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From:   Saravana Kannan <saravanak@google.com>
Date:   Fri, 3 Mar 2023 13:24:00 -0800
Message-ID: <CAGETcx-W3o=rQoVLnKkvk=oTAMiwEcqAZ_trcMPBuune-7Hoiw@mail.gmail.com>
Subject: Re: [PATCH v2] clk: Mark a fwnode as initialized when using
 CLK_OF_DECLARE() macro
To:     Linus Walleij <linus.walleij@linaro.org>
Cc:     Michael Turquette <mturquette@baylibre.com>,
        Stephen Boyd <sboyd@kernel.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        kernel-team@android.com, linux-clk@vger.kernel.org,
        linux-kernel@vger.kernel.org
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On Thu, Mar 2, 2023 at 5:14=E2=80=AFAM Linus Walleij <linus.walleij@linaro.=
org> wrote:
>
> On Thu, Mar 2, 2023 at 2:46 AM Saravana Kannan <saravanak@google.com> wro=
te:
>
> > We already mark fwnodes as initialized when they are registered as cloc=
k
> > providers. We do this so that fw_devlink can tell when a clock driver
> > doesn't use the driver core framework to probe/initialize its device.
> > This ensures fw_devlink doesn't block the consumers of such a clock
> > provider indefinitely.
> >
> > However, some users of CLK_OF_DECLARE() macros don't use the same node
> > that matches the macro as the node for the clock provider, but they
> > initialize the entire node. To cover these cases, also mark the nodes
> > that match the macros as initialized when the init callback function is
> > called.
> >
> > An example of this is "stericsson,u8500-clks" that's handled using
> > CLK_OF_DECLARE() and looks something like this:
> >
> > clocks {
> >         compatible =3D "stericsson,u8500-clks";
> >
> >         prcmu_clk: prcmu-clock {
> >                 #clock-cells =3D <1>;
> >         };
> >
> >         prcc_pclk: prcc-periph-clock {
> >                 #clock-cells =3D <2>;
> >         };
> >
> >         prcc_kclk: prcc-kernel-clock {
> >                 #clock-cells =3D <2>;
> >         };
> >
> >         prcc_reset: prcc-reset-controller {
> >                 #reset-cells =3D <2>;
> >         };
> >         ...
> >         ...
> > };
> >
> > This patch makes sure that "clocks" is marked as initialized so that
> > fw_devlink knows that all nodes under it have been initialized.
> >
> > If the driver creates struct devices for some of the subnodes,
> > fw_devlink is smart enough to know to wait for those devices to probe.
> > So, no special handling is required for those cases.
> >
> > Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> > Reported-by: Linus Walleij <linus.walleij@linaro.org>
> > Link: https://lore.kernel.org/lkml/CACRpkdamxDX6EBVjKX5=3DD3rkHp17f5pwG=
dBVhzFU90-0MHY6dQ@mail.gmail.com/
> > Fixes: 4a032827daa8 ("of: property: Simplify of_link_to_phandle()")
> > Signed-off-by: Saravana Kannan <saravanak@google.com>
>
> Works like a charm on U8500!
> Tested-by: Linus Walleij <linus.walleij@linaro.org>
> Reviewed-by: Linus Walleij <linus.walleij@linaro.org>

Stephen, Does this look good? Can we have Greg pull this in?

-Saravana