mfd: TWL4030 core driver

This patch adds the core of the TWL4030 driver, which supports
chips including the TPS65950.  These chips are multi-function; see

  http://focus.ti.com/docs/prod/folders/print/tps65950.html

Public specs are in the works.  For now, the block diagram on
the second page of the datasheet is fairly informative.

There are some known issues with this core code.  Most notably,
the IRQ dispatching needs simplification (to use more of genirq),
generalization (integrating support for secondary IRQ dispatch
as well as primary, and removing the build dependency on OMAP),
and then probably updating to leverage threaded IRQ support
(expected to arrive in mainline "soon").

Once the core is in mainline, drivers for other parts of this
chip can follow its lead and start swimming upstream too.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Samuel Ortiz <sameo@openedhand.com>
diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
index 5eff8ad..cccda99 100644
--- a/drivers/mfd/Kconfig
+++ b/drivers/mfd/Kconfig
@@ -59,6 +59,20 @@
 	  To compile this driver as a module, choose M here: the
 	  module will be called ucb1400_core.
 
+config TWL4030_CORE
+	bool "Texas Instruments TWL4030/TPS659x0 Support"
+	depends on I2C=y && GENERIC_HARDIRQS && (ARCH_OMAP2 || ARCH_OMAP3)
+	help
+	  Say yes here if you have TWL4030 family chip on your board.
+	  This core driver provides register access and IRQ handling
+	  facilities, and registers devices for the various functions
+	  so that function-specific drivers can bind to them.
+
+	  These multi-function chips are found on many OMAP2 and OMAP3
+	  boards, providing power management, RTC, GPIO, keypad, a
+	  high speed USB OTG transceiver, an audio codec (on most
+	  versions) and many other features.
+
 config MFD_TMIO
 	bool
 	default n