Issue in PHY address of KSZ8041

The SOM Colibri iMX6ULL 512MB IT is fitted in Colibri eval board. The SOM is having KSZ8041.

The physical address will be 2 as per datasheet (hope strapped AAA).

I tried to do read operation of the KSZ8041 using PHY tool. It looks like KSZ8041 is responding for the address 0 to 5. It suppose to respond only for the address 2.

Ex: Read the 0022h from register 2 for the address 0 to 5.

I made a setup for MII (enet1) for the chip KSZ8895FQX (eval board). The MDC/MDIO lines are shared between enet1 (KSZ8895FQX) and onboard enet 2 (KSZ8041). It looks the phy address is clashing and not able up the KSZ8895FQX.

Also there is no option to permanently reset the on board KSZ8041.

I done further testing using PHY tool.

KSZ8041 is responding correctly for the PHY address 0 and 2.

Hi @tavinoth,
I can check that it is showing 2 address as mentioned by you

Colibri iMX6ULL # mii info
PHY 0x00: OUI = 0x0885, Model = 0x11, Rev = 0x03, 100baseT, FDX
PHY 0x02: OUI = 0x0885, Model = 0x11, Rev = 0x03, 100baseT, FDX

However, the reason for this can been seen from the below statement from the KSZ8041 datasheet (sec 3.9)

Each KSZ8041NL/RNL device is assigned a unique PHY address between 1 and 7 by its PHYAD[2:0] strapping pins. Additionally, every KSZ8041NL/RNL device supports the broadcast PHY address 0, as defined per the IEEE 802.3 specification, which can be used to read or write to a single KSZ8041NL/RNL device, or write to multiple KSZ8041NL/RNL devices simultaneously