linux-kernel - Re: [PATCH] pinctrl: samsung: Calculate GPIO base for pinctrl_add_gpio

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Message-ID: <CA+Ln22FJ=Kg_HmfjhDst4fNeUoA8jh=QVsF-rUVeXgPrzunJ+w@mail.gmail.com>
Date:   Mon, 27 Feb 2017 11:13:59 +0900
From:   Tomasz Figa <tomasz.figa@...il.com>
To:     Charles Keepax <ckeepax@...nsource.wolfsonmicro.com>
Cc:     "linus.walleij@...aro.org" <linus.walleij@...aro.org>,
        Krzysztof Kozlowski <krzk@...nel.org>,
        Sylwester Nawrocki <s.nawrocki@...sung.com>,
        "linux-gpio@...r.kernel.org" <linux-gpio@...r.kernel.org>,
        "linux-samsung-soc@...r.kernel.org" 
        <linux-samsung-soc@...r.kernel.org>,
        linux-kernel <linux-kernel@...r.kernel.org>,
        patches@...nsource.wolfsonmicro.com
Subject: Re: [PATCH] pinctrl: samsung: Calculate GPIO base for pinctrl_add_gpio_range

Hi Charles,

2017-02-24 2:54 GMT+09:00 Charles Keepax <ckeepax@...nsource.wolfsonmicro.com>:
> As the pinctrl is now added before the GPIOs are registered we need to
> manually calculate what the GPIO base will be, otherwise the base for
> each gpio_range will be set to zero. Fortunately the driver
> already assigns a GPIO base, in samsung_gpiolib_register, and uses the
> same calculation it does for the pin_base. Meaning the two will always
> be the same and allowing us to reuse the pinbase and avoid the issue.

Please see my comment inline.

>
> Signed-off-by: Charles Keepax <ckeepax@...nsource.wolfsonmicro.com>
> ---
>
> Ok I might have spoken to soon there looks like there is a simple
> way to fix this up, at least in this case. It would be much more
> of an issue if the driver allocated its GPIO base dynamically.
>
> Thanks,
> Charles
>
>  drivers/pinctrl/samsung/pinctrl-samsung.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/pinctrl/samsung/pinctrl-samsung.c b/drivers/pinctrl/samsung/pinctrl-samsung.c
> index ddc8d6b..864d8b4d 100644
> --- a/drivers/pinctrl/samsung/pinctrl-samsung.c
> +++ b/drivers/pinctrl/samsung/pinctrl-samsung.c
> @@ -882,7 +882,7 @@ static int samsung_pinctrl_register(struct platform_device *pdev,
>                 pin_bank->grange.id = bank;
>                 pin_bank->grange.pin_base = drvdata->pin_base
>                                                 + pin_bank->pin_base;
> -               pin_bank->grange.base = pin_bank->gpio_chip.base;
> +               pin_bank->grange.base = pin_bank->grange.pin_base;

If we are not reading the base from the GPIO bank anymore, maybe it
could make sense to actually make samsung_gpiolib_register() use
bank->grange.base as gc->base? This way we would avoid explicitly
numbering two times.

Best regards,
Tomasz