Code review comment for lp://staging/~manjo/ubuntu/trusty/systemd/HP-m800

> Note that a rule can still refer to the general DMI data, like this:
>
> SUBSYSTEM=="input", KERNEL=="event*", SUBSYSTEMS=="platform",
> KERNELS=="gpio_keys.12", ATTR{[dmi/id]sys_vendor}=="HP*",
> ATTR{[dmi/id]product_name}=="SuperCalc 100[234]*", ATTRS{keys}=="116", TAG
> +="power-switch"
>
> So it is easily possible to limit such a rule to particular systems.

The systems in question don't provide DMI data. Do you know of an equivalent with device-tree? I don't see any device-tree attributes available in sysfs - the best system identifier I see is /proc/device-tree/model.