rtc: pcf8563: handle consequeces of lacking second alarm reg

To guarantee that a set alarm occurs in the future, the set alarm time
is rounded up to the nearest minute.  Also we cannot handle UIE as it
requires second precision.

Signed-off-by: Jan Kardell <jan.kardell@telliq.com>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Grant Likely <grant.likely@linaro.org>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Vincent Donnefort <vdonnefort@gmail.com>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 11 insertions, 0 deletions

diff --git a/drivers/rtc/rtc-pcf8563.c b/drivers/rtc/rtc-pcf8563.c
index 78f76d99bd35..ce6a11bc0fd7 100644
--- a/drivers/rtc/rtc-pcf8563.c
+++ b/drivers/rtc/rtc-pcf8563.c
@@ -361,6 +361,14 @@ static int pcf8563_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *tm)
         struct i2c_client *client = to_i2c_client(dev);
         unsigned char buf[4];
         int err;
+        unsigned long alarm_time;
+
+        /* The alarm has no seconds, round up to nearest minute */
+        if (tm->time.tm_sec) {
+                rtc_tm_to_time(&tm->time, &alarm_time);
+                alarm_time += 60-tm->time.tm_sec;
+                rtc_time_to_tm(alarm_time, &tm->time);
+        }
 
         dev_dbg(dev, "%s, min=%d hour=%d wday=%d mday=%d "
                 "enabled=%d pending=%d\n", __func__,
@@ -435,6 +443,9 @@ static int pcf8563_probe(struct i2c_client *client,
 
         }
 
+        /* the pcf8563 alarm only supports a minute accuracy */
+        pcf8563->rtc->uie_unsupported = 1;
+
         return 0;
 }