mtd: spi-nor: spansion: preserve CFR2V[7] when writing MEMLAT

CFR2V[7] is assigned to Flash's address mode (3- or 4-ybte) and must not
be changed when writing MEMLAT (CFR2V[3:0]). CFR2V shall be used in a read,
update, write back fashion.

Fixes: c3266af101f2 ("mtd: spi-nor: spansion: add support for Cypress Semper flash")
Signed-off-by: Takahiro Kuwano <Takahiro.Kuwano@infineon.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20230726075257.12985-3-tudor.ambarus@linaro.org
Signed-off-by: Tudor Ambarus <tudor.ambarus@linaro.org>

diff --git a/drivers/mtd/spi-nor/spansion.c b/drivers/mtd/spi-nor/spansion.c
index 6b2532e..6460d22 100644 (file)
--- a/drivers/mtd/spi-nor/spansion.c
+++ b/drivers/mtd/spi-nor/spansion.c
@@ -4,6 +4,7 @@
  * Copyright (C) 2014, Freescale Semiconductor, Inc.
  */
 
+#include <linux/bitfield.h>
 #include <linux/device.h>
 #include <linux/mtd/spi-nor.h>
 
@@ -28,6 +29,7 @@
 #define SPINOR_REG_CYPRESS_CFR2                        0x3
 #define SPINOR_REG_CYPRESS_CFR2V                                       \
        (SPINOR_REG_CYPRESS_VREG + SPINOR_REG_CYPRESS_CFR2)
+#define SPINOR_REG_CYPRESS_CFR2_MEMLAT_MASK    GENMASK(3, 0)
 #define SPINOR_REG_CYPRESS_CFR2_MEMLAT_11_24   0xb
 #define SPINOR_REG_CYPRESS_CFR2_ADRBYT         BIT(7)
 #define SPINOR_REG_CYPRESS_CFR3                        0x4
@@ -161,8 +163,18 @@ static int cypress_nor_octal_dtr_en(struct spi_nor *nor)
        int ret;
        u8 addr_mode_nbytes = nor->params->addr_mode_nbytes;
 
+       op = (struct spi_mem_op)
+               CYPRESS_NOR_RD_ANY_REG_OP(addr_mode_nbytes,
+                                         SPINOR_REG_CYPRESS_CFR2V, 0, buf);
+
+       ret = spi_nor_read_any_reg(nor, &op, nor->reg_proto);
+       if (ret)
+               return ret;
+
        /* Use 24 dummy cycles for memory array reads. */
-       *buf = SPINOR_REG_CYPRESS_CFR2_MEMLAT_11_24;
+       *buf &= ~SPINOR_REG_CYPRESS_CFR2_MEMLAT_MASK;
+       *buf |= FIELD_PREP(SPINOR_REG_CYPRESS_CFR2_MEMLAT_MASK,
+                          SPINOR_REG_CYPRESS_CFR2_MEMLAT_11_24);
        op = (struct spi_mem_op)
                CYPRESS_NOR_WR_ANY_REG_OP(addr_mode_nbytes,
                                          SPINOR_REG_CYPRESS_CFR2V, 1, buf);