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authorLinus Torvalds <torvalds@linux-foundation.org>2014-04-04 09:50:07 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2014-04-04 09:50:07 -0700
commit3c83e61e67256e0bb08c46cc2db43b58fd617251 (patch)
tree0233e1e04e6449c60b01ff5dea8bea85bcf22f08 /Documentation/DocBook/media/v4l/dev-sdr.xml
parent4a4389abdd9822fdf3cc2ac6ed87eb811fd43acc (diff)
parenta83b93a7480441a47856dc9104bea970e84cda87 (diff)
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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 ...
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+ <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>
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