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From:   Ulf Hansson <ulf.hansson@linaro.org>
Date:   Fri, 24 Sep 2021 13:49:55 +0200
Message-ID: <CAPDyKFqRR-GD=xZo27a9MgwzKT9mar4m0Bdki1VBxnsZaQy1_g@mail.gmail.com>
Subject: Re: [PATCH v3 1/2] drivers: bus: simple-pm-bus: Add support for
 probing simple bus only devices
To:     Saravana Kannan <saravanak@google.com>,
        Rob Herring <robh+dt@kernel.org>
Cc:     Russell King <linux@armlinux.org.uk>,
        Neil Armstrong <narmstrong@baylibre.com>,
        Geert Uytterhoeven <geert+renesas@glider.be>,
        Magnus Damm <magnus.damm@gmail.com>,
        Tony Lindgren <tony@atomide.com>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Will Deacon <will@kernel.org>,
        Damien Le Moal <damien.lemoal@wdc.com>,
        Android Kernel Team <kernel-team@android.com>,
        Linux ARM <linux-arm-kernel@lists.infradead.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        linux-oxnas@groups.io,
        Linux-Renesas <linux-renesas-soc@vger.kernel.org>,
        linux-omap <linux-omap@vger.kernel.org>,
        linux-riscv <linux-riscv@lists.infradead.org>
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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.

[...]

Kind regards
Uffe