Check ptp_clock_register() return not only for NULL but
also for error pointers, and also nullify adapter->ptp_clock
if ptp_clock_register() fails.
Fixes: 9c33e4208bce ("cxgb4: Add PTP Hardware Clock (PHC) support")
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: Ganesh Goudar <ganeshgr@chelsio.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
 
        adapter->ptp_clock = ptp_clock_register(&adapter->ptp_clock_info,
                                                &adapter->pdev->dev);
-       if (!adapter->ptp_clock) {
+       if (IS_ERR_OR_NULL(adapter->ptp_clock)) {
+               adapter->ptp_clock = NULL;
                dev_err(adapter->pdev_dev,
                        "PTP %s Clock registration has failed\n", __func__);
                return;