Does chan_usbradio decode DCS?

Can it be done?

I currently use pl tones but would like to do dcs.

I’m afraid not. It’s PL tones only. DPL/DCS is not a feature of that. But I do feel your pain. I too prefer DCS.

One can always use external hardware and trip the CTCSS line on input if it is important…
Most commercial gear has DCS so you just need a voltage indicator to use.