On Tue, 24 Nov 2015 14:25:31 -0500 (EST), David Miller wrote:

From: Jakub Kicinski <redacted>
Date: Mon, 23 Nov 2015 11:04:57 +0000

quoted

+#ifdef CONFIG_NFP_NET_DEBUG
+#define DEBUG
+#endif

Do not design ad-hoc debug logging facilities locally in your driver,
and instead use the existing tree wide facilities as they were designed
to be used so that any user can get debugging logs simply by turning it
on at run time rather than having the change magic config options in
their kernel.

True.  I picked this habit up from the rt2x00 driver long time ago.
Now I see nobody else is doing such things...