[media] Docbook: add missing vidioc-subdev-g-edid.xml

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

2 files changed, 153 insertions, 0 deletions

diff --git a/Documentation/DocBook/media/v4l/v4l2.xml b/Documentation/DocBook/media/v4l/v4l2.xml
index 0292ed106887..10ccde9d16d0 100644
--- a/Documentation/DocBook/media/v4l/v4l2.xml
+++ b/Documentation/DocBook/media/v4l/v4l2.xml
@@ -581,6 +581,7 @@ and discussions on the V4L mailing list.</revremark>
     &sub-subdev-enum-frame-size;
     &sub-subdev-enum-mbus-code;
     &sub-subdev-g-crop;
+    &sub-subdev-g-edid;
     &sub-subdev-g-fmt;
     &sub-subdev-g-frame-interval;
     &sub-subdev-g-selection;
diff --git a/Documentation/DocBook/media/v4l/vidioc-subdev-g-edid.xml b/Documentation/DocBook/media/v4l/vidioc-subdev-g-edid.xml
new file mode 100644
index 000000000000..bbd18f0e6ede
--- /dev/null
+++ b/Documentation/DocBook/media/v4l/vidioc-subdev-g-edid.xml
@@ -0,0 +1,152 @@
+<refentry id="vidioc-subdev-g-edid">
+  <refmeta>
+    <refentrytitle>ioctl VIDIOC_SUBDEV_G_EDID, VIDIOC_SUBDEV_S_EDID</refentrytitle>
+    &manvol;
+  </refmeta>
+
+  <refnamediv>
+    <refname>VIDIOC_SUBDEV_G_EDID</refname>
+    <refname>VIDIOC_SUBDEV_S_EDID</refname>
+    <refpurpose>Get or set the EDID of a video receiver/transmitter</refpurpose>
+  </refnamediv>
+
+  <refsynopsisdiv>
+    <funcsynopsis>
+      <funcprototype>
+	<funcdef>int <function>ioctl</function></funcdef>
+	<paramdef>int <parameter>fd</parameter></paramdef>
+	<paramdef>int <parameter>request</parameter></paramdef>
+	<paramdef>struct v4l2_subdev_edid *<parameter>argp</parameter></paramdef>
+      </funcprototype>
+    </funcsynopsis>
+    <funcsynopsis>
+      <funcprototype>
+	<funcdef>int <function>ioctl</function></funcdef>
+	<paramdef>int <parameter>fd</parameter></paramdef>
+	<paramdef>int <parameter>request</parameter></paramdef>
+	<paramdef>const struct v4l2_subdev_edid *<parameter>argp</parameter></paramdef>
+      </funcprototype>
+    </funcsynopsis>
+  </refsynopsisdiv>
+
+  <refsect1>
+    <title>Arguments</title>
+
+    <variablelist>
+      <varlistentry>
+	<term><parameter>fd</parameter></term>
+	<listitem>
+	  <para>&fd;</para>
+	</listitem>
+      </varlistentry>
+      <varlistentry>
+	<term><parameter>request</parameter></term>
+	<listitem>
+	  <para>VIDIOC_SUBDEV_G_EDID, VIDIOC_SUBDEV_S_EDID</para>
+	</listitem>
+      </varlistentry>
+      <varlistentry>
+	<term><parameter>argp</parameter></term>
+	<listitem>
+	  <para></para>
+	</listitem>
+      </varlistentry>
+    </variablelist>
+  </refsect1>
+
+  <refsect1>
+    <title>Description</title>
+    <para>These ioctls can be used to get or set an EDID associated with an input pad
+    from a receiver or an output pad of a transmitter subdevice.</para>
+
+    <para>To get the EDID data the application has to fill in the <structfield>pad</structfield>,
+    <structfield>start_block</structfield>, <structfield>blocks</structfield> and <structfield>edid</structfield>
+    fields and call <constant>VIDIOC_SUBDEV_G_EDID</constant>. The current EDID from block
+    <structfield>start_block</structfield> and of size <structfield>blocks</structfield>
+    will be placed in the memory <structfield>edid</structfield> points to. The <structfield>edid</structfield>
+    pointer must point to memory at least <structfield>blocks</structfield>&nbsp;*&nbsp;128 bytes
+    large (the size of one block is 128 bytes).</para>
+
