rtc: add support for the RTC in VIA VT8500 and compatibles

This adds a driver for the RTC devices in VIA and WonderMedia
Systems-on-Chip.  Alarm, 1Hz interrupts, reading and setting time are
supported.

Signed-off-by: Alexey Charkov <alchark@gmail.com>
Cc: Lars-Peter Clausen <lars@metafoo.de>
Cc: Alexey Charkov <alchark@gmail.com>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
index 8e437e2..3db52f0 100644
--- a/drivers/rtc/Kconfig
+++ b/drivers/rtc/Kconfig
@@ -884,6 +884,13 @@
          This RTC driver uses PXA RTC registers available since pxa27x
          series (RDxR, RYxR) instead of legacy RCNR, RTAR.
 
+config RTC_DRV_VT8500
+	tristate "VIA/WonderMedia 85xx SoC RTC"
+	depends on ARCH_VT8500
+	help
+	  If you say Y here you will get access to the real time clock
+	  built into your VIA VT8500 SoC or its relatives.
+
 
 config RTC_DRV_SUN4V
 	bool "SUN4V Hypervisor RTC"