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@nvidia.com>
---
 drivers/gpio/gpio-mlxbf3.c | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/drivers/gpio/gpio-mlxbf3.c b/drivers/gpio/gpio-mlxbf3.c
index e30cee108986..3828f5282b17 100644
--- a/drivers/gpio/gpio-mlxbf3.c
+++ b/drivers/gpio/gpio-mlxbf3.c
@@ -158,6 +158,24 @@ static const struct irq_chip gpio_mlxbf3_irqchip = {
 	GPIOCHIP_IRQ_RESOURCE_HELPERS,
 };
 
+static int mlxbf3_gpio_add_pin_ranges(struct gpio_chip *chip)
+{
+	int ret;
+	int id = 0;
+
+	id = !!(chip->ngpio % MLXBF3_GPIO_MAX_PINS_PER_BLOCK);
+
+	ret = gpiochip_add_pin_range(chip,
+			"MLNXBF34:00",
+			chip->base,
+			id * MLXBF3_GPIO_MAX_PINS_PER_BLOCK,
+			chip->ngpio);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
 static int mlxbf3_gpio_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
@@ -197,6 +215,7 @@ 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 +262,7 @@ 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@nvidia.com>");
 MODULE_LICENSE("Dual BSD/GPL");
-- 
2.30.1

On Wed, Aug 16, 2023 at 4:59 PM Asmaa Mnebhi <asmaa@nvidia.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.

...

> +static int mlxbf3_gpio_add_pin_ranges(struct gpio_chip *chip)
> +{
> +       int ret;
> +       int id = 0;

Redundant assignment.

> +       id = !!(chip->ngpio % MLXBF3_GPIO_MAX_PINS_PER_BLOCK);

Using int as boolean. Seems to me you wanted something different here.

> +       ret = gpiochip_add_pin_range(chip,
> +                       "MLNXBF34:00",
> +                       chip->base,
> +                       id * MLXBF3_GPIO_MAX_PINS_PER_BLOCK,
> +                       chip->ngpio);
> +       if (ret)
> +               return ret;
> +
> +       return 0;

You can return directly:

  return gpiochip_add_pin_range(...);

> +}

-- 
With Best Regards,
Andy Shevchenko