[FS#641] Quectel ECXX and Raw IP on 4.4 kernel

[LEDE Bugs]

A new Flyspray task has been opened.  Details are below. 

User who did this - Mikael Brostrom (mikaelbrostrom) 

Attached to Project - LEDE Project
Summary - Quectel ECXX and Raw IP on 4.4 kernel
Task Type - Bug Report
Category - Kernel
Status - Unconfirmed
Assigned To - 
Operating System - All
Severity - Low
Priority - Very Low
Reported Version - Trunk
Due in Version - Undecided
Due Date - Undecided
Details - Hi,

have a ZBT-WE826 with a 3/4g modem inside, shipped by ZBT.
modem is a Quectel EC25-E.

lsusb: Bus 001 Device 004: ID 2c7c:0125  

if i tell qmi_wwan to register the device using: echo "2c7c 0125" >/sys/bus/usb/drivers/qmi_wwan/new_id
device is detected and shows up in dmesg: qmi_wwan 1-1.2:1.4 wwan0: register 'qmi_wwan' at usb-101c0000.ehci-1.2, WWAN/QMI device, XXXXXXXXXXXXX, and /dev/cdc-wdm0 is created

when i try to talk to the device using uqmi, i don't get any response!
uqmi -d /dev/cdc-wdm0 --get-imei (command hangs)

it has to do with the DTR, found a patch for the device on this forum:
https://forum.turris.cz/t/lte-modem-typu-ec25-e-minipcie/2816/24

is it possible to patch the trunk, so this device get supported? 

also, if i use option usb serial driver i can connect using pppd
same here, i have to tell option1 driver to detect the deivce.
echo "2c7c 0125" >/sys/bus/usb-serial/drivers/option1/new_id


tested on current trunk and 17.01.0


More information can be found at the following URL:
https://bugs.lede-project.org/index.php?do=details&task_id=641