On Fri, Jun 16, 2023 at 02:25:12PM +0530, Amit Kumar Mahapatra wrote: > If the WP signal of the flash device is not connected and the software sets > the status register write disable (SRWD) bit in the status register then > thestatus register permanently becomes read-only. To avoid this added a new > boolean DT property "broken-wp". If WP signal is not connected, then this > property should be set in the DT to avoid setting the SRWD during status > register write operation. > > Signed-off-by: Amit Kumar Mahapatra <amit.kumar-mahapatra@xxxxxxx> > Reviewed-by: Conor Dooley <conor.dooley@xxxxxxxxxxxxx> > --- > .../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..10a6df752f6f 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. > > + broken-wp: In the tied low case, that's designed behavior rather than broken. The name should reflect that. > + 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 then status register permanently becomes > + read-only as the SRWD bit cannot be reset. This boolean flag can be used > + on systems in which WP signal is not connected, to avoid setting the SRWD > + bit while writing the status register. If the WP signal is hard strapped > + to LOW then it is not broken as it can be a valid use case. > + > reset-gpios: > description: > A GPIO line connected to the RESET (active low) signal of the device. > -- > 2.17.1 >
