[U-Boot] [PATCH] mxs_gpio: fix the handling in gpio_direction_output()

Michael Heimpold mhei at heimpold.de
Sun Nov 3 22:59:26 CET 2013


Setting the direction and an output value should be done by
1) set the desired output value,
2) switch to output.

If this is done in the inverse order, there can be a glitch on
the GPIO line.

This patch fixes this by using the order as described above.

Signed-off-by: Michael Heimpold <mhei at heimpold.de>
---
 drivers/gpio/mxs_gpio.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpio/mxs_gpio.c b/drivers/gpio/mxs_gpio.c
index d9a7a3a..da0199b 100644
--- a/drivers/gpio/mxs_gpio.c
+++ b/drivers/gpio/mxs_gpio.c
@@ -95,10 +95,10 @@ int gpio_direction_output(unsigned gpio, int value)
 	struct mxs_register_32 *reg =
 		(struct mxs_register_32 *)(MXS_PINCTRL_BASE + offset);
 
-	writel(1 << PAD_PIN(gpio), &reg->reg_set);
-
 	gpio_set_value(gpio, value);
 
+	writel(1 << PAD_PIN(gpio), &reg->reg_set);
+
 	return 0;
 }
 
-- 
1.7.10.4



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