linux-kernel - [PATCH] gpio: tegra: read output value when gpio is set in direction

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Date:	Thu, 8 Nov 2012 11:57:27 +0530
From:	Laxman Dewangan <ldewangan@...dia.com>
To:	<linus.walleij@...aro.org>, <grant.likely@...retlab.ca>
CC:	<swarren@...dia.com>, <linux-kernel@...r.kernel.org>,
	<linux-tegra@...r.kernel.org>,
	Laxman Dewangan <ldewangan@...dia.com>
Subject: [PATCH] gpio: tegra: read output value when gpio is set in direction_out

Read the output value when gpio is set for the output mode for
gpio_get_value(). Reading input value in direction out does not
give correct value.

Signed-off-by: Laxman Dewangan <ldewangan@...dia.com>
---
 drivers/gpio/gpio-tegra.c |    6 ++++++
 1 files changed, 6 insertions(+), 0 deletions(-)

diff --git a/drivers/gpio/gpio-tegra.c b/drivers/gpio/gpio-tegra.c
index c7c175a..0fb2ce7 100644
--- a/drivers/gpio/gpio-tegra.c
+++ b/drivers/gpio/gpio-tegra.c
@@ -135,6 +135,12 @@ static void tegra_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
 
 static int tegra_gpio_get(struct gpio_chip *chip, unsigned offset)
 {
+	int bit_val = BIT(GPIO_BIT(offset));
+
+	/* If gpio is in output mode then read from the out value */
+	if (tegra_gpio_readl(GPIO_OE(offset)) & bit_val)
+		return !!(tegra_gpio_readl(GPIO_OUT(offset)) & bit_val);
+
 	return (tegra_gpio_readl(GPIO_IN(offset)) >> GPIO_BIT(offset)) & 0x1;
 }
 
-- 
1.7.1.1

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