+    <para>If there are fewer blocks than specified, then the driver will set <structfield>blocks</structfield>
+    to the actual number of blocks. If there are no EDID blocks available at all, then the error code
+    ENODATA is set.</para>
+
+    <para>If blocks have to be retrieved from the sink, then this call will block until they
+    have been read.</para>
+
+    <para>To set the EDID blocks of a receiver the application has to fill in the <structfield>pad</structfield>,
+    <structfield>blocks</structfield> and <structfield>edid</structfield> fields and set
+    <structfield>start_block</structfield> to 0. It is not possible to set part of an EDID,
+    it is always all or nothing. Setting the EDID data is only valid for receivers as it makes
+    no sense for a transmitter.</para>
+
+    <para>The driver assumes that the full EDID is passed in. If there are more EDID blocks than
+    the hardware can handle then the EDID is not written, but instead the error code E2BIG is set
+    and <structfield>blocks</structfield> is set to the maximum that the hardware supports.
+    If <structfield>start_block</structfield> is any
+    value other than 0 then the error code EINVAL is set.</para>
+
+    <para>To disable an EDID you set <structfield>blocks</structfield> to 0. Depending on the
+    hardware this will drive the hotplug pin low and/or block the source from reading the EDID
+    data in some way. In any case, the end result is the same: the EDID is no longer available.
+    </para>
+
+    <table pgwide="1" frame="none" id="v4l2-subdev-edid">
+      <title>struct <structname>v4l2_subdev_edid</structname></title>
+      <tgroup cols="3">
+        &cs-str;
+	<tbody valign="top">
+	  <row>
+	    <entry>__u32</entry>
+	    <entry><structfield>pad</structfield></entry>
+	    <entry>Pad for which to get/set the EDID blocks.</entry>
+	  </row>
+	  <row>
+	    <entry>__u32</entry>
+	    <entry><structfield>start_block</structfield></entry>
+	    <entry>Read the EDID from starting with this block. Must be 0 when setting
+	    the EDID.</entry>
+	  </row>
+	  <row>
+	    <entry>__u32</entry>
+	    <entry><structfield>blocks</structfield></entry>
+	    <entry>The number of blocks to get or set. Must be less or equal to 256 (the
+	    maximum number of blocks as defined by the standard). When you set the EDID and
+	    <structfield>blocks</structfield> is 0, then the EDID is disabled or erased.</entry>
+	  </row>
+	  <row>
+	    <entry>__u8&nbsp;*</entry>
+	    <entry><structfield>edid</structfield></entry>
+	    <entry>Pointer to memory that contains the EDID. The minimum size is
+	    <structfield>blocks</structfield>&nbsp;*&nbsp;128.</entry>
+	  </row>
+	  <row>
+	    <entry>__u32</entry>
+	    <entry><structfield>reserved</structfield>[5]</entry>
+	    <entry>Reserved for future extensions. Applications and drivers must
+	    set the array to zero.</entry>
+	  </row>
+	</tbody>
+      </tgroup>
+    </table>
+  </refsect1>
+
+  <refsect1>
+    &return-value;
+
+    <variablelist>
+      <varlistentry>
+	<term><errorcode>ENODATA</errorcode></term>
+	<listitem>
+	  <para>The EDID data is not available.</para>
+	</listitem>
+      </varlistentry>
+      <varlistentry>
+	<term><errorcode>E2BIG</errorcode></term>
+	<listitem>
+	  <para>The EDID data you provided is more than the hardware can handle.</para>
+	</listitem>
+      </varlistentry>
+    </variablelist>
+  </refsect1>
+</refentry>