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authorLinus Torvalds <torvalds@linux-foundation.org>2009-09-21 09:03:10 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2009-09-21 09:03:10 -0700
commitc720f5655df159a630fa0290a0bd67c93e92b0bf (patch)
tree940d139d0ec1ff5201efddef6cc663166a8a2df3 /Documentation/DocBook/v4l/dev-radio.xml
parent33e6c1a0de818d3698cdab27c42915661011319d (diff)
parent84d6ae431f315e8973aac3c3fe1d550fc9240ef3 (diff)
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Merge branch 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-2.6
* 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-2.6: (222 commits) V4L/DVB (13033): pt1: Don't use a deprecated DMA_BIT_MASK macro V4L/DVB (13029): radio-si4713: remove #include <linux/version.h> V4L/DVB (13027): go7007: convert printks to v4l2_info V4L/DVB (13026): s2250-board: Implement brightness and contrast controls V4L/DVB (13025): s2250-board: Fix memory leaks V4L/DVB (13024): go7007: Implement vidioc_g_std and vidioc_querystd V4L/DVB (13023): go7007: Merge struct gofh and go declarations V4L/DVB (13022): go7007: Fix mpeg controls V4L/DVB (13021): go7007: Fix whitespace and line lengths V4L/DVB (13020): go7007: Updates to Kconfig and Makefile V4L/DVB (13019): video: initial support for ADV7180 V4L/DVB (13018): kzalloc failure ignored in au8522_probe() V4L/DVB (13017): gspca: kmalloc failure ignored in sd_start() V4L/DVB (13016): kmalloc failure ignored in lgdt3304_attach() and s921_attach() V4L/DVB (13015): kmalloc failure ignored in m920x_firmware_download() V4L/DVB (13014): Add support for Compro VideoMate E800 (DVB-T part only) V4L/DVB (13013): FM TX: si4713: Kconfig: Fixed two typos. V4L/DVB (13012): uvc: introduce missing kfree V4L/DVB (13011): Change tuner type of BeholdTV cards V4L/DVB (13009): gspca - stv06xx-hdcs: Reduce exposure range ...
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+ <title>Radio Interface</title>
+
+ <para>This interface is intended for AM and FM (analog) radio
+receivers and transmitters.</para>
+
+ <para>Conventionally V4L2 radio devices are accessed through
+character device special files named <filename>/dev/radio</filename>
+and <filename>/dev/radio0</filename> to
+<filename>/dev/radio63</filename> with major number 81 and minor
+numbers 64 to 127.</para>
+
+ <section>
+ <title>Querying Capabilities</title>
+
+ <para>Devices supporting the radio interface set the
+<constant>V4L2_CAP_RADIO</constant> and
+<constant>V4L2_CAP_TUNER</constant> or
+<constant>V4L2_CAP_MODULATOR</constant> flag in the
+<structfield>capabilities</structfield> field of &v4l2-capability;
+returned by the &VIDIOC-QUERYCAP; ioctl. Other combinations of
+capability flags are reserved for future extensions.</para>
+ </section>
+
+ <section>
+ <title>Supplemental Functions</title>
+
+ <para>Radio devices can support <link
+linkend="control">controls</link>, and must support the <link
+linkend="tuner">tuner or modulator</link> ioctls.</para>
+
+ <para>They do not support the video input or output, audio input
+or output, video standard, cropping and scaling, compression and
+streaming parameter, or overlay ioctls. All other ioctls and I/O
+methods are reserved for future extensions.</para>
+ </section>
+
+ <section>
+ <title>Programming</title>
+
+ <para>Radio devices may have a couple audio controls (as discussed
+in <xref linkend="control" />) such as a volume control, possibly custom
+controls. Further all radio devices have one tuner or modulator (these are
+discussed in <xref linkend="tuner" />) with index number zero to select
+the radio frequency and to determine if a monaural or FM stereo
+program is received/emitted. Drivers switch automatically between AM and FM
+depending on the selected frequency. The &VIDIOC-G-TUNER; or
+&VIDIOC-G-MODULATOR; ioctl
+reports the supported frequency range.</para>
+ </section>
+
+<!--
+Local Variables:
+mode: sgml
+sgml-parent-document: "v4l2.sgml"
+indent-tabs-mode: nil
+End:
+ -->
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