1 files changed, 55 insertions, 19 deletions

diff --git a/Documentation/DocBook/v4l/dev-rds.xml b/Documentation/DocBook/v4l/dev-rds.xml
index 0869d701b1e5..2427f54397e7 100644
--- a/Documentation/DocBook/v4l/dev-rds.xml
+++ b/Documentation/DocBook/v4l/dev-rds.xml
@@ -3,15 +3,16 @@
       <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
+interface is aimed at devices capable of receiving and/or transmitting 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>
+to the RDS standard. Any RDS decoder/encoder 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
@@ -21,16 +22,25 @@ 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
+    <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>
+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;.  If
+the driver only passes RDS blocks without interpreting the data
+the <constant>V4L2_TUNER_SUB_RDS_BLOCK_IO</constant> flag has to be
+set, see <link linkend="reading-rds-data">Reading RDS data</link>.
+For future use the
+flag <constant>V4L2_TUNER_SUB_RDS_CONTROLS</constant> has also been
+defined. However, a driver for a radio tuner with this capability does
+not yet exist, so if you are planning to write such a driver you
+should discuss this on the linux-media mailing list: &v4l-ml;.</para>
+
+    <para> 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
@@ -40,16 +50,32 @@ 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>
-
+bit in the <structfield>txsubchans</structfield> field of &v4l2-modulator;.
+If the driver only passes RDS blocks without interpreting the data
+the <constant>V4L2_TUNER_SUB_RDS_BLOCK_IO</constant> flag has to be set. If the
+tuner is capable of handling RDS entities like program identification codes and radio
+text, the flag <constant>V4L2_TUNER_SUB_RDS_CONTROLS</constant> should be set,
+see <link linkend="writing-rds-data">Writing RDS data</link> and
+<link linkend="fm-tx-controls">FM Transmitter Control Reference</link>.</para>
   </section>
 
-  <section>
+  <section  id="reading-rds-data">
     <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,
+with the &func-read; function. The data is packed in groups of three bytes.</para>
+  </section>
+
+  <section  id="writing-rds-data">
+    <title>Writing RDS data</title>
+
+      <para>RDS data can be written to the radio device
+with the &func-write; function. The data is packed in groups of three bytes,
 as follows:</para>
+  </section>
+
+  <section>
+    <title>RDS datastructures</title>
     <table frame="none" pgwide="1" id="v4l2-rds-data">
       <title>struct
 <structname>v4l2_rds_data</structname></title>
@@ -104,55 +130,65 @@ as follows:</para>
 
     <table frame="none" pgwide="1" id="v4l2-rds-block-codes">
       <title>Block defines</title>
-      <tgroup cols="3">
+      <tgroup cols="4">
         <colspec colname="c1" colwidth="1*" />
         <colspec colname="c2" colwidth="1*" />
-        <colspec colname="c3" colwidth="5*" />
+        <colspec colname="c3" colwidth="1*" />
+        <colspec colname="c4" colwidth="5*" />
         <tbody valign="top">
           <row>
             <entry>V4L2_RDS_BLOCK_MSK</entry>
+            <entry> </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> </entry>
             <entry>0</entry>
             <entry>Block A.</entry>
           </row>
           <row>
             <entry>V4L2_RDS_BLOCK_B</entry>
+            <entry> </entry>
             <entry>1</entry>
             <entry>Block B.</entry>
           </row>
           <row>
             <entry>V4L2_RDS_BLOCK_C</entry>
+            <entry> </entry>
             <entry>2</entry>
             <entry>Block C.</entry>
           </row>
           <row>
             <entry>V4L2_RDS_BLOCK_D</entry>
+            <entry> </entry>
             <entry>3</entry>
             <entry>Block D.</entry>
           </row>
           <row>
             <entry>V4L2_RDS_BLOCK_C_ALT</entry>
+            <entry> </entry>
             <entry>4</entry>
             <entry>Block C'.</entry>
           </row>
           <row>
             <entry>V4L2_RDS_BLOCK_INVALID</entry>
+            <entry>read-only</entry>
             <entry>7</entry>
             <entry>An invalid block.</entry>
           </row>
           <row>
             <entry>V4L2_RDS_BLOCK_CORRECTED</entry>
+            <entry>read-only</entry>
             <entry>0x40</entry>
             <entry>A bit error was detected but corrected.</entry>
           </row>
           <row>
             <entry>V4L2_RDS_BLOCK_ERROR</entry>
+            <entry>read-only</entry>
             <entry>0x80</entry>
-            <entry>An incorrectable error occurred.</entry>
+            <entry>An uncorrectable error occurred.</entry>
           </row>
         </tbody>
       </tgroup>