[PATCH 2/6] mtd: physmap_of: add a hook for Versatile write protection

[Linus Walleij]

On Sat, Mar 5, 2016 at 6:09 PM, Linus Walleij <linus.walleij at linaro.org> wrote:
> On Mon, Feb 22, 2016 at 8:09 PM, Linus Walleij <linus.walleij at linaro.org> wrote:
>> On Sat, Feb 13, 2016 at 2:19 PM, Linus Walleij <linus.walleij at linaro.org> wrote:
>>> On Tue, Jan 26, 2016 at 12:12 PM, Linus Walleij
>>> <linus.walleij at linaro.org> wrote:
>>>
>>>> In order to support device tree probing of Versatile NOR flash
>>>> chips, there must be a way to add the VPP (write protection)
>>>> enable/disable callback. The register in question is in the
>>>> system controllers of these machines. Apart from this quirk,
>>>> the ARM flash chips are standard CFI flash chips from various
>>>> vendors.
>>>>
>>>> Additionally, the Integrator/AP require you to set up the external
>>>> bus interface (EBI) to allow writes to the chip select where the
>>>> flash memory is connected.
>>>>
>>>> Solve this by looking for the arm,versatile-flash compatible
>>>> string in the flash device tree node. In the driver,
>>>> add a special hook to check for the various Versatile syscons and
>>>> register a callback for .set_vpp() if this compatible is present.
>>>>
>>>> Provide a special Kconfig entry for the addon hook so it will
>>>> not be compiled in if the Versatile boards are not supported.
>>>> Stubs in the header file make sure the impact will be zero on
>>>> other platforms. (Compilers optimze this out.)
>>>>
>>>> With this patch, a large slew of ARM board file code can be
>>>> removed.
>>>>
>>>> Cc: Grant Likely <grant.likely at linaro.org>
>>>> Cc: Rob Herring <robh at kernel.org>
>>>> Cc: Arnd Bergmann <arnd at arndb.de>
>>>> Signed-off-by: Linus Walleij <linus.walleij at linaro.org>
>>>
>>> Do you think my reply to this about reference counting and
>>> subsequent (accepted) patch to update the documentation
>>> to reflect 876fe76d793d03077
>>> "mtd: maps: physmap: Add reference counter to set_vpp()"
>>> is enough to warrant merging of this?
>>>
>>> If you want the code developed in any special direction
>>> just tell me.
>>
>> Ping.
>
> Ping.

Ping.

Yours,
Linus Walleij