linux-kernel - Re: [PATCH v2 2/2] gpio: mlxbf3: Support add_pin

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Message-ID: <CAHp75Vdp9TYTod6UBLxG_YrT_vD4azfyrM9dTrau8CPJuH_vrQ@mail.gmail.com>
Date:   Wed, 16 Aug 2023 18:49:27 +0300
From:   Andy Shevchenko <andy.shevchenko@...il.com>
To:     Asmaa Mnebhi <asmaa@...dia.com>
Cc:     linux-gpio@...r.kernel.org, linus.walleij@...aro.org,
        bgolaszewski@...libre.com, brgl@...ev.pl,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 2/2] gpio: mlxbf3: Support add_pin_ranges()

On Wed, Aug 16, 2023 at 6:45 PM Asmaa Mnebhi <asmaa@...dia.com> wrote:
>
> Support add_pin_ranges() so that pinctrl_gpio_request() can be called.
> The GPIO value is not modified when the user runs the "gpioset" tool.
> This is because when gpiochip_generic_request is invoked by the gpio-mlxbf3
> driver, "pin_ranges" is empty so it skips "pinctrl_gpio_request()".
> pinctrl_gpio_request() is essential in the code flow because it changes the
> mux value so that software has control over modifying the GPIO value.
> Adding add_pin_ranges() creates a dependency on the pinctrl-mlxbf3.c driver.

...

> v1->v2:
> - No changes.

Is this correct?

...

> +static int mlxbf3_gpio_add_pin_ranges(struct gpio_chip *chip)
> +{
> +       unsigned int id = 0;
> +       int ret;
> +
> +       if (chip->ngpio % MLXBF3_GPIO_MAX_PINS_PER_BLOCK)
> +               id = 1;

This id calculation seems wrong to me as I said in v1 review.
Why do you think the above is what you want and not just working by luck?

> +       return gpiochip_add_pin_range(chip, "MLNXBF34:00",
> +                       chip->base, id * MLXBF3_GPIO_MAX_PINS_PER_BLOCK,
> +                       chip->ngpio);
> +}

-- 
With Best Regards,
Andy Shevchenko