mfd: ab5500 chip register access

The analog baseband chip ab5500 is a multi functional chip
containing regulators, charging, gpio, USB and accessory detect.
It also contain various multimedia functionalities like digital
encoder and audio codec.
The core driver added with this patch provides register access via
i2c via PRCMU. Event handling implemented as irq_chip will come in
future patches since it depends on PRCMU functionality not yet
implemented.

Signed-off-by: Mattias Wallin <mattias.wallin@stericsson.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
index b01fbe2..8594de8 100644
--- a/drivers/mfd/Kconfig
+++ b/drivers/mfd/Kconfig
@@ -563,6 +563,15 @@
 	  This enables the PCAP ASIC present on EZX Phones. This is
 	  needed for MMC, TouchScreen, Sound, USB, etc..
 
+config AB5500_CORE
+	bool "ST-Ericsson AB5500 Mixed Signal Power Management chip"
+	depends on ABX500_CORE && MFD_DB5500_PRCMU
+	select MFD_CORE
+	help
+	  Select this option to enable access to AB5500 power management
+	  chip. This connects to the db5500 chip via the I2C bus via PRCMU.
+	  This chip embeds various other multimedia funtionalities as well.
+
 config AB8500_CORE
 	bool "ST-Ericsson AB8500 Mixed Signal Power Management chip"
 	depends on GENERIC_HARDIRQS && ABX500_CORE