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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 | ||
15 | /* device attributes */ | |
16 | ||
17 | static ssize_t rtc_sysfs_show_name(struct class_device *dev, char *buf) | |
18 | { | |
19 | return sprintf(buf, "%s\n", to_rtc_device(dev)->name); | |
20 | } | |
21 | static CLASS_DEVICE_ATTR(name, S_IRUGO, rtc_sysfs_show_name, NULL); | |
22 | ||
23 | static ssize_t rtc_sysfs_show_date(struct class_device *dev, char *buf) | |
24 | { | |
25 | ssize_t retval; | |
26 | struct rtc_time tm; | |
27 | ||
28 | retval = rtc_read_time(dev, &tm); | |
29 | if (retval == 0) { | |
30 | retval = sprintf(buf, "%04d-%02d-%02d\n", | |
31 | tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday); | |
32 | } | |
33 | ||
34 | return retval; | |
35 | } | |
36 | static CLASS_DEVICE_ATTR(date, S_IRUGO, rtc_sysfs_show_date, NULL); | |
37 | ||
38 | static ssize_t rtc_sysfs_show_time(struct class_device *dev, char *buf) | |
39 | { | |
40 | ssize_t retval; | |
41 | struct rtc_time tm; | |
42 | ||
43 | retval = rtc_read_time(dev, &tm); | |
44 | if (retval == 0) { | |
45 | retval = sprintf(buf, "%02d:%02d:%02d\n", | |
46 | tm.tm_hour, tm.tm_min, tm.tm_sec); | |
47 | } | |
48 | ||
49 | return retval; | |
50 | } | |
51 | static CLASS_DEVICE_ATTR(time, S_IRUGO, rtc_sysfs_show_time, NULL); | |
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 | ||
58 | retval = rtc_read_time(dev, &tm); | |
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 | } | |
67 | static CLASS_DEVICE_ATTR(since_epoch, S_IRUGO, rtc_sysfs_show_since_epoch, NULL); | |
68 | ||
69 | static struct attribute *rtc_attrs[] = { | |
70 | &class_device_attr_name.attr, | |
71 | &class_device_attr_date.attr, | |
72 | &class_device_attr_time.attr, | |
73 | &class_device_attr_since_epoch.attr, | |
74 | NULL, | |
75 | }; | |
76 | ||
77 | static struct attribute_group rtc_attr_group = { | |
78 | .attrs = rtc_attrs, | |
79 | }; | |
80 | ||
3925a5ce DB |
81 | |
82 | static ssize_t | |
83 | rtc_sysfs_show_wakealarm(struct class_device *dev, char *buf) | |
84 | { | |
85 | ssize_t retval; | |
86 | unsigned long alarm; | |
87 | struct rtc_wkalrm alm; | |
88 | ||
89 | /* Don't show disabled alarms; but the RTC could leave the | |
90 | * alarm enabled after it's already triggered. Alarms are | |
91 | * conceptually one-shot, even though some common hardware | |
92 | * (PCs) doesn't actually work that way. | |
93 | * | |
94 | * REVISIT maybe we should require RTC implementations to | |
95 | * disable the RTC alarm after it triggers, for uniformity. | |
96 | */ | |
97 | retval = rtc_read_alarm(dev, &alm); | |
98 | if (retval == 0 && alm.enabled) { | |
99 | rtc_tm_to_time(&alm.time, &alarm); | |
100 | retval = sprintf(buf, "%lu\n", alarm); | |
101 | } | |
102 | ||
103 | return retval; | |
104 | } | |
105 | ||
106 | static ssize_t | |
107 | rtc_sysfs_set_wakealarm(struct class_device *dev, const char *buf, size_t n) | |
108 | { | |
109 | ssize_t retval; | |
110 | unsigned long now, alarm; | |
111 | struct rtc_wkalrm alm; | |
112 | ||
113 | /* Only request alarms that trigger in the future. Disable them | |
114 | * by writing another time, e.g. 0 meaning Jan 1 1970 UTC. | |
115 | */ | |
116 | retval = rtc_read_time(dev, &alm.time); | |
117 | if (retval < 0) | |
118 | return retval; | |
119 | rtc_tm_to_time(&alm.time, &now); | |
120 | ||
121 | alarm = simple_strtoul(buf, NULL, 0); | |
122 | if (alarm > now) { | |
123 | /* Avoid accidentally clobbering active alarms; we can't | |
