Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
MIME-Version: 1.0
References: <20210904000543.2019010-1-saravanak@google.com>
 <20210904000543.2019010-2-saravanak@google.com> <CAPDyKFqkvN=ZrfAnj4CqfjBu_Pj0YH9txnkP-1d=FhaEhbPrPA@mail.gmail.com>
 <CAPDyKFqRR-GD=xZo27a9MgwzKT9mar4m0Bdki1VBxnsZaQy1_g@mail.gmail.com>
In-Reply-To: <CAPDyKFqRR-GD=xZo27a9MgwzKT9mar4m0Bdki1VBxnsZaQy1_g@mail.gmail.com>
From:   Saravana Kannan <saravanak@google.com>
Date:   Fri, 24 Sep 2021 13:20:02 -0700
Message-ID: <CAGETcx-ArdxuWkZcidGrRRPqrkLRzC-oVGmeGd5Mebps5k1fpA@mail.gmail.com>
Subject: Re: [PATCH v3 1/2] drivers: bus: simple-pm-bus: Add support for
 probing simple bus only devices
To:     Ulf Hansson <ulf.hansson@linaro.org>
Cc:     Rob Herring <robh+dt@kernel.org>,
        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>
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

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