Re: [PATCH 1/3] Device tree binding documentation for chromeos-firmware

[Martyn Welch]

On 02/12/15 18:44, Rob Herring wrote:
> On Wed, Dec 2, 2015 at 10:49 AM, Martyn Welch
> <martyn.welch@xxxxxxxxxxxxxxx> wrote:
> > On 02/12/15 15:15, Rob Herring wrote:
> > > On Tue, Dec 01, 2015 at 07:12:49PM +0000, Martyn Welch wrote:
> > > > This patch adds documentation for the chromeos-firmware binding.
> > > >
> > > > Cc: Rob Herring <robh+dt@xxxxxxxxxx>
> > > > Cc: Pawel Moll <pawel.moll@xxxxxxx>
> > > > Cc: Mark Rutland <mark.rutland@xxxxxxx>
> > > > Cc: Ian Campbell <ijc+devicetree@xxxxxxxxxxxxxx>
> > > > Cc: Kumar Gala <galak@xxxxxxxxxxxxxx>
> > > > Cc: devicetree@xxxxxxxxxxxxxxx
> > > > Signed-off-by: Martyn Welch <martyn.welch@xxxxxxxxxxxxxxx>
> > > > ---
> > > >    .../devicetree/bindings/misc/chromeos-firmware.txt | 27
> > > > ++++++++++++++++++++++
> > >
> > >
> > > bindings/firmware/ please.
> >
> > OK.
> >
> > > >    1 file changed, 27 insertions(+)
> > > >    create mode 100644
> > > > Documentation/devicetree/bindings/misc/chromeos-firmware.txt
> > > >
> > > > diff --git a/Documentation/devicetree/bindings/misc/chromeos-firmware.txt
> > > > b/Documentation/devicetree/bindings/misc/chromeos-firmware.txt
> > > > new file mode 100644
> > > > index 0000000..8240611
> > > > --- /dev/null
> > > > +++ b/Documentation/devicetree/bindings/misc/chromeos-firmware.txt
> > > > @@ -0,0 +1,27 @@
> > > > +Device-Tree bindings for chromeos-firmware.c.
> > >
> > >
> > > Perhaps a bit more description what this is.
> > >
> > > What aspect of this is firmware? How does this relate to the EC?
> >
> > With respect to write-protect, this line is the write protection for the
> > flash which holds the bootloader.
>
> What is driving the write-protect? Are trying to assign ownership of
> the SOC GPIOs to the bootloader/firmware? If so, I think this is all
> wrong.

The lines are typically driven by a debugging board plugged into a 
socket on the Chromebooks motherboard, not by the device it's self. The 
driver exposes a read-only interface to these signals.

Martyn
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