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 is controlled
by EVCR (Enhanced Volatile Configuration Register), 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.
Signed-off-by: bean huo <bean...@micron.com>
Acked-by: Marek Vasut <ma...@denx.de>
---
v1-v2:modified to that capture wait_till_ready()
return value,if error,directly return its
the value.
v2-v3:directly use the reurning error value of
read_reg and write_reg,instead of -EINVAL.
drivers/mtd/spi-nor/spi-nor.c | 46 +++++++++++++++++++++++++++++++++++++++++
include/linux/mtd/spi-nor.h | 6 ++++++
2 files changed, 52 insertions(+)
diff --git a/drivers/mtd/spi-nor/spi-nor.c b/drivers/mtd/spi-nor/spi-nor.c
index b5ad6be..486b167 100644
--- a/drivers/mtd/spi-nor/spi-nor.c
+++ b/drivers/mtd/spi-nor/spi-nor.c
@@ -878,6 +878,45 @@ static int spansion_quad_enable(struct spi_nor *nor)
return 0;
}
+static int micron_quad_enable(struct spi_nor *nor) {
+ int ret, val;
+
+ ret = nor->read_reg(nor, SPINOR_OP_RD_EVCR, &val, 1);
+ if (ret < 0) {
+ dev_err(nor->dev, "error %d reading EVCR\n", ret);
+ return ret;
+ }
+
+ write_enable(nor);
+
+ /* set EVCR ,enable quad I/O */
+ nor->cmd_buf[0] = val & ~EVCR_QUAD_EN_MICRON;
+ ret = nor->write_reg(nor, SPINOR_OP_WD_EVCR, nor->cmd_buf, 1, 0);
+ if (ret < 0) {
+ dev_err(nor->dev,
+ "error while writing EVCR register\n");
+ return ret;
+ }
+
+ ret = wait_till_ready(nor);
+ if (ret)
+ return ret;
+
+ /* read EVCR and check it */
+ ret = nor->read_reg(nor, SPINOR_OP_RD_EVCR, &val, 1);
+ if (ret < 0) {
+ dev_err(nor->dev, "error %d reading EVCR\n", ret);
+ return ret;
+ }
+ if (val & EVCR_QUAD_EN_MICRON) {
+ dev_err(nor->dev, "Micron EVCR Quad bit not clear\n");
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
static int set_quad_mode(struct spi_nor *nor, u32 jedec_id) {
int status;
@@ -890,6 +929,13 @@ static int set_quad_mode(struct spi_nor *nor, u32 jedec_id)
return -EINVAL;
}
return status;
+ case CFI_MFR_ST:
+ status = micron_quad_enable(nor);
+ if (status) {
+ dev_err(nor->dev, "Micron quad-read not enabled\n");
+ return -EINVAL;
+ }
+ return status;
default:
status = spansion_quad_enable(nor);
if (status) {
diff --git a/include/linux/mtd/spi-nor.h b/include/linux/mtd/spi-nor.h index
9e6294f..d71b659 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 +71,8 @@
#define SR_QUAD_EN_MX 0x40 /* Macronix Quad I/O */
+#define EVCR_QUAD_EN_MICRON 0x80 /* Micron Quad I/O */
+
/* Flag Status Register bits */
#define FSR_READY 0x80
--
1.7.9.5
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