Re: [PATCH v3 1/2] drivers: bus: simple-pm-bus: Add support for probing simple bus only devices

Saravana Kannan
2021-09-24T20:20:41Z

On Fri, Sep 24, 2021 at 4:50 AM Ulf Hansson <ulf.hansson@linaro.org> wrote:
>
> On Thu, 9 Sept 2021 at 13:01, Ulf Hansson <ulf.hansson@linaro.org> wrote:
> >
> > On Sat, 4 Sept 2021 at 02:05, Saravana Kannan <saravanak@google.com> wrote:
> > >
> > > fw_devlink could end up creating device links for bus only devices.
> > > However, bus only devices don't get probed and can block probe() or
> > > sync_state() [1] call backs of other devices. To avoid this, probe these
> > > devices using the simple-pm-bus driver.
> > >
> > > However, there are instances of devices that are not simple buses (they
> > > get probed by their specific drivers) that also list the "simple-bus"
> > > (or other bus only compatible strings) in their compatible property to
> > > automatically populate their child devices. We still want these devices
> > > to get probed by their specific drivers. So, we make sure this driver
> > > only probes devices that are only buses.
> > >
> > > [1] - https://lore.kernel.org/lkml/CAPDyKFo9Bxremkb1dDrr4OcXSpE0keVze94Cm=zrkOVxHHxBmQ@mail.gmail.com/
> > > Signed-off-by: Saravana Kannan <saravanak@google.com>
> > > Tested-by: Saravana Kannan <saravanak@google.com>
> >
> > Tested-by: Ulf Hansson <ulf.hansson@linaro.org>
>
> Saravana, Rob,
>
> I have been following your latest discussion in this thread - and it
> looks like you guys are moving towards a consensus.
>
> Although, if there is anything I can do to help to complete this, just
> tell me and I will jump in immediately.

Looks like we settled on the allow list approach during the BoF in
LPC. I'll send out a v4 with some tweaks.

-Saravana