mmc: Add bcm2835 sdhost controller

The BCM2835 family of SoCs has 2 different SD controllers: One based on
the SDHCI spec and a custom, home-grown one.

This patch implements a driver for the latter based on the Linux driver.
This is needed so that we can make use of device trees that assume driver
presence of both SD controllers.

Signed-off-by: Alexander Graf <agraf@suse.de>
diff --git a/drivers/mmc/Kconfig b/drivers/mmc/Kconfig
index bc29611..a1b21fd 100644
--- a/drivers/mmc/Kconfig
+++ b/drivers/mmc/Kconfig
@@ -261,6 +261,20 @@
 	  This selects support for the Matsushita SD/MMC Host Controller on
 	  SocioNext UniPhier and Renesas RCar SoCs.
 
+config MMC_BCM2835
+	bool "BCM2835 family custom SD/MMC Host Controller support"
+	depends on ARCH_BCM283X
+	depends on BLK && DM_MMC
+	depends on OF_CONTROL
+	default y
+	help
+	  This selects support for the custom SD host controller in the BCM2835
+	  family of devices.
+
+	  If you have a BCM2835 platform with SD or MMC devices, say Y here.
+
+	  If unsure, say N.
+
 config MMC_SANDBOX
 	bool "Sandbox MMC support"
 	depends on SANDBOX