[PATCH] i2c: New Xicor X1205 RTC driver

New driver for the Xicor X1205 RTC chip.

Signed-off-by: Alessandro Zummo <alessandro.zummo@towertech.it>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

Documentation/i2c/chips/x1205

@@ -0,0 +1,38 @@
+Kernel driver x1205
+===================
+
+Supported chips:
+  * Xicor X1205 RTC
+    Prefix: 'x1205'
+    Addresses scanned: none
+    Datasheet: http://www.intersil.com/cda/deviceinfo/0,1477,X1205,00.html
+
+Authors:
+	Karen Spearel <kas11@tampabay.rr.com>,
+	Alessandro Zummo <a.zummo@towertech.it>
+
+Description
+-----------
+
+This module aims to provide complete access to the Xicor X1205 RTC.
+Recently Xicor has merged with Intersil, but the chip is
+still sold under the Xicor brand.
+
+This chip is located at address 0x6f and uses a 2-byte register addressing.
+Two bytes need to be written to read a single register, while most
+other chips just require one and take the second one as the data
+to be written. To prevent corrupting unknown chips, the user must
+explicitely set the probe parameter.
+
+example:
+
+modprobe x1205 probe=0,0x6f
+
+The module supports one more option, hctosys, which is used to set the
+software clock from the x1205. On systems where the x1205 is the
+only hardware rtc, this parameter could be used to achieve a correct
+date/time earlier in the system boot sequence.
+
+example:
+
+modprobe x1205 probe=0,0x6f hctosys=1

drivers/i2c/chips/Kconfig

@@ -126,4 +126,13 @@ config SENSORS_MAX6875
 	  This driver can also be built as a module.  If so, the module
 	  will be called max6875.
 
+config RTC_X1205_I2C
+	tristate "Xicor X1205 RTC chip"
+	depends on I2C && EXPERIMENTAL
+	help
+	  If you say yes here you get support for the Xicor X1205 RTC chip.
+
+	  This driver can also be built as a module. If so, the module
+	  will be called x1205.
+
 endmenu

drivers/i2c/chips/Makefile

@@ -13,6 +13,7 @@ obj-$(CONFIG_SENSORS_PCF8591)	+= pcf8591.o
 obj-$(CONFIG_SENSORS_RTC8564)	+= rtc8564.o
 obj-$(CONFIG_ISP1301_OMAP)	+= isp1301_omap.o
 obj-$(CONFIG_TPS65010)		+= tps65010.o
+obj-$(CONFIG_RTC_X1205_I2C)	+= x1205.o
 
 ifeq ($(CONFIG_I2C_DEBUG_CHIP),y)
 EXTRA_CFLAGS += -DDEBUG