i2c: aspeed: added driver for Aspeed I2C

Added initial master support for Aspeed I2C controller. Supports
fourteen busses present in AST24XX and AST25XX BMC SoCs by Aspeed.
Signed-off-by: Brendan Higgins <brendanhiggins@google.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

drivers/i2c/busses/Kconfig

@@ -328,6 +328,16 @@ config I2C_POWERMAC
 
 comment "I2C system bus drivers (mostly embedded / system-on-chip)"
 
+config I2C_ASPEED
+	tristate "Aspeed I2C Controller"
+	depends on ARCH_ASPEED || COMPILE_TEST
+	help
+	  If you say yes to this option, support will be included for the
+	  Aspeed I2C controller.
+
+	  This driver can also be built as a module.  If so, the module
+	  will be called i2c-aspeed.
+
 config I2C_AT91
 	tristate "Atmel AT91 I2C Two-Wire interface (TWI)"
 	depends on ARCH_AT91

drivers/i2c/busses/Makefile

@@ -29,6 +29,7 @@ obj-$(CONFIG_I2C_HYDRA)		+= i2c-hydra.o
 obj-$(CONFIG_I2C_POWERMAC)	+= i2c-powermac.o
 
 # Embedded system I2C/SMBus host controller drivers
+obj-$(CONFIG_I2C_ASPEED)	+= i2c-aspeed.o
 obj-$(CONFIG_I2C_AT91)		+= i2c-at91.o
 obj-$(CONFIG_I2C_AU1550)	+= i2c-au1550.o
 obj-$(CONFIG_I2C_AXXIA)		+= i2c-axxia.o