rtc: bd70528: Initial support for ROHM bd70528 RTC

Support RTC block in ROHM bd70528 power management IC. Support
getting and setting the time and date as well as arming an alarm
which can also be used to wake the PMIC from standby state.

HW supports wake interrupt only for the next 24 hours (sec, minute
and hour information only) so we limit also the alarm interrupt to
this 24 hours for the sake of consistency.
Signed-off-by: Matti Vaittinen <matti.vaittinen@fi.rohmeurope.com>
Acked-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

drivers/rtc/Kconfig

@@ -497,6 +497,14 @@ config RTC_DRV_M41T80_WDT
 	help
 	  If you say Y here you will get support for the
 	  watchdog timer in the ST M41T60 and M41T80 RTC chips series.
+config RTC_DRV_BD70528
+	tristate "ROHM BD70528 PMIC RTC"
+	help
+	  If you say Y here you will get support for the RTC
+	  on ROHM BD70528 Power Management IC.
+
+	  This driver can also be built as a module. If so, the module
+	  will be called rtc-bd70528.
 
 config RTC_DRV_BQ32K
 	tristate "TI BQ32000"

drivers/rtc/Makefile

@@ -38,6 +38,7 @@ obj-$(CONFIG_RTC_DRV_ASPEED)	+= rtc-aspeed.o
 obj-$(CONFIG_RTC_DRV_AT91RM9200)+= rtc-at91rm9200.o
 obj-$(CONFIG_RTC_DRV_AT91SAM9)	+= rtc-at91sam9.o
 obj-$(CONFIG_RTC_DRV_AU1XXX)	+= rtc-au1xxx.o
+obj-$(CONFIG_RTC_DRV_BD70528)	+= rtc-bd70528.o
 obj-$(CONFIG_RTC_DRV_BQ32K)	+= rtc-bq32k.o
 obj-$(CONFIG_RTC_DRV_BQ4802)	+= rtc-bq4802.o
 obj-$(CONFIG_RTC_DRV_BRCMSTB)	+= rtc-brcmstb-waketimer.o