rtc: Add RTC range

Add a way for drivers to inform the core of the supported date/time range.
The core can then check whether the date/time or alarm is in the range
before calling ->set_time, ->set_mmss or ->set_alarm. It returns -ERANGE
when the time is out of range.

Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

1 files changed, 14 insertions, 0 deletions

diff --git a/drivers/rtc/interface.c b/drivers/rtc/interface.c
index 7e253be19ba7..c068daebeec2 100644
--- a/drivers/rtc/interface.c
+++ b/drivers/rtc/interface.c
@@ -70,6 +70,13 @@ int rtc_set_time(struct rtc_device *rtc, struct rtc_time *tm)
         if (err != 0)
                 return err;
 
+        if (rtc->range_min != rtc->range_max) {
+                time64_t time = rtc_tm_to_time64(tm);
+
+                if (time < rtc->range_min || time > rtc->range_max)
+                        return -ERANGE;
+        }
+
         err = mutex_lock_interruptible(&rtc->ops_lock);
         if (err)
                 return err;
@@ -374,6 +381,13 @@ int rtc_set_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
         if (err != 0)
                 return err;
 
+        if (rtc->range_min != rtc->range_max) {
+                time64_t time = rtc_tm_to_time64(&alarm->time);
+
+                if (time < rtc->range_min || time > rtc->range_max)
+                        return -ERANGE;
+        }
+
         err = mutex_lock_interruptible(&rtc->ops_lock);
         if (err)
                 return err;