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Subject[PATCHv3 1/2] mtd: spi-nor: add an API to restore the status of SPI flash chip
Date
From: Hou Zhiqiang <Zhiqiang.Hou@nxp.com>

Add this API to restore the status of SPI flash chip to the default
such as addressing mode, whenever detach the driver from device or
reboot the system.

Signed-off-by: Hou Zhiqiang <Zhiqiang.Hou@nxp.com>
---
V3:
- no change.

Documentation/mtd/spi-nor.txt | 3 +++
drivers/mtd/spi-nor/spi-nor.c | 10 ++++++++++
include/linux/mtd/spi-nor.h | 6 ++++++
3 files changed, 19 insertions(+)

diff --git a/Documentation/mtd/spi-nor.txt b/Documentation/mtd/spi-nor.txt
index 548d6306ebca..da1fbff5a24c 100644
--- a/Documentation/mtd/spi-nor.txt
+++ b/Documentation/mtd/spi-nor.txt
@@ -60,3 +60,6 @@ The main API is spi_nor_scan(). Before you call the hook, a driver should
initialize the necessary fields for spi_nor{}. Please see
drivers/mtd/spi-nor/spi-nor.c for detail. Please also refer to fsl-quadspi.c
when you want to write a new driver for a SPI NOR controller.
+Another API is spi_nor_restore(), this is used to restore the status of SPI
+flash chip such as addressing mode. Call it whenever detach the driver from
+device or reboot the system.
diff --git a/drivers/mtd/spi-nor/spi-nor.c b/drivers/mtd/spi-nor/spi-nor.c
index bc266f70a15b..4a925378d434 100644
--- a/drivers/mtd/spi-nor/spi-nor.c
+++ b/drivers/mtd/spi-nor/spi-nor.c
@@ -2713,6 +2713,16 @@ static void spi_nor_resume(struct mtd_info *mtd)
dev_err(dev, "resume() failed\n");
}

+void spi_nor_restore(struct spi_nor *nor)
+{
+ /* restore the addressing mode */
+ 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);
+}
+EXPORT_SYMBOL_GPL(spi_nor_restore);
+
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..0a182c3d0884 100644
--- a/include/linux/mtd/spi-nor.h
+++ b/include/linux/mtd/spi-nor.h
@@ -399,4 +399,10 @@ struct spi_nor_hwcaps {
int spi_nor_scan(struct spi_nor *nor, const char *name,
const struct spi_nor_hwcaps *hwcaps);

+/*
+ * spi_nor_restore_addr_mode() - restore the status of SPI NOR
+ * @nor: the spi_nor structure
+ */
+void spi_nor_restore(struct spi_nor *nor);
+
#endif
--
2.14.1
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