[media] media: Media device information query
Create the following ioctl and implement it at the media device level to
query device information.
- MEDIA_IOC_DEVICE_INFO: Query media device information
The ioctl and its data structure are defined in the new kernel header
linux/media.h available to userspace applications.
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
diff --git a/Documentation/DocBook/v4l/media-func-open.xml b/Documentation/DocBook/v4l/media-func-open.xml
new file mode 100644
index 0000000..f7df034
--- /dev/null
+++ b/Documentation/DocBook/v4l/media-func-open.xml
@@ -0,0 +1,94 @@
+<refentry id="media-func-open">
+ <refmeta>
+ <refentrytitle>media open()</refentrytitle>
+ &manvol;
+ </refmeta>
+
+ <refnamediv>
+ <refname>media-open</refname>
+ <refpurpose>Open a media device</refpurpose>
+ </refnamediv>
+
+ <refsynopsisdiv>
+ <funcsynopsis>
+ <funcsynopsisinfo>#include <fcntl.h></funcsynopsisinfo>
+ <funcprototype>
+ <funcdef>int <function>open</function></funcdef>
+ <paramdef>const char *<parameter>device_name</parameter></paramdef>
+ <paramdef>int <parameter>flags</parameter></paramdef>
+ </funcprototype>
+ </funcsynopsis>
+ </refsynopsisdiv>
+
+ <refsect1>
+ <title>Arguments</title>
+
+ <variablelist>
+ <varlistentry>
+ <term><parameter>device_name</parameter></term>
+ <listitem>
+ <para>Device to be opened.</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><parameter>flags</parameter></term>
+ <listitem>
+ <para>Open flags. Access mode must be either <constant>O_RDONLY</constant>
+ or <constant>O_RDWR</constant>. Other flags have no effect.</para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ </refsect1>
+ <refsect1>
+ <title>Description</title>
+ <para>To open a media device applications call <function>open()</function>
+ with the desired device name. The function has no side effects; the device
+ configuration remain unchanged.</para>
+ <para>When the device is opened in read-only mode, attemps to modify its
+ configuration will result in an error, and <varname>errno</varname> will be
+ set to <errorcode>EBADF</errorcode>.</para>
+ </refsect1>
+ <refsect1>
+ <title>Return Value</title>
+
+ <para><function>open</function> returns the new file descriptor on success.
+ On error, -1 is returned, and <varname>errno</varname> is set appropriately.
+ Possible error codes are:</para>
+
+ <variablelist>
+ <varlistentry>
+ <term><errorcode>EACCES</errorcode></term>
+ <listitem>
+ <para>The requested access to the file is not allowed.</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><errorcode>EMFILE</errorcode></term>
+ <listitem>
+ <para>The process already has the maximum number of files open.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><errorcode>ENFILE</errorcode></term>
+ <listitem>
+ <para>The system limit on the total number of open files has been
+ reached.</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><errorcode>ENOMEM</errorcode></term>
+ <listitem>
+ <para>Insufficient kernel memory was available.</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><errorcode>ENXIO</errorcode></term>
+ <listitem>
+ <para>No device corresponding to this device special file exists.
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ </refsect1>
+</refentry>