I am running LinuxPTP on the STM32MP157-C DK2 board. Is it possible to obtain a PTP PPS output on the ETH1_PPS_OUT (PG8 pin)?

[CodeRunner]

If it is possible is there an example or at least some guidance on how to implement the PPS output? Coming from Cortex-M4/RTOS development I am doing my best to learn Application Processor/Embedded Linux development.​

[AntonioST]

I don't think there is an example specific for this pin.

What you need to do is to modify the pinctrl configuration in the devicetree, adding PG8 in alternate function AF11 inside the list of pins of the ethernet.

Generic info about pinctrl in

https://wiki.st.com/stm32mpu/wiki/Pinctrl_overview

On DK2 board, the devicetree configuration uses for ethernet the pin configured in ethernet0_rgmii_pins_a

You can simply add PG8 there... well, it's not the cleaner way to do that, but should work for your tests

[CodeRunner]

I added PG8 in the ethernet0_rgmii_pins_a sections of the stm32mp157-pinctrl.dtsi in tmp-glibc/work sections for uboot-source and kernel-source sections. The I reran bitbake and put the image on the sdcard. Should that re-direct PG8 to the PPS signal? Also does the PPS automatically output when ptp4l is operational?