[PATCH for-4.4 1/2] mtd: spi-nor: fix Spansion regressions (aliased with Winbond)

[Matthias Schiffer]

On 12/15/2015 07:48 PM, Brian Norris wrote:
> Spansion and Winbond have occasionally used the same manufacturer ID,
> and they don't support the same features. Particularly, writing SR=0
> seems to break read access for Spansion's s25fl064k. Unfortunately, we
> don't currently have a way to differentiate these Spansion and Winbond
> parts, so rather than regressing support for these Spansion flash, let's
> drop the new Winbond lock/unlock support for now. We can try to address
> Winbond support during the next release cycle.
> 
> Original discussion:
> 
> http://patchwork.ozlabs.org/patch/549173/
> http://patchwork.ozlabs.org/patch/553683/
> 

I have a few devices with a s25fl064k lying around, and I was not able to
reproduce this issue. I've re-applied "mtd: spi-nor: disable protection for
Winbond flash at startup" and the flash is readable just fine.

On the contrary, I've come across a board with a s25fl064k that comes up
locked, so removing the protection bits would be necessary. (I was not yet
able to check if the patch actually fixes writing to the flash on this
board, as I don't have access to the device myself, but I hope to get a
response on that soon.)

Regards,
Matthias

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