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.. SPDX-License-Identifier: GPL-2.0
.. _gpio_errors:
*******************
GPIO Error Codes
*******************
.. _gpio-errors:
.. tabularcolumns:: |p{2.5cm}|p{15.0cm}|
.. flat-table:: Common GPIO error codes
:header-rows: 0
:stub-columns: 0
:widths: 1 16
- - ``EAGAIN`` (aka ``EWOULDBLOCK``)
- The device was opened in non-blocking mode and a read can't
be performed as there is no data available.
- - ``EBADF``
- The file descriptor is not valid.
- - ``EBUSY``
- The ioctl can't be handled because the device is busy. Typically
returned when an ioctl attempts something that would require the
usage of a resource that was already allocated. The ioctl must not
be retried without performing another action to fix the problem
first.
- - ``EFAULT``
- There was a failure while copying data from/to userspace, probably
caused by an invalid pointer reference.
- - ``EINVAL``
- One or more of the ioctl parameters are invalid or out of the
allowed range. This is a widely used error code.
- - ``ENODEV``
- Device not found or was removed.
- - ``ENOMEM``
- There's not enough memory to handle the desired operation.
- - ``EPERM``
- Permission denied. Typically returned in response to an attempt
to perform an action incompatible with the current line
configuration.
- - ``EIO``
- I/O error. Typically returned when there are problems communicating
with a hardware device or requesting features that hardware does not
support. This could indicate broken or flaky hardware.
It's a 'Something is wrong, I give up!' type of error.
- - ``ENXIO``
- No device corresponding to this device special file exists.
.. note::
#. This list is not exhaustive; ioctls may return other error codes.
Since errors may have side effects such as a driver reset,
applications should abort on unexpected errors, or otherwise
assume that the device is in a bad state.
#. Request-specific error codes are listed in the individual
requests descriptions.
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