aboutsummaryrefslogtreecommitdiff
path: root/Documentation/DocBook/v4l/dev-rds.xml
diff options
context:
space:
mode:
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-rds.xml
parent33e6c1a0de818d3698cdab27c42915661011319d (diff)
parent84d6ae431f315e8973aac3c3fe1d550fc9240ef3 (diff)
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 ...
Diffstat (limited to 'Documentation/DocBook/v4l/dev-rds.xml')
-rw-r--r--Documentation/DocBook/v4l/dev-rds.xml168
1 files changed, 168 insertions, 0 deletions
diff --git a/Documentation/DocBook/v4l/dev-rds.xml b/Documentation/DocBook/v4l/dev-rds.xml
new file mode 100644
index 00000000000..0869d701b1e
--- /dev/null
+++ b/Documentation/DocBook/v4l/dev-rds.xml
@@ -0,0 +1,168 @@
+ <title>RDS Interface</title>
+
+ <para>The Radio Data System transmits supplementary
+information in binary format, for example the station name or travel
+information, on an inaudible audio subcarrier of a radio program. This
+interface is aimed at devices capable of receiving and decoding RDS
+information.</para>
+
+ <para>For more information see the core RDS standard <xref linkend="en50067" />
+and the RBDS standard <xref linkend="nrsc4" />.</para>
+
+ <para>Note that the RBDS standard as is used in the USA is almost identical
+to the RDS standard. Any RDS decoder can also handle RBDS. Only some of the fields
+have slightly different meanings. See the RBDS standard for more information.</para>
+
+ <para>The RBDS standard also specifies support for MMBS (Modified Mobile Search).
+This is a proprietary format which seems to be discontinued. The RDS interface does not
+support this format. Should support for MMBS (or the so-called 'E blocks' in general)
+be needed, then please contact the linux-media mailing list: &v4l-ml;.</para>
+
+ <section>
+ <title>Querying Capabilities</title>
+
+ <para>Devices supporting the RDS capturing API
+set the <constant>V4L2_CAP_RDS_CAPTURE</constant> flag in
+the <structfield>capabilities</structfield> field of &v4l2-capability;
+returned by the &VIDIOC-QUERYCAP; ioctl.
+Any tuner that supports RDS will set the
+<constant>V4L2_TUNER_CAP_RDS</constant> flag in the <structfield>capability</structfield>
+field of &v4l2-tuner;.
+Whether an RDS signal is present can be detected by looking at
+the <structfield>rxsubchans</structfield> field of &v4l2-tuner;: the
+<constant>V4L2_TUNER_SUB_RDS</constant> will be set if RDS data was detected.</para>
+
+ <para>Devices supporting the RDS output API
+set the <constant>V4L2_CAP_RDS_OUTPUT</constant> flag in
+the <structfield>capabilities</structfield> field of &v4l2-capability;
+returned by the &VIDIOC-QUERYCAP; ioctl.
+Any modulator that supports RDS will set the
+<constant>V4L2_TUNER_CAP_RDS</constant> flag in the <structfield>capability</structfield>
+field of &v4l2-modulator;.
+In order to enable the RDS transmission one must set the <constant>V4L2_TUNER_SUB_RDS</constant>
+bit in the <structfield>txsubchans</structfield> field of &v4l2-modulator;.</para>
+
+ </section>
+
+ <section>
+ <title>Reading RDS data</title>
+
+ <para>RDS data can be read from the radio device
+with the &func-read; function. The data is packed in groups of three bytes,
+as follows:</para>
+ <table frame="none" pgwide="1" id="v4l2-rds-data">
+ <title>struct
+<structname>v4l2_rds_data</structname></title>
+ <tgroup cols="3">
+ <colspec colname="c1" colwidth="1*" />
+ <colspec colname="c2" colwidth="1*" />
+ <colspec colname="c3" colwidth="5*" />
+ <tbody valign="top">
+ <row>
+ <entry>__u8</entry>
+ <entry><structfield>lsb</structfield></entry>
+ <entry>Least Significant Byte of RDS Block</entry>
+ </row>
+ <row>
+ <entry>__u8</entry>
+ <entry><structfield>msb</structfield></entry>
+ <entry>Most Significant Byte of RDS Block</entry>
+ </row>
+ <row>
+ <entry>__u8</entry>
+ <entry><structfield>block</structfield></entry>
+ <entry>Block description</entry>
+ </row>
+ </tbody>
+ </tgroup>
+ </table>
+ <table frame="none" pgwide="1" id="v4l2-rds-block">
+ <title>Block description</title>
+ <tgroup cols="2">
+ <colspec colname="c1" colwidth="1*" />
+ <colspec colname="c2" colwidth="5*" />
+ <tbody valign="top">
+ <row>
+ <entry>Bits 0-2</entry>
+ <entry>Block (aka offset) of the received data.</entry>
+ </row>
+ <row>
+ <entry>Bits 3-5</entry>
+ <entry>Deprecated. Currently identical to bits 0-2. Do not use these bits.</entry>
+ </row>
+ <row>
+ <entry>Bit 6</entry>
+ <entry>Corrected bit. Indicates that an error was corrected for this data block.</entry>
+ </row>
+ <row>
+ <entry>Bit 7</entry>
+ <entry>Error bit. Indicates that an uncorrectable error occurred during reception of this block.</entry>
+ </row>
+ </tbody>
+ </tgroup>
+ </table>
+
+ <table frame="none" pgwide="1" id="v4l2-rds-block-codes">
+ <title>Block defines</title>
+ <tgroup cols="3">
+ <colspec colname="c1" colwidth="1*" />
+ <colspec colname="c2" colwidth="1*" />
+ <colspec colname="c3" colwidth="5*" />
+ <tbody valign="top">
+ <row>
+ <entry>V4L2_RDS_BLOCK_MSK</entry>
+ <entry>7</entry>
+ <entry>Mask for bits 0-2 to get the block ID.</entry>
+ </row>
+ <row>
+ <entry>V4L2_RDS_BLOCK_A</entry>
+ <entry>0</entry>
+ <entry>Block A.</entry>
+ </row>
+ <row>
+ <entry>V4L2_RDS_BLOCK_B</entry>
+ <entry>1</entry>
+ <entry>Block B.</entry>
+ </row>
+ <row>
+ <entry>V4L2_RDS_BLOCK_C</entry>
+ <entry>2</entry>
+ <entry>Block C.</entry>
+ </row>
+ <row>
+ <entry>V4L2_RDS_BLOCK_D</entry>
+ <entry>3</entry>
+ <entry>Block D.</entry>
+ </row>
+ <row>
+ <entry>V4L2_RDS_BLOCK_C_ALT</entry>
+ <entry>4</entry>
+ <entry>Block C'.</entry>
+ </row>
+ <row>
+ <entry>V4L2_RDS_BLOCK_INVALID</entry>
+ <entry>7</entry>
+ <entry>An invalid block.</entry>
+ </row>
+ <row>
+ <entry>V4L2_RDS_BLOCK_CORRECTED</entry>
+ <entry>0x40</entry>
+ <entry>A bit error was detected but corrected.</entry>
+ </row>
+ <row>
+ <entry>V4L2_RDS_BLOCK_ERROR</entry>
+ <entry>0x80</entry>
+ <entry>An incorrectable error occurred.</entry>
+ </row>
+ </tbody>
+ </tgroup>
+ </table>
+ </section>
+
+<!--
+Local Variables:
+mode: sgml
+sgml-parent-document: "v4l2.sgml"
+indent-tabs-mode: nil
+End:
+ -->