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authorLinus Torvalds <torvalds@linux-foundation.org>2008-10-16 15:18:16 -0400
committerLinus Torvalds <torvalds@linux-foundation.org>2008-10-16 15:18:16 -0400
commitd1b5726358ccebcf614fc9f97cdf3354178dcb80 (patch)
treed7bbd8e24bd312d9c2c18fc18f12f6a8ce9b084f /Documentation/DocBook
parentc472273f863c80b87e53356256c5466df24328f0 (diff)
parent656e6c0050fd63ce42c55a6cb454a9b4b2f9ccf7 (diff)
Merge branch 'docs' of git://git.lwn.net/linux-2.6
* 'docs' of git://git.lwn.net/linux-2.6: Document panic_on_unrecovered_nmi sysctl Add a reference to paper to SubmittingPatches Add kerneldoc documentation for new printk format extensions Remove videobook.tmpl doc: Test-by? Add the development process document Documentation/block/data-integrity.txt: Fix section numbers
Diffstat (limited to 'Documentation/DocBook')
-rw-r--r--Documentation/DocBook/Makefile2
-rw-r--r--Documentation/DocBook/videobook.tmpl1654
2 files changed, 1 insertions, 1655 deletions
diff --git a/Documentation/DocBook/Makefile b/Documentation/DocBook/Makefile
index 1615350b7b53..fabc06466b93 100644
--- a/Documentation/DocBook/Makefile
+++ b/Documentation/DocBook/Makefile
@@ -6,7 +6,7 @@
6# To add a new book the only step required is to add the book to the 6# To add a new book the only step required is to add the book to the
7# list of DOCBOOKS. 7# list of DOCBOOKS.
8 8
9DOCBOOKS := wanbook.xml z8530book.xml mcabook.xml videobook.xml \ 9DOCBOOKS := wanbook.xml z8530book.xml mcabook.xml \
10 kernel-hacking.xml kernel-locking.xml deviceiobook.xml \ 10 kernel-hacking.xml kernel-locking.xml deviceiobook.xml \
11 procfs-guide.xml writing_usb_driver.xml networking.xml \ 11 procfs-guide.xml writing_usb_driver.xml networking.xml \
12 kernel-api.xml filesystems.xml lsm.xml usb.xml kgdb.xml \ 12 kernel-api.xml filesystems.xml lsm.xml usb.xml kgdb.xml \
diff --git a/Documentation/DocBook/videobook.tmpl b/Documentation/DocBook/videobook.tmpl
deleted file mode 100644
index 0bc25949b668..000000000000
--- a/Documentation/DocBook/videobook.tmpl
+++ /dev/null
@@ -1,1654 +0,0 @@
1<?xml version="1.0" encoding="UTF-8"?>
2<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.1.2//EN"
3 "http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd" []>
4
5<book id="V4LGuide">
6 <bookinfo>
7 <title>Video4Linux Programming</title>
8
9 <authorgroup>
10 <author>
11 <firstname>Alan</firstname>
12 <surname>Cox</surname>
13 <affiliation>
14 <address>
15 <email>alan@redhat.com</email>
16 </address>
17 </affiliation>
18 </author>
19 </authorgroup>
20
21 <copyright>
22 <year>2000</year>
23 <holder>Alan Cox</holder>
24 </copyright>
25
26 <legalnotice>
27 <para>
28 This documentation is free software; you can redistribute
29 it and/or modify it under the terms of the GNU General Public
30 License as published by the Free Software Foundation; either
31 version 2 of the License, or (at your option) any later
32 version.
33 </para>
34
35 <para>
36 This program is distributed in the hope that it will be
37 useful, but WITHOUT ANY WARRANTY; without even the implied
38 warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
39 See the GNU General Public License for more details.
40 </para>
41
42 <para>
43 You should have received a copy of the GNU General Public
44 License along with this program; if not, write to the Free
45 Software Foundation, Inc., 59 Temple Place, Suite 330, Boston,
46 MA 02111-1307 USA
47 </para>
48
49 <para>
50 For more details see the file COPYING in the source
51 distribution of Linux.
