rtc: ds1307: rx8130: Fix alarm handling

When the EXTENSION.WADA bit is set, register 0x19 contains a bitmap of
week days, not a day of month. As Linux only handles a single alarm
without repetition using day of month is more flexible, so clear this
bit. (Otherwise a value depending on time.tm_wday would have to be
written to register 0x19.)

Also optimize setting the AIE bit to use a single register write instead
of a bulk write of three registers.

Fixes: ee0981be ("rtc: ds1307: Add support for Epson RX8130CE")
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

drivers/rtc/rtc-ds1307.c

@@ -554,8 +554,8 @@ static int rx8130_set_alarm(struct device *dev, struct rtc_wkalrm *t)
 	if (ret < 0)
 		return ret;
 
-	ctl[0] &= ~RX8130_REG_EXTENSION_WADA;
-	ctl[1] |= RX8130_REG_FLAG_AF;
+	ctl[0] &= RX8130_REG_EXTENSION_WADA;
+	ctl[1] &= ~RX8130_REG_FLAG_AF;
 	ctl[2] &= ~RX8130_REG_CONTROL0_AIE;
 
 	ret = regmap_bulk_write(ds1307->regmap, RX8130_REG_EXTENSION, ctl,
@@ -578,8 +578,7 @@ static int rx8130_set_alarm(struct device *dev, struct rtc_wkalrm *t)
 
 	ctl[2] |= RX8130_REG_CONTROL0_AIE;
 
-	return regmap_bulk_write(ds1307->regmap, RX8130_REG_EXTENSION, ctl,
-				 sizeof(ctl));
+	return regmap_write(ds1307->regmap, RX8130_REG_CONTROL0, ctl[2]);
 }
 
 static int rx8130_alarm_irq_enable(struct device *dev, unsigned int enabled)