On Tue, Jan 21, 2014 at 07:50:06PM +0100, Arnd Bergmann wrote:

> I should have another look at the debugfs representation, but isn't
> there a global namespace that gets used for all gpios?  Neither the
> con_id nor the name that the driver picks would be globally unique
> and stable across kernel versions, so they don't make a good user
> interface.

Currently the globally unique name is the GPIO number but that's not
stable since it gets dynamically assigned.  

> I think what we want here is a system-wide unique identifier for
> each gpio line that may get represented in debugfs, and use a new
> DT mechanism to communicate that.

We've mostly been using things based off dev_name() for stability.