[PATCH V4 0/3] net: stmmac: Fix Tegra234 MGBE clock

Jon Hunter
2026-04-01T10:30:02Z

The name of the PTP ref clock for the Tegra234 MGBE ethernet controller
does not match the generic name in the stmmac platform driver. Despite
this basic ethernet is functional on the Tegra234 platforms that use
this driver and as far as I know, we have not tested PTP support with
this driver. Hence, the risk of breaking any functionality is low.

The previous attempt to fix this in the stmmac platform driver, by
supporting the Tegra234 PTP clock name, was rejected [0]. The preference
from the netdev maintainers is to fix this in the DT binding for
Tegra234.

This series fixes this by correcting the device-tree binding to align
with the generic name for the PTP clock. I understand that this is
breaking the ABI for this device, which we should never do, but this
is a last resort for getting this fixed. I am open to any better ideas
to fix this. Please note that we still maintain backward compatibility
in the driver to allow older device-trees to work, but we don't
advertise this via the binding, because I did not see any value in doing
so.

Changes since V3:
- Added Krzysztof's reviewed-by for device-tree changes.
- Re-worked logic in MGBE driver for detecting the legacy clock to make
it more explicit and clear.

Changes since V2:
- Corrected example in dt-binding doc.

Changes since V1:
- Moved handling of different PTP clock names into Tegra234 MGBE driver.
- Add changes to update the Tegra234 MGBE DT binding and DT source.

[0] https://lore.kernel.org/linux-tegra/20250612062032.293275-1-jonathanh@nvidia.com/

Jon Hunter (3):
net: stmmac: Fix PTP ref clock for Tegra234
dt-bindings: net: Fix Tegra234 MGBE PTP clock
arm64: tegra: Fix Tegra234 MGBE PTP clock

.../bindings/net/nvidia,tegra234-mgbe.yaml | 4 ++--
arch/arm64/boot/dts/nvidia/tegra234.dtsi | 8 ++++----
.../net/ethernet/stmicro/stmmac/dwmac-tegra.c | 20 +++++++++++++++++--
3 files changed, 24 insertions(+), 8 deletions(-)

--
2.43.0