diff options
| author | Bean Huo 霍斌斌 (beanhuo) <beanhuo@micron.com> | 2014-12-17 07:35:45 +0000 |
|---|---|---|
| committer | Brian Norris <computersforpeace@gmail.com> | 2015-01-07 11:33:22 -0800 |
| commit | 548cd3ab54da10f896daa7ca422236847a915734 (patch) | |
| tree | b639d9d85db919c3ddfbf4be097cd25ab08f7e87 /include/linux/mtd | |
| parent | ed0215cc3b5292fc0f4af70e29dc61fa2d0aa76c (diff) | |
mtd: spi-nor: Add quad I/O support for Micron SPI NOR
This patch adds code which enables Quad I/O mode on Micron SPI NOR flashes.
For Micron SPI NOR flash, enabling or disabling quad I/O protocol can be
done By two methods, which are to use EVCR (Enhanced Volatile
Configuration Register) and the ENTER QUAD I/O MODE command. There is no
difference between these two methods. Unfortunately, for some Micron SPI
NOR flashes, there no ENTER Quad I/O command (35h), such as n25q064. But
for all current Micron SPI NOR, if it support quad I/O mode, using EVCR
definitely be supported. It is a recommended method to enable Quad I/O
mode by EVCR, Quad I/O protocol bit 7. When EVCR bit 7 is reset to 0,
the SPI NOR flash will operate in quad I/O mode.
This patch has been tested on N25Q512A and MT25TL256BAA1ESF. Micron SPI
NOR of spi_nor_ids[] table all support this method.
Signed-off-by: Bean Huo <beanhuo@micron.com>
Acked-by: Marek Vasut <marex@denx.de>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Diffstat (limited to 'include/linux/mtd')
| -rw-r--r-- | include/linux/mtd/spi-nor.h | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/include/linux/mtd/spi-nor.h b/include/linux/mtd/spi-nor.h index 63aeccf9ddc..4720b86ee73 100644 --- a/include/linux/mtd/spi-nor.h +++ b/include/linux/mtd/spi-nor.h @@ -56,6 +56,10 @@ /* Used for Spansion flashes only. */ #define SPINOR_OP_BRWR 0x17 /* Bank register write */ +/* Used for Micron flashes only. */ +#define SPINOR_OP_RD_EVCR 0x65 /* Read EVCR register */ +#define SPINOR_OP_WD_EVCR 0x61 /* Write EVCR register */ + /* Status Register bits. */ #define SR_WIP 1 /* Write in progress */ #define SR_WEL 2 /* Write enable latch */ @@ -67,6 +71,9 @@ #define SR_QUAD_EN_MX 0x40 /* Macronix Quad I/O */ +/* Enhanced Volatile Configuration Register bits */ +#define EVCR_QUAD_EN_MICRON 0x80 /* Micron Quad I/O */ + /* Flag Status Register bits */ #define FSR_READY 0x80 |