wcte13xp: wcxb: Add delayed reset firmware feature

Allow certain older firmwares to delay the hard reset until a full power cycle.
This way we can "preload" newer firmware images, without requiring the user to
physically power off/on their machine.

Signed-off-by: Russ Meyerriecks <rmeyerriecks@digium.com>
Acked-by: Shaun Ruffell <sruffell@digium.com>
xpp: deprecate dahdi_autoreg

Instead, use the inverse of dahdi.auto_assign_spans value.

Signed-off-by: Tzafrir Cohen <tzafrir.cohen@xorcom.com>
Acked-by: Russ Meyerriecks <rmeyerriecks@digium.com>
xpp: continue xpp.dahdi_autoreg deprecation

* Set it to 0 by default (as we use dahdi.auto_assign_spans now)
* Make it readonly (no runtime changes)
* Warn during startup if it was forced to 1

Signed-off-by: Tzafrir Cohen <tzafrir.cohen@xorcom.com>
Acked-by: Russ Meyerriecks <rmeyerriecks@digium.com>
README: xpp.dahdi_autoreg is deprecated

Signed-off-by: Tzafrir Cohen <tzafrir.cohen@xorcom.com>
Acked-by: Russ Meyerriecks <rmeyerriecks@digium.com>
sysfs: new device attribute: registration_time

Add a new sysfs attribute to dahdi_device: registration_time

* Records the time of the device's registration with DAHDI.
* Used by dahdi_auto_assign_compat to assign spans by device
  registration order when backward compatibility needed.

Signed-off-by: Tzafrir Cohen <tzafrir.cohen@xorcom.com>
Acked-by: Shaun Ruffell <sruffell@digium.com>
README: the new registration_time device attribute

Signed-off-by: Tzafrir Cohen <tzafrir.cohen@xorcom.com>
README: The sysfs class now includes no channels

Signed-off-by: Tzafrir Cohen <tzafrir.cohen@xorcom.com>