Re: [PATCH v1 1/1] gpio: mlxbf3: Support shutdown() function

[Andy Shevchenko <andy.shevchenko@xxxxxxxxx>]

On Tue, Jun 11, 2024 at 5:38 PM Asmaa Mnebhi <asmaa@xxxxxxxxxx> wrote:
>
> During Linux graceful reboot, the GPIO interrupts are not disabled.
> Since the drivers are not removed during graceful reboot,
> the logic to call mlxbf3_gpio_irq_disable() is not triggered.
> Interrupts that remain enabled can cause issues on subsequent boots.
>
> For example, the mlxbf-gige driver contains PHY logic to bring up the link.
> If the gpio-mlxbf3 driver loads first, the mlxbf-gige driver
> will use a GPIO interrupt to bring up the link.
> Otherwise, it will use polling.
> The next time Linux boots and loads the drivers in this order, we encounter the issue:
> - mlxbf-gige loads first. The gige driver uses polling while the GPIO10 interrupt
>   is still enabled from previous boot so if the interrupt triggers, there is nothing
>   to clear it.
> - gpio-mlxbf3 loads.
> - i2c-mlxbf loads. The interrupt doesn't trigger for I2C because it is shared with the gpio

GPIO

>   interrupt line which was not cleared.

> The solution is to add a shutdown function to the gpio driver to clear and disable

GPIO

> all interrupts. Also clear the interrupt after disabling it in mlxbf3_gpio_irq_disable().

...

> +#define MLXBF_GPIO_CLR_ALL_INTS           0xFFFFFFFF

GENMASK()

...

> +static void mlxbf3_gpio_shutdown(struct platform_device *pdev)
> +{
> +       struct mlxbf3_gpio_context *gs = dev_get_drvdata(&pdev->dev);

platform_get_drvdata()

> +       /* Disable and clear all interrupts */
> +       writel(0, gs->gpio_cause_io + MLXBF_GPIO_CAUSE_OR_EVTEN0);
> +       writel(MLXBF_GPIO_CLR_ALL_INTS, gs->gpio_cause_io + MLXBF_GPIO_CAUSE_OR_CLRCAUSE);
> +}

-- 
With Best Regards,
Andy Shevchenko