mtd: spi-nor: add spi_nor_init() function

This patch extracts some chunks from spi_nor_init_params and spi_nor_scan()
 and moves them into a new spi_nor_init() function.

Indeed, spi_nor_init() regroups all the required SPI flash commands to be
sent to the SPI flash memory before performing any runtime operations
(Fast Read, Page Program, Sector Erase, ...). Hence spi_nor_init():
1) removes the flash protection if applicable for certain vendors.
2) sets the Quad Enable bit, if needed, before using Quad SPI protocols.
3) makes the memory enter its (stateful) 4-byte address mode, if needed,
   for SPI flash memory > 128Mbits not supporting the 4-byte address
   instruction set.

spi_nor_scan() now ends by calling spi_nor_init() once the probe phase has
completed. Further patches could also use spi_nor_init() to implement the
mtd->_resume() handler for the spi-nor framework.

Signed-off-by: Kamal Dasu <kdasu.kdev@gmail.com>
Signed-off-by: Cyrille Pitchen <cyrille.pitchen@wedev4u.fr>

1 files changed, 10 insertions, 0 deletions

diff --git a/include/linux/mtd/spi-nor.h b/include/linux/mtd/spi-nor.h
index 1f0a7fc7772f..d0c66a0975cf 100644
--- a/include/linux/mtd/spi-nor.h
+++ b/include/linux/mtd/spi-nor.h
@@ -232,10 +232,17 @@ enum spi_nor_option_flags {
 };
 
 /**
+ * struct flash_info - Forward declaration of a structure used internally by
+ *                     spi_nor_scan()
+ */
+struct flash_info;
+
+/**
  * struct spi_nor - Structure for defining a the SPI NOR layer
  * @mtd:                point to a mtd_info structure
  * @lock:               the lock for the read/write/erase/lock/unlock operations
  * @dev:                point to a spi device, or a spi nor controller device.
+ * @info:               spi-nor part JDEC MFR id and other info
  * @page_size:          the page size of the SPI NOR
  * @addr_width:         number of address bytes
  * @erase_opcode:       the opcode for erasing a sector
@@ -262,6 +269,7 @@ enum spi_nor_option_flags {
  * @flash_lock:         [FLASH-SPECIFIC] lock a region of the SPI NOR
  * @flash_unlock:       [FLASH-SPECIFIC] unlock a region of the SPI NOR
  * @flash_is_locked:    [FLASH-SPECIFIC] check if a region of the SPI NOR is
+ * @quad_enable:        [FLASH-SPECIFIC] enables SPI NOR quad mode
  *                      completely locked
  * @priv:               the private data
  */
@@ -269,6 +277,7 @@ struct spi_nor {
         struct mtd_info         mtd;
         struct mutex            lock;
         struct device           *dev;
+        const struct flash_info *info;
         u32                     page_size;
         u8                      addr_width;
         u8                      erase_opcode;
@@ -296,6 +305,7 @@ struct spi_nor {
         int (*flash_lock)(struct spi_nor *nor, loff_t ofs, uint64_t len);
         int (*flash_unlock)(struct spi_nor *nor, loff_t ofs, uint64_t len);
         int (*flash_is_locked)(struct spi_nor *nor, loff_t ofs, uint64_t len);
+        int (*quad_enable)(struct spi_nor *nor);
 
         void *priv;
 };