gpio: sysfs: correct error handling on 'value' attribute read.

'value' attribute is supposed to only return 0 or 1 according to
the documentation.
With today's implementation, if gpiod_get_value_cansleep() fails
the printed 'value' is a negative value.

This patch ensures that an error is returned on read instead.

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

diff --git a/drivers/gpio/gpiolib-sysfs.c b/drivers/gpio/gpiolib-sysfs.c
index 3b2465bbd5e706d921112d0fb24db48217cf7c90..ef34b8f56bd1f32c02bb9b56e7a425c50f9a1b26 100644 (file)
--- a/drivers/gpio/gpiolib-sysfs.c
+++ b/drivers/gpio/gpiolib-sysfs.c
@@ -106,8 +106,12 @@ static ssize_t value_show(struct device *dev,
 
        mutex_lock(&data->mutex);
 
-       status = sprintf(buf, "%d\n", gpiod_get_value_cansleep(desc));
+       status = gpiod_get_value_cansleep(desc);
+       if (status < 0)
+               goto err;
 
+       status = sprintf(buf, "%d\n", status);
+err:
        mutex_unlock(&data->mutex);
 
        return status;