spi: Add OF binding support for SPI busses

This patch adds support for populating an SPI bus based on data in the
OF device tree.  This is useful for powerpc platforms which use the
device tree instead of discrete code for describing platform layout.

Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
diff --git a/include/linux/of_spi.h b/include/linux/of_spi.h
new file mode 100644
index 0000000..5f71ee8
--- /dev/null
+++ b/include/linux/of_spi.h
@@ -0,0 +1,18 @@
+/*
+ * OpenFirmware SPI support routines
+ * Copyright (C) 2008 Secret Lab Technologies Ltd.
+ *
+ * Support routines for deriving SPI device attachments from the device
+ * tree.
+ */
+
+#ifndef __LINUX_OF_SPI_H
+#define __LINUX_OF_SPI_H
+
+#include <linux/of.h>
+#include <linux/spi/spi.h>
+
+extern void of_register_spi_devices(struct spi_master *master,
+				    struct device_node *np);
+
+#endif /* __LINUX_OF_SPI */