linux-kernel - Re: [PATCH] pinctrl: Really force states during suspend/resume

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Message-ID: <CACRpkda=EhP9a7rGCJPz9fSjGcypxgXh2B-YWXbuCMcPRRwEEQ@mail.gmail.com>
Date:   Thu, 23 Feb 2017 11:23:09 +0100
From:   Linus Walleij <linus.walleij@...aro.org>
To:     Florian Fainelli <f.fainelli@...il.com>
Cc:     alcooperx@...il.com, Stephen Warren <swarren@...dia.com>,
        "open list:PIN CONTROL SUBSYSTEM" <linux-gpio@...r.kernel.org>,
        open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] pinctrl: Really force states during suspend/resume

Hi Florian, a big sorry for not looking into this earlier, I've been
having a mess in my inbox... and too much fun with the Gemini
hehe :)

On Wed, Feb 8, 2017 at 2:17 AM, Florian Fainelli <f.fainelli@...il.com> wrote:

> In case a platform only defaults a "default" set of pins, but not a
> "sleep" set of pins, and this particular platform suspends and resumes
> in a way that the pin states are not preserved by the hardware, when we
> resume, we would call pinctrl_single_resume() -> pinctrl_force_default()
> -> pinctrl_select_state() and the first thing we do is check that the
> pins state is the same as before, and do nothing.
>
> In order to fix this, decouple pinctrl_select_state and make it become
> __pinctrl_select_state(), taking an additional ignore_state_check
> boolean which allows us to bypass the state check during suspend/resume,
> since we really want to re-apply the previous pin states in these case.
>
> Fixes: 6e5e959dde0d ("pinctrl: API changes to support multiple states per device")
> Signed-off-by: Florian Fainelli <f.fainelli@...il.com>


>  /**
> - * pinctrl_select_state() - select/activate/program a pinctrl state to HW
> + * __pinctrl_select_state() - select/activate/program a pinctrl state to HW
>   * @p: the pinctrl handle for the device that requests configuration
>   * @state: the state handle to select/activate/program
> + * @force: ignore the state check (e.g: to re-apply default state during
> + * suspend/resume)
>   */
> -int pinctrl_select_state(struct pinctrl *p, struct pinctrl_state *state)
> +static int __pinctrl_select_state(struct pinctrl *p,
> +                                 struct pinctrl_state *state,
> +                                 bool ignore_state_check)

OMG no __prefix functions I'm allergic to that :D

Just come up with a new name that describe what this function is
really doing. I'm picky about syntax matching semantics.
Name it pinctrl_commit_state() if nothing better comes to mind.

>  static void devm_pinctrl_release(struct device *dev, void *res)
> @@ -1236,7 +1250,8 @@ void pinctrl_unregister_map(struct pinctrl_map const *map)
>  int pinctrl_force_sleep(struct pinctrl_dev *pctldev)
>  {
>         if (!IS_ERR(pctldev->p) && !IS_ERR(pctldev->hog_sleep))
> -               return pinctrl_select_state(pctldev->p, pctldev->hog_sleep);
> +               return __pinctrl_select_state(pctldev->p,
> +                                             pctldev->hog_sleep, true);
>         return 0;
>  }
>  EXPORT_SYMBOL_GPL(pinctrl_force_sleep);
> @@ -1248,7 +1263,8 @@ EXPORT_SYMBOL_GPL(pinctrl_force_sleep);
>  int pinctrl_force_default(struct pinctrl_dev *pctldev)
>  {
>         if (!IS_ERR(pctldev->p) && !IS_ERR(pctldev->hog_default))
> -               return pinctrl_select_state(pctldev->p, pctldev->hog_default);
> +               return __pinctrl_select_state(pctldev->p,
> +                                             pctldev->hog_default, true);

OK makes sense.

If you respin with a better function name I will queue it for fixes.

I guess also CC stable if you have problems with older kernels
including v4.10 at this point... sorry if I created a mess.

Yours,
Linus Walleij