SIMCOM SIM7070G UART Support

[Jorge Solla]

Hi,

I'm trying to configure a SIMCOM7070G modem to work with
ModemManager/NetworkManager.

I've observed there is already a plugin and some support, but unless I'm
mistaken, it looks like the current support expects this modem to be
connected via USB (4 ports provided by usb: AT cmds, data, gnss, etc).

My problem is I'm using it in a board where the modem is NOT connected to
the CPU via USB: The regular UART (UART1) provided by the modem is used.

So far, I already have some signals of life:

1. MODEM is detected by ModemManager as Generic GSM modem: I added the
following rule to /etc/udev/rules.d/ and works fine:

ACTION!="add|change|move|bind", GOTO="mm_whitelist_end"
KERNEL=="ttyS4" ENV{ID_MM_DEVICE_PROCESS}="1"
LABEL="mm_whitelist_end"

2. I Added a gsm connection to set the APN: (iot.t-mobile.nl)
I can see in ModemManager logs how it exchanges a lot of AT commands, etc
to finally launch PPP. And this is where I'm stuck.
After ppp gets launched, if I check the status of the connection using
nmcli I can see it is "getting ip address" and stays like that forever.

I'm attaching the whole log of ModemManager (debug mode). Not sure what I'm
missing/doing wrong.

Taking into account I want to establish a CAT-M, could somebody please help
me with the configuration?

Regards,
Jorge.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.freedesktop.org/archives/modemmanager-devel/attachments/20221006/34370305/attachment-0001.htm>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: ModemManager_SIM7070G_UART1_LOG.log
Type: text/x-log
Size: 150879 bytes
Desc: not available
URL: <https://lists.freedesktop.org/archives/modemmanager-devel/attachments/20221006/34370305/attachment-0001.bin>