i2c: core: Add support for 'i2c-bus' subnode
[cascardo/linux.git] / Documentation / DocBook / media / dvb / fe-read-status.xml
1 <refentry id="FE_READ_STATUS">
2   <refmeta>
3     <refentrytitle>ioctl FE_READ_STATUS</refentrytitle>
4     &manvol;
5   </refmeta>
6
7   <refnamediv>
8     <refname>FE_READ_STATUS</refname>
9     <refpurpose>Returns status information about the front-end. This call only
10  requires read-only access to the device</refpurpose>
11   </refnamediv>
12
13   <refsynopsisdiv>
14     <funcsynopsis>
15       <funcprototype>
16         <funcdef>int <function>ioctl</function></funcdef>
17         <paramdef>int <parameter>fd</parameter></paramdef>
18         <paramdef>int <parameter>request</parameter></paramdef>
19         <paramdef>unsigned int *<parameter>status</parameter></paramdef>
20       </funcprototype>
21     </funcsynopsis>
22   </refsynopsisdiv>
23
24   <refsect1>
25     <title>Arguments</title>
26         <variablelist>
27       <varlistentry>
28         <term><parameter>fd</parameter></term>
29         <listitem>
30           <para>&fe_fd;</para>
31         </listitem>
32       </varlistentry>
33       <varlistentry>
34         <term><parameter>request</parameter></term>
35         <listitem>
36           <para>FE_READ_STATUS</para>
37         </listitem>
38       </varlistentry>
39       <varlistentry>
40         <term><parameter>status</parameter></term>
41         <listitem>
42             <para>pointer to a bitmask integer filled with the values defined by
43                 &fe-status;.</para>
44         </listitem>
45       </varlistentry>
46     </variablelist>
47   </refsect1>
48
49   <refsect1>
50     <title>Description</title>
51
52     <para>All DVB frontend devices support the
53 <constant>FE_READ_STATUS</constant> ioctl. It is used to check about the
54 locking status of the frontend after being tuned. The ioctl takes a
55 pointer to an integer where the status will be written.
56 </para>
57 <para>NOTE: the size of status is actually sizeof(enum fe_status), with varies
58     according with the architecture. This needs to be fixed in the future.</para>
59 &return-value-dvb;
60 </refsect1>
61
62 <refsect1 id="fe-status-t">
63 <title>int fe_status</title>
64
65 <para>The fe_status parameter is used to indicate the current state
66     and/or state changes of the frontend hardware. It is produced using
67     the &fe-status; values on a bitmask</para>
68
69 <table pgwide="1" frame="none" id="fe-status">
70     <title>enum fe_status</title>
71     <tgroup cols="2">
72         &cs-def;
73         <thead>
74         <row>
75             <entry>ID</entry>
76             <entry>Description</entry>
77         </row>
78         </thead>
79         <tbody valign="top">
80         <row>
81             <entry align="char" id="FE-HAS-SIGNAL"><constant>FE_HAS_SIGNAL</constant></entry>
82             <entry align="char">The frontend has found something above the noise level</entry>
83         </row><row>
84             <entry align="char" id="FE-HAS-CARRIER"><constant>FE_HAS_CARRIER</constant></entry>
85             <entry align="char">The frontend has found a DVB signal</entry>
86         </row><row>
87             <entry align="char" id="FE-HAS-VITERBI"><constant>FE_HAS_VITERBI</constant></entry>
88             <entry align="char">The frontend FEC inner coding (Viterbi, LDPC or other inner code) is stable</entry>
89         </row><row>
90             <entry align="char" id="FE-HAS-SYNC"><constant>FE_HAS_SYNC</constant></entry>
91             <entry align="char">Synchronization bytes was found</entry>
92         </row><row>
93             <entry align="char" id="FE-HAS-LOCK"><constant>FE_HAS_LOCK</constant></entry>
94             <entry align="char">The DVB were locked and everything is working</entry>
95         </row><row>
96             <entry align="char" id="FE-TIMEDOUT"><constant>FE_TIMEDOUT</constant></entry>
97             <entry align="char">no lock within the last about 2 seconds</entry>
98         </row><row>
99             <entry align="char" id="FE-REINIT"><constant>FE_REINIT</constant></entry>
100             <entry align="char">The frontend was reinitialized, application is
101             recommended to reset DiSEqC, tone and parameters</entry>
102         </row>
103         </tbody>
104     </tgroup>
105 </table>
106 </refsect1>
107 </refentry>