mtd: spi-nor: add the framework for SPI NOR

This patch cloned most of the m25p80.c. In theory, it adds a new spi-nor layer.

Before this patch, the layer is like:

                   MTD
         ------------------------
                  m25p80
         ------------------------
	       spi bus driver
         ------------------------
	        SPI NOR chip

After this patch, the layer is like:
                   MTD
         ------------------------
                  spi-nor
         ------------------------
                  m25p80
         ------------------------
	       spi bus driver
         ------------------------
	       SPI NOR chip

With the spi-nor controller driver(Freescale Quadspi), it looks like:
                   MTD
         ------------------------
                  spi-nor
         ------------------------
                fsl-quadspi
         ------------------------
	       SPI NOR chip

New APIs:
   spi_nor_scan: used to scan a spi-nor flash.

Signed-off-by: Huang Shijie <b32955@freescale.com>
Acked-by: Marek Vasut <marex@denx.de>
[Brian: rebased to include additional m25p_ids[] entry]
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

1 files changed, 20 insertions, 0 deletions

diff --git a/include/linux/mtd/spi-nor.h b/include/linux/mtd/spi-nor.h
index 3a3c3872c8cd..16d8409abcdc 100644
--- a/include/linux/mtd/spi-nor.h
+++ b/include/linux/mtd/spi-nor.h
@@ -162,4 +162,24 @@ struct spi_nor {
 
 	void *priv;
 };
+
+/**
+ * spi_nor_scan() - scan the SPI NOR
+ * @nor:	the spi_nor structure
+ * @id:		the spi_device_id provided by the driver
+ * @mode:	the read mode supported by the driver
+ *
+ * The drivers can use this fuction to scan the SPI NOR.
+ * In the scanning, it will try to get all the necessary information to
+ * fill the mtd_info{} and the spi_nor{}.
+ *
+ * The board may assigns a spi_device_id with @id which be used to compared with
+ * the spi_device_id detected by the scanning.
+ *
+ * Return: 0 for success, others for failure.
+ */
+int spi_nor_scan(struct spi_nor *nor, const struct spi_device_id *id,
+			enum read_mode mode);
+extern const struct spi_device_id spi_nor_ids[];
+
 #endif