Re: [PATCH] gpio: sa1100: defer GPIO chip registration to postcore_initcall

[Guenter Roeck <linux@roeck-us.net>]

On 10/29/26 11:58, Dmitry Torokhov wrote:
> Registering the software node and the GPIO chip for the SA-1100 GPIO
> controller during early IRQ initialization causes boot hangs on
> SA-1100 platforms because the software node subsystem has not yet
> been initialized. At that early boot stage, attempting to register
> software nodes dereferences a NULL kset pointer before console or
> driver model initialization.
> 
> Nothing on SA-1100 platforms requests GPIO lines via gpiolib during
> early boot before initcalls run; only the GPIO IRQ controller and
> domain must be initialized during init_IRQ(). Defer registering the
> software node, assigning its firmware node, and registering the GPIO
> chip with gpiolib to postcore_initcall, running after driver and
> gpiolib device initialization and before board consumers register.
> 
> Fixes: e4671f292ebb ("gpio: sa1100: register software node for GPIO controller")
> Cc: stable@vger.kernel.org
> Reported-by: Guenter Roeck <linux@roeck-us.net>
> Closes: https://lore.kernel.org/r/2a561a27-a3bf-4cac-a4dc-bfbc5c859f45@roeck-us.net
> Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

Tested-by: Guenter Roeck <linux@roeck-us.net>

> ---
>   drivers/gpio/gpio-sa1100.c | 32 +++++++++++++++++++++++++++-----
>   1 file changed, 27 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/gpio/gpio-sa1100.c b/drivers/gpio/gpio-sa1100.c
> index e4f3bf949b87..1916200ebbd5 100644
> --- a/drivers/gpio/gpio-sa1100.c
> +++ b/drivers/gpio/gpio-sa1100.c
> @@ -8,6 +8,7 @@
>   #include <linux/init.h>
>   #include <linux/module.h>
>   #include <linux/io.h>
> +#include <linux/printk.h>
>   #include <linux/syscore_ops.h>
>   #include <soc/sa1100/pwer.h>
>   #include <mach/hardware.h>
> @@ -322,7 +323,6 @@ static const int sa1100_gpio_irqs[] __initconst = {
>   void __init sa1100_init_gpio(void)
>   {
>   	struct sa1100_gpio_chip *sgc = &sa1100_gpio_chip;
> -	struct gpio_chip *gc = &sgc->chip;
>   	int i;
>   
>   	/* clear all GPIO edge detects */
> @@ -330,10 +330,6 @@ void __init sa1100_init_gpio(void)
>   	writel_relaxed(0, sgc->membase + R_GRER);
>   	writel_relaxed(-1, sgc->membase + R_GEDR);
>   
> -	software_node_register(&sa1100_gpiochip_node);
> -	gc->fwnode = software_node_fwnode(&sa1100_gpiochip_node);
> -	gpiochip_add_data(gc, NULL);
> -
>   	sa1100_gpio_irqdomain = irq_domain_create_simple(NULL,
>   			28, IRQ_GPIO0,
>   			&sa1100_gpio_irqdomain_ops, sgc);
> @@ -342,3 +338,29 @@ void __init sa1100_init_gpio(void)
>   		irq_set_chained_handler_and_data(sa1100_gpio_irqs[i],
>   						 sa1100_gpio_handler, sgc);
>   }
> +
> +static int __init sa1100_gpio_init_chip(void)
> +{
> +	struct gpio_chip *gc = &sa1100_gpio_chip.chip;
> +	int error;
> +
> +	error = software_node_register(&sa1100_gpiochip_node);
> +	if (error) {
> +		pr_err("failed to register sa1100 gpiochip software node: %d\n",
> +		       error);
> +		return error;
> +	}
> +
> +	gc->fwnode = software_node_fwnode(&sa1100_gpiochip_node);
> +
> +	error = gpiochip_add_data(gc, NULL);
> +	if (error) {
> +		pr_err("failed to add sa1100 gpiochip: %d\n", error);
> +		gc->fwnode = NULL;
> +		software_node_unregister(&sa1100_gpiochip_node);
> +		return error;
> +	}
> +
> +	return 0;
> +}
> +postcore_initcall(sa1100_gpio_init_chip);
> 
> ---
> base-commit: 6d0933ae9d46674a6ea63a87e9e9ab4e662670c9
> change-id: 20261029-sa1100-swnode-fix-11499713eb7a
> 
> Thanks.
>