sysdev_driver_register - Register auxillary driver
int sysdev_driver_register (struct sysdev_class * cls, struct sysdev_driver * drv);
cls Device class driver belongs to. drv Driver.
If cls is valid, then drv is inserted into cls->drivers to be called on each operation on devices of that class. The refcount of cls is incremented. Otherwise, drv is inserted into sysdev_drivers, and called for each device.