daniel-p-carvalho opened a new pull request, #20206: URL: https://github.com/apache/nuttx/pull/20206
## Summary The STM32F4 platform page has no section about the Ethernet MAC, so nothing tells a user how to use the PTP support that the legacy STM32 Ethernet driver has, and the driver got a `/dev/ptp0` PTP hardware clock in #20180. This PR adds an "Ethernet" section to `Documentation/platforms/arm/stm32f4/index.rst`. It changes documentation only. The section describes, checked against `arch/arm/src/common/stm32/stm32_eth_m3m4_v1.c`, `Kconfig.eth` and the pin maps: - The time counter of the MAC (32-bit seconds and 31-bit sub-second parts, clocked from `SYSCLK`, rate adjustable by up to +/- 50 %) and why a PTP daemon needs it. - The options `CONFIG_STM32_ETH_PTP`, `CONFIG_STM32_ETH_ENHANCEDDESC`, `CONFIG_STM32_ETH_TIMESTAMP_RX`, `CONFIG_STM32_ETH_PTP_GPIO` (with the two possible pins on the STM32F40xxx and STM32F42xxx parts and the `GPIO_ETH_PPS_OUT` that the board defines in its `board.h`) and `CONFIG_STM32_ETH_PTP_RTC_HIRES`. - The `/dev/ptp0` clock: the numbering (the number of the Ethernet interface), the operations it offers (time, resolution, frequency, phase) and the one it does not (cross timestamp), with a link to the PTP clock driver page. - That the timestamps of received packets are values of the MAC counter and not of `CLOCK_REALTIME`, so a program has to compare them with `/dev/ptp0`. It shows how to start `ptpd` that way (`ptpd -H -p /dev/ptp0 -i eth0`) and a configuration that enables everything. - That the driver stamps received packets only. Transmit timestamps are not described here because they are not in `master` yet; the section will get them when they are. ## Impact Documentation only, no code change. Only the page `platforms/arm/stm32f4` changes. ## Testing Built the documentation with Sphinx 6.2.1 and the packages of `Documentation/Pipfile`, without `-W`: the build succeeds, the new section renders and the link to the PTP clock driver page resolves. None of the 19 warnings (duplicate C declarations in other pages) is from this file. `./tools/checkpatch.sh` passes. The statements were checked by reading the driver and the pin maps. The configuration example and the `ptpd` command line were not built or run as written here; the driver and `ptpd` were run on an STM32F4 board with a similar configuration. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
