linux-kernel - Re: [PATCH v2 -next] Input: gpio_keys: set input direction explicitly for gpio keys

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Date:   Wed, 16 Nov 2016 09:36:56 -0800
From:   Dmitry Torokhov <dmitry.torokhov@...il.com>
To:     Sudeep Holla <sudeep.holla@....com>
Cc:     linux-input@...r.kernel.org, linux-kernel@...r.kernel.org,
        Linus Walleij <linus.walleij@...aro.org>,
        Geert Uytterhoeven <geert+renesas@...der.be>,
        Mika Westerberg <mika.westerberg@...ux.intel.com>
Subject: Re: [PATCH v2 -next] Input: gpio_keys: set input direction
 explicitly for gpio keys

On Wed, Nov 16, 2016 at 01:42:14PM +0000, Sudeep Holla wrote:
> Commit 700a38b27eef ("Input: gpio_keys - switch to using generic device
> properties") switched to use generic device properties for GPIO keys and
> commit 5feeca3c1e39 ("Input: gpio_keys - add support for GPIO descriptors")
> switched from legacy GPIO numbers to GPIO descriptors.
> 
> Previously devm_gpio_request_one was explicitly passed GPIOF_DIR_IN flag
> to set the GPIO direction as input. However devm_get_gpiod_from_child
> doesn't have such provisions and hence fwnode_get_named_gpiod can't set
> it as input.
> 
> This breaks few platforms with the following error:
> " gpiochip_lock_as_irq: tried to flag a GPIO set as output for IRQ
>   unable to lock HW IRQ <n> for IRQ
>   genirq: Failed to request resources for POWER (irq <x>) on irqchip
>   gpio_keys: Unable to claim irq <x>; error -22
>   gpio-keys: probe failed with error -22 "
> 
> This patch fixes the issue by setting input direction explicitly for
> gpio input keys. It also remove the existing GPIOF_DIR_IN flag setting
> for the legacy gpios and merges into single gpiod_direction_input call.
> 
> Fixes: 700a38b27eef ("Input: gpio_keys - switch to using generic device properties")
> Cc: Dmitry Torokhov <dmitry.torokhov@...il.com>
> Cc: Linus Walleij <linus.walleij@...aro.org>
> Cc: Geert Uytterhoeven <geert+renesas@...der.be>
> Cc: Mika Westerberg <mika.westerberg@...ux.intel.com>
> Signed-off-by: Sudeep Holla <sudeep.holla@....com>
> ---
>  drivers/input/keyboard/gpio_keys.c        | 5 ++++-
>  drivers/input/keyboard/gpio_keys_polled.c | 5 ++++-
>  2 files changed, 8 insertions(+), 2 deletions(-)
> 
> v1->v2:
> 	- Fix the build(had sent a wrong version by accident)
> 
> Hi Dmitry,
> 
> The other option would be to pass the flag explicitly and add support to
> handle it in the path devm_get_gpiod_from_child would take.

Hi Sudeep,

No, I think explicitly configuring it for input is good (at least for
now), but we need error handling.

Thanks!

> 
> Let me know your opinion.
> 
> Regards,
> Sudeep
> 
> diff --git a/drivers/input/keyboard/gpio_keys.c b/drivers/input/keyboard/gpio_keys.c
> index 5576f2ae0b71..f5e2d377f5c1 100644
> --- a/drivers/input/keyboard/gpio_keys.c
> +++ b/drivers/input/keyboard/gpio_keys.c
> @@ -502,7 +502,7 @@ static int gpio_keys_setup_key(struct platform_device *pdev,
>  		 * Legacy GPIO number, so request the GPIO here and
>  		 * convert it to descriptor.
>  		 */
> -		unsigned flags = GPIOF_IN;
> +		unsigned flags = 0;
> 
>  		if (button->active_low)
>  			flags |= GPIOF_ACTIVE_LOW;
> @@ -521,6 +521,9 @@ static int gpio_keys_setup_key(struct platform_device *pdev,
>  	}
> 
>  	if (bdata->gpiod) {
> +		/* set the GPIO direction to input */
> +		gpiod_direction_input(bdata->gpiod);
> +
>  		if (button->debounce_interval) {
>  			error = gpiod_set_debounce(bdata->gpiod,
>  					button->debounce_interval * 1000);
> diff --git a/drivers/input/keyboard/gpio_keys_polled.c b/drivers/input/keyboard/gpio_keys_polled.c
> index 72b350315d43..56bf0dc5e2e4 100644
> --- a/drivers/input/keyboard/gpio_keys_polled.c
> +++ b/drivers/input/keyboard/gpio_keys_polled.c
> @@ -319,7 +319,7 @@ static int gpio_keys_polled_probe(struct platform_device *pdev)
>  			 * Legacy GPIO number so request the GPIO here and
>  			 * convert it to descriptor.
>  			 */
> -			unsigned flags = GPIOF_IN;
> +			unsigned flags = 0;
> 
>  			if (button->active_low)
>  				flags |= GPIOF_ACTIVE_LOW;
> @@ -342,6 +342,9 @@ static int gpio_keys_polled_probe(struct platform_device *pdev)
>  			}
>  		}
> 
> +		/* set the GPIO direction to input */
> +		gpiod_direction_input(bdata->gpiod);
> +
>  		bdata->last_state = -1;
>  		bdata->threshold = DIV_ROUND_UP(button->debounce_interval,
>  						pdata->poll_interval);
> --
> 2.7.4
> 

-- 
Dmitry