dm: mmc: Add an MMC uclass

Add basic support for MMC, providing a uclass which can set up an MMC
device. This allows MMC drivers to move to using driver model.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/drivers/mmc/mmc-uclass.c b/drivers/mmc/mmc-uclass.c
new file mode 100644
index 0000000..777489f
--- /dev/null
+++ b/drivers/mmc/mmc-uclass.c
@@ -0,0 +1,34 @@
+/*
+ * Copyright (C) 2015 Google, Inc
+ * Written by Simon Glass <sjg@chromium.org>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <common.h>
+#include <mmc.h>
+#include <dm.h>
+#include <dm/lists.h>
+#include <dm/root.h>
+
+struct mmc *mmc_get_mmc_dev(struct udevice *dev)
+{
+	struct mmc_uclass_priv *upriv;
+
+	if (!device_active(dev))
+		return NULL;
+	upriv = dev_get_uclass_priv(dev);
+	return upriv->mmc;
+}
+
+U_BOOT_DRIVER(mmc) = {
+	.name	= "mmc",
+	.id	= UCLASS_MMC,
+};
+
+UCLASS_DRIVER(mmc) = {
+	.id		= UCLASS_MMC,
+	.name		= "mmc",
+	.flags		= DM_UC_FLAG_SEQ_ALIAS,
+	.per_device_auto_alloc_size = sizeof(struct mmc_uclass_priv),
+};