Re: [PATCH] checkpatch: Don't emit warnings for USB & PCI device DT compatible prefixes

[Joe Perches <joe@perches.com>]

On Thu, 2026-05-14 at 10:40 -0700, Brian Norris wrote:
> Hi Chen-Yu,
> On Thu, May 14, 2026 at 06:51:50PM +0800, Chen-Yu Tsai wrote:
> The USB and PCI device bindings define some compatible patterns based
> > on device IDs that use the comma to separate vendor and product IDs.
> > 
> > These patterns include:
> > 
> >   - usb[0-9a-f]{1,4},[0-9a-f]{1,4}
> >   - pci[0-9a-f]{2,4},[0-9a-f]{1,4}
> >   - pciclass,[01][0-9a-f]{3}([0-9a-f]{2})?
> > 
> > These are not real vendor prefixes. Don't emit warnings for them.
> > 
> > Signed-off-by: Chen-Yu Tsai <[wenst@chromium.org](mailto:wenst@chromium.org)>
> > ---
> > This is a simplified version of what Brian Norris previously posted [1],
> 
> Wow, almost forgot about that one. Thanks for the blast from the past.

You know Brian, you're different than me.
I completely forgot about that one.

> > but more comprehensive and more perl-y than what Yingying Tang posted
> Is "perl-y" a good thing? :)

My sweet wife thinks so.  It's spelled differently though.

> > Hopefully everyone likes this version.
> I like any version that eliminates obvious false positives!
> 
> But one thing that can be improved: your version still requires that the
> full ID string be documented explicitly. For example, this still gives a
> false warning:
> 
> $ git format-patch -1 --stdout 24af105962c8004edb9f5bf84bc587cbb30e52de | scripts/checkpatch.pl
> [...]
> WARNING: DT compatible string "pci0014,7a24.0" appears un-documented -- check ./Documentation/devicetree/bindings/
> #234: FILE: arch/mips/boot/dts/loongson/ls7a-pch.dtsi:37:
> +				compatible = "pci0014,7a24.0",
> The dtschema is clear that anything matching the pci pattern is OK, and
> we don't need to list every possible variation in a yaml file.

> > diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
[]
> > @@ -3795,6 +3795,9 @@ sub process {
> >  
> >  				next if $compat !~ /^([a-zA-Z0-9\-]+)\,/;
> >  				my $vendor = $1;
> > +				next if $vendor eq "pciclass";
> > +				next if $vendor =~ /^pci[a-f0-9]{2,4}$/;

Maybe

+				next if $vendor =~ /^pci[a-f0-9]{2,4}/;

?

> > +				next if $vendor =~ /^usb(if)?[a-f0-9]{1,4}$/;