RTC: Revert UIE emulation removal

Uwe pointed out that my alarm based UIE emulation is not sufficient
to replace the older timer/polling based UIE emulation on devices
where there is no alarm irq. This causes rtc devices without alarms
to return -EINVAL to UIE ioctls. The fix is to re-instate the old
timer/polling method for devices without alarm irqs.

This patch reverts the following commits:
042620a018afcfba1d678062b62e46 - Remove UIE emulation
1daeddd5962acad1bea55e524fc0fa - Cleanup removed UIE emulation declaration
b5cc8ca1c9c3a37eaddf709b2fd3e1 - Remove Kconfig symbol for UIE emulation

The emulation mode will still need to be wired-in with a following
patch before it will work.

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>
Signed-off-by: John Stultz <john.stultz@linaro.org>

1 files changed, 14 insertions, 0 deletions

diff --git a/include/linux/rtc.h b/include/linux/rtc.h
index a0b639f8e805..80408e711bed 100644
--- a/include/linux/rtc.h
+++ b/include/linux/rtc.h
@@ -203,6 +203,18 @@ struct rtc_device
         struct hrtimer pie_timer; /* sub second exp, so needs hrtimer */
         int pie_enabled;
         struct work_struct irqwork;
+
+
+#ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
+        struct work_struct uie_task;
+        struct timer_list uie_timer;
+        /* Those fields are protected by rtc->irq_lock */
+        unsigned int oldsecs;
+        unsigned int uie_irq_active:1;
+        unsigned int stop_uie_polling:1;
+        unsigned int uie_task_active:1;
+        unsigned int uie_timer_active:1;
+#endif
 };
 #define to_rtc_device(d) container_of(d, struct rtc_device, dev)
 
@@ -235,6 +247,8 @@ extern int rtc_irq_set_freq(struct rtc_device *rtc,
                                 struct rtc_task *task, int freq);
 extern int rtc_update_irq_enable(struct rtc_device *rtc, unsigned int enabled);
 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_aie_update_irq(void *private);
 void rtc_uie_update_irq(void *private);