Hello all, I'm looking for some guidance related to a possible MHI client for serial ports signals management implementation. Testing the AT channels with Telit modems I noted that unsolicited indications do not show: the root cause for this is DTR not set for those ports through MHI channels 18/19, something that with current upstream code can't be done due to the missing DTR client driver. I currently have an hack, based on the very first mhi stack submission (see https://lore.kernel.org/lkml/1524795811-21399-2-git-send-email-sdias@xxxxxxxxxxxxxx/#Z31drivers:bus:mhi:core:mhi_dtr.c), solving my issue, but I would like to understand which would be the correct way, so maybe I can contribute some code. Should the MHI DTR client be part of the WWAN subsystem? If yes, does it make sense to have an associated port exposed as a char device? I guess the answer is no, since it should be used just by the AT ports created by mhi_wwan_ctrl, but I'm not sure if that's possible. Or should the DTR management be somehow part of the MHI stack and mhi_wwan_ctrl interacts with that through exported functions? Thanks a lot in advance, Daniele
