Re: [PATCH 1/2] gpio: Fix crash in gpiod_set_debounce()

[Stephen Warren <swarren@wwwdotorg.org>]

On 09/03/2013 04:39 AM, Thierry Reding wrote:
> Return an error if neither the ->set() nor the ->set_debounce() function
> is implemented by the chip. Furthermore move locking further down so the
> lock doesn't have to be unlocked on error. This is safe to do because at
> this point the lock doesn't protect anything.

> diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c

>  	chip = desc->chip;
>  	if (!chip->set || !chip->set_debounce) {
>  	  pr_warn("%s: missing set() or set_debounce() operations\n",
>  		  __func__);
> +		return -EIO;
>  	}

BTW, I'm not sure that error-path should pr_warn(). For example, if this
error-patch is taken due to a call from
gpio_keys.c:gpio_keys_setup_key(), then a timer will be used for
debounce instead, which is all perfectly valid, and probably not
something that should be spewed to the kernel log.