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

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Date:   Tue, 14 Feb 2017 06:46:11 -0800
From:   Florian Fainelli <f.fainelli@...il.com>
To:     linus.walleij@...aro.org
Cc:     alcooperx@...il.com, 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



On 02/07/2017 05:17 PM, Florian Fainelli 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>
> ---
> Linus,
> 
> This is against your "fixes" branch, thank you!

Linus, can you provide some feedback here so I know whether this should
be addressed differently? Thanks

> 
>  drivers/pinctrl/core.c | 26 +++++++++++++++++++++-----
>  1 file changed, 21 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/pinctrl/core.c b/drivers/pinctrl/core.c
> index fb38e208f32d..8b8017dc9e15 100644
> --- a/drivers/pinctrl/core.c
> +++ b/drivers/pinctrl/core.c
> @@ -992,17 +992,21 @@ struct pinctrl_state *pinctrl_lookup_state(struct pinctrl *p,
>  EXPORT_SYMBOL_GPL(pinctrl_lookup_state);
>  
>  /**
> - * 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)
>  {
>  	struct pinctrl_setting *setting, *setting2;
>  	struct pinctrl_state *old_state = p->state;
>  	int ret;
>  
> -	if (p->state == state)
> +	if (p->state == state && !ignore_state_check)
>  		return 0;
>  
>  	if (p->state) {
> @@ -1068,6 +1072,16 @@ int pinctrl_select_state(struct pinctrl *p, struct pinctrl_state *state)
>  
>  	return ret;
>  }
> +
> +/**
> + * 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
> + */
> +int pinctrl_select_state(struct pinctrl *p, struct pinctrl_state *state)
> +{
> +	return __pinctrl_select_state(p, state, false);
> +}
>  EXPORT_SYMBOL_GPL(pinctrl_select_state);
>  
>  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);
>  	return 0;
>  }
>  EXPORT_SYMBOL_GPL(pinctrl_force_default);
> 

-- 
Florian