rtc_device *rtc) |
c5c3e192 AZ |
201 | { |
202 | int err; | |
203 | ||
446ecbd9 DB |
204 | /* not all RTCs support both alarms and wakeup */ |
205 | if (!rtc_does_wakealarm(rtc)) | |
206 | return; | |
c5c3e192 | 207 | |
cd966209 | 208 | err = device_create_file(&rtc->dev, &dev_attr_wakealarm); |
c5c3e192 | 209 | if (err) |
898eb71c JP |
210 | dev_err(rtc->dev.parent, |
211 | "failed to create alarm attribute, %d\n", err); | |
c5c3e192 AZ |
212 | } |
213 | ||
446ecbd9 | 214 | void rtc_sysfs_del_device(struct rtc_device *rtc) |
c5c3e192 | 215 | { |
446ecbd9 DB |
216 | /* REVISIT did we add it successfully? */ |
217 | if (rtc_does_wakealarm(rtc)) | |
cd966209 | 218 | device_remove_file(&rtc->dev, &dev_attr_wakealarm); |
c5c3e192 AZ |
219 | } |
220 | ||
446ecbd9 | 221 | void __init rtc_sysfs_init(struct class *rtc_class) |
c5c3e192 | 222 | { |
cd966209 | 223 | rtc_class->dev_attrs = rtc_attrs; |
c5c3e192 | 224 | } |