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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 | ||
20 | static ssize_t rtc_sysfs_show_name(struct class_device *dev, char *buf) | |
21 | { | |
22 | return sprintf(buf, "%s\n", to_rtc_device(dev)->name); | |
23 | } | |
c5c3e192 AZ |
24 | |
25 | static ssize_t rtc_sysfs_show_date(struct class_device *dev, char *buf) | |
26 | { | |
27 | ssize_t retval; | |
28 | struct rtc_time tm; | |
29 | ||
ab6a2d70 | 30 | retval = rtc_read_time(to_rtc_device(dev), &tm); |
c5c3e192 AZ |
31 | if (retval == 0) { |
32 | retval = sprintf(buf, "%04d-%02d-%02d\n", | |
33 | tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday); | |
34 | } | |
35 | ||
36 | return retval; | |
37 | } | |
c5c3e192 AZ |
38 | |
39 | static ssize_t rtc_sysfs_show_time(struct class_device *dev, char *buf) | |
40 | { | |
41 | ssize_t retval; | |
42 | struct rtc_time tm; | |
43 | ||
ab6a2d70 | 44 | retval = rtc_read_time(to_rtc_device(dev), &tm); |
c5c3e192 AZ |
45 | if (retval == 0) { |
46 | retval = sprintf(buf, "%02d:%02d:%02d\n", | |
47 | tm.tm_hour, tm.tm_min, tm.tm_sec); | |
48 | } | |
49 | ||
50 | return retval; | |
51 | } | |
c5c3e192 AZ |
52 | |
53 | static ssize_t rtc_sysfs_show_since_epoch(struct class_device *dev, char *buf) | |
54 | { | |
55 | ssize_t retval; | |
56 | struct rtc_time tm; | |
57 | ||
ab6a2d70 | 58 | retval = rtc_read_time(to_rtc_device(dev), &tm); |
c5c3e192 AZ |
59 | if (retval == 0) { |
60 | unsigned long time; | |
61 | rtc_tm_to_time(&tm, &time); | |
62 | retval = sprintf(buf, "%lu\n", time); | |
63 | } | |
64 | ||
65 | return retval; | |
66 | } | |
c5c3e192 | 67 | |
446ecbd9 DB |
68 | static struct class_device_attribute rtc_attrs[] = { |
69 | __ATTR(name, S_IRUGO, rtc_sysfs_show_name, NULL), | |
70 | __ATTR(date, S_IRUGO, rtc_sysfs_show_date, NULL), | |
71 | __ATTR(time, S_IRUGO, rtc_sysfs_show_time, NULL), | |
72 | __ATTR(since_epoch, S_IRUGO, rtc_sysfs_show_since_epoch, NULL), | |
73 | { }, | |
c5c3e192 AZ |
74 | }; |
75 | ||
3925a5ce DB |
76 | static ssize_t |
77 | rtc_sysfs_show_wakealarm(struct class_device *dev, char *buf) | |
78 | { | |
79 | ssize_t retval; | |
80 | unsigned long alarm; | |
81 | struct rtc_wkalrm alm; | |
82 | ||
83 | /* Don't show disabled alarms; but the RTC could leave the | |
84 | * alarm enabled after it's already triggered. Alarms are | |
85 | * conceptually one-shot, even though some common hardware | |
86 | * (PCs) doesn't actually work that way. | |
87 | * | |
88 | * REVISIT maybe we should require RTC implementations to | |
89 | * disable the RTC alarm after it triggers, for uniformity. | |
90 | */ | |
ab6a2d70 | 91 | retval = rtc_read_alarm(to_rtc_device(dev), &alm); |
3925a5ce DB |
92 | if (retval == 0 && alm.enabled) { |
93 | rtc_tm_to_time(&alm.time, &alarm); | |
94 | retval = sprintf(buf, "%lu\n", alarm); | |
95 | } | |
96 | ||
97 | return retval; | |
98 | } | |
99 | ||
100 | static ssize_t | |
101 | rtc_sysfs_set_wakealarm(struct class_device *dev, const char *buf, size_t n) | |
102 | { | |
103 | ssize_t retval; | |
104 | unsigned long now, alarm; | |
105 | struct rtc_wkalrm alm; | |
