Custom device overlay or cape-universal - decisions...

[Hugh Frater]

Hi everyone, I'm building a custom piece of mechatronics as part of my day job. We have a custom interface cape laid out (it doesn't have an eeprom) and I've mapped out the 16 lines we need to go back to the BBB. I've written a custom device tree for these lines which compiles with dtc fine, no errors. I've configured uEnv.txt to not load any other overlays, everything we don't need is disabled. As a result of the universal-cape not being loaded, I can't use config-pin to query if my pins have been setup correctly through my device tree.

Should I ditch my device tree based setup, and use the universal-cape along with a script to configure my pimuxing? Would this approach be easier to debug/verify?

Thanks in advance, Hugh

[Hugh Frater]

Ok, looking at this again in the cold light of day - looks like config-pin refuses to setup eQEP1 on P8_31 onwards... I get a:

bash: line 0: echo: write error: No such device
Cannot write pinmux file: /sys/devices/platform/ocp/ocp:P8_31_pinmux/state

Error...

Anyone have any ideas about this?

[Hugh Frater]

More for my own reference, but I'll post up my findings so far... Most of these errors seem to stem from my lack of understanding about how various things work together. Anyway:

Not using universal-cape and config-pin allows me to setup the 2x eqep's I need using the built in dtbo's for eqep1 and eqep2b. monitoring this from /sys/kernel/debug/pinctrl/44e10800.pinmux/pingroups

Perhaps I'll just use those 2 overlays to configure the eqeps and do everything else in a cut down version of my custom overlay...