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author | Mauro Carvalho Chehab <mchehab+huawei@kernel.org> | 2020-03-04 10:21:39 +0100 |
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committer | Mauro Carvalho Chehab <mchehab+huawei@kernel.org> | 2020-04-14 10:31:49 +0200 |
commit | 54f38fcae536ea202ce7d6a359521492fba30c1f (patch) | |
tree | dd1a2b36d8de0b13702f2716526ad3b91650e090 /Documentation/userspace-api/media/dvb/fe-get-property.rst | |
parent | 5dfb8db56b273740a76e8687ee7efb4b2c0ec83b (diff) |
media: docs: move uAPI book to userspace-api/media
Since 2017, there is an space reserved for userspace API,
created by changeset 1d596dee3862 ("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>
Diffstat (limited to 'Documentation/userspace-api/media/dvb/fe-get-property.rst')
-rw-r--r-- | Documentation/userspace-api/media/dvb/fe-get-property.rst | 83 |
1 files changed, 83 insertions, 0 deletions
diff --git a/Documentation/userspace-api/media/dvb/fe-get-property.rst b/Documentation/userspace-api/media/dvb/fe-get-property.rst new file mode 100644 index 000000000000..088d4e319405 --- /dev/null +++ b/Documentation/userspace-api/media/dvb/fe-get-property.rst @@ -0,0 +1,83 @@ +.. Permission is granted to copy, distribute and/or modify this +.. document under the terms of the GNU Free Documentation License, +.. Version 1.1 or any later version published by the Free Software +.. Foundation, with no Invariant Sections, no Front-Cover Texts +.. and no Back-Cover Texts. A copy of the license is included at +.. Documentation/userspace-api/media/fdl-appendix.rst. +.. +.. TODO: replace it to GFDL-1.1-or-later WITH no-invariant-sections + +.. _FE_GET_PROPERTY: + +************************************** +ioctl FE_SET_PROPERTY, FE_GET_PROPERTY +************************************** + +Name +==== + +FE_SET_PROPERTY - FE_GET_PROPERTY - FE_SET_PROPERTY sets one or more frontend properties. - FE_GET_PROPERTY returns one or more frontend properties. + + +Synopsis +======== + +.. c:function:: int ioctl( int fd, FE_GET_PROPERTY, struct dtv_properties *argp ) + :name: FE_GET_PROPERTY + +.. c:function:: int ioctl( int fd, FE_SET_PROPERTY, struct dtv_properties *argp ) + :name: FE_SET_PROPERTY + + +Arguments +========= + +``fd`` + File descriptor returned by :ref:`open() <frontend_f_open>`. + +``argp`` + Pointer to struct :c:type:`dtv_properties`. + + +Description +=========== + +All Digital TV frontend devices support the ``FE_SET_PROPERTY`` and +``FE_GET_PROPERTY`` ioctls. The supported properties and statistics +depends on the delivery system and on the device: + +- ``FE_SET_PROPERTY:`` + + - This ioctl is used to set one or more frontend properties. + + - This is the basic command to request the frontend to tune into + some frequency and to start decoding the digital TV signal. + + - This call requires read/write access to the device. + +.. note:: + + At return, the values aren't updated to reflect the actual + parameters used. If the actual parameters are needed, an explicit + call to ``FE_GET_PROPERTY`` is needed. + +- ``FE_GET_PROPERTY:`` + + - This ioctl is used to get properties and statistics from the + frontend. + + - No properties are changed, and statistics aren't reset. + + - This call only requires read-only access to the device. + + +Return Value +============ + +On success 0 is returned. + +On error -1 is returned, and the ``errno`` variable is set +appropriately. + +Generic error codes are described at the +:ref:`Generic Error Codes <gen-errors>` chapter. |