Documentation/DocBook/media/v4l/vidioc-dbg-g-chip-ident.xml - kernel/msm-4.19 - Gitiles

 <refentry id="vidioc-dbg-g-chip-ident">
   <refmeta>
     <refentrytitle>ioctl VIDIOC_DBG_G_CHIP_IDENT</refentrytitle>
     &manvol;
   </refmeta>

   <refnamediv>
     <refname>VIDIOC_DBG_G_CHIP_IDENT</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_ident
 *<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_IDENT</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>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-ident;
 and call <constant>VIDIOC_DBG_G_CHIP_IDENT</constant> with a pointer to
 this structure. On success the driver stores information about the
 selected chip in the <structfield>ident</structfield> and
 <structfield>revision</structfield> fields. On failure the structure
 remains unchanged.</para>

     <para>When <structfield>match.type</structfield> is
 <constant>V4L2_CHIP_MATCH_HOST</constant>,
 <structfield>match.addr</structfield> selects the nth non-&i2c; 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_IDENT</constant> fails with an &EINVAL;.
 The number zero always selects the host chip, &eg; the chip connected
 to the PCI or USB bus.</para>

     <para>When <structfield>match.type</structfield> is
 <constant>V4L2_CHIP_MATCH_I2C_DRIVER</constant>,
 <structfield>match.name</structfield> contains the I2C driver name.
 For instance
 <constant>"saa7127"</constant> will match any chip
 supported by the saa7127 driver, regardless of its &i2c; bus address.
 When multiple chips supported by the same driver are present, the
 ioctl will return <constant>V4L2_IDENT_AMBIGUOUS</constant> in the
 <structfield>ident</structfield> field.</para>

     <para>When <structfield>match.type</structfield> is
 <constant>V4L2_CHIP_MATCH_I2C_ADDR</constant>,
 <structfield>match.addr</structfield> selects a chip by its 7 bit
 &i2c; bus address.</para>

     <para>When <structfield>match.type</structfield> is
 <constant>V4L2_CHIP_MATCH_AC97</constant>,
 <structfield>match.addr</structfield> selects the nth AC97 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_IDENT</constant> fails with an &EINVAL;.</para>

     <para>On success, the <structfield>ident</structfield> field will
 contain a chip ID from the Linux
 <filename>media/v4l2-chip-ident.h</filename> header file, and the
 <structfield>revision</structfield> field will contain a driver
 specific value, or zero if no particular revision is associated with
 this chip.</para>

     <para>When the driver could not identify the selected chip,
 <structfield>ident</structfield> will contain
 <constant>V4L2_IDENT_UNKNOWN</constant>. When no chip matched
 the ioctl will succeed but the
 <structfield>ident</structfield> field will contain
 <constant>V4L2_IDENT_NONE</constant>. If multiple chips matched,
 <structfield>ident</structfield> will contain
 <constant>V4L2_IDENT_AMBIGUOUS</constant>. In all these cases the
 <structfield>revision</structfield> field remains unchanged.</para>

     <para>This ioctl is optional, not all drivers may support it. It
 was introduced in Linux 2.6.21, but the API was changed to the
 one described here in 2.6.29.</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="ident-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="ident-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-ident">
       <title>struct <structname>v4l2_dbg_chip_ident</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="ident-v4l2-dbg-match" />.</entry>
 	  </row>
 	  <row>
 	    <entry>__u32</entry>
 	    <entry><structfield>ident</structfield></entry>
 	    <entry>A chip identifier as defined in the Linux
 <filename>media/v4l2-chip-ident.h</filename> header file, or one of
 the values from <xref linkend="chip-ids" />.</entry>
 	  </row>
 	  <row>
 	    <entry>__u32</entry>
 	    <entry><structfield>revision</structfield></entry>
 	    <entry>A chip revision, chip and driver specific.</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="ident-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.</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.</entry>
 	  </row>
 	  <row>
 	    <entry><constant>V4L2_CHIP_MATCH_AC97</constant></entry>
 	    <entry>3</entry>
 	    <entry>Match the nth anciliary AC97 chip.</entry>
 	  </row>
 	  <row>
 	    <entry><constant>V4L2_CHIP_MATCH_SUBDEV</constant></entry>
 	    <entry>4</entry>
 	    <entry>Match the nth sub-device. Can't be used with this ioctl.</entry>
 	  </row>
 	</tbody>
       </tgroup>
     </table>

