Am 2023-06-25 12:02, schrieb Amit Kumar Mahapatra:
If the WP# signal of the flash device is either not connected or is
wrongly
tied to GND (that includes internal pull-downs), and the software sets
the
status register write disable (SRWD) bit in the status register then
the
status register permanently becomes read-only. To avoid this added a
new
boolean DT property "no-wp". If this property is set in the DT then the
software avoids setting the SRWD during status register write
operation.
Signed-off-by: Amit Kumar Mahapatra <amit.kumar-mahapatra@xxxxxxx>
---
As the DT property name has changed so, removed Reviewed-by tag.
@Cornor if possible, could you please review this updated patch.
---
.../devicetree/bindings/mtd/jedec,spi-nor.yaml | 15 +++++++++++++++
1 file changed, 15 insertions(+)
diff --git a/Documentation/devicetree/bindings/mtd/jedec,spi-nor.yaml
b/Documentation/devicetree/bindings/mtd/jedec,spi-nor.yaml
index 89959e5c47ba..97344969b02d 100644
--- a/Documentation/devicetree/bindings/mtd/jedec,spi-nor.yaml
+++ b/Documentation/devicetree/bindings/mtd/jedec,spi-nor.yaml
@@ -70,6 +70,21 @@ properties:
be used on such systems, to denote the absence of a reliable
reset
mechanism.
+ no-wp:
+ type: boolean
+ description:
+ The status register write disable (SRWD) bit in status register,
combined
+ with the WP# signal, provides hardware data protection for the
device. When
+ the SRWD bit is set to 1, and the WP# signal is either driven
LOW or hard
+ strapped to LOW, the status register nonvolatile bits become
read-only and
+ the WRITE STATUS REGISTER operation will not execute. The only
way to exit
+ this hardware-protected mode is to drive WP# HIGH. If the WP#
signal of the
+ flash device is not connected or is wrongly tied to GND (that
includes internal
+ pull-downs) then status register permanently becomes read-only
as the SRWD bit
+ cannot be reset. This boolean flag can be used on such systems
to avoid setting
+ the SRWD bit while writing the status register. WP# signal hard
strapped to GND
+ can be a valid use case.
+
Sounds good! Thank you.
Reviewed-by: Michael Walle <michael@xxxxxxxx>
-michael
