[Arm-netbook] Testing: GPIO

[Richard Wilbur]

On Mar 1, 2018, at 20:30, Luke Kenneth Casson Leighton <lkcl at lkcl.net> wrote:


Sent from my iPhone
> On Thu, Mar 1, 2018 at 9:46 PM, Richard Wilbur <richard.wilbur at gmail.com> wrote:
>> It looks to me like the fastest way to test the GPIO lines connected
>> on the micro-desktop board to VESA_SCL and VESA_SDA would simply be to
>> connect a VGA monitor to the micro-desktop and make sure it is
>> properly detected and a test image looks right on it.
> 
> yep, pretty much... with one slight fly in the ointment: the SCL and
> SDA lines are straight GPIO and will need a bit-banging I2C linux
> kernel driver.  once that's configured, doing i2cdetect _should_ be
> enough to test the circuit, although scanning the data and running
> read-edid on it would be awesome and amazing: it would mean being able
> to *really* do proper VESA detection.

Is someone already working on that?  Sounds like we need the device tree for the micro-desktop to be populated.  If we did it for micro-desktop v1.7 it would be something to build off for micro-desktop v1.8 and also a good place to begin for the laptop.

From what I'm hearing, once the device tree is ready we could work on "automagically" configuring the VESA DDC driver to bit-bang the correct GPIO pins. Does the bit-banging VESA DDC driver exist already?  (I wrote a bit-banging I2C driver in VxWorks at a previous position so the topic is not foreign.)

If none of this is underway I'll continue mapping things out so we can create the device tree for the micro-desktop.  If I remember correctly we also should create a device tree for the DS-113 v2.7.4 and v2.7.5?

I'd be happy to work on that if you think that is the highest priority right now.  It sounds like it will help both testing and deployment.