rtc: add alarm/update irq interfaces

Add standard interfaces for alarm/update irqs enabling.  Drivers are no
more required to implement equivalent ioctl code as rtc-dev will provide
it.

UIE emulation should now be handled correctly and will work even for those
RTC drivers who cannot be configured to do both UIE and AIE.

Signed-off-by: Alessandro Zummo <a.zummo@towertech.it>
Cc: David Brownell <david-b@pacbell.net>
Cc: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Cc: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

3 files changed, 94 insertions, 17 deletions

diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
index 123092d8a984..165a81843357 100644
--- a/drivers/rtc/Kconfig
+++ b/drivers/rtc/Kconfig
@@ -102,9 +102,13 @@ config RTC_INTF_DEV_UIE_EMUL
         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
+          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 a04c1b6b1575..fd2c652504ff 100644
--- a/drivers/rtc/interface.c
+++ b/drivers/rtc/interface.c
@@ -307,6 +307,60 @@ int rtc_set_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
 }
 EXPORT_SYMBOL_GPL(rtc_set_alarm);
 
+int rtc_alarm_irq_enable(struct rtc_device *rtc, unsigned int enabled)
+{
+        int err = mutex_lock_interruptible(&rtc->ops_lock);
+        if (err)
+                return err;
+
+        if (!rtc->ops)
+                err = -ENODEV;
+        else if (!rtc->ops->alarm_irq_enable)
+                err = -EINVAL;
+        else
+                err = rtc->ops->alarm_irq_enable(rtc->dev.parent, enabled);
+
+        mutex_unlock(&rtc->ops_lock);
+        return err;
+}
+EXPORT_SYMBOL_GPL(rtc_alarm_irq_enable);
+
+int rtc_update_irq_enable(struct rtc_device *rtc, unsigned int enabled)
+{
+        int err = mutex_lock_interruptible(&rtc->ops_lock);
+        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, enabled);
+        }
+#endif
+
+        if (!rtc->ops)
+                err = -ENODEV;
+        else if (!rtc->ops->update_irq_enable)
+                err = -EINVAL;
+        else
+                err = rtc->ops->update_irq_enable(rtc->dev.parent, enabled);
+
+        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;
+}
+EXPORT_SYMBOL_GPL(rtc_update_irq_enable);
+
 /**
  * rtc_update_irq - report RTC periodic, alarm, and/or update irqs
  * @rtc: the rtc device
diff --git a/drivers/rtc/rtc-dev.c b/drivers/rtc/rtc-dev.c
index ecdea44ae4e5..45152f4952d6 100644
--- a/drivers/rtc/rtc-dev.c
+++ b/drivers/rtc/rtc-dev.c
@@ -92,10 +92,10 @@ static void rtc_uie_timer(unsigned long data)
         spin_unlock_irqrestore(&rtc->irq_lock, flags);
 }
 
-static void clear_uie(struct rtc_device *rtc)
+static int clear_uie(struct rtc_device *rtc)
 {
         spin_lock_irq(&rtc->irq_lock);
-        if (rtc->irq_active) {
+        if (rtc->uie_irq_active) {
                 rtc->stop_uie_polling = 1;
                 if (rtc->uie_timer_active) {
                         spin_unlock_irq(&rtc->irq_lock);
@@ -108,9 +108,10 @@ static void clear_uie(struct rtc_device *rtc)
                         flush_scheduled_work();
                         spin_lock_irq(&rtc->irq_lock);
                 }
-                rtc->irq_active = 0;
+                rtc->uie_irq_active = 0;
         }
         spin_unlock_irq(&rtc->irq_lock);
+        return 0;
 }
 
 static int set_uie(struct rtc_device *rtc)
@@ -122,8 +123,8 @@ static int set_uie(struct rtc_device *rtc)
         if (err)
                 return err;
         spin_lock_irq(&rtc->irq_lock);
-        if (!rtc->irq_active) {
-                rtc->irq_active = 1;
+        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;
@@ -134,6 +135,16 @@ static int set_uie(struct rtc_device *rtc)
         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
@@ -357,6 +368,22 @@ static long rtc_dev_ioctl(struct file *file,
                 err = rtc_irq_set_state(rtc, NULL, 0);
                 break;
 
+        case RTC_AIE_ON:
+                mutex_unlock(&rtc->ops_lock);
+                return rtc_alarm_irq_enable(rtc, 1);
+
+        case RTC_AIE_OFF:
+                mutex_unlock(&rtc->ops_lock);
+                return rtc_alarm_irq_enable(rtc, 0);
+
+        case RTC_UIE_ON:
+                mutex_unlock(&rtc->ops_lock);
+                return rtc_update_irq_enable(rtc, 1);
+
+        case RTC_UIE_OFF:
+                mutex_unlock(&rtc->ops_lock);
+                return rtc_update_irq_enable(rtc, 0);
+
         case RTC_IRQP_SET:
                 err = rtc_irq_set_freq(rtc, NULL, arg);
                 break;
@@ -401,17 +428,6 @@ static long rtc_dev_ioctl(struct file *file,
                         err = -EFAULT;
                 return err;
 
-#ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
-        case RTC_UIE_OFF:
-                mutex_unlock(&rtc->ops_lock);
-                clear_uie(rtc);
-                return 0;
-
-        case RTC_UIE_ON:
-                mutex_unlock(&rtc->ops_lock);
-                err = set_uie(rtc);
-                return err;
-#endif
         default:
                 err = -ENOTTY;
                 break;
@@ -440,7 +456,10 @@ static int rtc_dev_release(struct inode *inode, struct file *file)
          * Leave the alarm alone; it may be set to trigger a system wakeup
          * later, or be used by kernel code, and is a one-shot event anyway.
          */
+
+        /* Keep ioctl until all drivers are converted */
         rtc_dev_ioctl(file, RTC_UIE_OFF, 0);
+        rtc_update_irq_enable(rtc, 0);
         rtc_irq_set_state(rtc, NULL, 0);
 
         if (rtc->ops->release)