/* * RTC subsystem, sysfs interface * * Copyright (C) 2005 Tower Technologies * Author: Alessandro Zummo * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. */ #include #include /* device attributes */ static ssize_t rtc_sysfs_show_name(struct class_device *dev, char *buf) { return sprintf(buf, "%s\n", to_rtc_device(dev)->name); } static CLASS_DEVICE_ATTR(name, S_IRUGO, rtc_sysfs_show_name, NULL); static ssize_t rtc_sysfs_show_date(struct class_device *dev, char *buf) { ssize_t retval; struct rtc_time tm; retval = rtc_read_time(dev, &tm); if (retval == 0) { retval = sprintf(buf, "%04d-%02d-%02d\n", tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday); } return retval; } static CLASS_DEVICE_ATTR(date, S_IRUGO, rtc_sysfs_show_date, NULL); static ssize_t rtc_sysfs_show_time(struct class_device *dev, char *buf) { ssize_t retval; struct rtc_time tm; retval = rtc_read_time(dev, &tm); if (retval == 0) { retval = sprintf(buf, "%02d:%02d:%02d\n", tm.tm_hour, tm.tm_min, tm.tm_sec); } return retval; } static CLASS_DEVICE_ATTR(time, S_IRUGO, rtc_sysfs_show_time, NULL); static ssize_t rtc_sysfs_show_since_epoch(struct class_device *dev, char *buf) { ssize_t retval; struct rtc_time tm; retval = rtc_read_time(dev, &tm); if (retval == 0) { unsigned long time; rtc_tm_to_time(&tm, &time); retval = sprintf(buf, "%lu\n", time); } return retval; } static CLASS_DEVICE_ATTR(since_epoch, S_IRUGO, rtc_sysfs_show_since_epoch, NULL); static struct attribute *rtc_attrs[] = { &class_device_attr_name.attr, &class_device_attr_date.attr, &class_device_attr_time.attr, &class_device_attr_since_epoch.attr, NULL, }; static struct attribute_group rtc_attr_group = { .attrs = rtc_attrs, }; static ssize_t rtc_sysfs_show_wakealarm(struct class_device *dev, char *buf) { ssize_t retval; unsigned long alarm; struct rtc_wkalrm alm; /* Don't show disabled alarms; but the RTC could leave the * alarm enabled after it's already triggered. Alarms are * conceptually one-shot, even though some common hardware * (PCs) doesn't actually work that way. * * REVISIT maybe we should require RTC implementations to * disable the RTC alarm after it triggers, for uniformity. */ retval = rtc_read_alarm(dev, &alm); if (retval == 0 && alm.enabled) { rtc_tm_to_time(&alm.time, &alarm); retval = sprintf(buf, "%lu\n", alarm); } return retval; } static ssize_t rtc_sysfs_set_wakealarm(struct class_device *dev, const char *buf, size_t n) { ssize_t retval; unsigned long now, alarm; struct rtc_wkalrm alm; /* Only request alarms that trigger in the future. Disable them * by writing another time, e.g. 0 meaning Jan 1 1970 UTC. */ retval = rtc_read_time(dev, &alm.time); if (retval < 0) return retval; rtc_tm_to_time(&alm.time, &now); alarm = simple_strtoul(buf, NULL, 0); if (alarm > now) { /* Avoid accidentally clobbering active alarms; we can't * entirely prevent that here, without even the minimal * locking from the /dev/rtcN api. */ retval = rtc_read_alarm(dev, &alm); if (retval < 0) return retval; if (alm.enabled) return -EBUSY; alm.enabled = 1; } else { alm.enabled = 0; /* Provide a valid future alarm time. Linux isn't EFI, * this time won't be ignored when disabling the alarm. */ alarm = now + 300; } rtc_time_to_tm(alarm, &alm.time); retval = rtc_set_alarm(dev, &alm); return (retval < 0) ? retval : n; } static const CLASS_DEVICE_ATTR(wakealarm, S_IRUGO | S_IWUSR, rtc_sysfs_show_wakealarm, rtc_sysfs_set_wakealarm); /* The reason to trigger an alarm with no process watching it (via sysfs) * is its side effect: waking from a system state like suspend-to-RAM or * suspend-to-disk. So: no attribute unless that side effect is possible. * (Userspace may disable that mechanism later.) */ static inline int rtc_does_wakealarm(struct class_device *class_dev) { struct rtc_device *rtc; if (!device_can_wakeup(class_dev->dev)) return 0; rtc = to_rtc_device(class_dev); return rtc->ops->set_alarm != NULL; } static int rtc_sysfs_add_device(struct class_device *class_dev, struct class_interface *class_intf) { int err; dev_dbg(class_dev->dev, "rtc intf: sysfs\n"); err = sysfs_create_group(&class_dev->kobj, &rtc_attr_group); if (err) dev_err(class_dev->dev, "failed to create %s\n", "sysfs attributes"); else if (rtc_does_wakealarm(class_dev)) { /* not all RTCs support both alarms and wakeup */ err = class_device_create_file(class_dev, &class_device_attr_wakealarm); if (err) { dev_err(class_dev->dev, "failed to create %s\n", "alarm attribute"); sysfs_remove_group(&class_dev->kobj, &rtc_attr_group); } } return err; } static void rtc_sysfs_remove_device(struct class_device *class_dev, struct class_interface *class_intf) { if (rtc_does_wakealarm(class_dev)) class_device_remove_file(class_dev, &class_device_attr_wakealarm); sysfs_remove_group(&class_dev->kobj, &rtc_attr_group); } /* interface registration */ static struct class_interface rtc_sysfs_interface = { .add = &rtc_sysfs_add_device, .remove = &rtc_sysfs_remove_device, }; static int __init rtc_sysfs_init(void) { return rtc_interface_register(&rtc_sysfs_interface); } static void __exit rtc_sysfs_exit(void) { class_interface_unregister(&rtc_sysfs_interface); } subsys_initcall(rtc_sysfs_init); module_exit(rtc_sysfs_exit); MODULE_AUTHOR("Alessandro Zummo "); MODULE_DESCRIPTION("RTC class sysfs interface"); MODULE_LICENSE("GPL");