mfd: add U300 AB3100 core support

This adds a core driver for the AB3100 mixed-signal circuit
found in the ST-Ericsson U300 series platforms. This driver
is a singleton proxy for all accesses to the AB3100
sub-drivers which will be merged on top of this one, RTC,
regulators, battery and system power control, vibrator,
LEDs, and an ALSA codec.

Signed-off-by: Linus Walleij <linus.walleij@stericsson.com>
Reviewed-by: Mike Rapoport <mike@compulab.co.il>
Reviewed-by: Ben Dooks <ben-linux@fluff.org>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

drivers/mfd/Kconfig

@@ -241,6 +241,20 @@ config PCF50633_GPIO
 	 Say yes here if you want to include support GPIO for pins on
 	 the PCF50633 chip.
 
+config AB3100_CORE
+	tristate "ST-Ericsson AB3100 Mixed Signal Circuit core functions"
+	depends on I2C
+	default y if ARCH_U300
+	help
+	  Select this to enable the AB3100 Mixed Signal IC core
+	  functionality. This connects to a AB3100 on the I2C bus
+	  and expose a number of symbols needed for dependent devices
+	  to read and write registers and subscribe to events from
+	  this multi-functional IC. This is needed to use other features
+	  of the AB3100 such as battery-backed RTC, charging control,
+	  LEDs, vibrator, system power and temperature, power management
+	  and ALSA sound.
+
 endmenu
 
 menu "Multimedia Capabilities Port drivers"

drivers/mfd/Makefile

@@ -40,4 +40,5 @@ obj-$(CONFIG_PMIC_DA903X)	+= da903x.o
 
 obj-$(CONFIG_MFD_PCF50633)	+= pcf50633-core.o
 obj-$(CONFIG_PCF50633_ADC)	+= pcf50633-adc.o
-obj-$(CONFIG_PCF50633_GPIO)	+= pcf50633-gpio.o
+obj-$(CONFIG_PCF50633_GPIO)	+= pcf50633-gpio.o
+obj-$(CONFIG_AB3100_CORE)	+= ab3100-core.o