54f38fcae5
Since 2017, there is an space reserved for userspace API,
created by changeset 1d596dee38 ("docs: Create a user-space API guide").
As the media subsystem was one of the first subsystems to use
Sphinx, until this patch, we were keeping things on a separate
place.
Let's just use the new location, as having all uAPI altogether
will likely make things easier for developers.
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
66 lines
1.8 KiB
ReStructuredText
66 lines
1.8 KiB
ReStructuredText
.. Permission is granted to copy, distribute and/or modify this
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.. document under the terms of the GNU Free Documentation License,
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.. Version 1.1 or any later version published by the Free Software
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.. Foundation, with no Invariant Sections, no Front-Cover Texts
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.. and no Back-Cover Texts. A copy of the license is included at
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.. Documentation/userspace-api/media/fdl-appendix.rst.
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..
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.. TODO: replace it to GFDL-1.1-or-later WITH no-invariant-sections
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.. _FE_SET_TONE:
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*****************
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ioctl FE_SET_TONE
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*****************
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Name
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====
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FE_SET_TONE - Sets/resets the generation of the continuous 22kHz tone.
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Synopsis
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========
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.. c:function:: int ioctl( int fd, FE_SET_TONE, enum fe_sec_tone_mode tone )
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:name: FE_SET_TONE
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Arguments
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=========
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``fd``
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File descriptor returned by :ref:`open() <frontend_f_open>`.
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``tone``
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an integer enumered value described at :c:type:`fe_sec_tone_mode`
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Description
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===========
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This ioctl is used to set the generation of the continuous 22kHz tone.
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This call requires read/write permissions.
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Usually, satellite antenna subsystems require that the digital TV device
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to send a 22kHz tone in order to select between high/low band on some
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dual-band LNBf. It is also used to send signals to DiSEqC equipment, but
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this is done using the DiSEqC ioctls.
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.. attention:: If more than one device is connected to the same antenna,
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setting a tone may interfere on other devices, as they may lose the
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capability of selecting the band. So, it is recommended that applications
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would change to SEC_TONE_OFF when the device is not used.
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Return Value
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============
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On success 0 is returned.
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On error -1 is returned, and the ``errno`` variable is set
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appropriately.
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Generic error codes are described at the
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:ref:`Generic Error Codes <gen-errors>` chapter.
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