mmc: sdhci-sprd: Add Spreadtrum's initial host controller

This patch adds the initial support of Secure Digital Host Controller
Interface compliant controller found in some latest Spreadtrum chipsets.
This patch has been tested on the version of SPRD-R11 controller.

R11 is a variant based on SD v4.0 specification.

With this driver, R11 mmc can be initialized, can be mounted, read and
written.
Original-by: Billows Wu <billows.wu@unisoc.com>
Signed-off-by: Chunyan Zhang <chunyan.zhang@unisoc.com>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

drivers/mmc/host/Kconfig

@@ -593,6 +593,19 @@ config MMC_SDRICOH_CS
 	  To compile this driver as a module, choose M here: the
 	  module will be called sdricoh_cs.
 
+config MMC_SDHCI_SPRD
+	tristate "Spreadtrum SDIO host Controller"
+	depends on ARCH_SPRD
+	depends on MMC_SDHCI_PLTFM
+	select MMC_SDHCI_IO_ACCESSORS
+	help
+	  This selects the SDIO Host Controller in Spreadtrum
+	  SoCs, this driver supports R11(IP version: R11P0).
+
+	  If you have a controller with this interface, say Y or M here.
+
+	  If unsure, say N.
+
 config MMC_TMIO_CORE
 	tristate
 

drivers/mmc/host/Makefile

@@ -92,6 +92,7 @@ obj-$(CONFIG_MMC_SDHCI_ST)		+= sdhci-st.o
 obj-$(CONFIG_MMC_SDHCI_MICROCHIP_PIC32)	+= sdhci-pic32.o
 obj-$(CONFIG_MMC_SDHCI_BRCMSTB)		+= sdhci-brcmstb.o
 obj-$(CONFIG_MMC_SDHCI_OMAP)		+= sdhci-omap.o
+obj-$(CONFIG_MMC_SDHCI_SPRD)		+= sdhci-sprd.o
 obj-$(CONFIG_MMC_CQHCI)			+= cqhci.o
 
 ifeq ($(CONFIG_CB710_DEBUG),y)