diff options
author | Linus Torvalds <torvalds@g5.osdl.org> | 2006-06-27 21:22:13 -0400 |
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committer | Linus Torvalds <torvalds@g5.osdl.org> | 2006-06-27 21:22:13 -0400 |
commit | 12e56b601f66a415f88e7d60f6b6707a19c430c9 (patch) | |
tree | c294adb1c5c1f80bbb2de82e6e41da97b3f5800f /Documentation | |
parent | ca6f8792bd5281ebaf04bf23a43ed486e5e453a9 (diff) | |
parent | c78059f0a948404fb515db6be4bca5ec93eecd2a (diff) |
Merge master.kernel.org:/pub/scm/linux/kernel/git/mchehab/v4l-dvb
* master.kernel.org:/pub/scm/linux/kernel/git/mchehab/v4l-dvb: (26 commits)
V4L/DVB (4263): Fix warning when compiling on 64 bit machines
V4L/DVB (4261): Included required header for in-kernel compilation
V4L/DVB (4260): Stradis.c: make 2 functions static
V4L/DVB (4259): Pass an explicit log prefix to cx2341x_log_status
V4L/DVB (4257): Fix 64-bit compile warnings.
V4L/DVB (4255): Tda9887 default TOP value is 0x10
V4L/DVB (4254): Remove obsoleted tuner_debug option.
V4L/DVB (4253): IVTV VBI format description too long.
V4L/DVB (4252): Remove duplicate 'tda9887' in info messages.
V4L/DVB (4245): Reduce the amount of pvrusb2-sourced noise going into the system log
V4L/DVB (4244): Implement use of cx2341x module in pvrusb2 driver
V4L/DVB (4243): Exploit new V4L control features in pvrusb2
V4L/DVB (4242): Don't suspend encoder when changing its attributes (in pvrusb2)
V4L/DVB (4241): Fix faulty encoder error recovery in pvrusb2
V4L/DVB (4240): Various V4L control enhancements in pvrusb2
V4L/DVB (4239): Handle boolean controls in pvrusb2
V4L/DVB (4238): Make sure flags field is initialized when quering a control in pvrusb2
V4L/DVB (4237): Move LOG_STATUS bracketing to a different part of the pvrusb2 driver
V4L/DVB (4236): Rearrange things in pvrusb2 driver in preparation for using cx2341x module
V4L/DVB (4235): Increase the maximum number of controls that pvrusb2-sysfs.c can handle.
...
Diffstat (limited to 'Documentation')
-rw-r--r-- | Documentation/video4linux/README.pvrusb2 | 212 |
1 files changed, 212 insertions, 0 deletions
diff --git a/Documentation/video4linux/README.pvrusb2 b/Documentation/video4linux/README.pvrusb2 new file mode 100644 index 000000000000..c73a32c34528 --- /dev/null +++ b/Documentation/video4linux/README.pvrusb2 | |||
@@ -0,0 +1,212 @@ | |||
1 | |||
2 | $Id$ | ||
3 | Mike Isely <isely@pobox.com> | ||
4 | |||
5 | pvrusb2 driver | ||
6 | |||
7 | Background: | ||
8 | |||
9 | This driver is intended for the "Hauppauge WinTV PVR USB 2.0", which | ||
10 | is a USB 2.0 hosted TV Tuner. This driver is a work in progress. | ||
11 | Its history started with the reverse-engineering effort by Björn | ||
12 | Danielsson <pvrusb2@dax.nu> whose web page can be found here: | ||
13 | |||
14 | http://pvrusb2.dax.nu/ | ||
15 | |||
16 | From there Aurelien Alleaume <slts@free.fr> began an effort to | ||
17 | create a video4linux compatible driver. I began with Aurelien's | ||
18 | last known snapshot and evolved the driver to the state it is in | ||
19 | here. | ||
20 | |||
21 | More information on this driver can be found at: | ||
22 | |||
23 | http://www.isely.net/pvrusb2.html | ||
24 | |||
25 | |||
26 | This driver has a strong separation of layers. They are very | ||
27 | roughly: | ||
28 | |||
29 | 1a. Low level wire-protocol implementation with the device. | ||
30 | |||
31 | 1b. I2C adaptor implementation and corresponding I2C client drivers | ||
32 | implemented elsewhere in V4L. | ||
33 | |||
34 | 1c. High level hardware driver implementation which coordinates all | ||
35 | activities that ensure correct operation of the device. | ||
36 | |||
37 | 2. A "context" layer which manages instancing of driver, setup, | ||
38 | tear-down, arbitration, and interaction with high level | ||
39 | interfaces appropriately as devices are hotplugged in the | ||
40 | system. | ||
41 | |||
42 | 3. High level interfaces which glue the driver to various published | ||
43 | Linux APIs (V4L, sysfs, maybe DVB in the future). | ||
44 | |||
45 | The most important shearing layer is between the top 2 layers. A | ||
46 | lot of work went into the driver to ensure that any kind of | ||
47 | conceivable API can be laid on top of the core driver. (Yes, the | ||
48 | driver internally leverages V4L to do its work but that really has | ||
49 | nothing to do with the API published by the driver to the outside | ||
50 | world.) The architecture allows for different APIs to | ||
51 | simultaneously access the driver. I have a strong sense of fairness | ||
