/* * 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.*/ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt #include <linux/module.h>#include <linux/of.h>#include <linux/rtc.h>#include <linux/kdev_t.h>#include <linux/idr.h>#include <linux/slab.h>#include <linux/workqueue.h> #include "rtc-core.h"  static DEFINE_IDA(rtc_ida);struct class *rtc_class; static void rtc_device_release(struct device *dev){	struct rtc_device *rtc = to_rtc_device(dev);	ida_simple_remove(&rtc_ida, rtc->id);	kfree(rtc);} #ifdef CONFIG_RTC_HCTOSYS_DEVICE/* Result of the last RTC to system clock attempt. */int rtc_hctosys_ret = -ENODEV;#endif #if defined(CONFIG_PM_SLEEP) && 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 old_rtc, old_system, old_delta;  static int rtc_suspend(struct device *dev){	struct rtc_device	*rtc = to_rtc_device(dev);	struct rtc_time		tm;	struct timespec		delta, delta_delta;	int err; 	if (has_persistent_clock())		return 0; 	if (strcmp(dev_name(&rtc->dev), CONFIG_RTC_HCTOSYS_DEVICE) != 0)		return 0; 	/* snapshot the current RTC and system time at suspend*/	err = rtc_read_time(rtc, &tm);	if (err < 0) {		pr_debug("%s:  fail to read rtc time\n", dev_name(&rtc->dev));		return 0;	} 	getnstimeofday(&old_system);	rtc_tm_to_time(&tm, &old_rtc.tv_sec);  	/*	 * To avoid drift caused by repeated suspend/resumes,	 * which each can add ~1 second drift error,	 * try to compensate so the difference in system time	 * and rtc time stays close to constant.	 */	delta = timespec_sub(old_system, old_rtc);	delta_delta = timespec_sub(delta, old_delta);	if (delta_delta.tv_sec < -2 || delta_delta.tv_sec >= 2) {		/*		 * if delta_delta is too large, assume time correction		 * has occured and set old_delta to the current delta.		 */		old_delta = delta;	} else {		/* Otherwise try to adjust old_system to compensate */		old_system = timespec_sub(old_system, delta_delta);	} 	return 0;} static int rtc_resume(struct device *dev){	struct rtc_device	*rtc = to_rtc_device(dev);	struct rtc_time		tm;	struct timespec		new_system, new_rtc;	struct timespec		sleep_time;	int err; 	if (has_persistent_clock())		return 0; 	rtc_hctosys_ret = -ENODEV;	if (strcmp(dev_name(&rtc->dev), CONFIG_RTC_HCTOSYS_DEVICE) != 0)		return 0; 	/* snapshot the current rtc and system time at resume */	getnstimeofday(&new_system);	err = rtc_read_time(rtc, &tm);	if (err < 0) {		pr_debug("%s:  fail to read rtc time\n", dev_name(&rtc->dev));		return 0;	} 	if (rtc_valid_tm(&tm) != 0) {		pr_debug("%s:  bogus resume time\n", dev_name(&rtc->dev));		return 0;	}	rtc_tm_to_time(&tm, &new_rtc.tv_sec);	new_rtc.tv_nsec = 0; 	if (new_rtc.tv_sec < old_rtc.tv_sec) {		pr_debug("%s:  time travel!\n", dev_name(&rtc->dev));		return 0;	} 	/* calculate the RTC time delta (sleep time)*/	sleep_time = timespec_sub(new_rtc, old_rtc); 	/*	 * Since these RTC suspend/resume handlers are not called	 * at the very end of suspend or the start of resume,	 * some run-time may pass on either sides of the sleep time	 * so subtract kernel run-time between rtc_suspend to rtc_resume	 * to keep things accurate.	 */	sleep_time = timespec_sub(sleep_time,			timespec_sub(new_system, old_system)); 	if (sleep_time.tv_sec >= 0)		timekeeping_inject_sleeptime(&sleep_time);	rtc_hctosys_ret = 0;	return 0;} static SIMPLE_DEV_PM_OPS(rtc_class_dev_pm_ops, rtc_suspend, rtc_resume);#define RTC_CLASS_DEV_PM_OPS	(&rtc_class_dev_pm_ops)#else#define RTC_CLASS_DEV_PM_OPS	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;	struct rtc_wkalrm alrm;	int of_id = -1, id = -1, err; 	if (dev->of_node)		of_id = of_alias_get_id(dev->of_node, "rtc");	else if (dev->parent && dev->parent->of_node)		of_id = of_alias_get_id(dev->parent->of_node, "rtc"); 	if (of_id >= 0) {		id = ida_simple_get(&rtc_ida, of_id, of_id + 