rtc: file close() consistently disables repeating irqs

Make the rtc framework consistent about disabling 1/second update IRQs
that may have been activated through the /dev interface, when that /dev
file is closed.  (It may have closed because of coredump, etc.) This was
previously done only for emulated update IRQs ...  now, do it always.

Also comment the current policy: repeating IRQs (periodic, update) that
userspace enabled will be cleanly disabled, but alarms are left alone.
Such repeating IRQs are a constant and pointless system load.

Update some RTC drivers to remove now-needless release() methods.  Most
such methods just enforce that policy.  The others all seem to be buggy,
and mistreat in-kernel clients of periodic or alarm IRQs.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Acked-by: Andrew Sharp <andy.sharp@onstor.com>
Cc: Angelo Castello <angelo.castello@st.com>
Acked-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Acked-by: Paul Mundt <lethal@linux-sh.org>
Cc: Thomas Hommel <thomas.hommel@gefanuc.com>
Acked-by: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/rtc/rtc-ds1511.c

@@ -379,18 +379,6 @@ ds1511_interrupt(int irq, void *dev_id)
 	return IRQ_HANDLED;
 }
 
- static void
-ds1511_rtc_release(struct device *dev)
-{
-	struct platform_device *pdev = to_platform_device(dev);
-	struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
-
-	if (pdata->irq >= 0) {
-		pdata->irqen = 0;
-		ds1511_rtc_update_alarm(pdata);
-	}
-}
-
  static int
 ds1511_rtc_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
 {
@@ -428,7 +416,6 @@ static const struct rtc_class_ops ds1511_rtc_ops = {
 	.set_time	= ds1511_rtc_set_time,
 	.read_alarm	= ds1511_rtc_read_alarm,
 	.set_alarm	= ds1511_rtc_set_alarm,
-	.release	= ds1511_rtc_release,
 	.ioctl		= ds1511_rtc_ioctl,
 };