[PATCH] "RTC-framework" driver for DS1307 and similar RTC chips

This is an "RTC-framework" driver for DS1307 and similar RTC chips,

It should be a full replacement for the existing ds1337.c driver (using the
older RTC glue), giving a net increase in the number of RTC chips that work
out-of-the-box.  There's a whole cluster of RTCs that are very similar, but
the 1337 driver was a bit too picky to work with most of them.

Still no support for RTC alarm IRQs (on chips that support them).

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: James Chapman <jchapman@katalix.com>
Signed-off-by: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

drivers/rtc/Kconfig

@@ -86,6 +86,24 @@ config RTC_DRV_X1205
 	  This driver can also be built as a module. If so, the module
 	  will be called rtc-x1205.
 
+config RTC_DRV_DS1307
+	tristate "Dallas/Maxim DS1307 and similar I2C RTC chips"
+	depends on RTC_CLASS && I2C
+	help
+	  If you say yes here you get support for various compatible RTC
+	  chips (often with battery backup) connected with I2C.  This driver
+	  should handle DS1307, DS1337, DS1338, DS1339, DS1340, ST M41T00,
+	  and probably other chips.  In some cases the RTC must already
+	  have been initialized (by manufacturing or a bootloader).
+
+	  The first seven registers on these chips hold an RTC, and other
+	  registers may add features such as NVRAM, a trickle charger for
+	  the RTC/NVRAM backup power, and alarms.  This driver may not
+	  expose all those available chip features.
+
+	  This driver can also be built as a module. If so, the module
+	  will be called rtc-ds1307.
+
 config RTC_DRV_DS1672
 	tristate "Dallas/Maxim DS1672"
 	depends on RTC_CLASS && I2C

drivers/rtc/Makefile

@@ -13,6 +13,7 @@ obj-$(CONFIG_RTC_INTF_DEV)	+= rtc-dev.o
 
 obj-$(CONFIG_RTC_DRV_X1205)	+= rtc-x1205.o
 obj-$(CONFIG_RTC_DRV_TEST)	+= rtc-test.o
+obj-$(CONFIG_RTC_DRV_DS1307)	+= rtc-ds1307.o
 obj-$(CONFIG_RTC_DRV_DS1672)	+= rtc-ds1672.o
 obj-$(CONFIG_RTC_DRV_PCF8563)	+= rtc-pcf8563.o
 obj-$(CONFIG_RTC_DRV_RS5C372)	+= rtc-rs5c372.o