ofono with serial modem

ofono with serial modem

[Andrea Galbusera]

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Hi! I'm new to the list and ofono project. In these days I'm trying to
figure out if ofono can help me with some embedded projects involving
M2M GPRS connections on serial modems.
I have a few questions I was not able to give an answer to, neither
from wiki nor from doc files in source code. Hope not to bother with
too newbish questions here!

1. Are non-hot-pluggable serial modem supported by ofono? I believe
they should run with the atmodem driver: is this correct?

2. Is udev detection the only way to let ofono know about a modem? If
I'm not wrong, I read about support for some kind of static
configuration in the past (modem.conf file), but it seems gone in
these days. I'm definitely fine with udev: just need some hints on how
to setup a rule to let ofono know I have a pretty standard AT modem
on, say, ttyS0. I looked at ofono.rules, but I think it deals mainly
with usb modem.

3. ofono looks very promising for its integration with d-bus. I'm
looking forward to be able to have different applications to manage
GPRS context activation/deactivation while, i.e., monitoring signal
strength and maybe asynchronous notifications by the modem itself. Are
these tasks in the ofono's scope or not?

Thanks in advance for any clarifications!

Regards,
Andrea

Re: ofono with serial modem

[Denis Kenzior]

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Hi Andrea,

On 12/02/2011 04:52 AM, Andrea Galbusera wrote:
> Hi! I'm new to the list and ofono project. In these days I'm trying to
> figure out if ofono can help me with some embedded projects involving
> M2M GPRS connections on serial modems.
> I have a few questions I was not able to give an answer to, neither
> from wiki nor from doc files in source code. Hope not to bother with
> too newbish questions here!
> 
> 1. Are non-hot-pluggable serial modem supported by ofono? I believe
> they should run with the atmodem driver: is this correct?

Yes they are, however they are still detected via udev and require a
proper modem driver. 'atmodem' is a collection of atom drivers that
implement generic 27.007 functionality.  The difference should be
explained nicely in the presentations posted on the site.

See the calypso modem driver in plugins/calypso.c for an example as well
as doc/calypso-modem.txt for an example udev rule.

> 
> 2. Is udev detection the only way to let ofono know about a modem? If
> I'm not wrong, I read about support for some kind of static
> configuration in the past (modem.conf file), but it seems gone in
> these days. I'm definitely fine with udev: just need some hints on how
> to setup a rule to let ofono know I have a pretty standard AT modem
> on, say, ttyS0. I looked at ofono.rules, but I think it deals mainly
> with usb modem.

A udev rule like:
KERNEL=="ttyS0", ENV{OFONO_DRIVER}="your_driver"

should be all that is needed.

> 
> 3. ofono looks very promising for its integration with d-bus. I'm
> looking forward to be able to have different applications to manage
> GPRS context activation/deactivation while, i.e., monitoring signal
> strength and maybe asynchronous notifications by the modem itself. Are
> these tasks in the ofono's scope or not?

Yes all the things you have listed are possible.

> 
> Thanks in advance for any clarifications!
> 

Regards,
-Denis

Re: ofono with serial modem

[Andrea Galbusera]

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Hi, Denis!
Thank you for clarifications. I'm getting better understanding of
ofono architecture now. See a few more comments below.

On Wed, Nov 30, 2011 at 10:15 AM, Denis Kenzior <denkenz@gmail.com> wrote:
>> 1. Are non-hot-pluggable serial modem supported by ofono? I believe
>> they should run with the atmodem driver: is this correct?
>
> Yes they are, however they are still detected via udev and require a
> proper modem driver. 'atmodem' is a collection of atom drivers that
> implement generic 27.007 functionality.  The difference should be
> explained nicely in the presentations posted on the site.

Just a suggestion here. It was quite difficult for me to find those
presentations: links are only available as pretty old blog posts!
It would probably be nice to link them in the Documentation section or
in the wiki.

> See the calypso modem driver in plugins/calypso.c for an example as well
> as doc/calypso-modem.txt for an example udev rule.

At moment I'm interested in using ofono with a Telit GPRS module with
serial interface.
As far as I understand, there already exist a driver for Telit UC864-G
in plugins dir. I'm trying to figure out how much of this driver can
be used for other modules by Telit. I'm trying to follow the code path
from udev detection down to driver selection. I'm therefore slightly
confused by the interaction of the two modules udev.c and udevng.c. I
see setup and init function for different modems in both of them. Are
they supposed to provide different functions or is "ng" a short for
new-generation or the like? If so, and supposed I need to write a new
driver for the modem, where should I hook it?

Thanks again for your help
Regards,
Andrea

Re: ofono with serial modem

[Denis Kenzior]

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Hi Andrea,

>> See the calypso modem driver in plugins/calypso.c for an example as well
>> as doc/calypso-modem.txt for an example udev rule.
> 
> At moment I'm interested in using ofono with a Telit GPRS module with
> serial interface.
> As far as I understand, there already exist a driver for Telit UC864-G
> in plugins dir. I'm trying to figure out how much of this driver can
> be used for other modules by Telit. I'm trying to follow the code path
> from udev detection down to driver selection. I'm therefore slightly
> confused by the interaction of the two modules udev.c and udevng.c. I

udev is the old detection code, udevng is the next generation detection
code.  They work together at the moment.

> see setup and init function for different modems in both of them. Are
> they supposed to provide different functions or is "ng" a short for
> new-generation or the like? If so, and supposed I need to write a new
> driver for the modem, where should I hook it?

If you're adding a new serial modem then likely you want to put it into
udev.c for now.  udevng is limited to USB devices only at the moment.

Regards,
-Denis