rtc: add device driver for Dallas DS3234 SPI RTC chip

Add support for the Dallas DS3234 chip - extremely accurate SPI bus RTC
with integrated crystal and SRAM.

[akpm@linux-foundation.org: don't use BIN2BCD/BCD2BIN]
Signed-off-by: Dennis Aberilla <denzzzhome@yahoo.com>
Signed-off-by: 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>
diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
index f3d7fd3..16bc33c 100644
--- a/drivers/rtc/Kconfig
+++ b/drivers/rtc/Kconfig
@@ -319,6 +319,15 @@
 	  This driver can also be built as a module. If so, the module
 	  will be called rtc-rs5c348.
 
+config RTC_DRV_DS3234
+	tristate "Maxim/Dallas DS3234"
+	help
+	  If you say yes here you get support for the
+	  Maxim/Dallas DS3234 SPI RTC chip.
+
+	  This driver can also be built as a module. If so, the module
+	  will be called rtc-ds3234.
+
 endif # SPI_MASTER
 
 comment "Platform RTC drivers"