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author | Linus Torvalds <torvalds@linux-foundation.org> | 2014-04-04 09:50:07 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2014-04-04 09:50:07 -0700 |
commit | 3c83e61e67256e0bb08c46cc2db43b58fd617251 (patch) | |
tree | 0233e1e04e6449c60b01ff5dea8bea85bcf22f08 /Documentation/DocBook/media/v4l/dev-sdr.xml | |
parent | 4a4389abdd9822fdf3cc2ac6ed87eb811fd43acc (diff) | |
parent | a83b93a7480441a47856dc9104bea970e84cda87 (diff) | |
download | op-kernel-dev-3c83e61e67256e0bb08c46cc2db43b58fd617251.zip op-kernel-dev-3c83e61e67256e0bb08c46cc2db43b58fd617251.tar.gz |
Merge branch 'v4l_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media
Pull media updates from Mauro Carvalho Chehab:
"The main set of series of patches for media subsystem, including:
- document RC sysfs class
- added an API to setup scancode to allow waking up systems using the
Remote Controller
- add API for SDR devices. Drivers are still on staging
- some API improvements for getting EDID data from media
inputs/outputs
- new DVB frontend driver for drx-j (ATSC)
- one driver (it913x/it9137) got removed, in favor of an improvement
on another driver (af9035)
- added a skeleton V4L2 PCI driver at documentation
- added a dual flash driver (lm3646)
- added a new IR driver (img-ir)
- added an IR scancode decoder for the Sharp protocol
- some improvements at the usbtv driver, to allow its core to be
reused.
- added a new SDR driver (rtl2832u_sdr)
- added a new tuner driver (msi001)
- several improvements at em28xx driver to fix PM support, device
removal and to split the V4L2 specific bits into a separate
sub-driver
- one driver got converted to videobuf2 (s2255drv)
- the e4000 tuner driver now follows an improved binding model
- some fixes at V4L2 compat32 code
- several fixes and enhancements at videobuf2 code
- some cleanups at V4L2 API documentation
- usual driver enhancements, new board additions and misc fixups"
[ NOTE! This merge effective drops commit 4329b93b283c ("of: Reduce
indentation in of_graph_get_next_endpoint").
The of_graph_get_next_endpoint() function was moved and renamed by
commit fd9fdb78a9bf ("[media] of: move graph helpers from
drivers/media/v4l2-core to drivers/of"). It was originally called
v4l2_of_get_next_endpoint() and lived in the file
drivers/media/v4l2-core/v4l2-of.c.
In that original location, it was then fixed to support empty port
nodes by commit b9db140c1e46 ("[media] v4l: of: Support empty port
nodes"), and that commit clashes badly with the dropped "Reduce
intendation" commit. I had to choose one or the other, and decided
that the "Support empty port nodes" commit was more important ]
* 'v4l_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media: (426 commits)
[media] em28xx-dvb: fix PCTV 461e tuner I2C binding
Revert "[media] em28xx-dvb: fix PCTV 461e tuner I2C binding"
[media] em28xx: fix PCTV 290e LNA oops
[media] em28xx-dvb: fix PCTV 461e tuner I2C binding
[media] m88ds3103: fix bug on .set_tone()
[media] saa7134: fix WARN_ON during resume
[media] v4l2-dv-timings: add module name, description, license
[media] videodev2.h: add parenthesis around macro arguments
[media] saa6752hs: depends on CRC32
[media] si4713: fix Kconfig dependencies
[media] Sensoray 2255 uses videobuf2
[media] adv7180: free an interrupt on failure paths in init_device()
[media] e4000: make VIDEO_V4L2 dependency optional
[media] af9033: Don't export functions for the hardware filter
[media] af9035: use af9033 PID filters
[media] af9033: implement PID filter
[media] rtl2832_sdr: do not use dynamic stack allocation
[media] e4000: fix 32-bit build error
[media] em28xx-audio: make sure audio is unmuted on open()
[media] DocBook media: v4l2_format_sdr was renamed to v4l2_sdr_format
...
