summaryrefslogtreecommitdiff
path: root/include/linux/mtd
diff options
context:
space:
mode:
authorBean Huo 霍斌斌 (beanhuo) <beanhuo@micron.com>2014-12-17 07:35:45 +0000
committerBrian Norris <computersforpeace@gmail.com>2015-01-07 11:33:22 -0800
commit548cd3ab54da10f896daa7ca422236847a915734 (patch)
treeb639d9d85db919c3ddfbf4be097cd25ab08f7e87 /include/linux/mtd
parented0215cc3b5292fc0f4af70e29dc61fa2d0aa76c (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.h7
1 files changed, 7 insertions, 0 deletions
diff --git a/include/linux/mtd/spi-nor.h b/include/linux/mtd/spi-nor.h
index 63aeccf9ddc8..4720b86ee73d 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