On Tue, 15 Apr 2025 12:18:04 +0200 Matthias Schiffer <matthias.schiffer@xxxxxxxxxxxxxxx> wrote: > Historially, the RGMII PHY modes specified in Device Trees have been ^^^^^^^^^^^ Historically > used inconsistently, often referring to the usage of delays on the PHY > side rather than describing the board; many drivers still implement this > incorrectly. > > Require a comment in Devices Trees using these modes (usually mentioning > that the delay is relalized on the PCB), so we can avoid adding more > incorrect uses (or will at least notice which drivers still need to be > fixed). > > Suggested-by: Andrew Lunn <andrew@xxxxxxx> > Signed-off-by: Matthias Schiffer <matthias.schiffer@xxxxxxxxxxxxxxx> > --- > Documentation/dev-tools/checkpatch.rst | 9 +++++++++ > scripts/checkpatch.pl | 11 +++++++++++ > 2 files changed, 20 insertions(+) > > diff --git a/Documentation/dev-tools/checkpatch.rst b/Documentation/dev-tools/checkpatch.rst > index abb3ff6820766..8692d3bc155f1 100644 > --- a/Documentation/dev-tools/checkpatch.rst > +++ b/Documentation/dev-tools/checkpatch.rst > @@ -513,6 +513,15 @@ Comments > > See: https://lore.kernel.org/lkml/20131006222342.GT19510@leaf/ > > + **UNCOMMENTED_RGMII_MODE** > + Historially, the RGMII PHY modes specified in Device Trees have been ^^^^^^^^^^^ Historically > + used inconsistently, often referring to the usage of delays on the PHY > + side rather than describing the board. > + > + PHY modes "rgmii", "rgmii-rxid" and "rgmii-txid" modes require the clock > + signal to be delayed on the PCB; this unusual configuration should be > + described in a comment. If they are not (meaning that the delay is realized > + internally in the MAC or PHY), "rgmii-id" is the correct PHY mode. > > Commit message > -------------- > diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl > index 784912f570e9d..57fcbd4b63ede 100755 > --- a/scripts/checkpatch.pl > +++ b/scripts/checkpatch.pl > @@ -3735,6 +3735,17 @@ sub process { > } > } > > +# Check for RGMII phy-mode with delay on PCB > + if ($realfile =~ /\.dtsi?$/ && $line =~ /^\+\s*(phy-mode|phy-connection-type)\s*=\s*"/ && > + !ctx_has_comment($first_line, $linenr)) { > + my $prop = $1; > + my $mode = get_quoted_string($line, $rawline); > + if ($mode =~ /^"rgmii(?:|-rxid|-txid)"$/) { > + CHK("UNCOMMENTED_RGMII_MODE", > + "$prop $mode without comment -- delays on the PCB should be described, otherwise use \"rgmii-id\"\n" . $herecurr); > + } > + } > + My Perl-fu isn't good enough for me to review this properly... I think though that Andrew mentioned something along the lines of 'Comment should include PCB somewhere', but I don't know if this is easily doable with checkpatch though. Maxime
