[PATCH 1/2] mtd: spi-nor: add a API to restore the addressing mode

[Zhiqiang Hou]

From: Hou Zhiqiang <Zhiqiang.Hou@xxxxxxx>

It's better to restore the addressing mode of the SPI flash
whenever remove the driver or reboot the system.

Signed-off-by: Hou Zhiqiang <Zhiqiang.Hou@xxxxxxx>
---
 drivers/mtd/spi-nor/spi-nor.c | 8 ++++++++
 include/linux/mtd/spi-nor.h   | 1 +
 2 files changed, 9 insertions(+)

diff --git a/drivers/mtd/spi-nor/spi-nor.c b/drivers/mtd/spi-nor/spi-nor.c
index bc266f70a15b..801cbe99b059 100644
--- a/drivers/mtd/spi-nor/spi-nor.c
+++ b/drivers/mtd/spi-nor/spi-nor.c
@@ -2713,6 +2713,14 @@ static void spi_nor_resume(struct mtd_info *mtd)
 		dev_err(dev, "resume() failed\n");
 }
 
+void spi_nor_restore_addr_mode(struct spi_nor *nor)
+{
+	if ((nor->addr_width == 4) &&
+	    (JEDEC_MFR(nor->info) != SNOR_MFR_SPANSION) &&
+	    !(nor->info->flags & SPI_NOR_4B_OPCODES))
+		set_4byte(nor, nor->info, 0);
+}
+
 int spi_nor_scan(struct spi_nor *nor, const char *name,
 		 const struct spi_nor_hwcaps *hwcaps)
 {
diff --git a/include/linux/mtd/spi-nor.h b/include/linux/mtd/spi-nor.h
index d0c66a0975cf..fe9357da2049 100644
--- a/include/linux/mtd/spi-nor.h
+++ b/include/linux/mtd/spi-nor.h
@@ -398,5 +398,6 @@ struct spi_nor_hwcaps {
  */
 int spi_nor_scan(struct spi_nor *nor, const char *name,
 		 const struct spi_nor_hwcaps *hwcaps);
+void spi_nor_restore_addr_mode(struct spi_nor *nor);
 
 #endif
-- 
2.14.1