[media] mfd: Add header files and Kbuild plumbing for SI476x MFD core

This patch adds all necessary header files and Kbuild plumbing for the
core driver for Silicon Laboratories Si476x series of AM/FM tuner
chips.
The driver as a whole is implemented as an MFD device and this patch
adds a core portion of it that provides all the necessary
functionality to the two other drivers that represent radio and audio
codec subsystems of the chip.

Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/mfd/Kconfig

@@ -976,6 +976,18 @@ config MFD_WL1273_CORE
 	  driver connects the radio-wl1273 V4L2 module and the wl1273
 	  audio codec.
 
+config MFD_SI476X_CORE
+	tristate "Support for Silicon Laboratories 4761/64/68 AM/FM radio."
+	depends on I2C
+	select MFD_CORE
+	help
+	  This is the core driver for the SI476x series of AM/FM
+	  radio. This MFD driver connects the radio-si476x V4L2 module
+	  and the si476x audio codec.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called si476x-core.
+
 config MFD_OMAP_USB_HOST
 	bool "Support OMAP USBHS core and TLL driver"
 	depends on USB_EHCI_HCD_OMAP || USB_OHCI_HCD_OMAP3

drivers/mfd/Makefile

@@ -131,6 +131,10 @@ obj-$(CONFIG_MFD_JZ4740_ADC)	+= jz4740-adc.o
 obj-$(CONFIG_MFD_TPS6586X)	+= tps6586x.o
 obj-$(CONFIG_MFD_VX855)		+= vx855.o
 obj-$(CONFIG_MFD_WL1273_CORE)	+= wl1273-core.o
+
+si476x-core-y := si476x-cmd.o si476x-prop.o si476x-i2c.o
+obj-$(CONFIG_MFD_SI476X_CORE)	+= si476x-core.o
+
 obj-$(CONFIG_MFD_CS5535)	+= cs5535-mfd.o
 obj-$(CONFIG_MFD_OMAP_USB_HOST)	+= omap-usb-host.o omap-usb-tll.o
 obj-$(CONFIG_MFD_PM8921_CORE) 	+= pm8921-core.o