1,				    GFP_KERNEL);		if (id < 0)			dev_warn(dev, "/aliases ID %d not available\n",				    of_id);	} 	if (id < 0) {		id = ida_simple_get(&rtc_ida, 0, 0, GFP_KERNEL);		if (id < 0) {			err = id;			goto exit;		}	} 	rtc = kzalloc(sizeof(struct rtc_device), GFP_KERNEL);	if (rtc == NULL) {		err = -ENOMEM;		goto exit_ida;	} 	rtc->id = id;	rtc->ops = ops;	rtc->owner = owner;	rtc->irq_freq = 1;	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); 	/* Init timerqueue */	timerqueue_init_head(&rtc->timerqueue);	INIT_WORK(&rtc->irqwork, rtc_timer_do_work);	/* Init aie timer */	rtc_timer_init(&rtc->aie_timer, rtc_aie_update_irq, (void *)rtc);	/* Init uie timer */	rtc_timer_init(&rtc->uie_rtctimer, rtc_uie_update_irq, (void *)rtc);	/* Init pie timer */	hrtimer_init(&rtc->pie_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);	rtc->pie_timer.function = rtc_pie_update_irq;	rtc->pie_enabled = 0; 	/* Check to see if there is an ALARM already set in hw */	err = __rtc_read_alarm(rtc, &alrm); 	if (!err && !rtc_valid_tm(&alrm.time))		rtc_initialize_alarm(rtc, &alrm); 	strlcpy(rtc->name, name, RTC_DEVICE_NAME_SIZE);	dev_set_name(&rtc->dev, "rtc%d", id); 	rtc_dev_prepare(rtc); 	err = device_register(&rtc->dev);	if (err) {		put_device(&rtc->dev);		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, dev_name(&rtc->dev)); 	return rtc; exit_kfree:	kfree(rtc); exit_ida:	ida_simple_remove(&rtc_ida, id); 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 void devm_rtc_device_release(struct device *dev, void *res){	struct rtc_device *rtc = *(struct rtc_device **)res; 	rtc_device_unregister(rtc);} static int devm_rtc_device_match(struct device *dev, void *res, void *data){	struct rtc **r = res; 	return *r == data;} /** * devm_rtc_device_register - resource managed rtc_device_register() * @dev: the device to register * @name: the name of the device * @ops: the rtc operations structure * @owner: the module owner * * @return a struct rtc on success, or an ERR_PTR on error * * Managed rtc_device_register(). The rtc_device returned from this function * are automatically freed on driver detach. See rtc_device_register() * for more information. */ struct rtc_device *devm_rtc_device_register(struct device *dev,					const char *name,					const struct rtc_class_ops *ops,					struct module *owner){	struct rtc_device **ptr, *rtc; 	ptr = devres_alloc(devm_rtc_device_release, sizeof(*ptr), GFP_KERNEL);	if (!ptr)		return ERR_PTR(-ENOMEM); 	rtc = rtc_device_register(name, dev, ops, owner);	if (!IS_ERR(rtc)) {		*ptr = rtc;		devres_add(dev, ptr);	} else {		devres_free(ptr);	} 	return rtc;}EXPORT_SYMBOL_GPL(devm_rtc_device_register); /** * devm_rtc_device_unregister - resource managed devm_rtc_device_unregister() * @dev: the device to unregister * @rtc: the RTC class device to unregister * * Deallocated a rtc allocated with devm_rtc_device_register(). Normally this * function will not need to be called and the resource management code will * ensure that the resource is freed. */void devm_rtc_device_unregister(struct device *dev, struct rtc_device *rtc){	int rc; 	rc = devres_release(dev, devm_rtc_device_release,				devm_rtc_device_match, rtc);	WARN_ON(rc);}EXPORT_SYMBOL_GPL(devm_rtc_device_unregister); static int __init rtc_init(void){	rtc_class = class_create(THIS_MODULE, "rtc");	if (IS_ERR(rtc_class)) {		pr_err("couldn't create class\n");		return PTR_ERR(rtc_class);	}	rtc_class->pm = RTC_CLASS_DEV_PM_OPS;	rtc_dev_init();	rtc_sysfs_init(rtc_class);	return 0;} static void __exit rtc_exit(void){	rtc_dev_exit();	class_destroy(rtc_class);	ida_destroy(&rtc_ida);} subsys_initcall(rtc_init);module_exit(rtc_exit); MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>");MODULE_DESCRIPTION("RTC class support");MODULE_LICENSE("GPL");