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Commit 655066c3 authored by Atsushi Nemoto's avatar Atsushi Nemoto Committed by Linus Torvalds
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[PATCH] RTC: rtc-dev UIE emulation 



Import genrtc's RTC UIE emulation (CONFIG_GEN_RTC_X) to rtc-dev driver with
slight adjustments/refinements.  This makes UIE-less rtc drivers work
better with programs doing read/poll on /dev/rtc, such as hwclock.  This
emulation should not harm rtc drivers with UIE support, since
rtc_dev_ioctl() calls underlaying rtc driver's ioctl() first.

Signed-off-by: default avatarAtsushi Nemoto <anemo@mba.ocn.ne.jp>
Acked-by: default avatarAlessandro Zummo <a.zummo@towertech.it>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 1abb0dc9

drivers/rtc/Kconfig

+7 −0
Original line number Diff line number Diff line
@@ -73,6 +73,13 @@ config RTC_INTF_DEV 
	  This driver can also be built as a module. If so, the module

	  will be called rtc-dev.



config RTC_INTF_DEV_UIE_EMUL

	bool "RTC UIE emulation on dev interface"

	depends on RTC_INTF_DEV

	help

	  Provides an emulation for RTC_UIE if the underlaying rtc chip

	  driver did not provide RTC_UIE ioctls.



comment "RTC drivers"

	depends on RTC_CLASS

drivers/rtc/rtc-dev.c

+102 −0
Original line number Diff line number Diff line
@@ -48,6 +48,93 @@ static int rtc_dev_open(struct inode *inode, struct file *file) 
	return err;

}



#ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL

/*

 * Routine to poll RTC seconds field for change as often as possible,

 * after first RTC_UIE use timer to reduce polling

 */

static void rtc_uie_task(void *data)

{

	struct rtc_device *rtc = data;

	struct rtc_time tm;

	int num = 0;

	int err;



	err = rtc_read_time(&rtc->class_dev, &tm);

	spin_lock_irq(&rtc->irq_lock);

	if (rtc->stop_uie_polling || err) {

		rtc->uie_task_active = 0;

	} else if (rtc->oldsecs != tm.tm_sec) {

		num = (tm.tm_sec + 60 - rtc->oldsecs) % 60;

		rtc->oldsecs = tm.tm_sec;

		rtc->uie_timer.expires = jiffies + HZ - (HZ/10);

		rtc->uie_timer_active = 1;

		rtc->uie_task_active = 0;

		add_timer(&rtc->uie_timer);

	} else if (schedule_work(&rtc->uie_task) == 0) {

		rtc->uie_task_active = 0;

	}

	spin_unlock_irq(&rtc->irq_lock);

	if (num)

		rtc_update_irq(&rtc->class_dev, num, RTC_UF | RTC_IRQF);

}



static void rtc_uie_timer(unsigned long data)

{

	struct rtc_device *rtc = (struct rtc_device *)data;

	unsigned long flags;



	spin_lock_irqsave(&rtc->irq_lock, flags);

	rtc->uie_timer_active = 0;

	rtc->uie_task_active = 1;

	if ((schedule_work(&rtc->uie_task) == 0))

		rtc->uie_task_active = 0;

	spin_unlock_irqrestore(&rtc->irq_lock, flags);

}



static void clear_uie(struct rtc_device *rtc)

{

	spin_lock_irq(&rtc->irq_lock);

	if (rtc->irq_active) {

		rtc->stop_uie_polling = 1;

		if (rtc->uie_timer_active) {

			spin_unlock_irq(&rtc->irq_lock);

			del_timer_sync(&rtc->uie_timer);

			spin_lock_irq(&rtc->irq_lock);

			rtc->uie_timer_active = 0;

		}

		if (rtc->uie_task_active) {

			spin_unlock_irq(&rtc->irq_lock);

			flush_scheduled_work();

			spin_lock_irq(&rtc->irq_lock);

		}

		rtc->irq_active = 0;

	}

	spin_unlock_irq(&rtc->irq_lock);

}



static int set_uie(struct rtc_device *rtc)

{

	struct rtc_time tm;

	int err;



	err = rtc_read_time(&rtc->class_dev, &tm);

	if (err)

		return err;

	spin_lock_irq(&rtc->irq_lock);

	if (!rtc->irq_active) {

		rtc->irq_active = 1;

		rtc->stop_uie_polling = 0;

		rtc->oldsecs = tm.tm_sec;

		rtc->uie_task_active = 1;

		if (schedule_work(&rtc->uie_task) == 0)

			rtc->uie_task_active = 0;

	}

	rtc->irq_data = 0;

	spin_unlock_irq(&rtc->irq_lock);

	return 0;

}

#endif /* CONFIG_RTC_INTF_DEV_UIE_EMUL */



static ssize_t

rtc_dev_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
@@ -232,6 +319,14 @@ static int rtc_dev_ioctl(struct inode *inode, struct file *file, 
			return -EFAULT;

		break;



#ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL

	case RTC_UIE_OFF:

		clear_uie(rtc);

		return 0;



	case RTC_UIE_ON:

		return set_uie(rtc);

#endif

	default:

		err = -ENOTTY;

		break;
@@ -244,6 +339,9 @@ static int rtc_dev_release(struct inode *inode, struct file *file) 
{

	struct rtc_device *rtc = to_rtc_device(file->private_data);



#ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL

	clear_uie(rtc);

#endif

	if (rtc->ops->release)

		rtc->ops->release(rtc->class_dev.dev);
@@ -284,6 +382,10 @@ static int rtc_dev_add_device(struct class_device *class_dev, 
	mutex_init(&rtc->char_lock);

	spin_lock_init(&rtc->irq_lock);

	init_waitqueue_head(&rtc->irq_queue);

#ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL

	INIT_WORK(&rtc->uie_task, rtc_uie_task, rtc);

	setup_timer(&rtc->uie_timer, rtc_uie_timer, (unsigned long)rtc);

#endif



	cdev_init(&rtc->char_dev, &rtc_dev_fops);

	rtc->char_dev.owner = rtc->owner;

include/linux/rtc.h

+10 −0
Original line number Diff line number Diff line
@@ -155,6 +155,16 @@ struct rtc_device 
	struct rtc_task *irq_task;

	spinlock_t irq_task_lock;

	int irq_freq;

#ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL

	struct work_struct uie_task;

	struct timer_list uie_timer;

	/* Those fields are protected by rtc->irq_lock */

	unsigned int oldsecs;

	unsigned int irq_active:1;

	unsigned int stop_uie_polling:1;

	unsigned int uie_task_active:1;

	unsigned int uie_timer_active:1;

#endif

};

#define to_rtc_device(d) container_of(d, struct rtc_device, class_dev)