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From:   Geert Uytterhoeven <geert@linux-m68k.org>
Date:   Wed, 3 Feb 2021 08:54:59 +0100
Message-ID: <CAMuHMdWN4JA4w+6MUAc-ogRAE602G8KSgy+71dtx7QQ60t1XZQ@mail.gmail.com>
Subject: Re: [PATCH v2 0/3] Make fw_devlink=on more forgiving
To:     Saravana Kannan <saravanak@google.com>
Cc:     Martin Kaiser <martin@kaiser.cx>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        "Rafael J. Wysocki" <rafael@kernel.org>,
        Marek Szyprowski <m.szyprowski@samsung.com>,
        Marc Zyngier <maz@kernel.org>,
        Tudor Ambarus <Tudor.Ambarus@microchip.com>,
        Linus Walleij <linus.walleij@linaro.org>,
        Bartosz Golaszewski <bgolaszewski@baylibre.com>,
        Rob Herring <robh+dt@kernel.org>,
        Frank Rowand <frowand.list@gmail.com>,
        Len Brown <lenb@kernel.org>,
        LKML <linux-kernel@vger.kernel.org>,
        "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" 
        <devicetree@vger.kernel.org>,
        ACPI Devel Maling List <linux-acpi@vger.kernel.org>,
        Android Kernel Team <kernel-team@android.com>
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On Tue, Feb 2, 2021 at 11:44 PM Saravana Kannan <saravanak@google.com> wrote:
> On Tue, Feb 2, 2021 at 1:22 PM Martin Kaiser <martin@kaiser.cx> wrote:
> > Thus wrote Saravana Kannan (saravanak@google.com):
> > All of those drivers have a gpio in
> > their device-tree node, such as
> >
> > my_driver {
> >    gpio_test1 = <&gpio1 0 0>;
> >    ...
> > };
> >
> > with gpio1 from arch/arm/boot/dts/imx25.dtsi.
> >
> > The probe function calls
> >
> > of_get_named_gpio(np, "gpio_test1", 0);
> >
> > to get the gpio. This fails with -EINVAL.
>
> And you didn't see this issue with the fsl,avic patch?
>
> The property you are using is not a standard GPIO binding (-gpios,
> gpio, gpios) and I'm not surprised it's not working. The gpio1 is
> probably getting probe deferred and ends up running after "my_driver".

So my_driver doesn't support deferred probe, as of_get_named_gpio()
returns -EINVAL instead of -EPROBE_DEFER?
Converting my_driver from of_get_named_gpio() to the gpiod_*() API
should at least make the driver support probe deferral, after which I
expect it to start working again on reprobe?

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds