drivers/rtc/class.c - kernel/mindspeed - Git at Google

 /*
  * 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 <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);
 }

 #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 old_rtc, old_system, old_delta;


 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		delta, delta_delta;
 	if (strcmp(dev_name(&rtc->dev), CONFIG_RTC_HCTOSYS_DEVICE) != 0)
 		return 0;

 	/* snapshot the current RTC and system time at suspend*/
 	rtc_read_time(rtc, &tm);
 	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;

 	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);
 	rtc_read_time(rtc, &tm);
 	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);
 	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;
 	struct rtc_wkalrm alrm;
 	int id, err;

 	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 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);
 	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");
	/*
	* 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 <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);
	}

	#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 old_rtc, old_system, old_delta;


	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 delta, delta_delta;
	if (strcmp(dev_name(&rtc->dev), CONFIG_RTC_HCTOSYS_DEVICE) != 0)
	return 0;

	/* snapshot the current RTC and system time at suspend*/
	rtc_read_time(rtc, &tm);
	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;

	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);
	rtc_read_time(rtc, &tm);
	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);
	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;
	struct rtc_wkalrm alrm;
	int id, err;

	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 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);
	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");