ssb: Implement SDIO host bus support

Add support for communicating with a Sonics Silicon Backplane through a
SDIO interface, as found in the Nintendo Wii WLAN daughter card.

The Nintendo Wii WLAN card includes a custom Broadcom 4318 chip with
a SDIO host interface.

Signed-off-by: Albert Herranz <albert_herranz@yahoo.es>
Signed-off-by: Michael Buesch <mb@bu3sch.de>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/ssb/Kconfig b/drivers/ssb/Kconfig
index 540a294..2d8cc45 100644
--- a/drivers/ssb/Kconfig
+++ b/drivers/ssb/Kconfig
@@ -66,6 +66,20 @@
 
 	  If unsure, say N
 
+config SSB_SDIOHOST_POSSIBLE
+	bool
+	depends on SSB && (MMC = y || MMC = SSB)
+	default y
+
+config SSB_SDIOHOST
+	bool "Support for SSB on SDIO-bus host"
+	depends on SSB_SDIOHOST_POSSIBLE
+	help
+	  Support for a Sonics Silicon Backplane on top
+	  of a SDIO device.
+
+	  If unsure, say N
+
 config SSB_SILENT
 	bool "No SSB kernel messages"
 	depends on SSB && EMBEDDED