On Sat, Feb 13, 2016 at 2:19 PM, Linus Walleij [off-list ref] wrote:

On Tue, Jan 26, 2016 at 12:12 PM, Linus Walleij
[off-list ref] wrote:

quoted

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 <redacted>
Cc: Rob Herring <robh@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Linus Walleij <redacted>

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.

Yours,
Linus Walleij