Greg Kroah-Hartman
598cf27219
Link: https://lore.kernel.org/r/20260217200002.683975158@linuxfoundation.org Tested-by: Florian Fainelli <florian.fainelli@broadcom.com> Tested-by: Takeshi Ogasawara <takeshi.ogasawara@futuring-girl.com> Tested-by: Peter Schneider <pschneider1968@googlemail.com> Tested-by: Jon Hunter <jonathanh@nvidia.com> Tested-by: Salvatore Bonaccorso <carnil@debian.org> Tested-by: Brett A C Sheffield <bacs@librecast.net> Tested-by: Mark Brown <broonie@kernel.org> Tested-by: Luna Jernberg <droidbittin@gmail.com> Tested-by: Ronald Warsow <rwarsow@gmx.de> Tested-by: Justin M. Forbes <jforbes@fedoraproject.org> Tested-by: Ron Economos <re@w6rz.net> Tested-by: Miguel Ojeda <ojeda@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
59 lines
1.7 KiB
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59 lines
1.7 KiB
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.. SPDX-License-Identifier: GPL-2.0
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.. _GPIO_V2_LINE_GET_VALUES_IOCTL:
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*****************************
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GPIO_V2_LINE_GET_VALUES_IOCTL
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*****************************
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Name
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====
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GPIO_V2_LINE_GET_VALUES_IOCTL - Get the values of requested lines.
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Synopsis
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========
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.. c:macro:: GPIO_V2_LINE_GET_VALUES_IOCTL
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``int ioctl(int req_fd, GPIO_V2_LINE_GET_VALUES_IOCTL, struct gpio_v2_line_values *values)``
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Arguments
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=========
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``req_fd``
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The file descriptor of the GPIO character device, as returned in the
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:c:type:`request.fd<gpio_v2_line_request>` by gpio-v2-get-line-ioctl.rst.
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``values``
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The :c:type:`line_values<gpio_v2_line_values>` to get with the ``mask`` set
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to indicate the subset of requested lines to get.
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Description
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===========
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Get the values of requested lines.
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The values returned are logical, indicating if the line is active or inactive.
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The ``GPIO_V2_LINE_FLAG_ACTIVE_LOW`` flag controls the mapping between physical
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values (high/low) and logical values (active/inactive).
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If ``GPIO_V2_LINE_FLAG_ACTIVE_LOW`` is not set then high is active and low is
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inactive. If ``GPIO_V2_LINE_FLAG_ACTIVE_LOW`` is set then low is active and
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high is inactive.
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The values of both input and output lines may be read.
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For output lines, the value returned is driver and configuration dependent and
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may be either the output buffer (the last requested value set) or the input
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buffer (the actual level of the line), and depending on the hardware and
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configuration these may differ.
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Return Value
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============
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On success 0 and the corresponding :c:type:`values.bits<gpio_v2_line_values>`
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contain the value read.
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On error -1 and the ``errno`` variable is set appropriately.
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Common error codes are described in error-codes.rst.
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