It would make sense to return -EPERM if the bit was already set (already
used), not if it was cleared. Before this fix pins can only be exported on
the 2nd attempt:
$ echo 522 > /sys/class/gpio/export
sh: write error: Operation not permitted
$ echo 522 > /sys/class/gpio/export
Fixes:
35b545332b80 ("gpio: remove gpio_lock")
Signed-off-by: Alexander Sverdlin <alexander.sverdlin@gmail.com>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
if (!guard.gc)
return -ENODEV;
if (!guard.gc)
return -ENODEV;
- if (!test_and_set_bit(FLAG_EXPORT, &desc->flags))
+ if (test_and_set_bit(FLAG_EXPORT, &desc->flags))
return -EPERM;
gdev = desc->gdev;
return -EPERM;
gdev = desc->gdev;