i2c: altera: Add Altera I2C Controller driver

Add driver support for the Altera I2C Controller. The I2C
controller is soft IP for use in FPGAs.
Signed-off-by: Thor Thayer <thor.thayer@linux.intel.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

MAINTAINERS

@@ -644,6 +644,11 @@ ALPS PS/2 TOUCHPAD DRIVER
 R:	Pali Rohár <pali.rohar@gmail.com>
 F:	drivers/input/mouse/alps.*
 
+ALTERA I2C CONTROLLER DRIVER
+M:	Thor Thayer <thor.thayer@linux.intel.com>
+S:	Maintained
+F:	drivers/i2c/busses/i2c-altera.c
+
 ALTERA MAILBOX DRIVER
 M:	Ley Foon Tan <lftan@altera.com>
 L:	nios2-dev@lists.rocketboards.org (moderated for non-subscribers)

drivers/i2c/busses/Kconfig

@@ -336,6 +336,16 @@ config I2C_POWERMAC
 
 comment "I2C system bus drivers (mostly embedded / system-on-chip)"
 
+config I2C_ALTERA
+	tristate "Altera Soft IP I2C"
+	depends on (ARCH_SOCFPGA || NIOS2) && OF
+	help
+	  If you say yes to this option, support will be included for the
+	  Altera Soft IP I2C interfaces on SoCFPGA and Nios2 architectures.
+
+	  This driver can also be built as a module.  If so, the module
+	  will be called i2c-altera.
+
 config I2C_ASPEED
 	tristate "Aspeed I2C Controller"
 	depends on ARCH_ASPEED || COMPILE_TEST

drivers/i2c/busses/Makefile

@@ -30,6 +30,7 @@ obj-$(CONFIG_I2C_HYDRA)		+= i2c-hydra.o
 obj-$(CONFIG_I2C_POWERMAC)	+= i2c-powermac.o
 
 # Embedded system I2C/SMBus host controller drivers
+obj-$(CONFIG_I2C_ALTERA)	+= i2c-altera.o
 obj-$(CONFIG_I2C_ASPEED)	+= i2c-aspeed.o
 obj-$(CONFIG_I2C_AT91)		+= i2c-at91.o
 obj-$(CONFIG_I2C_AU1550)	+= i2c-au1550.o