doc-rst: linux_tv DocBook to reST migration (docs-next)

This is the restructuredText (reST) migration of the ``media``
DocBook-XML set from the linux_tv project.

Signed-off-by: Markus Heiser <markus.heiser@darmarIT.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

1 files changed, 122 insertions, 0 deletions

diff --git a/Documentation/linux_tv/media/dvb/dvbproperty.rst b/Documentation/linux_tv/media/dvb/dvbproperty.rst
new file mode 100644
index 000000000000..a68b17808bc2
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+.. -*- coding: utf-8; mode: rst -*-
+
+.. _frontend-properties:
+
+DVB Frontend properties
+=======================
+
+Tuning into a Digital TV physical channel and starting decoding it
+requires changing a set of parameters, in order to control the tuner,
+the demodulator, the Linear Low-noise Amplifier (LNA) and to set the
+antenna subsystem via Satellite Equipment Control (SEC), on satellite
+systems. The actual parameters are specific to each particular digital
+TV standards, and may change as the digital TV specs evolves.
+
+In the past, the strategy used was to have a union with the parameters
+needed to tune for DVB-S, DVB-C, DVB-T and ATSC delivery systems grouped
+there. The problem is that, as the second generation standards appeared,
+those structs were not big enough to contain the additional parameters.
+Also, the union didn't have any space left to be expanded without
+breaking userspace. So, the decision was to deprecate the legacy
+union/struct based approach, in favor of a properties set approach.
+
+NOTE: on Linux DVB API version 3, setting a frontend were done via
+:ref:`struct dvb_frontend_parameters <dvb-frontend-parameters>`.
+This got replaced on version 5 (also called "S2API", as this API were
+added originally_enabled to provide support for DVB-S2), because the
+old API has a very limited support to new standards and new hardware.
+This section describes the new and recommended way to set the frontend,
+with suppports all digital TV delivery systems.
+
+Example: with the properties based approach, in order to set the tuner
+to a DVB-C channel at 651 kHz, modulated with 256-QAM, FEC 3/4 and
+symbol rate of 5.217 Mbauds, those properties should be sent to
+:ref:`FE_SET_PROPERTY <FE_GET_PROPERTY>` ioctl:
+
+-  :ref:`DTV_DELIVERY_SYSTEM <DTV-DELIVERY-SYSTEM>` =
+   SYS_DVBC_ANNEX_A
+
+-  :ref:`DTV_FREQUENCY <DTV-FREQUENCY>` = 651000000
+
+-  :ref:`DTV_MODULATION <DTV-MODULATION>` = QAM_256
+
+-  :ref:`DTV_INVERSION <DTV-INVERSION>` = INVERSION_AUTO
+
+-  :ref:`DTV_SYMBOL_RATE <DTV-SYMBOL-RATE>` = 5217000
+
+-  :ref:`DTV_INNER_FEC <DTV-INNER-FEC>` = FEC_3_4
+
+-  :ref:`DTV_TUNE <DTV-TUNE>`
+
+The code that would do the above is:
+
+
+.. code-block:: c
+
+    #include <stdio.h>
+    #include <fcntl.h>
+    #include <sys/ioctl.h>
+    #include <linux/dvb/frontend.h>
+
+    static struct dtv_property props[] = {
+        { .cmd = DTV_DELIVERY_SYSTEM, .u.data = SYS_DVBC_ANNEX_A },
+        { .cmd = DTV_FREQUENCY,       .u.data = 651000000 },
+        { .cmd = DTV_MODULATION,      .u.data = QAM_256 },
+        { .cmd = DTV_INVERSION,       .u.data = INVERSION_AUTO },
+        { .cmd = DTV_SYMBOL_RATE,     .u.data = 5217000 },
+        { .cmd = DTV_INNER_FEC,       .u.data = FEC_3_4 },
+        { .cmd = DTV_TUNE }
+    };
+
+    static struct dtv_properties dtv_prop = {
+        .num = 6, .props = props
+    };
+
+    int main(void)
+    {
+        int fd = open("/dev/dvb/adapter0/frontend0", O_RDWR);
+
+        if (!fd) {
+            perror ("open");
+            return -1;
+        }
+        if (ioctl(fd, FE_SET_PROPERTY, &dtv_prop) == -1) {
+            perror("ioctl");
+            return -1;
+        }
+        printf("Frontend set\\n");
+        return 0;
+    }
+
+NOTE: While it is possible to directly call the Kernel code like the
+above example, it is strongly recommended to use
+`libdvbv5 <https://linuxtv.org/docs/libdvbv5/index.html>`__, as it
+provides abstraction to work with the supported digital TV standards and
+provides methods for usual operations like program scanning and to
+read/write channel descriptor files.
+
+
+.. toctree::
+    :maxdepth: 1
+
+    dtv-stats
+    dtv-fe-stats
+    dtv-property
+    dtv-properties
+    dvbproperty-006
+    fe_property_parameters
+    frontend-stat-properties
+    frontend-property-terrestrial-systems
+    frontend-property-cable-systems
+    frontend-property-satellite-systems
+
+
+
+
+.. ------------------------------------------------------------------------------
+.. This file was automatically converted from DocBook-XML with the dbxml
+.. library (https://github.com/return42/sphkerneldoc). The origin XML comes
+.. from the linux kernel, refer to:
+..
+.. * https://github.com/torvalds/linux/tree/master/Documentation/DocBook
+.. ------------------------------------------------------------------------------