Re: [PATCH] pinctrl: core: Fix regression caused by delayed work for hogs

Re: [PATCH] pinctrl: core: Fix regression caused by delayed work for hogs

[Geert Uytterhoeven]

Hi Tony,

On Wed, Jan 11, 2017 at 11:13 PM, Tony Lindgren <tony@atomide.com> wrote:
> Commit df61b366af26 ("pinctrl: core: Use delayed work for hogs") caused a
> regression at least with sh-pfc that is also a GPIO controller as
> noted by Geert Uytterhoeven <geert@linux-m68k.org>.
>
> As the original pinctrl_register() has issues calling pin controller
> driver functions early before the controller has finished registering,
> we can't just revert commit df61b366af26. That would break the drivers
> using GENERIC_PINCTRL_GROUPS or GENERIC_PINMUX_FUNCTIONS.
>
> So let's fix the issue with the following steps as a single patch:
>
> 1. Revert the late_init parts of commit df61b366af26.
>
>    The late_init clearly won't work and we have to just give up
>    on fixing pinctrl_register() for GENERIC_PINCTRL_GROUPS and
>    GENERIC_PINMUX_FUNCTIONS.
>
> 2. Split pinctrl_register() into two parts
>
>    By splitting pinctrl_register() into pinctrl_init_controller()
>    and pinctrl_create_and_start() we have better control over when
>    it's safe to call pinctrl_create().
>
> 3. Introduce a new pinctrl_register_and_init() function
>
>    As suggested by Linus Walleij <linus.walleij@linaro.org>, we
>    can just introduce a new function for the controllers that need
>    pinctrl_create() called later.
>
> 4. Convert the four known problem cases to use new function
>
>    Let's convert pinctrl-imx, pinctrl-single, sh-pfc and ti-iodelay
>    to use the new function to fix the issues. The rest of the drivers
>    can be converted later. Let's also update Documentation/pinctrl.txt
>    accordingly because of the known issues with pinctrl_register().
>
> Fixes: df61b366af26 ("pinctrl: core: Use delayed work for hogs")
> Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
> Cc: Gary Bisson <gary.bisson@boundarydevices.com>
> Signed-off-by: Tony Lindgren <tony@atomide.com>

Thanks, this fixes r8a7740/armadillo.

Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>

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

Re: [PATCH] pinctrl: core: Fix regression caused by delayed work for hogs

[Tony Lindgren]

* Geert Uytterhoeven <geert@linux-m68k.org> [170112 00:44]:
> Hi Tony,
> 
> On Wed, Jan 11, 2017 at 11:13 PM, Tony Lindgren <tony@atomide.com> wrote:
> > Commit df61b366af26 ("pinctrl: core: Use delayed work for hogs") caused a
> > regression at least with sh-pfc that is also a GPIO controller as
> > noted by Geert Uytterhoeven <geert@linux-m68k.org>.
> >
> > As the original pinctrl_register() has issues calling pin controller
> > driver functions early before the controller has finished registering,
> > we can't just revert commit df61b366af26. That would break the drivers
> > using GENERIC_PINCTRL_GROUPS or GENERIC_PINMUX_FUNCTIONS.
> >
> > So let's fix the issue with the following steps as a single patch:
> >
> > 1. Revert the late_init parts of commit df61b366af26.
> >
> >    The late_init clearly won't work and we have to just give up
> >    on fixing pinctrl_register() for GENERIC_PINCTRL_GROUPS and
> >    GENERIC_PINMUX_FUNCTIONS.
> >
> > 2. Split pinctrl_register() into two parts
> >
> >    By splitting pinctrl_register() into pinctrl_init_controller()
> >    and pinctrl_create_and_start() we have better control over when
> >    it's safe to call pinctrl_create().
> >
> > 3. Introduce a new pinctrl_register_and_init() function
> >
> >    As suggested by Linus Walleij <linus.walleij@linaro.org>, we
> >    can just introduce a new function for the controllers that need
> >    pinctrl_create() called later.
> >
> > 4. Convert the four known problem cases to use new function
> >
> >    Let's convert pinctrl-imx, pinctrl-single, sh-pfc and ti-iodelay
> >    to use the new function to fix the issues. The rest of the drivers
> >    can be converted later. Let's also update Documentation/pinctrl.txt
> >    accordingly because of the known issues with pinctrl_register().
> >
> > Fixes: df61b366af26 ("pinctrl: core: Use delayed work for hogs")
> > Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
> > Cc: Gary Bisson <gary.bisson@boundarydevices.com>
> > Signed-off-by: Tony Lindgren <tony@atomide.com>
> 
> Thanks, this fixes r8a7740/armadillo.
> 
> Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>

OK thanks for testing, good to hear it works for you.

Thanks,

Tony