I'm having trouble passing digital tuning using an FMCOMMS3 on FMC carrier board with a ported reference design. The carrier flips several of the differential pairs on FMC connector. I figured that was okay since the AD9361 can be programmed to invert these pairs with registers 0x3D and 0x3E. So far, I've tried:
1. Letting tuning fail, writing 0x3D/0x3E after boot and retuning.
This didn't work for me, as the driver probe fails and I don't get the digital_tuning file in the debug driver.
2. Skip tuning with the "adi,digital-tuning-interface-tune-skip-mode=2" setting in the Devicetree.
I can boot and load the driver with this, but running echo 0 3 > digital_tune seems to do nothing. According to guides on this site, I should have the tuning results in dmesg, but I don't them. Perhaps it doesn't run in this mode?
3. Setting adi,lvds-invert1/2-control in the Devicetree.
The driver probe still failed on tuning.
What would be the best way forward to address the inverted bits? In particular, how can I better debug my setup?