[PATCH] mtd: m25p80: make it possible to use 4K erase block

[Antony Pavlov]

We already have the MTD_SPI_NOR_USE_4K_SECTORS option handling in C code
for 4K erase block support. Alas this 4K erase block support code
can't be used because the MTD_SPI_NOR_USE_4K_SECTORS option support
is missed in Kconfig.

This patch imports necessary Kconfig MTD_SPI_NOR_USE_4K_SECTORS option
declaration from linux v4.11-rc8.

Signed-off-by: Antony Pavlov <antonynpavlov at gmail.com>
---
 drivers/mtd/spi-nor/Kconfig | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/drivers/mtd/spi-nor/Kconfig b/drivers/mtd/spi-nor/Kconfig
index a84591fdd1..8ede3c90be 100644
--- a/drivers/mtd/spi-nor/Kconfig
+++ b/drivers/mtd/spi-nor/Kconfig
@@ -7,6 +7,20 @@ menuconfig MTD_SPI_NOR
 
 if MTD_SPI_NOR
 
+config MTD_SPI_NOR_USE_4K_SECTORS
+	bool "Use small 4096 B erase sectors"
+	default y
+	help
+	  Many flash memories support erasing small (4096 B) sectors. Depending
+	  on the usage this feature may provide performance gain in comparison
+	  to erasing whole blocks (32/64 KiB).
+	  Changing a small part of the flash's contents is usually faster with
+	  small sectors. On the other hand erasing should be faster when using
+	  64 KiB block instead of 16 × 4 KiB sectors.
+
+	  Please note that some tools/drivers/filesystems may not work with
+	  4096 B erase size (e.g. UBIFS requires 15 KiB as a minimum).
+
 config SPI_CADENCE_QUADSPI
 	tristate "Cadence Quad SPI controller"
 	help
-- 
2.11.0