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authorLinus Torvalds <torvalds@linux-foundation.org>2011-02-18 14:20:46 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2011-02-18 14:20:46 -0800
commit0cc9d5257857608ba85885b75fcada13d359b5d1 (patch)
treec36289844c623f2a3026f629d47cee793fb535ff /drivers/rtc
parent4c3021da451fe0ea1deaba8fa3805d8d065ec84e (diff)
parent456d66ecd09e3bc326b93174745faafb6ac378d6 (diff)
downloadlinux-2.6.38-lt-ux500-0cc9d5257857608ba85885b75fcada13d359b5d1.tar.gz
Merge branch 'rtc-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'rtc-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: RTC: Re-enable UIE timer/polling emulation RTC: Revert UIE emulation removal RTC: Release mutex in error path of rtc_alarm_irq_enable
Diffstat (limited to 'drivers/rtc')
-rw-r--r--drivers/rtc/Kconfig12
-rw-r--r--drivers/rtc/interface.c23
-rw-r--r--drivers/rtc/rtc-dev.c104
3 files changed, 135 insertions, 4 deletions
diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
index cdd97192dc6..4941cade319 100644
--- a/drivers/rtc/Kconfig
+++ b/drivers/rtc/Kconfig
@@ -97,6 +97,18 @@ config RTC_INTF_DEV
If unsure, say Y.
+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 underlying rtc chip
+ driver does not expose RTC_UIE ioctls. Those requests generate
+ once-per-second update interrupts, used for synchronization.
+
+ The emulation code will read the time from the hardware
+ clock several times per second, please enable this option
+ only if you know that you really need it.
+
config RTC_DRV_TEST
tristate "Test driver/device"
help
diff --git a/drivers/rtc/interface.c b/drivers/rtc/interface.c
index a0c01967244..cb2f0728fd7 100644
--- a/drivers/rtc/interface.c
+++ b/drivers/rtc/interface.c
@@ -209,9 +209,8 @@ int rtc_alarm_irq_enable(struct rtc_device *rtc, unsigned int enabled)
}
if (err)
- return err;
-
- if (!rtc->ops)
+ /* nothing */;
+ else if (!rtc->ops)
err = -ENODEV;
else if (!rtc->ops->alarm_irq_enable)
err = -EINVAL;
@@ -229,6 +228,12 @@ int rtc_update_irq_enable(struct rtc_device *rtc, unsigned int enabled)
if (err)
return err;
+#ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
+ if (enabled == 0 && rtc->uie_irq_active) {
+ mutex_unlock(&rtc->ops_lock);
+ return rtc_dev_update_irq_enable_emul(rtc, 0);
+ }
+#endif
/* make sure we're changing state */
if (rtc->uie_rtctimer.enabled == enabled)
goto out;
@@ -248,6 +253,16 @@ int rtc_update_irq_enable(struct rtc_device *rtc, unsigned int enabled)
out:
mutex_unlock(&rtc->ops_lock);
+#ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
+ /*
+ * Enable emulation if the driver did not provide
+ * the update_irq_enable function pointer or if returned
+ * -EINVAL to signal that it has been configured without
+ * interrupts or that are not available at the moment.
+ */
+ if (err == -EINVAL)
+ err = rtc_dev_update_irq_enable_emul(rtc, enabled);
+#endif
return err;
}
@@ -263,7 +278,7 @@ EXPORT_SYMBOL_GPL(rtc_update_irq_enable);
*
* Triggers the registered irq_task function callback.
*/
-static void rtc_handle_legacy_irq(struct rtc_device *rtc, int num, int mode)
+void rtc_handle_legacy_irq(struct rtc_device *rtc, int num, int mode)
{
unsigned long flags;
diff --git a/drivers/rtc/rtc-dev.c b/drivers/rtc/rtc-dev.c
index 37c3cc1b3dd..d0e06edb14c 100644
--- a/drivers/rtc/rtc-dev.c
+++ b/drivers/rtc/rtc-dev.c
@@ -46,6 +46,105 @@ 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(struct work_struct *work)
+{
+ struct rtc_device *rtc =
+ container_of(work, struct rtc_device, uie_task);
+ struct rtc_time tm;
+ int num = 0;
+ int err;
+
+ err = rtc_read_time(rtc, &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_handle_legacy_irq(rtc, num, RTC_UF);
+}
+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 int clear_uie(struct rtc_device *rtc)
+{
+ spin_lock_irq(&rtc->irq_lock);
+ if (rtc->uie_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->uie_irq_active = 0;
+ }
+ spin_unlock_irq(&rtc->irq_lock);
+ return 0;
+}
+
+static int set_uie(struct rtc_device *rtc)
+{
+ struct rtc_time tm;
+ int err;
+
+ err = rtc_read_time(rtc, &tm);
+ if (err)
+ return err;
+ spin_lock_irq(&rtc->irq_lock);
+ if (!rtc->uie_irq_active) {
+ rtc->uie_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;
+}
+
+int rtc_dev_update_irq_enable_emul(struct rtc_device *rtc, unsigned int enabled)
+{
+ if (enabled)
+ return set_uie(rtc);
+ else
+ return clear_uie(rtc);
+}
+EXPORT_SYMBOL(rtc_dev_update_irq_enable_emul);
+
+#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)
@@ -387,6 +486,11 @@ void rtc_dev_prepare(struct rtc_device *rtc)
rtc->dev.devt = MKDEV(MAJOR(rtc_devt), rtc->id);
+#ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
+ INIT_WORK(&rtc->uie_task, rtc_uie_task);
+ 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;
}