mfd: Add VIA VX855 multi-function device support

This device has GPIO, SPI and I2C capabilities.

The hardware can be found in the OLPC XO-1.5 laptop.

Based on earlier work by Harald Welte.

Signed-off-by: Daniel Drake <dsd@laptop.org>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
index 256fabd..9735f58 100644
--- a/drivers/mfd/Kconfig
+++ b/drivers/mfd/Kconfig
@@ -576,6 +576,15 @@
 	  This driver can also be built as a module.  If so, the module
 	  will be called tps6586x.
 
+config MFD_VX855
+	tristate "Support for VIA VX855/VX875 integrated south bridge"
+	depends on PCI
+	select MFD_CORE
+	help
+	  Say yes here to enable support for various functions of the
+	  VIA VX855/VX875 south bridge. You will need to enable the vx855_spi
+	  and/or vx855_gpio drivers for this to do anything useful.
+
 endif # MFD_SUPPORT
 
 menu "Multimedia Capabilities Port drivers"