32a0a0da53
Add documentation for the GPIO character device userspace API. Added to the userspace-api book, but also provide a link from the admin-guide book, as historically the GPIO documentation has been there. Signed-off-by: Kent Gibson <warthog618@gmail.com> Reviewed-by: Linus Walleij <linus.walleij@linaro.org> Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
51 lines
1.1 KiB
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51 lines
1.1 KiB
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.. SPDX-License-Identifier: GPL-2.0
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.. _GPIO_V2_GET_LINEINFO_IOCTL:
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**************************
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GPIO_V2_GET_LINEINFO_IOCTL
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**************************
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Name
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====
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GPIO_V2_GET_LINEINFO_IOCTL - Get the publicly available information for a line.
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Synopsis
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========
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.. c:macro:: GPIO_V2_GET_LINEINFO_IOCTL
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``int ioctl(int chip_fd, GPIO_V2_GET_LINEINFO_IOCTL, struct gpio_v2_line_info *info)``
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Arguments
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=========
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``chip_fd``
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The file descriptor of the GPIO character device returned by `open()`.
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``info``
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The :c:type:`line_info<gpio_v2_line_info>` to be populated, with the
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``offset`` field set to indicate the line to be collected.
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Description
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===========
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Get the publicly available information for a line.
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This information is available independent of whether the line is in use.
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.. note::
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The line info does not include the line value.
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The line must be requested using gpio-v2-get-line-ioctl.rst to access its
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value.
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Return Value
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============
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On success 0 and ``info`` is populated with the chip info.
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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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