On Tue, Jan 26, 2016 at 12:37 PM, Russell King - ARM Linux
[off-list ref] wrote:

On Tue, Jan 26, 2016 at 12:12:01PM +0100, Linus Walleij wrote:

quoted

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.

You are aware that the "write enable" applies to all flash devices
on the board, and not just NOR flash.  What that means is if you
have drivers for the other flash devices, you need to have a way
to enable writes when _any_ driver wants write access.

So, it shouldn't be part of the flash driver at all.

Yes this is correct ... I put in the current code to be able to
test writes on the hardware. As to actually write to flash on
the Integrator both flags must be set to 1.

I don't see why it would just be a problem just for write
enable though, as I guess the VPP bit is *also* shared by all
devices?

After
commit 876fe76d793d03077
"mtd: maps: physmap: Add reference counter to set_vpp()"

As long as the flash devices are all physmap this reference
counter should hold VPP+WP enabled with this code as
long as any flash device has called .set_vpp().

It is a bit unintuitive that .set_vpp() is named like that though.
.enable_write() or something would be better I guess.
(The reference count also makes it start to reimplement
the regulator infrastructure.)

Yours,
Linus Walleij