Re: [PATCH] Input: adp5588-keys - cache GPIO state before registering the gpiochip

[Nuno Sá]

On Tue, Aug 18, 2026 at 06:00:02PM +0200, Alvin Šipraga wrote:
> So as not to clobber any pre-programmed GPIO state in the execution
> of its gpiochip ops, the driver caches things during probe time.
> However, since those ops can be called both during and immediately after
> the call to devm_gpiochip_add_data(), it is imperative that things are
> cached before that. That's not the case right now, so reorder the two
> steps to prevent any clobbering.
> 
> In a conrete example which motivated this change, a bootloader was
> preconfiguring an important GPIO output to HIGH before booting the
> kernel. Linux would then inadvertently set that output to LOW while
> configuring a GPIO hog on a discrete GPIO line within the same 8-bit
> bank (because the cached value was 0=LOW).
> 
> Fixes: ba9f507a1bea ("Input: adp5588-keys - export unused GPIO pins")
> Signed-off-by: Alvin Šipraga <alvin.sipraga@xxxxxxxxxx>
> ---

Reviewed-by: Nuno Sá <nuno.sa@xxxxxxxxxx>

>  drivers/input/keyboard/adp5588-keys.c | 12 ++++++------
>  1 file changed, 6 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/input/keyboard/adp5588-keys.c b/drivers/input/keyboard/adp5588-keys.c
> index 40371f5bd9ba..4f0ddff5baba 100644
> --- a/drivers/input/keyboard/adp5588-keys.c
> +++ b/drivers/input/keyboard/adp5588-keys.c
> @@ -446,12 +446,6 @@ static int adp5588_gpio_add(struct adp5588_kpad *kpad)
>  
>  	mutex_init(&kpad->gpio_lock);
>  
> -	error = devm_gpiochip_add_data(dev, &kpad->gc, kpad);
> -	if (error) {
> -		dev_err(dev, "gpiochip_add failed: %d\n", error);
> -		return error;
> -	}
> -
>  	for (i = 0; i <= ADP5588_BANK(ADP5588_MAXGPIO); i++) {
>  		kpad->dat_out[i] = adp5588_read(kpad->client,
>  						GPIO_DAT_OUT1 + i);
> @@ -459,6 +453,12 @@ static int adp5588_gpio_add(struct adp5588_kpad *kpad)
>  		kpad->pull_dis[i] = adp5588_read(kpad->client, GPIO_PULL1 + i);
>  	}
>  
> +	error = devm_gpiochip_add_data(dev, &kpad->gc, kpad);
> +	if (error) {
> +		dev_err(dev, "gpiochip_add failed: %d\n", error);
> +		return error;
> +	}
> +
>  	return 0;
>  }
>  
> 
> ---
> base-commit: 44f3468a0aef1aabdad551898ab7cfa2a9d20e99
> change-id: 20260818-adp5588-gpio-cache-23fb8d0a3190
> 
> Best regards,
> --  
> Alvin Šipraga <alvin.sipraga@xxxxxxxxxx>
>