Re: [PATCH v7 4/4] gpio: mxc: fix race between gpiochip registration and IRQ domain setup

[Frank Li <Frank.li@oss.nxp.com>]

On Tue, Oct 13, 2026 at 02:01:12PM +0800, Peng Fan (OSS) wrote:
> From: Peng Fan <peng.fan@nxp.com>
>
> devm_gpiochip_add_data() makes the GPIO chip visible to consumers
> immediately. Since the chip sets .to_irq = mxc_gpio_to_irq, which calls
> irq_find_mapping(port->domain, offset), any to_irq() call between
> gpiochip registration and IRQ domain creation will operate on a NULL
> domain.
>
> Fix by moving devm_gpiochip_add_data() after the IRQ domain and generic
> irq chip are fully initialized, ensuring port->domain and the irq chip
> handlers are ready before the chip becomes visible to consumers.
>
> Fixes: d37a65bb4663 ("gpio/mxc: Move Freescale MXC gpio driver to drivers/gpio")
> Signed-off-by: Peng Fan <peng.fan@nxp.com>

Reviewed-by: Frank Li <Frank.Li@nxp.com>

> ---
>  drivers/gpio/gpio-mxc.c | 13 +++++++++----
>  1 file changed, 9 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/gpio/gpio-mxc.c b/drivers/gpio/gpio-mxc.c
> index e3a80f17d041..32ded7b548fb 100644
> --- a/drivers/gpio/gpio-mxc.c
> +++ b/drivers/gpio/gpio-mxc.c
> @@ -500,10 +500,6 @@ static int mxc_gpio_probe(struct platform_device *pdev)
>  	else /* silence boot time warning */
>  		port->gen_gc.gc.base = -1;
>
> -	err = devm_gpiochip_add_data(&pdev->dev, &port->gen_gc.gc, port);
> -	if (err)
> -		goto out_bgio;
> -
>  	irq_base = devm_irq_alloc_descs(&pdev->dev, -1, 0, 32, numa_node_id());
>  	if (irq_base < 0) {
>  		err = irq_base;
> @@ -524,6 +520,15 @@ static int mxc_gpio_probe(struct platform_device *pdev)
>  	if (err < 0)
>  		goto out_irqdomain_remove;
>
> +	/*
> +	 * Register the GPIO chip last: devm_gpiochip_add_data() makes the
> +	 * chip visible to consumers immediately, so the IRQ domain and
> +	 * generic irq chip must be ready before any to_irq() call.
> +	 */
> +	err = devm_gpiochip_add_data(&pdev->dev, &port->gen_gc.gc, port);
> +	if (err)
> +		goto out_irqdomain_remove;
> +
>  	list_add_tail(&port->node, &mxc_gpio_ports);
>
>  	mxc_update_irq_chained_handler(port, true);
>
> --
> 2.51.0
>
>