52 </para>
53 </legalnotice>
54 </bookinfo>
55
56<toc></toc>
57
58 <chapter id="intro">
59 <title>Introduction</title>
60 <para>
61 Parts of this document first appeared in Linux Magazine under a
62 ninety day exclusivity.
63 </para>
64 <para>
65 Video4Linux is intended to provide a common programming interface
66 for the many TV and capture cards now on the market, as well as
67 parallel port and USB video cameras. Radio, teletext decoders and
68 vertical blanking data interfaces are also provided.
69 </para>
70 </chapter>
71 <chapter id="radio">
72 <title>Radio Devices</title>
73 <para>
74 There are a wide variety of radio interfaces available for PC's, and these
75 are generally very simple to program. The biggest problem with supporting
76 such devices is normally extracting documentation from the vendor.
77 </para>
78 <para>
79 The radio interface supports a simple set of control ioctls standardised
80 across all radio and tv interfaces. It does not support read or write, which
81 are used for video streams. The reason radio cards do not allow you to read
82 the audio stream into an application is that without exception they provide
83 a connection on to a soundcard. Soundcards can be used to read the radio
84 data just fine.
85 </para>
86 <sect1 id="registerradio">
87 <title>Registering Radio Devices</title>
88 <para>
89 The Video4linux core provides an interface for registering devices. The
90 first step in writing our radio card driver is to register it.
91 </para>
92 <programlisting>
93
94
95static struct video_device my_radio
96{
97 "My radio",
98 VID_TYPE_TUNER,
99 radio_open.
100 radio_close,
101 NULL, /* no read */
102 NULL, /* no write */
103 NULL, /* no poll */
104 radio_ioctl,
105 NULL, /* no special init function */
106 NULL /* no private data */
107};
108
109
110 </programlisting>
111 <para>
112 This declares our video4linux device driver interface. The VID_TYPE_ value
113 defines what kind of an interface we are, and defines basic capabilities.
114 </para>
115 <para>
116 The only defined value relevant for a radio card is VID_TYPE_TUNER which
117 indicates that the device can be tuned. Clearly our radio is going to have some
118 way to change channel so it is tuneable.
119 </para>
120 <para>
121 We declare an open and close routine, but we do not need read or write,
122 which are used to read and write video data to or from the card itself. As
123 we have no read or write there is no poll function.
124 </para>
125 <para>
126 The private initialise function is run when the device is registered. In
127 this driver we've already done all the work needed. The final pointer is a
128 private data pointer that can be used by the device driver to attach and
129 retrieve private data structures. We set this field "priv" to NULL for
130 the moment.
131 </para>
132 <para>
133 Having the structure defined is all very well but we now need to register it
134 with the kernel.
135 </para>
136 <programlisting>
137
138
139static int io = 0x320;
140
141int __init myradio_init(struct video_init *v)
142{
143 if(!request_region(io, MY_IO_SIZE, "myradio"))
144 {
145 printk(KERN_ERR
146 "myradio: port 0x%03X is in use.\n", io);
147 return -EBUSY;
148 }
149
150 if(video_device_register(&amp;my_radio, VFL_TYPE_RADIO)==-1) {
151 release_region(io, MY_IO_SIZE);
152 return -EINVAL;
153 }
154 return 0;
155}
156
157 </programlisting>
158 <para>
159 The first stage of the initialisation, as is normally the case, is to check
160 that the I/O space we are about to fiddle with doesn't belong to some other
161 driver. If it is we leave well alone. If the user gives the address of the
162 wrong device then we will spot this. These policies will generally avoid
163 crashing the machine.
164 </para>
165 <para>
166 Now we ask the Video4Linux layer to register the device for us. We hand it
167 our carefully designed video_device structure and also tell it which group
168 of devices we want it registered with. In this case VFL_TYPE_RADIO.
169 </para> <