rtc: Add driver for RTC in Sunplus SP7021

Add driver for RTC in Sunplus SP7021
Signed-off-by: Vincent Shih <vincent.sunplus@gmail.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/1638517579-10316-2-git-send-email-vincent.sunplus@gamil.com

MAINTAINERS

@@ -18216,6 +18216,12 @@ L:	netdev@vger.kernel.org
 S:	Maintained
 F:	drivers/net/ethernet/dlink/sundance.c
 
+SUNPLUS RTC DRIVER
+M:	Vincent Shih <vincent.sunplus@gmail.com>
+L:	linux-rtc@vger.kernel.org
+S:	Maintained
+F:	drivers/rtc/rtc-sunplus.c
+
 SUPERH
 M:	Yoshinori Sato <ysato@users.sourceforge.jp>
 M:	Rich Felker <dalias@libc.org>

drivers/rtc/Kconfig

@@ -1455,6 +1455,19 @@ config RTC_DRV_SH
 	  To compile this driver as a module, choose M here: the
 	  module will be called rtc-sh.
 
+config RTC_DRV_SUNPLUS
+	tristate "Sunplus SP7021 RTC"
+	depends on SOC_SP7021
+	help
+	  Say 'yes' to get support for the real-time clock present in
+	  Sunplus SP7021 - a SoC for industrial applications. It provides
+	  RTC status check, timer/alarm functionalities, user data
+	  reservation with the battery over 2.5V, RTC power status check
+	  and battery charge.
+
+	  This driver can also be built as a module. If so, the module
+	  will be called rtc-sunplus.
+
 config RTC_DRV_VR41XX
 	tristate "NEC VR41XX"
 	depends on CPU_VR41XX || COMPILE_TEST

drivers/rtc/Makefile

@@ -166,6 +166,7 @@ obj-$(CONFIG_RTC_DRV_STM32) 	+= rtc-stm32.o
 obj-$(CONFIG_RTC_DRV_STMP)	+= rtc-stmp3xxx.o
 obj-$(CONFIG_RTC_DRV_SUN4V)	+= rtc-sun4v.o
 obj-$(CONFIG_RTC_DRV_SUN6I)	+= rtc-sun6i.o
+obj-$(CONFIG_RTC_DRV_SUNPLUS)	+= rtc-sunplus.o
 obj-$(CONFIG_RTC_DRV_SUNXI)	+= rtc-sunxi.o
 obj-$(CONFIG_RTC_DRV_TEGRA)	+= rtc-tegra.o
 obj-$(CONFIG_RTC_DRV_TEST)	+= rtc-test.o