This patch is to enable Huawei EM770 modem, which is a full feature modem that supports
voicecall, phonebook, call forwarding, call barring, etc.
There are two known parts of code that may have problem and need your comments.
1. Once connecting this modem to PC via USB, we can get 5 tty ports: ttyUSB0, ttyUSB1,
ttyUSB2, ttyUSB3 and ttyUSB4. The correct way to talk to this modem is using ttyUSB2.
I'm not sure if I handled this correctly in file udev.c.
2. When creating the modem, a global modem id will be appended to the name of it while
constructing the path. This modem has name "huawei_em770", thus the path becomes
things like "/huawei_em7700" or "/huawei_em7701". This looks strange.
Need I change the name of this modem, or can we use some smarter way to append the modem
There is also one known issue for this modem: The return of "CSMS=?" from this
modem is not compatible with spec. This is deemed as a modem issue, so the sms
wouldn't work before this hardware issue get solved.
Comments are welcome!