Ericsson C5621gw and GPS support

[Aleksander Morgado]

On Mon, May 12, 2014 at 4:41 PM, Bjørn Mork <bjorn at mork.no> wrote:
>>
>> I'm having C5621gw modem in my thinkpad helix, and it works quite well
>> for internet. I tried to follow
>> http://www.thinkwiki.org/wiki/Ericsson_F3507g_Mobile_Broadband_Module
>> and after sending commands AT*E2GPSCTL=1,1,1 to /dev/ttyACM1 and
>> AT*E2GPSNPD to /dev/ttyACM2 I could see nmea data.
>>
>> So, I think it will be good to implement support of gps for this modem
>> in ModemManager. I would like to try, but need a help.
>> 1. What is correct way to add support of GPS to ModemManager mdm plugin?
>
> I guess you would have to implement a MMIfaceModemLocation interface in
> the "mbm" plugin.  There is an example of an AT command based GPS
> interface in plugins/option/mm-broadband-modem-hso.c
>

Yes.

Worth noting, that in the HSO plugin the NMEA port is known from the
very beginning. In the case of the MBM plugin, I'm not sure whether we
can know which the NMEA port is in advance for all GPS-capable devices
(i.e. I'm not sure we can add a udev tag based on e.g. interface
number), so we would likely need to:
 * Enable GPS using the primary port.
 * Go over the non-AT non-QCDM ttys in the list of ports and try to
discover which one is the GPS port sending out NMEA traces.

I'm not really familiar to how Ericsson sets up the interfaces in the
USB interface, so it may be that the GPS port is always a specific
interface number or something, so worth checking that first. If that
is the case, udev tag would be much easier.

>> 2. How AGPS feature could be added? (E.g. I would like to help gps get
>> fix faster, when internet is on)
>
> Do you know how to manage that?  Are there any magic AT commands
> configuring it?

I have a branch "aleksander/agps" in git master adding A-GPS support
in QMI devices via a SUPL server:
http://cgit.freedesktop.org/ModemManager/ModemManager/log/?h=aleksander/agps

-- 
Aleksander
https://aleksander.es