diff --git a/drivers/mmc/host/Kconfig b/drivers/mmc/host/Kconfig
index 68fb052..5fef678 100644
--- a/drivers/mmc/host/Kconfig
+++ b/drivers/mmc/host/Kconfig
@@ -35,6 +35,23 @@
 
 	  If unsure, say N.
 
+config MMC_RICOH_MMC
+	tristate "Ricoh MMC Controller Disabler  (EXPERIMENTAL)"
+	depends on PCI && EXPERIMENTAL && MMC_SDHCI
+	help
+	  This selects the disabler for the Ricoh MMC Controller. This
+	  proprietary controller is unnecessary because the SDHCI driver
+	  supports MMC cards on the SD controller, but if it is not
+	  disabled, it will steal the MMC cards away - rendering them
+	  useless. It is safe to select this driver even if you don't
+	  have a Ricoh based card reader.
+
+
+	  To compile this driver as a module, choose M here:
+	  the module will be called ricoh_mmc.
+
+	  If unsure, say Y.
+
 config MMC_OMAP
 	tristate "TI OMAP Multimedia Card Interface support"
 	depends on ARCH_OMAP
diff --git a/drivers/mmc/host/Makefile b/drivers/mmc/host/Makefile
index 8dc82ce..3877c87 100644
--- a/drivers/mmc/host/Makefile
+++ b/drivers/mmc/host/Makefile
@@ -10,6 +10,7 @@
 obj-$(CONFIG_MMC_PXA)		+= pxamci.o
 obj-$(CONFIG_MMC_IMX)		+= imxmmc.o
 obj-$(CONFIG_MMC_SDHCI)		+= sdhci.o
+obj-$(CONFIG_MMC_RICOH_MMC)	+= ricoh_mmc.o
 obj-$(CONFIG_MMC_WBSD)		+= wbsd.o
 obj-$(CONFIG_MMC_AU1X)		+= au1xmmc.o
 obj-$(CONFIG_MMC_OMAP)		+= omap.o
diff --git a/drivers/mmc/host/ricoh_mmc.c b/drivers/mmc/host/ricoh_mmc.c
new file mode 100644
index 0000000..1e87045
--- /dev/null
+++ b/drivers/mmc/host/ricoh_mmc.c
@@ -0,0 +1,151 @@
+/*
+ *  ricoh_mmc.c - Dummy driver to disable the Rioch MMC controller.
+ *
+ *  Copyright (C) 2007 Philip Langdale, All Rights Reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or (at
+ * your option) any later version.
+ */
+
+/*
+ * This is a conceptually ridiculous driver, but it is required by the way
+ * the Ricoh multi-function R5C832 works. This chip implements firewire
+ * and four different memory card controllers. Two of those controllers are
+ * an SDHCI controller and a proprietary MMC controller. The linux SDHCI
+ * driver supports MMC cards but the chip detects MMC cards in hardware
+ * and directs them to the MMC controller - so the SDHCI driver never sees
+ * them. To get around this, we must disable the useless MMC controller.
+ * At that point, the SDHCI controller will start seeing them. As a bonus,
+ * a detection event occurs immediately, even if the MMC card is already
+ * in the reader.
+ *
+ * The relevant registers live on the firewire function, so this is unavoidably
+ * ugly. Such is life.
