linux-kernel - [PATCH] extcon: gpio: Request gpio pin before modifying its state

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Message-Id: <1385141161-7785-1-git-send-email-linux@roeck-us.net>
Date:	Fri, 22 Nov 2013 09:26:01 -0800
From:	Guenter Roeck <linux@...ck-us.net>
To:	linux-kernel@...r.kernel.org
Cc:	MyungJoo Ham <myungjoo.ham@...sung.com>,
	Chanwoo Choi <cw00.choi@...sung.com>,
	Guenter Roeck <linux@...ck-us.net>
Subject: [PATCH] extcon: gpio: Request gpio pin before modifying its state

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@...ck-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

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