linux-kernel - Re: [PATCH v5 2/2] gpio: mlxbf3: Support add_pin

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Message-ID: <CAMRc=Mccsc=RY5Evw4-k8LYDrfuxFoWsn6wajybY4SY_89fjNw@mail.gmail.com>
Date:   Mon, 21 Aug 2023 14:38:49 +0200
From:   Bartosz Golaszewski <brgl@...ev.pl>
To:     Asmaa Mnebhi <asmaa@...dia.com>
Cc:     andy.shevchenko@...il.com, linux-gpio@...r.kernel.org,
        linus.walleij@...aro.org, bgolaszewski@...libre.com,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v5 2/2] gpio: mlxbf3: Support add_pin_ranges()

On Fri, Aug 18, 2023 at 6:43 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.
>
> Fixes: cd33f216d24 ("gpio: mlxbf3: Add gpio driver support")
> Signed-off-by: Asmaa Mnebhi <asmaa@...dia.com>
> Reviewed-by: Andy Shevchenko <andy.shevchenko@...il.com>
> ---
> v4->v5:
> - Add "Reviewed-By" Tag
> v3->v4:
> - Drop the common define for MLXBF3_GPIO_MAX_PINS_BLOCK0
> v2->v3:
> - Replace boolean logic by clear switch statement logic in
>   mlxbf3_gpio_add_pin_ranges()
> v1->v2:
> - Cleanup mlxbf3_gpio_add_pin_ranges()
>
>  drivers/gpio/gpio-mlxbf3.c | 24 ++++++++++++++++++++++++
>  1 file changed, 24 insertions(+)
>
> diff --git a/drivers/gpio/gpio-mlxbf3.c b/drivers/gpio/gpio-mlxbf3.c
> index e30cee108986..0a5f241a8352 100644
> --- a/drivers/gpio/gpio-mlxbf3.c
> +++ b/drivers/gpio/gpio-mlxbf3.c
> @@ -19,6 +19,8 @@
>   * gpio[1]: HOST_GPIO32->HOST_GPIO55
>   */
>  #define MLXBF3_GPIO_MAX_PINS_PER_BLOCK 32
> +#define MLXBF3_GPIO_MAX_PINS_BLOCK0    32
> +#define MLXBF3_GPIO_MAX_PINS_BLOCK1    24
>
>  /*
>   * fw_gpio[x] block registers and their offset
> @@ -158,6 +160,26 @@ static const struct irq_chip gpio_mlxbf3_irqchip = {
>         GPIOCHIP_IRQ_RESOURCE_HELPERS,
>  };
>
> +static int mlxbf3_gpio_add_pin_ranges(struct gpio_chip *chip)
> +{
> +       unsigned int id;
> +
> +       switch(chip->ngpio) {
> +       case MLXBF3_GPIO_MAX_PINS_BLOCK0:
> +               id = 0;
> +               break;
> +       case MLXBF3_GPIO_MAX_PINS_BLOCK1:
> +               id = 1;
> +               break;
> +       default:
> +               return -EINVAL;
> +       }
> +
> +       return gpiochip_add_pin_range(chip, "MLNXBF34:00",
> +                       chip->base, id * MLXBF3_GPIO_MAX_PINS_PER_BLOCK,
> +                       chip->ngpio);
> +}
> +
>  static int mlxbf3_gpio_probe(struct platform_device *pdev)
>  {
>         struct device *dev = &pdev->dev;
> @@ -197,6 +219,7 @@ static int mlxbf3_gpio_probe(struct platform_device *pdev)
>         gc->request = gpiochip_generic_request;
>         gc->free = gpiochip_generic_free;
>         gc->owner = THIS_MODULE;
> +       gc->add_pin_ranges = mlxbf3_gpio_add_pin_ranges;
>
>         irq = platform_get_irq(pdev, 0);
>         if (irq >= 0) {
> @@ -243,6 +266,7 @@ static struct platform_driver mlxbf3_gpio_driver = {
>  };
>  module_platform_driver(mlxbf3_gpio_driver);
>
> +MODULE_SOFTDEP("pre: pinctrl-mlxbf3");
>  MODULE_DESCRIPTION("NVIDIA BlueField-3 GPIO Driver");
>  MODULE_AUTHOR("Asmaa Mnebhi <asmaa@...dia.com>");
>  MODULE_LICENSE("Dual BSD/GPL");
> --
> 2.30.1
>

It's not clear to me whether this depends on patch 1? If only at
run-time then I guess Linus and I can take the two patches through
ours respective trees?

Bart