Re: [PATCH 2/2] gpiolib: Allow drivers to return EOPNOTSUPP from config

[Joe Perches]

On Mon, 2021-03-29 at 14:59 +0300, Andy Shevchenko wrote:
> On Mon, Mar 29, 2021 at 2:43 PM Matti Vaittinen
> <matti.vaittinen@xxxxxxxxxxxxxxxxx> wrote:
> > 
> > The checkpacth instructs to switch from ENOSUPP to EOPNOTSUPP.
> > > WARNING: ENOTSUPP is not a SUSV4 error code, prefer EOPNOTSUPP
> > 
> > Make the gpiolib allow drivers to return both so driver developers
> > can avoid one of the checkpatch complaints.
> 
> Internally we are fine to use the ENOTSUPP.
> Checkpatch false positives there.
> 
> I doubt we need this change. Rather checkpatch should rephrase this to
> point out that this is only applicable to _user-visible_ error path.
> Cc'ed Joe.

Adding CC for Jakub Kicinski who added that particular rule/test.

And the output message report of the rule is merely a suggestion indicating
a preference.  It's always up to an individual to accept/reject.

At best, perhaps wordsmithing the checkpatch message might be an OK option.

+# ENOTSUPP is not a standard error code and should be avoided in new patches.
+# Folks usually mean EOPNOTSUPP (also called ENOTSUP), when they type ENOTSUPP.
+# Similarly to ENOSYS warning a small number of false positives is expected.
+               if (!$file && $line =~ /\bENOTSUPP\b/) {
+                       if (WARN("ENOTSUPP",
+                                "ENOTSUPP is not a SUSV4 error code, prefer EOPNOTSUPP\n" . $herecurr) &&
+                           $fix) {
+                               $fixed[$fixlinenr] =~ s/\bENOTSUPP\b/EOPNOTSUPP/;
+                       }
+               }
+