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* [PATCH] extcon: gpio: Request gpio pin before modifying its state
@ 2013-11-22 17:26 Guenter Roeck
  2013-11-26  7:55 ` Chanwoo Choi
  0 siblings, 1 reply; 5+ messages in thread
From: Guenter Roeck @ 2013-11-22 17:26 UTC (permalink / raw)
  To: linux-kernel; +Cc: MyungJoo Ham, Chanwoo Choi, Guenter Roeck

Commit 338de0ca (extcon: gpio: Use gpio driver/chip debounce if supported)
introduced a call to gpio_set_debounce() before actually requesting the
respective gpio pin from the gpio subsystem.

The gpio subsystem expects that a gpio pin was requested before modifying its
state. Not doing so results in a warning from gpiolib, and the gpio pin is
auto-requested. This in turn causes the subsequent devm_gpio_request_one()
to fail. So devm_gpio_request_one() must be called prior to calling
gpio_set_debounce().

Signed-off-by: Guenter Roeck <linux@roeck-us.net>
---
 drivers/extcon/extcon-gpio.c |   11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/drivers/extcon/extcon-gpio.c b/drivers/extcon/extcon-gpio.c
index 7e0dff5..4736a9c 100644
--- a/drivers/extcon/extcon-gpio.c
+++ b/drivers/extcon/extcon-gpio.c
@@ -105,6 +105,12 @@ static int gpio_extcon_probe(struct platform_device *pdev)
 	extcon_data->state_off = pdata->state_off;
 	if (pdata->state_on && pdata->state_off)
 		extcon_data->edev.print_state = extcon_gpio_print_state;
+
+	ret = devm_gpio_request_one(&pdev->dev, extcon_data->gpio, GPIOF_DIR_IN,
+				    pdev->name);
+	if (ret < 0)
+		return ret;
+
 	if (pdata->debounce) {
 		ret = gpio_set_debounce(extcon_data->gpio,
 					pdata->debounce * 1000);
@@ -117,11 +123,6 @@ static int gpio_extcon_probe(struct platform_device *pdev)
 	if (ret < 0)
 		return ret;
 
-	ret = devm_gpio_request_one(&pdev->dev, extcon_data->gpio, GPIOF_DIR_IN,
-				    pdev->name);
-	if (ret < 0)
-		goto err;
-
 	INIT_DELAYED_WORK(&extcon_data->work, gpio_extcon_work);
 
 	extcon_data->irq = gpio_to_irq(extcon_data->gpio);
-- 
1.7.9.7


^ permalink raw reply related	[flat|nested] 5+ messages in thread
* Re: [PATCH] extcon: gpio: Request gpio pin before modifying its state
@ 2013-11-25  2:37 MyungJoo Ham
  0 siblings, 0 replies; 5+ messages in thread
From: MyungJoo Ham @ 2013-11-25  2:37 UTC (permalink / raw)
  To: Guenter Roeck, linux-kernel@vger.kernel.org; +Cc: 최찬우

[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #1: Type: text/plain; charset=euc-kr, Size: 1986 bytes --]

> Commit 338de0ca (extcon: gpio: Use gpio driver/chip debounce if supported)
> introduced a call to gpio_set_debounce() before actually requesting the
> respective gpio pin from the gpio subsystem.
> 
> The gpio subsystem expects that a gpio pin was requested before modifying its
> state. Not doing so results in a warning from gpiolib, and the gpio pin is
> auto-requested. This in turn causes the subsequent devm_gpio_request_one()
> to fail. So devm_gpio_request_one() must be called prior to calling
> gpio_set_debounce().
> 
> Signed-off-by: Guenter Roeck <linux@roeck-us.net>

Thank you.


Acked-by: MyungJoo Ham <myungjoo.ham@samsung.com>

> ---
>  drivers/extcon/extcon-gpio.c |   11 ++++++-----
>  1 file changed, 6 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/extcon/extcon-gpio.c b/drivers/extcon/extcon-gpio.c
> index 7e0dff5..4736a9c 100644
> --- a/drivers/extcon/extcon-gpio.c
> +++ b/drivers/extcon/extcon-gpio.c
> @@ -105,6 +105,12 @@ static int gpio_extcon_probe(struct platform_device *pdev)
>  	extcon_data->state_off = pdata->state_off;
>  	if (pdata->state_on && pdata->state_off)
>  		extcon_data->edev.print_state = extcon_gpio_print_state;
> +
> +	ret = devm_gpio_request_one(&pdev->dev, extcon_data->gpio, GPIOF_DIR_IN,
> +				    pdev->name);
> +	if (ret < 0)
> +		return ret;
> +
>  	if (pdata->debounce) {
>  		ret = gpio_set_debounce(extcon_data->gpio,
>  					pdata->debounce * 1000);
> @@ -117,11 +123,6 @@ static int gpio_extcon_probe(struct platform_device *pdev)
>  	if (ret < 0)
>  		return ret;
>  
> -	ret = devm_gpio_request_one(&pdev->dev, extcon_data->gpio, GPIOF_DIR_IN,
> -				    pdev->name);
> -	if (ret < 0)
> -		goto err;
> -
>  	INIT_DELAYED_WORK(&extcon_data->work, gpio_extcon_work);
>  
>  	extcon_data->irq = gpio_to_irq(extcon_data->gpio);
> -- 
> 1.7.9.7
> 
> 
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^ permalink raw reply	[flat|nested] 5+ messages in thread

end of thread, other threads:[~2013-11-26 22:41 UTC | newest]

Thread overview: 5+ messages (download: mbox.gz follow: Atom feed
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2013-11-22 17:26 [PATCH] extcon: gpio: Request gpio pin before modifying its state Guenter Roeck
2013-11-26  7:55 ` Chanwoo Choi
2013-11-26 12:07   ` Guenter Roeck
2013-11-26 22:41     ` Chanwoo Choi
  -- strict thread matches above, loose matches on Subject: below --
2013-11-25  2:37 MyungJoo Ham

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