MDIO issue?

[woutervh]

My phy (a marvell 88e6071 switch) does not seem to respond on my mdio commands.

I think maybe my timings are wrong? What can be causing this? Mdio data seems to change on the rising clock. And at turnaround time, the marvell does not take over. Any idea? This screen was taken in U-boot, but it's not working in linux either...

Edit: one remark, the marvell is supplying the ethernet reference clock to the imx. Don't know if that matters...

Edit2: I added a hold time of 4 to the mxc_fec, so I see the data shifting to the middle of the pulse. But still no answer from the marvell...

[alexander_yakov]

In your scope screenshot I see last rising has is very weak slope, this may cause remote side to incorrectly detect the state of data line as "0" and get confused of this extra "0" and the end. Obviously, this slow slope is created by weak pull-up resistor, so I recommend placing more strong pull-up resistor on MDIO line ans check if this will solve the problem.

Have a great day,
Alexander
TIC

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