Re: [PATCHv8 0/6] n_gsm serdev support and GNSS driver for droid4

Tony Lindgren
2020-07-28T08:36:25Z

* Pavel Machek <pavel@denx.de> [200726 08:25]:
> Hi!
>
> > > Here's the updated set of these patches fixed up for Johan's and
> > > Pavel's earlier comments.
> > >
> > > This series does the following:
> > >
> > > 1. Adds functions to n_gsm.c for serdev-ngsm.c driver to use
> > >
> > > 2. Adds a generic serdev-ngsm.c driver that brings up the TS 27.010
> > > TTY ports configured in devicetree with help of n_gsm.c
> > >
> > > 3. Allows the use of standard Linux device drivers for dedicated
> > > TS 27.010 channels for devices like GNSS and ALSA found on some
> > > modems for example
> >
> > Unfortunately that does not seem to be the case just yet. Your gnss
> > driver is still aware that it's using n_gsm for the transport and calls
> > into the "parent" serdev-ngsm driver instead of using the serdev
> > interface (e.g. as if this was still and MFD driver).
> >
> > If you model this right, the GNSS driver should work equally well
> > regardless of whether you use the serial interface (with n_gsm) or USB
> > (e.g. cdc-acm or usb-serial).
>
> We are not going to see that protocol anywhere else, so why is that
> a good goal?

Yes it seems this GNSS implementation is different from the one
provided by gobi.

> Anyway, Tony, is there newer version of this patchset? It would be
> good to get something in...

Sorry it will likely be few more weeks before I can look at this
stuff again.

> Can I help somehow?

I think I'm pretty clear on what needs to be done regarding this
patchset. Probably taking a look at if we could implement a
minimal raw /dev/gsmtty* read/write access in ofono using ell
instead of gatchat would help most :)

So something that mbim modem is already doing I think, sorry have
not had a chance to look at that either.

The /dev/gsmtty* devices should not change even with the further
changes to this patchset.

Regards,

Tony