124 | * entirely prevent that here, without even the minimal | |
125 | * locking from the /dev/rtcN api. | |
126 | */ | |
127 | retval = rtc_read_alarm(dev, &alm); | |
128 | if (retval < 0) | |
129 | return retval; | |
130 | if (alm.enabled) | |
131 | return -EBUSY; | |
132 | ||
133 | alm.enabled = 1; | |
134 | } else { | |
135 | alm.enabled = 0; | |
136 | ||
137 | /* Provide a valid future alarm time. Linux isn't EFI, | |
138 | * this time won't be ignored when disabling the alarm. | |
139 | */ | |
140 | alarm = now + 300; | |
141 | } | |
142 | rtc_time_to_tm(alarm, &alm.time); | |
143 | ||
144 | retval = rtc_set_alarm(dev, &alm); | |
145 | return (retval < 0) ? retval : n; | |
146 | } | |
147 | static const CLASS_DEVICE_ATTR(wakealarm, S_IRUGO | S_IWUSR, | |
148 | rtc_sysfs_show_wakealarm, rtc_sysfs_set_wakealarm); | |
149 | ||
150 | ||
151 | /* The reason to trigger an alarm with no process watching it (via sysfs) | |
152 | * is its side effect: waking from a system state like suspend-to-RAM or | |
153 | * suspend-to-disk. So: no attribute unless that side effect is possible. | |
154 | * (Userspace may disable that mechanism later.) | |
155 | */ | |
156 | static inline int rtc_does_wakealarm(struct class_device *class_dev) | |
157 | { | |
158 | struct rtc_device *rtc; | |
159 | ||
160 | if (!device_can_wakeup(class_dev->dev)) | |
161 | return 0; | |
162 | rtc = to_rtc_device(class_dev); | |
163 | return rtc->ops->set_alarm != NULL; | |
164 | } | |
165 | ||
166 | ||
a8d814b5 | 167 | static int rtc_sysfs_add_device(struct class_device *class_dev, |
c5c3e192 AZ |
168 | struct class_interface *class_intf) |
169 | { | |
170 | int err; | |
171 | ||
5a6534e4 | 172 | dev_dbg(class_dev->dev, "rtc intf: sysfs\n"); |
c5c3e192 AZ |
173 | |
174 | err = sysfs_create_group(&class_dev->kobj, &rtc_attr_group); | |
175 | if (err) | |
3925a5ce DB |
176 | dev_err(class_dev->dev, "failed to create %s\n", |
177 | "sysfs attributes"); | |
178 | else if (rtc_does_wakealarm(class_dev)) { | |
179 | /* not all RTCs support both alarms and wakeup */ | |
180 | err = class_device_create_file(class_dev, | |
181 | &class_device_attr_wakealarm); | |
182 | if (err) { | |
183 | dev_err(class_dev->dev, "failed to create %s\n", | |
184 | "alarm attribute"); | |
185 | sysfs_remove_group(&class_dev->kobj, &rtc_attr_group); | |
186 | } | |
187 | } | |
c5c3e192 AZ |
188 | |
189 | return err; | |
190 | } | |
191 | ||
192 | static void rtc_sysfs_remove_device(struct class_device *class_dev, | |
193 | struct class_interface *class_intf) | |
194 | { | |
3925a5ce DB |
195 | if (rtc_does_wakealarm(class_dev)) |
196 | class_device_remove_file(class_dev, | |
197 | &class_device_attr_wakealarm); | |
c5c3e192 AZ |
198 | sysfs_remove_group(&class_dev->kobj, &rtc_attr_group); |
199 | } | |
200 | ||
201 | /* interface registration */ | |
202 | ||
203 | static struct class_interface rtc_sysfs_interface = { | |
204 | .add = &rtc_sysfs_add_device, | |
205 | .remove = &rtc_sysfs_remove_device, | |
206 | }; | |
207 | ||
208 | static int __init rtc_sysfs_init(void) | |
209 | { | |
210 | return rtc_interface_register(&rtc_sysfs_interface); | |
211 | } | |
212 | ||
213 | static void __exit rtc_sysfs_exit(void) | |
214 | { | |
215 | class_interface_unregister(&rtc_sysfs_interface); | |
216 | } | |
217 | ||
4e9011d5 | 218 | subsys_initcall(rtc_sysfs_init); |
c5c3e192 AZ |
219 | module_exit(rtc_sysfs_exit); |
220 | ||
221 | MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>"); | |
222 | MODULE_DESCRIPTION("RTC class sysfs interface"); | |
223 | MODULE_LICENSE("GPL"); |