Re: [PATCH v1] gpiolib: Don't probe gpio_device if it's not the primary device

[Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>]

Hi Saravana,

On Fri, Feb 5, 2021 at 3:09 AM Saravana Kannan <saravanak@xxxxxxxxxx> wrote:
> Dmitry reported[1] boot error messages caused by
> commit 4731210c09f5 ("gpiolib: Bind gpio_device to a driver to enable fw_devlink=on by default").
>
> gpio-1022 (cpu-pwr-req-hog): hogged as input
> max77620-pinctrl max77620-pinctrl: pin gpio4 already requested by max77620-pinctrl; cannot claim for gpiochip1
> max77620-pinctrl max77620-pinctrl: pin-4 (gpiochip1) status -22
> max77620-pinctrl max77620-pinctrl: could not request pin 4 (gpio4) from group gpio4  on device max77620-pinctrl
> gpio_stub_drv gpiochip1: Error applying setting, reverse things back
> gpio_stub_drv: probe of gpiochip1 failed with error -22

Similar issue on Salvator-XS:

    sh-pfc e6060000.pinctrl: pin GP_2_0 already requested by 7-0030;
cannot claim for gpiochip9
    sh-pfc e6060000.pinctrl: pin-64 (gpiochip9) status -22
    sh-pfc e6060000.pinctrl: could not request pin 64 (GP_2_0) from
group intc_ex_irq0  on device sh-pfc
    gpio_stub_drv gpiochip9: Error applying setting, reverse things back
    gpio_stub_drv: probe of gpiochip9 failed with error -22

> This happens because when we try to probe a device, driver core calls
> into pinctrl to set up the pins. However, if the GPIO DT node already
> has a proper device created and probed, trying to probe the gpio_device
> with a stub driver makes the pins be claimed twice. pinctrl doesn't like
> this and throws an error.
>
> So, this patch makes sure the gpio_stub_drv doesn't match with a
> gpio_device if it's not the primary device for the fwnode.
>
> [1] - https://lore.kernel.org/lkml/544ad0e4-0954-274c-8e77-866aaa5661a8@xxxxxxxxx/
> Fixes: 4731210c09f5 ("gpiolib: Bind gpio_device to a driver to enable fw_devlink=on by default")
> Signed-off-by: Saravana Kannan <saravanak@xxxxxxxxxx>
> Tested-by: Dmitry Osipenko <digetx@xxxxxxxxx>

Tested-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx

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