linux-kernel - Re: [PATCH v3 2/2] net: wwan: mhi: Add network support for Foxconn T99W760

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Message-ID: <CAFEp6-1kSMGY0ydJjTvZqB4okXQgcwkvhMni8r-tOMzXyY7P_g@mail.gmail.com>
Date: Thu, 20 Nov 2025 08:44:14 +0100
From: Loic Poulain <loic.poulain@....qualcomm.com>
To: Slark Xiao <slark_xiao@....com>, Manivannan Sadhasivam <mani@...nel.org>
Cc: Dmitry Baryshkov <dmitry.baryshkov@....qualcomm.com>,
        ryazanov.s.a@...il.com, johannes@...solutions.net,
        andrew+netdev@...n.ch, davem@...emloft.net, edumazet@...gle.com,
        kuba@...nel.org, pabeni@...hat.com, mhi@...ts.linux.dev,
        linux-arm-msm@...r.kernel.org, netdev@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3 2/2] net: wwan: mhi: Add network support for Foxconn T99W760

On Thu, Nov 20, 2025 at 6:41 AM Manivannan Sadhasivam <mani@...nel.org> wrote:
>
> On Wed, Nov 19, 2025 at 02:08:33PM +0100, Loic Poulain wrote:
> > On Wed, Nov 19, 2025 at 12:27 PM Dmitry Baryshkov
> > <dmitry.baryshkov@....qualcomm.com> wrote:
> > >
> > > On Wed, Nov 19, 2025 at 06:56:15PM +0800, Slark Xiao wrote:
> > > > T99W760 is designed based on Qualcomm SDX35 chip. It use similar
> > > > architechture with SDX72/SDX75 chip. So we need to assign initial
> > > > link id for this device to make sure network available.
> > > >
> > > > Signed-off-by: Slark Xiao <slark_xiao@....com>
> > > > ---
> > > >  drivers/net/wwan/mhi_wwan_mbim.c | 3 ++-
> > > >  1 file changed, 2 insertions(+), 1 deletion(-)
> > > >
> > > > diff --git a/drivers/net/wwan/mhi_wwan_mbim.c b/drivers/net/wwan/mhi_wwan_mbim.c
> > > > index c814fbd756a1..a142af59a91f 100644
> > > > --- a/drivers/net/wwan/mhi_wwan_mbim.c
> > > > +++ b/drivers/net/wwan/mhi_wwan_mbim.c
> > > > @@ -98,7 +98,8 @@ static struct mhi_mbim_link *mhi_mbim_get_link_rcu(struct mhi_mbim_context *mbim
> > > >  static int mhi_mbim_get_link_mux_id(struct mhi_controller *cntrl)
> > > >  {
> > > >       if (strcmp(cntrl->name, "foxconn-dw5934e") == 0 ||
> > > > -         strcmp(cntrl->name, "foxconn-t99w515") == 0)
> > > > +         strcmp(cntrl->name, "foxconn-t99w515") == 0 ||
> > > > +         strcmp(cntrl->name, "foxconn-t99w760") == 0)
> > >
> > > Can we replace this list of strinc comparisons with some kind of device
> > > data, being set in the mhi-pci-generic driver?
> >
> > If we move this MBIM-specific information into mhi-pci-generic, we
> > should consider using a software node (e.g. via
> > device_add_software_node) so that these properties can be accessed
> > through the generic device-property API.
> >
>
> MHI has to business in dealing with MBIM specific information as we already
> concluded. So it should be handled within the WWAN subsystem.

it doesn’t make sense to include MBIM-specific fields in a generic MHI
structure. However, attaching fwnode properties could be reasonable
since the MHI PCI driver is responsible for device enumeration, and
that would keep device model specific handling fully covered in that
driver.

It’s fine to keep device-specific handling within WWAN/MBIM. However,
next time, please introduce a dedicated device data structure for the
mux-id instead of adding another strcmp.

Regards,
Loic