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

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Message-ID: <CAMuHMdXGaDoBbNGkS8oYRiNUNbtUNand6qkNY-s4QNSt5Fj0ZQ@mail.gmail.com>
Date:   Thu, 12 Jan 2017 09:43:21 +0100
From:   Geert Uytterhoeven <geert@...ux-m68k.org>
To:     Tony Lindgren <tony@...mide.com>
Cc:     Linus Walleij <linus.walleij@...aro.org>,
        Haojian Zhuang <haojian.zhuang@...aro.org>,
        Masahiro Yamada <yamada.masahiro@...ionext.com>,
        Grygorii Strashko <grygorii.strashko@...com>,
        Nishanth Menon <nm@...com>,
        "linux-gpio@...r.kernel.org" <linux-gpio@...r.kernel.org>,
        "devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "linux-omap@...r.kernel.org" <linux-omap@...r.kernel.org>,
        Gary Bisson <gary.bisson@...ndarydevices.com>,
        Linux-Renesas <linux-renesas-soc@...r.kernel.org>
Subject: Re: [PATCH] pinctrl: core: Fix regression caused by delayed work for hogs

Hi Tony,

On Wed, Jan 11, 2017 at 11:13 PM, Tony Lindgren <tony@...mide.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@...ux-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@...aro.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@...ux-m68k.org>
> Cc: Gary Bisson <gary.bisson@...ndarydevices.com>
> Signed-off-by: Tony Lindgren <tony@...mide.com>

Thanks, this fixes r8a7740/armadillo.

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

Gr{oetje,eeting}s,

                        Geert

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