Is cmux support required for modem_cellular.c ?

[dnlplm]

Hello,

is cmux support a mandatory modem requirement for being supported by modem_cellular.c ?

I currently have a modem which does not support cmux and I would like to use it with modem_cellular.c, but looking at the code I'm not sure that it's possible.

Thanks,
Daniele

[jukkar]

The CMUX support is not mandatory and CMUX support is only enabled if you set CONFIG_MODEM_CMUX=y. If you cannot use it, just do not set the option.

[dnlplm]

@jukkar, thanks for your reply!

However, I see that CONFIG_MODEM_CELLULAR is forcing CONFIG_MODEM_CMUX, so I'm probably missing something.

[jukkar]

Not sure what is going on there, sounds like we should do imply MODEM_CMUX instead of select so that the user could disable cmux if needed, @bjarki-andreasen any idea?

[bjarki-andreasen]

The modem_cellular.c driver is built around CMUX, its very much required for it specifically, a modem driver which does not use CMUX could surely be created, but it would function very differently, given we don't have dedicated channels for PPP and AT commands in that case, so the behavior of the driver would be quite different :)

[dnlplm]

Thanks a lot @bjarki-andreasen and @jukkar, this clarifies the topic.