On Fri, Dec 23, 2016 at 01:56:11PM +0100, Geert Uytterhoeven wrote:

On Fri, Dec 23, 2016 at 12:35 PM, Lars-Peter Clausen [off-list ref] wrote:

quoted

cooperation between kernel- and userspace. Kernelspace offering an interface
to export a device for userspace access and userspace making use of that
interface to request access to a device. In a similar way to how vfio is
structured.

...

We do not have bindings to describe GPIOs connected to e.g. relays.

Well, it depends what the relays are doing in the system of course...

Switching external devices (the internals of those devices not described
itself in DT, like in an industrial context), sounds more like something to
be handled by IIO, doesn't it?

The BayLibre ACME systems have a case like this with their power
metering stuff (I've got a similar but more overenginered board I'm in
theory working on with actual relays).  The system itself is controlling
a power line, it knows nothing about what's connected.  It seems like
this is coming up often enough that someone should probably just write
an external system control binding, also tying in things like references
to the console and so on.