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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-08-07 13:11:22 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-08-07 13:11:22 +0000 |
commit | b20732900e4636a467c0183a47f7396700f5f743 (patch) | |
tree | 42f079ff82e701ebcb76829974b4caca3e5b6798 /Documentation/userspace-api/gpio/gpio-handle-get-line-values-ioctl.rst | |
parent | Adding upstream version 6.8.12. (diff) | |
download | linux-b20732900e4636a467c0183a47f7396700f5f743.tar.xz linux-b20732900e4636a467c0183a47f7396700f5f743.zip |
Adding upstream version 6.9.7.upstream/6.9.7
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'Documentation/userspace-api/gpio/gpio-handle-get-line-values-ioctl.rst')
-rw-r--r-- | Documentation/userspace-api/gpio/gpio-handle-get-line-values-ioctl.rst | 56 |
1 files changed, 56 insertions, 0 deletions
diff --git a/Documentation/userspace-api/gpio/gpio-handle-get-line-values-ioctl.rst b/Documentation/userspace-api/gpio/gpio-handle-get-line-values-ioctl.rst new file mode 100644 index 0000000000..25263b8f05 --- /dev/null +++ b/Documentation/userspace-api/gpio/gpio-handle-get-line-values-ioctl.rst @@ -0,0 +1,56 @@ +.. SPDX-License-Identifier: GPL-2.0 + +.. _GPIOHANDLE_GET_LINE_VALUES_IOCTL: + +******************************** +GPIOHANDLE_GET_LINE_VALUES_IOCTL +******************************** +.. warning:: + This ioctl is part of chardev_v1.rst and is obsoleted by + gpio-v2-line-get-values-ioctl.rst. + +Name +==== + +GPIOHANDLE_GET_LINE_VALUES_IOCTL - Get the values of all requested lines. + +Synopsis +======== + +.. c:macro:: GPIOHANDLE_GET_LINE_VALUES_IOCTL + +``int ioctl(int handle_fd, GPIOHANDLE_GET_LINE_VALUES_IOCTL, struct gpiohandle_data *values)`` + +Arguments +========= + +``handle_fd`` + The file descriptor of the GPIO character device, as returned in the + :c:type:`request.fd<gpiohandle_request>` by gpio-get-linehandle-ioctl.rst. + +``values`` + The :c:type:`line_values<gpiohandle_data>` to be populated. + +Description +=========== + +Get the values of all requested lines. + +The values of both input and output lines may be read. + +For output lines, the value returned is driver and configuration dependent and +may be either the output buffer (the last requested value set) or the input +buffer (the actual level of the line), and depending on the hardware and +configuration these may differ. + +This ioctl can also be used to read the line value for line events, +substituting the ``event_fd`` for the ``handle_fd``. As there is only +one line requested in that case, only the one value is returned in ``values``. + +Return Value +============ + +On success 0 and ``values`` populated with the values read. + +On error -1 and the ``errno`` variable is set appropriately. +Common error codes are described in error-codes.rst. |