[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: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Acked-by: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
index 9e24965..725d6b6 100644
--- a/drivers/rtc/Kconfig
+++ b/drivers/rtc/Kconfig
@@ -73,6 +73,13 @@
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
diff --git a/drivers/rtc/rtc-dev.c b/drivers/rtc/rtc-dev.c
index 2011567..07387c9 100644
--- a/drivers/rtc/rtc-dev.c
+++ b/drivers/rtc/rtc-dev.c
@@ -48,6 +48,93 @@
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 @@
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 @@
{
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 @@
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;