- struct device_pm_info 
  - Defined in include/linux/pm.h.
  - Statically allocated in struct device (->power)
  - Body is empty if CONFIG_PM=n

- deivce_pm_{add,remove}
  - Called from device_{add,del} respectively.
  - Adds device to internal list of power managed objects and creates
    attribute group for device. 
    (Group currently empty, but placeholder directory is created for now)
  - Are defined as empty statc inline's when CONFIG_PM=n.