rtc: support for the Amlogic on-chip RTC

This is the third amlogic driver. The RTC hardware of A4 SoC is different
from the previous one. This RTC hardware includes a timing function and
an alarm function. But the existing has only timing function, alarm
function is using the system clock to implement a virtual alarm. Add
the RTC driver to support it.

Signed-off-by: Yiting Deng <yiting.deng@amlogic.com>
Signed-off-by: Xianwei Zhao <xianwei.zhao@amlogic.com>
Link: https://lore.kernel.org/r/20241112-rtc-v6-2-a71b60d2f354@amlogic.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

Author: Yiting Deng

drivers/rtc/Kconfig

@@ -2091,4 +2091,16 @@ config RTC_DRV_SSD202D
 	  This driver can also be built as a module, if so, the module
 	  will be called "rtc-ssd20xd".
 
+config RTC_DRV_AMLOGIC_A4
+	tristate "Amlogic RTC"
+	depends on ARCH_MESON || COMPILE_TEST
+	select REGMAP_MMIO
+	default y
+	help
+	  If you say yes here you get support for the RTC block on the
+	  Amlogic A113L2(A4) and A113X2(A5) SoCs.
+
+	  This driver can also be built as a module. If so, the module
+	  will be called "rtc-amlogic-a4".
+
 endif # RTC_CLASS

drivers/rtc/Makefile

@@ -27,6 +27,7 @@ obj-$(CONFIG_RTC_DRV_ABB5ZES3)	+= rtc-ab-b5ze-s3.o
 obj-$(CONFIG_RTC_DRV_ABEOZ9)	+= rtc-ab-eoz9.o
 obj-$(CONFIG_RTC_DRV_ABX80X)	+= rtc-abx80x.o
 obj-$(CONFIG_RTC_DRV_AC100)	+= rtc-ac100.o
+obj-$(CONFIG_RTC_DRV_AMLOGIC_A4)	+= rtc-amlogic-a4.o
 obj-$(CONFIG_RTC_DRV_ARMADA38X)	+= rtc-armada38x.o
 obj-$(CONFIG_RTC_DRV_AS3722)	+= rtc-as3722.o
 obj-$(CONFIG_RTC_DRV_ASM9260)	+= rtc-asm9260.o