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>

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;
 }