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authorMatthias Schiffer <matthias.schiffer@ew.tq-group.com>2025-06-24 12:53:34 +0200
committerPaolo Abeni <pabeni@redhat.com>2025-06-26 14:49:10 +0200
commite02adac7c84bf2883ce5d5a828a03871c0c1d4f9 (patch)
tree0f9b811ef8cedfcc53ff173de8271cc0621371c6 /Documentation/dev-tools
parentca13b249f291f4920466638d1adbfb3f9c8db6e9 (diff)
checkpatch: check for comment explaining rgmii(|-rxid|-txid) PHY modes
Historically, the RGMII PHY modes specified in Device Trees have been 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 realized 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@lunn.ch> Signed-off-by: Matthias Schiffer <matthias.schiffer@ew.tq-group.com> Reviewed-by: Andrew Lunn <andrew@lunn.ch> Link: https://patch.msgid.link/bc112b8aa510cf9df9ab33178d122f234d0aebf7.1750756583.git.matthias.schiffer@ew.tq-group.com Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Diffstat (limited to 'Documentation/dev-tools')
-rw-r--r--Documentation/dev-tools/checkpatch.rst9
1 files changed, 9 insertions, 0 deletions
diff --git a/Documentation/dev-tools/checkpatch.rst b/Documentation/dev-tools/checkpatch.rst
index 76bd0ddb0041..d5c47e560324 100644
--- a/Documentation/dev-tools/checkpatch.rst
+++ b/Documentation/dev-tools/checkpatch.rst
@@ -495,6 +495,15 @@ Comments
See: https://lore.kernel.org/lkml/20131006222342.GT19510@leaf/
+ **UNCOMMENTED_RGMII_MODE**
+ Historically, the RGMII PHY modes specified in Device Trees have been
+ 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.
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