linux-kernel - [PATCH v2 1/1] gpio: twl4030: Fix regression for twl gpio LED output

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Message-ID: <1386235415-27670-1-git-send-email-rogerq@ti.com>
Date:	Thu, 5 Dec 2013 11:23:35 +0200
From:	Roger Quadros <rogerq@...com>
To:	<linus.walleij@...aro.org>
CC:	<tony@...mide.com>, <peter.ujfalusi@...com>, <nm@...com>,
	<tomi.valkeinen@...com>, <balbi@...com>,
	<linux-gpio@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
	<linux-omap@...r.kernel.org>,
	<linux-arm-kernel@...ts.infradead.org>,
	Roger Quadros <rogerq@...com>
Subject: [PATCH v2 1/1] gpio: twl4030: Fix regression for twl gpio LED output

Commit 0b2aa8be introduced a regression that causes failure
in setting LED GPO direction to OUT.

This causes USB host probe failures for Beagleboard C4.

[    2.075469] platform usb_phy_gen_xceiv.2: Driver usb_phy_gen_xceiv requests probe deferral
[    2.090454] hsusb2_vcc: Failed to request enable GPIO510: -22
[    2.100982] reg-fixed-voltage reg-fixed-voltage.0.auto: Failed to register regulator: -22
[    2.109954] reg-fixed-voltage: probe of reg-fixed-voltage.0.auto failed with error -22

direction_out/direction_in must return 0 if the operation succeeded.

Also, don't update direction flag and output data if twl4030_set_gpio_direction()
failed inside twl_direction_out();

Signed-off-by: Roger Quadros <rogerq@...com>
---
 drivers/gpio/gpio-twl4030.c | 15 ++++++++++++---
 1 file changed, 12 insertions(+), 3 deletions(-)

diff --git a/drivers/gpio/gpio-twl4030.c b/drivers/gpio/gpio-twl4030.c
index b97d6a6..f999689 100644
--- a/drivers/gpio/gpio-twl4030.c
+++ b/drivers/gpio/gpio-twl4030.c
@@ -300,7 +300,7 @@ static int twl_direction_in(struct gpio_chip *chip, unsigned offset)
 	if (offset < TWL4030_GPIO_MAX)
 		ret = twl4030_set_gpio_direction(offset, 1);
 	else
-		ret = -EINVAL;
+		ret = -EINVAL;	/* LED outputs can't be set as input */
 
 	if (!ret)
 		priv->direction &= ~BIT(offset);
@@ -354,11 +354,20 @@ static void twl_set(struct gpio_chip *chip, unsigned offset, int value)
 static int twl_direction_out(struct gpio_chip *chip, unsigned offset, int value)
 {
 	struct gpio_twl4030_priv *priv = to_gpio_twl4030(chip);
-	int ret = -EINVAL;
+	int ret = 0;
 
 	mutex_lock(&priv->mutex);
-	if (offset < TWL4030_GPIO_MAX)
+	if (offset < TWL4030_GPIO_MAX) {
 		ret = twl4030_set_gpio_direction(offset, 0);
+		if (ret) {
+			mutex_unlock(&priv->mutex);
+			return ret;
+		}
+	}
+
+	/*
+	 *  LED gpios i.e. offset >= TWL4030_GPIO_MAX are always output
+	 */
 
 	priv->direction |= BIT(offset);
 	mutex_unlock(&priv->mutex);
-- 
1.8.3.2

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