memory: emif: add device tree support to emif driver

Device tree support for the EMIF driver. LPDDR2 generic timings
extraction from device is managed using couple of helper
functions which can be used by other memory controller
drivers.

Reviewed-by: Benoit Cousson <b-cousson@ti.com>
Reviewed-by: Grant Likely <grant.likely@secretlab.ca>
Tested-by: Lokesh Vutla <lokeshvutla@ti.com>
Signed-off-by: Aneesh V <aneesh@ti.com>
Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/memory/of_memory.h b/drivers/memory/of_memory.h
new file mode 100644
index 0000000..20b496e
--- /dev/null
+++ b/drivers/memory/of_memory.h
@@ -0,0 +1,36 @@
+/*
+ * OpenFirmware helpers for memory drivers
+ *
+ * Copyright (C) 2012 Texas Instruments, Inc.
+ *
+ * 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.
+ */
+
+#ifndef __LINUX_MEMORY_OF_REG_H
+#define __LINUX_MEMORY_OF_REG_H
+
+#ifdef CONFIG_OF
+extern const struct lpddr2_min_tck *of_get_min_tck(struct device_node *np,
+		struct device *dev);
+extern const struct lpddr2_timings
+	*of_get_ddr_timings(struct device_node *np_ddr, struct device *dev,
+	u32 device_type, u32 *nr_frequencies);
+#else
+static inline const struct lpddr2_min_tck
+	*of_get_min_tck(struct device_node *np, struct device *dev)
+{
+	return NULL;
+}
+
+static inline const struct lpddr2_timings
+	*of_get_ddr_timings(struct device_node *np_ddr, struct device *dev,
+	u32 device_type, u32 *nr_frequencies)
+{
+	return NULL;
+}
+#endif /* CONFIG_OF */
+
+#endif /* __LINUX_MEMORY_OF_REG_ */