Re: [PATCH] bus: mhi: Add Qcom WWAN control driver

[Loic Poulain]

Hi Jakub,

On Mon, 8 Mar 2021 at 19:51, Jakub Kicinski <kuba@xxxxxxxxxx> wrote:
>
> On Mon,  8 Mar 2021 19:40:51 +0100 Loic Poulain wrote:
> > The MHI WWWAN control driver allows MHI Qcom based modems to expose
> > different modem control protocols to userspace, so that userspace
> > modem tools or daemon (e.g. ModemManager) can control WWAN config
> > and state (APN config, SMS, provider selection...). A Qcom based
> > modem can expose one or several of the following protocols:
> > - AT: Well known AT commands interactive protocol (microcom, minicom...)
> > - MBIM: Mobile Broadband Interface Model (libmbim, mbimcli)
> > - QMI: Qcom MSM/Modem Interface (libqmi, qmicli)
> > - QCDM: Qcom Modem diagnostic interface (libqcdm)
> > - FIREHOSE: XML-based protocol for Modem firmware management
> >           (qmi-firmware-update)
> >
> > The different interfaces are exposed as character devices, in the same
> > way as for USB modem variants.
> >
> > Note that this patch is mostly a rework of the earlier MHI UCI
> > tentative that was a generic interface for accessing MHI bus from
> > userspace. As suggested, this new version is WWAN specific and is
> > dedicated to only expose channels used for controlling a modem, and
> > for which related opensource user support exist. Other MHI channels
> > not fitting the requirements will request either to be plugged to
> > the right Linux subsystem (when available) or to be discussed as a
> > new MHI driver (e.g AI accelerator, WiFi debug channels, etc...).
> >
> > Co-developed-by: Hemant Kumar <hemantk@xxxxxxxxxxxxxx>
> > Signed-off-by: Hemant Kumar <hemantk@xxxxxxxxxxxxxx>
> > Signed-off-by: Loic Poulain <loic.poulain@xxxxxxxxxx>
>
> You need to CC netdev.
>
> >  drivers/bus/mhi/Kconfig     |  12 +
> >  drivers/bus/mhi/Makefile    |   3 +
> >  drivers/bus/mhi/wwan_ctrl.c | 559 ++++++++++++++++++++++++++++++++++++++++++++
>
> Linux kernel tree is not organized by bus. This belongs somewhere under
> drivers/net.

Ok, so this driver will fall under networking, which makes some sense
for something called WWAN.
I guess it's time to create at least a wwan directory as a common
place for WWAN related drivers.

Regards,
Loic