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Diffstat (limited to 'Documentation/DocBook/media/v4l/vidioc-dbg-g-chip-info.xml')
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diff --git a/Documentation/DocBook/media/v4l/vidioc-dbg-g-chip-info.xml b/Documentation/DocBook/media/v4l/vidioc-dbg-g-chip-info.xml new file mode 100644 index 000000000000..e1cece6c5de1 --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-dbg-g-chip-info.xml @@ -0,0 +1,223 @@ +<refentry id="vidioc-dbg-g-chip-info"> + <refmeta> + <refentrytitle>ioctl VIDIOC_DBG_G_CHIP_INFO</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>VIDIOC_DBG_G_CHIP_INFO</refname> + <refpurpose>Identify the chips on a TV card</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_dbg_chip_info +*<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_DBG_G_CHIP_INFO</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>argp</parameter></term> + <listitem> + <para></para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <note> + <title>Experimental</title> + + <para>This is an <link +linkend="experimental">experimental</link> interface and may change in +the future.</para> + </note> + + <para>For driver debugging purposes this ioctl allows test +applications to query the driver about the chips present on the TV +card. Regular applications must not use it. When you found a chip +specific bug, please contact the linux-media mailing list (&v4l-ml;) +so it can be fixed.</para> + + <para>Additionally the Linux kernel must be compiled with the +<constant>CONFIG_VIDEO_ADV_DEBUG</constant> option to enable this ioctl.</para> + + <para>To query the driver applications must initialize the +<structfield>match.type</structfield> and +<structfield>match.addr</structfield> or <structfield>match.name</structfield> +fields of a &v4l2-dbg-chip-info; +and call <constant>VIDIOC_DBG_G_CHIP_INFO</constant> with a pointer to +this structure. On success the driver stores information about the +selected chip in the <structfield>name</structfield> and +<structfield>flags</structfield> fields. On failure the structure +remains unchanged.</para> + + <para>When <structfield>match.type</structfield> is +<constant>V4L2_CHIP_MATCH_BRIDGE</constant>, +<structfield>match.addr</structfield> selects the nth bridge 'chip' +on the TV card. You can enumerate all chips by starting at zero and +incrementing <structfield>match.addr</structfield> by one until +<constant>VIDIOC_DBG_G_CHIP_INFO</constant> fails with an &EINVAL;. +The number zero always selects the bridge chip itself, ⪚ the chip +connected to the PCI or USB bus. Non-zero numbers identify specific +parts of the bridge chip such as an AC97 register block.</para> + + <para>When <structfield>match.type</structfield> is +<constant>V4L2_CHIP_MATCH_SUBDEV</constant>, +<structfield>match.addr</structfield> selects the nth sub-device. This +allows you to enumerate over all sub-devices.</para> + + <para>On success, the <structfield>name</structfield> field will +contain a chip name and the <structfield>flags</structfield> field will +contain <constant>V4L2_CHIP_FL_READABLE</constant> if the driver supports +reading registers from the device or <constant>V4L2_CHIP_FL_WRITABLE</constant> +if the driver supports writing registers to the device.</para> + + <para>We recommended the <application>v4l2-dbg</application> +utility over calling this ioctl directly. It is available from the +LinuxTV v4l-dvb repository; see <ulink +url="http://linuxtv.org/repo/">http://linuxtv.org/repo/</ulink> for +access instructions.</para> + + <!-- Note for convenience vidioc-dbg-g-register.sgml + contains a duplicate of this table. --> + <table pgwide="1" frame="none" id="name-v4l2-dbg-match"> + <title>struct <structname>v4l2_dbg_match</structname></title> + <tgroup cols="4"> + &cs-ustr; + <tbody valign="top"> + <row> + <entry>__u32</entry> + <entry><structfield>type</structfield></entry> + <entry>See <xref linkend="name-chip-match-types" /> for a list of +possible types.</entry> + </row> + <row> + <entry>union</entry> + <entry>(anonymous)</entry> + </row> + <row> + <entry></entry> + <entry>__u32</entry> + <entry><structfield>addr</structfield></entry> + <entry>Match a chip by this number, interpreted according +to the <structfield>type</structfield> field.</entry> + </row> + <row> + <entry></entry> + <entry>char</entry> + <entry><structfield>name[32]</structfield></entry> + <entry>Match a chip by this name, interpreted according +to the <structfield>type</structfield> field.</entry> + </row> + </tbody> + </tgroup> + </table> + + <table pgwide="1" frame="none" id="v4l2-dbg-chip-info"> + <title>struct <structname>v4l2_dbg_chip_info</structname></title> + <tgroup cols="3"> + &cs-str; + <tbody valign="top"> + <row> + <entry>struct v4l2_dbg_match</entry> + <entry><structfield>match</structfield></entry> + <entry>How to match the chip, see <xref linkend="name-v4l2-dbg-match" />.</entry> + </row> + <row> + <entry>char</entry> + <entry><structfield>name[32]</structfield></entry> + <entry>The name of the chip.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>flags</structfield></entry> + <entry>Set by the driver. If <constant>V4L2_CHIP_FL_READABLE</constant> +is set, then the driver supports reading registers from the device. If +<constant>V4L2_CHIP_FL_WRITABLE</constant> is set, then it supports writing registers.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>reserved[8]</structfield></entry> + <entry>Reserved fields, both application and driver must set these to 0.</entry> + </row> + </tbody> + </tgroup> + </table> + + <!-- Note for convenience vidioc-dbg-g-register.sgml + contains a duplicate of this table. --> + <table pgwide="1" frame="none" id="name-chip-match-types"> + <title>Chip Match Types</title> + <tgroup cols="3"> + &cs-def; + <tbody valign="top"> + <row> + <entry><constant>V4L2_CHIP_MATCH_BRIDGE</constant></entry> + <entry>0</entry> + <entry>Match the nth chip on the card, zero for the + bridge chip. Does not match sub-devices.</entry> + </row> + <row> + <entry><constant>V4L2_CHIP_MATCH_I2C_DRIVER</constant></entry> + <entry>1</entry> + <entry>Match an &i2c; chip by its driver name. Can't be used with this ioctl.</entry> + </row> + <row> + <entry><constant>V4L2_CHIP_MATCH_I2C_ADDR</constant></entry> + <entry>2</entry> + <entry>Match a chip by its 7 bit &i2c; bus address. Can't be used with this ioctl.</entry> + </row> + <row> + <entry><constant>V4L2_CHIP_MATCH_AC97</constant></entry> + <entry>3</entry> + <entry>Match the nth anciliary AC97 chip. Can't be used with this ioctl.</entry> + </row> + <row> + <entry><constant>V4L2_CHIP_MATCH_SUBDEV</constant></entry> + <entry>4</entry> + <entry>Match the nth sub-device.</entry> + </row> + </tbody> + </tgroup> + </table> + </refsect1> + + <refsect1> + &return-value; + + <variablelist> + <varlistentry> + <term><errorcode>EINVAL</errorcode></term> + <listitem> + <para>The <structfield>match_type</structfield> is invalid or +no device could be matched.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> +</refentry> |