Associate II
December 2, 2025
Question
STM32MP157 Device Tree for Fixed Phy RGMII using RCC125 Clk
- December 2, 2025
- 2 replies
- 520 views
Hi
We have a Custom Board based from MB1272 dev kit.
Our system needs to connect the RGMII to a Marvell Switch Chip where that Switch is Managed MDIO from a different MPU.
As such we need our STM32MP157 MPU to run in a fixed phy mode and use the RCC to be its 125Mhz clk.
Please see simplified drawing

I have looked at the https://wiki.st.com/stm32mpu/wiki/Ethernet_device_tree_configuration#RGMII_with_Crystal_on_PHY-2C_no_125Mhz_from_PHY
but still confused as to how to do this
We have tried a few DT settings but no success,
would really appreciate some help on this one
Thanks
