/* * RTC subsystem, base class * * Copyright (C) 2005 Tower Technologies * Author: Alessandro Zummo <a.zummo@towertech.it> * * class skeleton from drivers/hwmon/hwmon.c * * 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 <linux/module.h> #include <linux/rtc.h> #include <linux/kdev_t.h> #include <linux/idr.h> #include "rtc-core.h" static DEFINE_IDR(rtc_idr); static DEFINE_MUTEX(idr_lock); struct class *rtc_class; static void rtc_device_release(struct device *dev) { struct rtc_device *rtc = to_rtc_device(dev); mutex_lock(&idr_lock); idr_remove(&rtc_idr, rtc->id); mutex_unlock(&idr_lock); kfree(rtc); } #if defined(CONFIG_PM) && defined(CONFIG_RTC_HCTOSYS_DEVICE) /* * On suspend(), measure the delta between one RTC and the * system's wall clock; restore it on resume(). */ static struct timespec delta; static time_t oldtime; static int rtc_suspend(struct device *dev, pm_message_t mesg) { struct rtc_device *rtc = to_rtc_device(dev); struct rtc_time tm; struct timespec ts = current_kernel_time(); if (strncmp(rtc->dev.bus_id, CONFIG_RTC_HCTOSYS_DEVICE, BUS_ID_SIZE) != 0) return 0; rtc_read_time(rtc, &tm); rtc_tm_to_time(&tm, &oldtime); /* RTC precision is 1 second; adjust delta for avg 1/2 sec err */ set_normalized_timespec(&delta, ts.tv_sec - oldtime, ts.tv_nsec - (NSEC_PER_SEC >> 1)); return 0; } static int rtc_resume(struct device *dev) { struct rtc_device *rtc = to_rtc_device(dev); struct rtc_time tm; time_t newtime; struct timespec time; if (strncmp(rtc->dev.bus_id, CONFIG_RTC_HCTOSYS_DEVICE, BUS_ID_SIZE) != 0) return 0; rtc_read_time(rtc, &tm); if (rtc_valid_tm(&tm) != 0) { pr_debug("%s: bogus resume time\n", rtc->dev.bus_id); return 0; } rtc_tm_to_time(&tm, &newtime); if (newtime <= oldtime) { if (newtime < oldtime) pr_debug("%s: time travel!\n", rtc->dev.bus_id); return 0; } /* restore wall clock using delta against this RTC; * adjust again for avg 1/2 second RTC sampling error */ set_normalized_timespec(&time, newtime + delta.tv_sec, (NSEC_PER_SEC >> 1) + delta.tv_nsec); do_settimeofday(&time); return 0; } #else #define rtc_suspend NULL #define rtc_resume NULL #endif /** * rtc_device_register - register w/ RTC class * @dev: the device to register * * rtc_device_unregister() must be called when the class device is no * longer needed. * * Returns the pointer to the new struct class device. */ struct rtc_device *rtc_device_register(const char *name, struct device *dev, const struct rtc_class_ops *ops, struct module *owner) { struct rtc_device *rtc; int id, err; if (idr_pre_get(&rtc_idr, GFP_KERNEL) == 0) { err = -ENOMEM; goto exit; } mutex_lock(&idr_lock); err = idr_get_new(&rtc_idr, NULL, &id); mutex_unlock(&idr_lock); if (err < 0) goto exit; id = id & MAX_ID_MASK; rtc = kzalloc(sizeof(struct rtc_device), GFP_KERNEL); if (rtc == NULL) { err = -ENOMEM; goto exit_idr; } rtc->id = id; rtc->ops = ops; rtc->owner = owner; rtc->max_user_freq = 64; rtc->dev.parent = dev; rtc->dev.class = rtc_class; rtc->dev.release = rtc_device_release; mutex_init(&rtc->ops_lock); spin_lock_init(&rtc->irq_lock); spin_lock_init(&rtc->irq_task_lock); init_waitqueue_head(&rtc->irq_queue); strlcpy(rtc->name, name, RTC_DEVICE_NAME_SIZE); snprintf(rtc->dev.bus_id, BUS_ID_SIZE, "rtc%d", id); rtc_dev_prepare(rtc); err = device_register(&rtc->dev); if (err) goto exit_kfree; rtc_dev_add_device(rtc); rtc_sysfs_add_device(rtc); rtc_proc_add_device(rtc); dev_info(dev, "rtc core: registered %s as %s\n", rtc->name, rtc->dev.bus_id); return rtc; exit_kfree: kfree(rtc); exit_idr: mutex_lock(&idr_lock); idr_remove(&rtc_idr, id); mutex_unlock(&idr_lock); exit: dev_err(dev, "rtc core: unable to register %s, err = %d\n", name, err); return ERR_PTR(err); } EXPORT_SYMBOL_GPL(rtc_device_register); /** * rtc_device_unregister - removes the previously registered RTC class device * * @rtc: the RTC class device to destroy */ void rtc_device_unregister(struct rtc_device *rtc) { if (get_device(&rtc->dev) != NULL) { mutex_lock(&rtc->ops_lock); /* remove innards of this RTC, then disable it, before * letting any rtc_class_open() users access it again */ rtc_sysfs_del_device(rtc); rtc_dev_del_device(rtc); rtc_proc_del_device(rtc); device_unregister(&rtc->dev); rtc->ops = NULL; mutex_unlock(&rtc->ops_lock); put_device(&rtc->dev); } } EXPORT_SYMBOL_GPL(rtc_device_unregister); static int __init rtc_init(void) { rtc_class = class_create(THIS_MODULE, "rtc"); if (IS_ERR(rtc_class)) { printk(KERN_ERR "%s: couldn't create class\n", __FILE__); return PTR_ERR(rtc_class); } rtc_class->suspend = rtc_suspend; rtc_class->resume = rtc_resume; rtc_dev_init(); rtc_sysfs_init(rtc_class); return 0; } static void __exit rtc_exit(void) { rtc_dev_exit(); class_destroy(rtc_class); } subsys_initcall(rtc_init); module_exit(rtc_exit); MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>"); MODULE_DESCRIPTION("RTC class support"); MODULE_LICENSE("GPL");