rtc: max77686: Remove unused code to read in 12-hour mode

The MAX77714 RTC chip is explicitly set to 24-hour mode in
max77686_rtc_probe() -> max77686_rtc_init_reg() and never changed back to
12-hour mode. Accordingly info->rtc_24hr_mode is set to 1 in the same place
and never modified later, so it is de facto a constant. Yet there is code
to read 12-hour time, which is unreachable.

Remove the unused variable, the unreachable code to manage 12-hour mode and
the defines that become unused due to the above changes.
Signed-off-by: Luca Ceresoli <luca@lucaceresoli.net>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Acked-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

drivers/rtc/rtc-max77686.c

@@ -34,9 +34,6 @@
 #define RTC_UDR_MASK			BIT(RTC_UDR_SHIFT)
 #define RTC_RBUDR_SHIFT			4
 #define RTC_RBUDR_MASK			BIT(RTC_RBUDR_SHIFT)
-/* RTC Hour register */
-#define HOUR_PM_SHIFT			6
-#define HOUR_PM_MASK			BIT(HOUR_PM_SHIFT)
 /* RTC Alarm Enable */
 #define ALARM_ENABLE_SHIFT		7
 #define ALARM_ENABLE_MASK		BIT(ALARM_ENABLE_SHIFT)
@@ -99,7 +96,6 @@ struct max77686_rtc_info {
 
 	int rtc_irq;
 	int virq;
-	int rtc_24hr_mode;
 };
 
 enum MAX77686_RTC_OP {
@@ -278,13 +274,7 @@ static void max77686_rtc_data_to_tm(u8 *data, struct rtc_time *tm,
 
 	tm->tm_sec = data[RTC_SEC] & mask;
 	tm->tm_min = data[RTC_MIN] & mask;
-	if (info->rtc_24hr_mode) {
-		tm->tm_hour = data[RTC_HOUR] & 0x1f;
-	} else {
-		tm->tm_hour = data[RTC_HOUR] & 0x0f;
-		if (data[RTC_HOUR] & HOUR_PM_MASK)
-			tm->tm_hour += 12;
-	}
+	tm->tm_hour = data[RTC_HOUR] & 0x1f;
 
 	/* Only a single bit is set in data[], so fls() would be equivalent */
 	tm->tm_wday = ffs(data[RTC_WEEKDAY] & mask) - 1;
@@ -662,8 +652,6 @@ static int max77686_rtc_init_reg(struct max77686_rtc_info *info)
 	data[0] = (1 << BCD_EN_SHIFT) | (1 << MODEL24_SHIFT);
 	data[1] = (0 << BCD_EN_SHIFT) | (1 << MODEL24_SHIFT);
 
-	info->rtc_24hr_mode = 1;
-
 	ret = regmap_bulk_write(info->rtc_regmap,
 				info->drv_data->map[REG_RTC_CONTROLM],
 				data, ARRAY_SIZE(data));