On 2015-05-20 07:25, Fabio Estevam wrote:

On Wed, May 20, 2015 at 10:17 AM, Yannick Calmettes
<yannick.calmettes@analogway.com> wrote:

Sorry Fabio, it stills return 512.

How do you read the pins exactly? From kernel or from userspace?

What was the response in 3.10.53?

I assume he's using SYSFS

The GPIO driver (drivers/gpio/gpiolib.c) changed behaviour between
these two versions.  In 3.10.53, it will show either 0 or 1.  In
3.14.28 it will show the exact bit value as Yannick is experiencing.

You could try this patch (untested):

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 50c4922..45aa695 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -376,7 +376,7 @@ static ssize_t gpio_value_show(struct device *dev,
        if (!test_bit(FLAG_EXPORT, &desc->flags))
                status = -EIO;
        else
-               status = sprintf(buf, "%d\n", gpiod_get_value_cansleep(desc));
+               status = sprintf(buf, "%d\n", !!gpiod_get_value_cansleep(desc));

        mutex_unlock(&sysfs_lock);
        return status;