rtc: add support for STK17TA8 chip

This patch adds support for the Simtek STK17TA8 timekeeping chip.

The STK17TA8 is quite similar to the DS1553, but differs in register layout
and in various control bits in the registers.  I chose to make this a new
driver to avoid confusion in the code and to not get lost in #ifdefs.
Signed-off-by: Thomas Hommel <thomas.hommel@gefanuc.com>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: David Brownell <david-b@pacbell.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/rtc/Kconfig

@@ -308,6 +308,16 @@ config RTC_DRV_DS1553
 	  This driver can also be built as a module. If so, the module
 	  will be called rtc-ds1553.
 
+config RTC_DRV_STK17TA8
+	tristate "Simtek STK17TA8"
+	depends on RTC_CLASS
+	help
+	  If you say yes here you get support for the
+	  Simtek STK17TA8 timekeeping chip.
+
+	  This driver can also be built as a module. If so, the module
+	  will be called rtc-stk17ta8.
+
 config RTC_DRV_DS1742
 	tristate "Dallas DS1742/1743"
 	depends on RTC_CLASS

drivers/rtc/Makefile

@@ -32,6 +32,7 @@ obj-$(CONFIG_RTC_DRV_RS5C348)	+= rtc-rs5c348.o
 obj-$(CONFIG_RTC_DRV_M41T80)	+= rtc-m41t80.o
 obj-$(CONFIG_RTC_DRV_M48T86)	+= rtc-m48t86.o
 obj-$(CONFIG_RTC_DRV_DS1553)	+= rtc-ds1553.o
+obj-$(CONFIG_RTC_DRV_STK17TA8)	+= rtc-stk17ta8.o
 obj-$(CONFIG_RTC_DRV_RS5C313)	+= rtc-rs5c313.o
 obj-$(CONFIG_RTC_DRV_EP93XX)	+= rtc-ep93xx.o
 obj-$(CONFIG_RTC_DRV_SA1100)	+= rtc-sa1100.o