ab6a2d70 | 106 | struct rtc_device *rtc = to_rtc_device(dev); |
3925a5ce DB |
107 | |
108 | /* Only request alarms that trigger in the future. Disable them | |
109 | * by writing another time, e.g. 0 meaning Jan 1 1970 UTC. | |
110 | */ | |
ab6a2d70 | 111 | retval = rtc_read_time(rtc, &alm.time); |
3925a5ce DB |
112 | if (retval < 0) |
113 | return retval; | |
114 | rtc_tm_to_time(&alm.time, &now); | |
115 | ||
116 | alarm = simple_strtoul(buf, NULL, 0); | |
117 | if (alarm > now) { | |
118 | /* Avoid accidentally clobbering active alarms; we can't | |
119 | * entirely prevent that here, without even the minimal | |
120 | * locking from the /dev/rtcN api. | |
121 | */ | |
ab6a2d70 | 122 | retval = rtc_read_alarm(rtc, &alm); |
3925a5ce DB |
123 | if (retval < 0) |
124 | return retval; | |
125 | if (alm.enabled) | |
126 | return -EBUSY; | |
127 | ||
128 | alm.enabled = 1; | |
129 | } else { | |
130 | alm.enabled = 0; | |
131 | ||
132 | /* Provide a valid future alarm time. Linux isn't EFI, | |
133 | * this time won't be ignored when disabling the alarm. | |
134 | */ | |
135 | alarm = now + 300; | |
136 | } | |
137 | rtc_time_to_tm(alarm, &alm.time); | |
138 | ||
ab6a2d70 | 139 | retval = rtc_set_alarm(rtc, &alm); |
3925a5ce DB |
140 | return (retval < 0) ? retval : n; |
141 | } | |
142 | static const CLASS_DEVICE_ATTR(wakealarm, S_IRUGO | S_IWUSR, | |
143 | rtc_sysfs_show_wakealarm, rtc_sysfs_set_wakealarm); | |
144 | ||
145 | ||
146 | /* The reason to trigger an alarm with no process watching it (via sysfs) | |
147 | * is its side effect: waking from a system state like suspend-to-RAM or | |
148 | * suspend-to-disk. So: no attribute unless that side effect is possible. | |
149 | * (Userspace may disable that mechanism later.) | |
150 | */ | |
446ecbd9 | 151 | static inline int rtc_does_wakealarm(struct rtc_device *rtc) |
3925a5ce | 152 | { |
446ecbd9 | 153 | if (!device_can_wakeup(rtc->class_dev.dev)) |
3925a5ce | 154 | return 0; |
3925a5ce DB |
155 | return rtc->ops->set_alarm != NULL; |
156 | } | |
157 | ||
158 | ||
446ecbd9 | 159 | void rtc_sysfs_add_device(struct rtc_device *rtc) |
c5c3e192 AZ |
160 | { |
161 | int err; | |
162 | ||
446ecbd9 DB |
163 | /* not all RTCs support both alarms and wakeup */ |
164 | if (!rtc_does_wakealarm(rtc)) | |
165 | return; | |
c5c3e192 | 166 | |
446ecbd9 DB |
167 | err = class_device_create_file(&rtc->class_dev, |
168 | &class_device_attr_wakealarm); | |
c5c3e192 | 169 | if (err) |
446ecbd9 DB |
170 | dev_err(rtc->class_dev.dev, "failed to create " |
171 | "alarm attribute, %d", | |
172 | err); | |
c5c3e192 AZ |
173 | } |
174 | ||
446ecbd9 | 175 | void rtc_sysfs_del_device(struct rtc_device *rtc) |
c5c3e192 | 176 | { |
446ecbd9 DB |
177 | /* REVISIT did we add it successfully? */ |
178 | if (rtc_does_wakealarm(rtc)) | |
179 | class_device_remove_file(&rtc->class_dev, | |
3925a5ce | 180 | &class_device_attr_wakealarm); |
c5c3e192 AZ |
181 | } |
182 | ||
446ecbd9 | 183 | void __init rtc_sysfs_init(struct class *rtc_class) |
c5c3e192 | 184 | { |
446ecbd9 | 185 | rtc_class->class_dev_attrs = rtc_attrs; |
c5c3e192 | 186 | } |