Re: RFC - Add AT interface to qmi device

[Tony Lindgren <tony@atomide.com>]

* Denis Kenzior <denkenz@gmail.com> [240520 18:58]:
> > > Have you considered simply using AT commands for calls and SMS?
> > 
> > At least on Droid4 the ttyUSB AT interface is bit buggy.. But there may be
> > a generic way to trigger lost QMI events based on the USB AT interface
> > notifications.
> 
> Hmm, okay.
> 
> > 
> > What we accidentally discovered with the Maemo Droid4 modem patches was
> > that triggering a dummy QMI call on serial (muxed TS 27.010) notifications
> 
> Can you clarify? QMI call on the QMI character device or on the AT port itself?

I think any QMI command on the USB QMI interface will trigger the pending
USB QMI notifications.

> > int mot_qmi_trigger_events(struct ofono_modem *modem)
> > {
> > 	struct motmdm_data *data = ofono_modem_get_data(modem);
> > 
> > 	if (data->wms == NULL)
> > 		return -ENODEV;
> > 
> > 	return qmi_service_send(data->wms, QMI_WMS_GET_SMSC_ADDR, NULL,
> > 						NULL, NULL, g_free);
> > };
> > 
> 
> I'm fine with this approach if the handling of this quirk is done by the
> modem driver.  The modem driver can manage both QMI and AT ports.  What I
> want to avoid is coupling between technologies in the atom drivers
> themselves.  In other words, QMI SMS driver should not depend on anything
> related to AT commands.

OK yes doing it as needed from the modem driver makes sense.

Note that there may not even be a need for proper AT commands in this case.
It may be possible to use just ell directly, and just kick the USB QMI
interface on any output from the ttyUSB AT interface basically. Not sure
if any thing needs to be acked on the ttyUSB AT interface.

Regards,

Tony