linux-kernel - [PATCH] gpio: twl4030: fix regression for twl gpio outputs for led pins

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Message-ID: <1386953222-26396-1-git-send-email-nm@ti.com>
Date:	Fri, 13 Dec 2013 10:47:02 -0600
From:	Nishanth Menon <nm@...com>
To:	Tony Lindgren <tony@...mide.com>,
	Linus Walleij <linus.walleij@...aro.org>
CC:	Peter Ujfalusi <peter.ujfalusi@...com>,
	Roger Quadros <rogerq@...com>, <linux-gpio@...r.kernel.org>,
	<linux-kernel@...r.kernel.org>, <linux-omap@...r.kernel.org>,
	Nishanth Menon <nm@...com>
Subject: [PATCH] gpio: twl4030: fix regression for twl gpio outputs for led pins

Commit 0b2aa8b (gpio: twl4030: Fix regression for twl gpio output)
introduces yet another regression by ignoring the fact that we use twl
gpio even for LED. For example, leda (offset 18) is used for USB port2
power on beagleboard-xm.

The original logic was supposed to setup the TWL4030 GPIO direction
if the offset was < TWL4030_GPIO_MAX, and anything greater used
twl4030_led_set_value as part of twl_set to setup the LED pin. However,
with the commit mentioned above, LEDa pin request will result in fail
as the GPIO number for LEDa is equal to TWL4030_GPIO_MAX and USB fails
to function on beagleboard-xm. This is reported in the log as:
hsusb2_vbus: Failed to request enable GPIO510: -22

To fix this, we should handle the fail case of
twl4030_set_gpio_direction independent of the offset < TWL4030_GPIO_MAX
check.

Signed-off-by: Nishanth Menon <nm@...com>
---
Applies on v3.13-rc3

Tested on beagleboard-xm which uses ethernet over usb:
before the patch (USB regression): http://pastebin.mozilla.org/3769443
After this patch: http://pastebin.mozilla.org/3769454

 drivers/gpio/gpio-twl4030.c |    9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/gpio/gpio-twl4030.c b/drivers/gpio/gpio-twl4030.c
index b97d6a6..9242276 100644
--- a/drivers/gpio/gpio-twl4030.c
+++ b/drivers/gpio/gpio-twl4030.c
@@ -354,11 +354,16 @@ 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;
+		}
+	}

 	priv->direction |= BIT(offset);
 	mutex_unlock(&priv->mutex);
-- 
1.7.9.5

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