+ */
+
+#include <linux/pci.h>
+
+#define DRIVER_NAME "ricoh-mmc"
+
+static const struct pci_device_id pci_ids[] __devinitdata = {
+	{
+		.vendor		= PCI_VENDOR_ID_RICOH,
+		.device		= PCI_DEVICE_ID_RICOH_R5C843,
+		.subvendor	= PCI_ANY_ID,
+		.subdevice	= PCI_ANY_ID,
+	},
+	{ /* end: all zeroes */ },
+};
+
+MODULE_DEVICE_TABLE(pci, pci_ids);
+
+static int __devinit ricoh_mmc_probe(struct pci_dev *pdev,
+				     const struct pci_device_id *ent)
+{
+	u8 rev;
+
+	struct pci_dev *fw_dev = NULL;
+
+	BUG_ON(pdev == NULL);
+	BUG_ON(ent == NULL);
+
+	pci_read_config_byte(pdev, PCI_CLASS_REVISION, &rev);
+
+	printk(KERN_INFO DRIVER_NAME
+		": Ricoh MMC controller found at %s [%04x:%04x] (rev %x)\n",
+		pci_name(pdev), (int)pdev->vendor, (int)pdev->device,
+		(int)rev);
+
+	while ((fw_dev = pci_get_device(PCI_VENDOR_ID_RICOH, PCI_DEVICE_ID_RICOH_R5C832, fw_dev))) {
+		if (PCI_SLOT(pdev->devfn) == PCI_SLOT(fw_dev->devfn) &&
+		    pdev->bus == fw_dev->bus) {
+			u8 write_enable;
+			u8 disable;
+
+			pci_read_config_byte(fw_dev, 0xCB, &disable);
+			if (disable & 0x02) {
+				printk(KERN_INFO DRIVER_NAME
+				       ": Controller already disabled. Nothing to do.\n");
+				return -ENODEV;
+			}
+
+			pci_read_config_byte(fw_dev, 0xCA, &write_enable);
+			pci_write_config_byte(fw_dev, 0xCA, 0x57);
+			pci_write_config_byte(fw_dev, 0xCB, disable | 0x02);
+			pci_write_config_byte(fw_dev, 0xCA, write_enable);
+
+			pci_set_drvdata(pdev, fw_dev);
+
+			printk(KERN_INFO DRIVER_NAME
+			       ": Controller is now disabled.\n");
+
+			break;
+		}
+	}
+
+	if (pci_get_drvdata(pdev) == NULL) {
+		printk(KERN_WARNING DRIVER_NAME
+		       ": Main firewire function not found. Cannot disable controller.\n");
+		return -ENODEV;
+	}
+
+	return 0;
+}
+
+static void __devexit ricoh_mmc_remove(struct pci_dev *pdev)
+{
+	u8 write_enable;
+	u8 disable;
+	struct pci_dev *fw_dev = NULL;
+
+	fw_dev = pci_get_drvdata(pdev);
+	BUG_ON(fw_dev == NULL);
+
+	pci_read_config_byte(fw_dev, 0xCA, &write_enable);
+	pci_read_config_byte(fw_dev, 0xCB, &disable);
+	pci_write_config_byte(fw_dev, 0xCA, 0x57);
+	pci_write_config_byte(fw_dev, 0xCB, disable & ~0x02);
+	pci_write_config_byte(fw_dev, 0xCA, write_enable);
+
+	printk(KERN_INFO DRIVER_NAME
+	       ": Controller is now re-enabled.\n");
+
+	pci_set_drvdata(pdev, NULL);
+}
+
+static struct pci_driver ricoh_mmc_driver = {
+	.name = 	DRIVER_NAME,
+	.id_table =	pci_ids,
+	.probe = 	ricoh_mmc_probe,
+	.remove =	__devexit_p(ricoh_mmc_remove),
+};
+
+/*****************************************************************************\
+ *                                                                           *
+ * Driver init/exit                                                          *
+ *                                                                           *
+\*****************************************************************************/
+
+static int __init ricoh_mmc_drv_init(void)
+{
+	printk(KERN_INFO DRIVER_NAME
+		": Ricoh MMC Controller disabling driver\n");
+	printk(KERN_INFO DRIVER_NAME ": Copyright(c) Philip Langdale\n");
+
+	return pci_register_driver(&ricoh_mmc_driver);
+}
+
+static void __exit ricoh_mmc_drv_exit(void)
+{
+	pci_unregister_driver(&ricoh_mmc_driver);
+}
+
+module_init(ricoh_mmc_drv_init);
+module_exit(ricoh_mmc_drv_exit);
+
+MODULE_AUTHOR("Philip Langdale <philipl@alumni.utexas.net>");
+MODULE_DESCRIPTION("Ricoh MMC Controller disabling driver");
+MODULE_LICENSE("GPL");
+