Re: [PATCH] Input: gpio_keys_polled - defer probing if GPIO probing is deferred

[Gabor Juhos <juhosg@openwrt.org>]

2012.12.23. 11:06 keltezéssel, Dmitry Torokhov írta:

> Well spotted, thanks. However I think the patch should look like the one
> below as we should propagate all errors, not only -EPROBE_DEFER, up the
> stack.
> 
> Thanks.
> 
> 
> Input: gpio_keys_polled - defer probing if GPIO probing is deferred
> 
> From: Gabor Juhos <juhosg@openwrt.org>
> 
> If GPIO probing is deferred, the driver tries to claim an invalid GPIO line
> which leads to an error message like this:
> 
>   gpio-keys-polled buttons.2: unable to claim gpio 4294966779, err=-22
>   gpio-keys-polled: probe of buttons.2 failed with error -22
> 
> The patch ensures that error code returned by of_get_gpio_flags (including
> -EPROBE_DEFER) is propagated up the stack.
> 
> Cc: stable@vger.kernel.org
> Signed-off-by: Gabor Juhos <juhosg@openwrt.org>
> Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
> ---
>  drivers/input/keyboard/gpio_keys_polled.c |   13 ++++++++++++-
>  1 file changed, 12 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/input/keyboard/gpio_keys_polled.c b/drivers/input/keyboard/gpio_keys_polled.c
> index f686fd9..e75ca6b 100644
> --- a/drivers/input/keyboard/gpio_keys_polled.c
> +++ b/drivers/input/keyboard/gpio_keys_polled.c
> @@ -135,6 +135,7 @@ static struct gpio_keys_platform_data *gpio_keys_polled_get_devtree_pdata(struct
>  
>  	i = 0;
>  	for_each_child_of_node(node, pp) {
> +		int gpio;
>  		enum of_gpio_flags flags;
>  
>  		if (!of_find_property(pp, "gpios", NULL)) {
> @@ -143,9 +144,19 @@ static struct gpio_keys_platform_data *gpio_keys_polled_get_devtree_pdata(struct
>  			continue;
>  		}
>  
> +		gpio = of_get_gpio_flags(pp, 0, &flags);
> +		if (gpio < 0) {
> +			error = gpio;
> +			if (error != -EPROBE_DEFER)
> +				dev_err(dev,
> +					"Failed to get gpio flags, error: %d\n",
> +					error);
> +			goto err_free_pdata;
> +		}
> +
>  		button = &pdata->buttons[i++];
>  
> -		button->gpio = of_get_gpio_flags(pp, 0, &flags);
> +		button->gpio = gpio;
>  		button->active_low = flags & OF_GPIO_ACTIVE_LOW;
>  
>  		if (of_property_read_u32(pp, "linux,code", &button->code)) {

Yes, this looks saner. I have replaced my patch with this, and it is working as
intended. The kernel says this:

platform buttons.2: Driver gpio-keys-polled requests probe deferral

BTW, it seems that the gpio-keys driver needs a similar fix.

-Gabor
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