52 | about APIs and also feel that it is a good design principle to keep | ||
53 | implementation and interface isolated from each other. Thus while | ||
54 | right now the V4L high level interface is the most complete, the | ||
55 | sysfs high level interface will work equally well for similar | ||
56 | functions, and there's no reason I see right now why it shouldn't be | ||
57 | possible to produce a DVB high level interface that can sit right | ||
58 | alongside V4L. | ||
59 | |||
60 | NOTE: Complete documentation on the pvrusb2 driver is contained in | ||
61 | the html files within the doc directory; these are exactly the same | ||
62 | as what is on the web site at the time. Browse those files | ||
63 | (especially the FAQ) before asking questions. | ||
64 | |||
65 | |||
66 | Building | ||
67 | |||
68 | To build these modules essentially amounts to just running "Make", | ||
69 | but you need the kernel source tree nearby and you will likely also | ||
70 | want to set a few controlling environment variables first in order | ||
71 | to link things up with that source tree. Please see the Makefile | ||
72 | here for comments that explain how to do that. | ||
73 | |||
74 | |||
75 | Source file list / functional overview: | ||
76 | |||
77 | (Note: The term "module" used below generally refers to loosely | ||
78 | defined functional units within the pvrusb2 driver and bears no | ||
79 | relation to the Linux kernel's concept of a loadable module.) | ||
80 | |||
81 | pvrusb2-audio.[ch] - This is glue logic that resides between this | ||
82 | driver and the msp3400.ko I2C client driver (which is found | ||
83 | elsewhere in V4L). | ||
84 | |||
85 | pvrusb2-context.[ch] - This module implements the context for an | ||
86 | instance of the driver. Everything else eventually ties back to | ||
87 | or is otherwise instanced within the data structures implemented | ||
88 | here. Hotplugging is ultimately coordinated here. All high level | ||
89 | interfaces tie into the driver through this module. This module | ||
90 | helps arbitrate each interface's access to the actual driver core, | ||
91 | and is designed to allow concurrent access through multiple | ||
92 | instances of multiple interfaces (thus you can for example change | ||
93 | the tuner's frequency through sysfs while simultaneously streaming | ||
94 | video through V4L out to an instance of mplayer). | ||
95 | |||
96 | pvrusb2-debug.h - This header defines a printk() wrapper and a mask | ||
97 | of debugging bit definitions for the various kinds of debug | ||
98 | messages that can be enabled within the driver. | ||
99 | |||
100 | pvrusb2-debugifc.[ch] - This module implements a crude command line | ||
101 | oriented debug interface into the driver. Aside from being part | ||
102 | of the process for implementing manual firmware extraction (see | ||
103 | the pvrusb2 web site mentioned earlier), probably I'm the only one | ||
104 | who has ever used this. It is mainly a debugging aid. | ||
105 | |||
106 | pvrusb2-eeprom.[ch] - This is glue logic that resides between this | ||
107 | driver the tveeprom.ko module, which is itself implemented | ||
108 | elsewhere in V4L. | ||
109 | |||
110 | pvrusb2-encoder.[ch] - This module implements all protocol needed to | ||
111 | interact with the Conexant mpeg2 encoder chip within the pvrusb2 | ||
112 | device. It is a crude echo of corresponding logic in ivtv, | ||
113 | however the design goals (strict isolation) and physical layer | ||
114 | (proxy through USB instead of PCI) are enough different that this | ||
115 | implementation had to be completely different. | ||
116 | |||
117 | pvrusb2-hdw-internal.h - This header defines the core data structure | ||
118 | in the driver used to track ALL internal state related to control | ||
119 | of the hardware. Nobody outside of the core hardware-handling | ||
120 | modules should have any business using this header. All external | ||
121 | access to the driver should be through one of the high level | ||
122 | interfaces (e.g. V4L, sysfs, etc), and in fact even those high | ||
123 | level interfaces are restricted to the API defined in | ||
124 | pvrusb2-hdw.h and NOT this header. | ||
125 | |||
126 | pvrusb2-hdw.h - This header defines the full internal API for | ||
127 | controlling the hardware. High level interfaces (e.g. V4L, sysfs) | ||
128 | will work through here. | ||
129 | |||
130 | pvrusb2-hdw.c - This module implements all the various bits of logic | ||
131 | that handle overall control of a specific pvrusb2 device. | ||
132 | (Policy, instantiation, and arbitration of pvrusb2 devices fall | ||
