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

Martyn Welch
2015-12-02T21:47:25Z

On 02/12/15 18:44, Rob Herring wrote:
> On Wed, Dec 2, 2015 at 10:49 AM, Martyn Welch
> <martyn.welch@collabora.co.uk> 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@kernel.org>
>>>> Cc: Pawel Moll <pawel.moll@arm.com>
>>>> Cc: Mark Rutland <mark.rutland@arm.com>
>>>> Cc: Ian Campbell <ijc+devicetree@hellion.org.uk>
>>>> Cc: Kumar Gala <galak@codeaurora.org>
>>>> Cc: devicetree@vger.kernel.org
>>>> Signed-off-by: Martyn Welch <martyn.welch@collabora.co.uk>
>>>> ---
>>>> .../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