Q: How to disable TX path of ethernet PHY in embedded linux? In a yocto-based embedded device I use ethernet only to receive UDP packets. Now I want save energy as the device (as well as the UDP transmitter) is battery powered, and the ethernet PHY (a micrel KSZ9031) needs more than 150 mW for idle transmit only.
The PHY doesn't seem to have any "disable TX" register. By destroying the PCB wire between the TX clock from the controller (an i.MX6) and the PHY, I can achieve the power saving without problems on the receiving side, but I don't understand how to disable the clock in the device tree.
Did someone achieve such energy saving? If yes, how did you do it? If no, what would you try?
