patches/0571-mtd-spi-nor-add-an-API-to-restore-the-status-of-SPI-.patch

From 332f6b3068078bfc3b9235ebf8dae07d126564c3 Mon Sep 17 00:00:00 2001
From: Hou Zhiqiang <Zhiqiang.Hou@nxp.com>
Date: Wed, 6 Dec 2017 10:53:41 +0800
Subject: [PATCH 0571/1795] mtd: spi-nor: add an API to restore the status of
 SPI flash chip

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>
Signed-off-by: Cyrille Pitchen <cyrille.pitchen@wedev4u.fr>
(cherry picked from commit 8dee1d971af9af2f7b5f54c2eac4ebd04c5c237c)
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
---
 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 4daec97e9997..d458523716d7 100644
--- a/drivers/mtd/spi-nor/spi-nor.c
+++ b/drivers/mtd/spi-nor/spi-nor.c
@@ -2672,6 +2672,16 @@ static int spi_nor_init(struct spi_nor *nor)
 	return 0;
 }
 
+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..db78a3c22126 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
-- 
2.19.0