Diffstat (limited to 'Documentation/DocBook/media/v4l/dev-sdr.xml')
-rw-r--r-- | Documentation/DocBook/media/v4l/dev-sdr.xml | 110 |
1 files changed, 110 insertions, 0 deletions
diff --git a/Documentation/DocBook/media/v4l/dev-sdr.xml b/Documentation/DocBook/media/v4l/dev-sdr.xml new file mode 100644 index 0000000..dc14804 --- /dev/null +++ b/Documentation/DocBook/media/v4l/dev-sdr.xml @@ -0,0 +1,110 @@ + <title>Software Defined Radio Interface (SDR)</title> + + <note> + <title>Experimental</title> + <para>This is an <link linkend="experimental"> experimental </link> + interface and may change in the future.</para> + </note> + + <para> +SDR is an abbreviation of Software Defined Radio, the radio device +which uses application software for modulation or demodulation. This interface +is intended for controlling and data streaming of such devices. + </para> + + <para> +SDR devices are accessed through character device special files named +<filename>/dev/swradio0</filename> to <filename>/dev/swradio255</filename> +with major number 81 and dynamically allocated minor numbers 0 to 255. + </para> + + <section> + <title>Querying Capabilities</title> + + <para> +Devices supporting the SDR receiver interface set the +<constant>V4L2_CAP_SDR_CAPTURE</constant> and +<constant>V4L2_CAP_TUNER</constant> flag in the +<structfield>capabilities</structfield> field of &v4l2-capability; +returned by the &VIDIOC-QUERYCAP; ioctl. That flag means the device has an +Analog to Digital Converter (ADC), which is a mandatory element for the SDR receiver. +At least one of the read/write, streaming or asynchronous I/O methods must +be supported. + </para> + </section> + + <section> + <title>Supplemental Functions</title> + + <para> +SDR devices can support <link linkend="control">controls</link>, and must +support the <link linkend="tuner">tuner</link> ioctls. Tuner ioctls are used +for setting the ADC sampling rate (sampling frequency) and the possible RF tuner +frequency. + </para> + + <para> +The <constant>V4L2_TUNER_ADC</constant> tuner type is used for ADC tuners, and +the <constant>V4L2_TUNER_RF</constant> tuner type is used for RF tuners. The +tuner index of the RF tuner (if any) must always follow the ADC tuner index. +Normally the ADC tuner is #0 and the RF tuner is #1. + </para> + + <para> +The &VIDIOC-S-HW-FREQ-SEEK; ioctl is not supported. + </para> + </section> + + <section> + <title>Data Format Negotiation</title> + + <para> +The SDR capture device uses the <link linkend="format">format</link> ioctls to +select the capture format. Both the sampling resolution and the data streaming +format are bound to that selectable format. In addition to the basic +<link linkend="format">format</link> ioctls, the &VIDIOC-ENUM-FMT; ioctl +must be supported as well. + </para> + + <para> +To use the <link linkend="format">format</link> ioctls applications set the +<structfield>type</structfield> field of a &v4l2-format; to +<constant>V4L2_BUF_TYPE_SDR_CAPTURE</constant> and use the &v4l2-sdr-format; +<structfield>sdr</structfield> member of the <structfield>fmt</structfield> +union as needed per the desired operation. +Currently only the <structfield>pixelformat</structfield> field of +&v4l2-sdr-format; is used. The content of that field is the V4L2 fourcc code +of the data format. + </para> + + <table pgwide="1" frame="none" id="v4l2-sdr-format"> + <title>struct <structname>v4l2_sdr_format</structname></title> + <tgroup cols="3"> + &cs-str; + <tbody valign="top"> + <row> + <entry>__u32</entry> + <entry><structfield>pixelformat</structfield></entry> + <entry> +The data format or type of compression, set by the application. This is a +little endian <link linkend="v4l2-fourcc">four character code</link>. +V4L2 defines SDR formats in <xref linkend="sdr-formats" />. + </entry> + </row> + <row> + <entry>__u8</entry> + <entry><structfield>reserved[28]</structfield></entry> + <entry>This array is reserved for future extensions. +Drivers and applications must set it to zero.</entry> + </row> + </tbody> + </tgroup> + </table> + + <para> +An SDR device may support <link linkend="rw">read/write</link> +and/or streaming (<link linkend="mmap">memory mapping</link> +or <link linkend="userp">user pointer</link>) I/O. + </para> + + </section> |