133 | within the jurisdiction of pvrusb-context not here). | ||
134 | |||
135 | pvrusb2-i2c-chips-*.c - These modules implement the glue logic to | ||
136 | tie together and configure various I2C modules as they attach to | ||
137 | the I2C bus. There are two versions of this file. The "v4l2" | ||
138 | version is intended to be used in-tree alongside V4L, where we | ||
139 | implement just the logic that makes sense for a pure V4L | ||
140 | environment. The "all" version is intended for use outside of | ||
141 | V4L, where we might encounter other possibly "challenging" modules | ||
142 | from ivtv or older kernel snapshots (or even the support modules | ||
143 | in the standalone snapshot). | ||
144 | |||
145 | pvrusb2-i2c-cmd-v4l1.[ch] - This module implements generic V4L1 | ||
146 | compatible commands to the I2C modules. It is here where state | ||
147 | changes inside the pvrusb2 driver are translated into V4L1 | ||
148 | commands that are in turn send to the various I2C modules. | ||
149 | |||
150 | pvrusb2-i2c-cmd-v4l2.[ch] - This module implements generic V4L2 | ||
151 | compatible commands to the I2C modules. It is here where state | ||
152 | changes inside the pvrusb2 driver are translated into V4L2 | ||
153 | commands that are in turn send to the various I2C modules. | ||
154 | |||
155 | pvrusb2-i2c-core.[ch] - This module provides an implementation of a | ||
156 | kernel-friendly I2C adaptor driver, through which other external | ||
157 | I2C client drivers (e.g. msp3400, tuner, lirc) may connect and | ||
158 | operate corresponding chips within the the pvrusb2 device. It is | ||
159 | through here that other V4L modules can reach into this driver to | ||
160 | operate specific pieces (and those modules are in turn driven by | ||
161 | glue logic which is coordinated by pvrusb2-hdw, doled out by | ||
162 | pvrusb2-context, and then ultimately made available to users | ||
163 | through one of the high level interfaces). | ||
164 | |||
165 | pvrusb2-io.[ch] - This module implements a very low level ring of | ||
166 | transfer buffers, required in order to stream data from the | ||
167 | device. This module is *very* low level. It only operates the | ||
168 | buffers and makes no attempt to define any policy or mechanism for | ||
169 | how such buffers might be used. | ||
170 | |||
171 | pvrusb2-ioread.[ch] - This module layers on top of pvrusb2-io.[ch] | ||
172 | to provide a streaming API usable by a read() system call style of | ||
173 | I/O. Right now this is the only layer on top of pvrusb2-io.[ch], | ||
174 | however the underlying architecture here was intended to allow for | ||
175 | other styles of I/O to be implemented with additonal modules, like | ||
176 | mmap()'ed buffers or something even more exotic. | ||
177 | |||
178 | pvrusb2-main.c - This is the top level of the driver. Module level | ||
179 | and USB core entry points are here. This is our "main". | ||
180 | |||
181 | pvrusb2-sysfs.[ch] - This is the high level interface which ties the | ||
182 | pvrusb2 driver into sysfs. Through this interface you can do | ||
183 | everything with the driver except actually stream data. | ||
184 | |||
185 | pvrusb2-tuner.[ch] - This is glue logic that resides between this | ||
186 | driver and the tuner.ko I2C client driver (which is found | ||
187 | elsewhere in V4L). | ||
188 | |||
189 | pvrusb2-util.h - This header defines some common macros used | ||
190 | throughout the driver. These macros are not really specific to | ||
191 | the driver, but they had to go somewhere. | ||
192 | |||
193 | pvrusb2-v4l2.[ch] - This is the high level interface which ties the | ||
194 | pvrusb2 driver into video4linux. It is through here that V4L | ||
195 | applications can open and operate the driver in the usual V4L | ||
196 | ways. Note that **ALL** V4L functionality is published only | ||
197 | through here and nowhere else. | ||
198 | |||
199 | pvrusb2-video-*.[ch] - This is glue logic that resides between this | ||
200 | driver and the saa711x.ko I2C client driver (which is found | ||
201 | elsewhere in V4L). Note that saa711x.ko used to be known as | ||
202 | saa7115.ko in ivtv. There are two versions of this; one is | ||
203 | selected depending on the particular saa711[5x].ko that is found. | ||
204 | |||
205 | pvrusb2.h - This header contains compile time tunable parameters | ||
206 | (and at the moment the driver has very little that needs to be | ||
207 | tuned). | ||
208 | |||
209 | |||
210 | -Mike Isely | ||
211 | isely@pobox.com | ||
212 | |||