RTC: Re-enable UIE timer/polling emulation

This patch re-enables UIE timer/polling emulation for rtc devices
that do not support alarm irqs.

CC: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
CC: Thomas Gleixner <tglx@linutronix.de>
Reported-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Tested-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: John Stultz <john.stultz@linaro.org>

3 files changed, 19 insertions, 2 deletions

diff --git a/drivers/rtc/interface.c b/drivers/rtc/interface.c
index 413ae0537915..cb2f0728fd70 100644
--- a/drivers/rtc/interface.c
+++ b/drivers/rtc/interface.c
@@ -228,6 +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;
@@ -247,6 +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;
 
 }
@@ -262,7 +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 dfa72c9c2687..d0e06edb14c5 100644
--- a/drivers/rtc/rtc-dev.c
+++ b/drivers/rtc/rtc-dev.c
@@ -76,7 +76,7 @@ static void rtc_uie_task(struct work_struct *work)
         }
         spin_unlock_irq(&rtc->irq_lock);
         if (num)
-                rtc_update_irq(rtc, num, RTC_UF | RTC_IRQF);
+                rtc_handle_legacy_irq(rtc, num, RTC_UF);
 }
 static void rtc_uie_timer(unsigned long data)
 {
diff --git a/include/linux/rtc.h b/include/linux/rtc.h
index 80408e711bed..89c3e5182991 100644
--- a/include/linux/rtc.h
+++ b/include/linux/rtc.h
@@ -250,6 +250,7 @@ extern int rtc_alarm_irq_enable(struct rtc_device *rtc, unsigned int enabled);
 extern int rtc_dev_update_irq_enable_emul(struct rtc_device *rtc,
                                                 unsigned int enabled);
 
+void rtc_handle_legacy_irq(struct rtc_device *rtc, int num, int mode);
 void rtc_aie_update_irq(void *private);
 void rtc_uie_update_irq(void *private);
 enum hrtimer_restart rtc_pie_update_irq(struct hrtimer *timer);