mfd: Add realtek USB card reader driver

Realtek USB card reader provides a channel to transfer command or data to flash
memory cards. This driver exports host instances for mmc and memstick subsystems
and handles basic works.
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Roger Tseng <rogerable@realtek.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

drivers/mfd/Kconfig

@@ -516,6 +516,16 @@ config MFD_RTSX_PCI
 	  types of memory cards, such as Memory Stick, Memory Stick Pro,
 	  Secure Digital and MultiMediaCard.
 
+config MFD_RTSX_USB
+	tristate "Realtek USB card reader"
+	depends on USB
+	select MFD_CORE
+	help
+	  Select this option to get support for Realtek USB 2.0 card readers
+	  including RTS5129, RTS5139, RTS5179 and RTS5170.
+	  Realtek card reader supports access to many types of memory cards,
+	  such as Memory Stick Pro, Secure Digital and MultiMediaCard.
+
 config MFD_RC5T583
 	bool "Ricoh RC5T583 Power Management system device"
 	depends on I2C=y

drivers/mfd/Makefile

@@ -14,6 +14,7 @@ obj-$(CONFIG_MFD_CROS_EC_SPI)	+= cros_ec_spi.o
 
 rtsx_pci-objs			:= rtsx_pcr.o rts5209.o rts5229.o rtl8411.o rts5227.o rts5249.o
 obj-$(CONFIG_MFD_RTSX_PCI)	+= rtsx_pci.o
+obj-$(CONFIG_MFD_RTSX_USB)	+= rtsx_usb.o
 
 obj-$(CONFIG_HTC_EGPIO)		+= htc-egpio.o
 obj-$(CONFIG_HTC_PASIC3)	+= htc-pasic3.o