in pps.c [331:345]
static void pps_device_destruct(struct device *dev)
{
struct pps_device *pps = dev_get_drvdata(dev);
cdev_del(&pps->cdev);
/* Now we can release the ID for re-use */
pr_debug("deallocating pps%d\n", pps->id);
mutex_lock(&pps_idr_lock);
idr_remove(&pps_idr, pps->id);
mutex_unlock(&pps_idr_lock);
kfree(dev);
kfree(pps);
}