I saw a question on the list about PTP support on the STM32H743. I've been
working on PTP in NuttX for a few weeks, validated on a real bench
(STM32F4Discovery as slave, a real GPS Grandmaster as master) — I added P2P
support, hardware TX timestamping, and frequency/phase discipline of the
MAC's own hardware counter, which before only existed partially or only in
software.

On that question specifically: I looked at the H7 driver
(`arch/arm/src/stm32h7/stm32_ethernet.c`) and PTP support there was never
actually implemented — `CONFIG_STM32_ETH_PTP` only configures the PPS pin,
with a `#warning "CONFIG_STM32_ETH_PTP is not yet supported"` right in the
code. It's not a point bug, it's a real gap: the H7 uses a different MAC IP
than the one I worked on for the F4 (Synopsys GMAC, with its own PTP
register layout), so it's not a direct port - it would mean adding PTP
support to the existing driver, following the same pattern I already
validated on the F4.

I don't have H7 hardware to do that yet, but it's my next target. The F4
fixes are under review at apache/nuttx#20148 and
apache/nuttx-apps#3779/#3782, in case they're useful as a reference for
when I add H7 support.

If anyone has specific PTP requirements on the H7 (delay mechanism,
precision, hardware timestamping) or is already looking into this, I'd be
glad to hear about it - happy to coordinate and implement this together,
since I'll need to do this work anyway.

Daniel Pereira de Carvalho

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