     <!-- This is an anonymous enum in media/v4l2-chip-ident.h. -->
     <table pgwide="1" frame="none" id="chip-ids">
       <title>Chip Identifiers</title>
       <tgroup cols="3">
 	&cs-def;
 	<tbody valign="top">
 	  <row>
 	    <entry><constant>V4L2_IDENT_NONE</constant></entry>
 	    <entry>0</entry>
 	    <entry>No chip matched.</entry>
 	  </row>
 	  <row>
 	    <entry><constant>V4L2_IDENT_AMBIGUOUS</constant></entry>
 	    <entry>1</entry>
 	    <entry>Multiple chips matched.</entry>
 	  </row>
 	  <row>
 	    <entry><constant>V4L2_IDENT_UNKNOWN</constant></entry>
 	    <entry>2</entry>
 	    <entry>A chip is present at this address, but the driver
 could not identify it.</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.</para>
 	</listitem>
       </varlistentry>
      </variablelist>
   </refsect1>
 </refentry>
	<refentry id="vidioc-dbg-g-chip-ident">
	<refmeta>
	<refentrytitle>ioctl VIDIOC_DBG_G_CHIP_IDENT</refentrytitle>
	&manvol;
	</refmeta>

	<refnamediv>
	<refname>VIDIOC_DBG_G_CHIP_IDENT</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_ident
	*<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_IDENT</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>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-ident;
	and call <constant>VIDIOC_DBG_G_CHIP_IDENT</constant> with a pointer to
	this structure. On success the driver stores information about the
	selected chip in the <structfield>ident</structfield> and
	<structfield>revision</structfield> fields. On failure the structure
	remains unchanged.</para>

	<para>When <structfield>match.type</structfield> is
	<constant>V4L2_CHIP_MATCH_HOST</constant>,
	<structfield>match.addr</structfield> selects the nth non-&i2c; 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_IDENT</constant> fails with an &EINVAL;.
	The number zero always selects the host chip, &eg; the chip connected
	to the PCI or USB bus.</para>

	<para>When <structfield>match.type</structfield> is
	<constant>V4L2_CHIP_MATCH_I2C_DRIVER</constant>,
	<structfield>match.name</structfield> contains the I2C driver name.
	For instance
	<constant>"saa7127"</constant> will match any chip
	supported by the saa7127 driver, regardless of its &i2c; bus address.
	When multiple chips supported by the same driver are present, the
	ioctl will return <constant>V4L2_IDENT_AMBIGUOUS</constant> in the
	<structfield>ident</structfield> field.</para>

	<para>When <structfield>match.type</structfield> is
	<constant>V4L2_CHIP_MATCH_I2C_ADDR</constant>,
	<structfield>match.addr</structfield> selects a chip by its 7 bit
	&i2c; bus address.</para>

	<para>When <structfield>match.type</structfield> is
	<constant>V4L2_CHIP_MATCH_AC97</constant>,
	<structfield>match.addr</structfield> selects the nth AC97 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_IDENT</constant> fails with an &EINVAL;.</para>

	<para>On success, the <structfield>ident</structfield> field will
	contain a chip ID from the Linux
	<filename>media/v4l2-chip-ident.h</filename> header file, and the
	<structfield>revision</structfield> field will contain a driver
	specific value, or zero if no particular revision is associated with
	this chip.</para>

	<para>When the driver could not identify the selected chip,
	<structfield>ident</structfield> will contain
	<constant>V4L2_IDENT_UNKNOWN</constant>. When no chip matched
	the ioctl will succeed but the
	<structfield>ident</structfield> field will contain
	<constant>V4L2_IDENT_NONE</constant>. If multiple chips matched,
	<structfield>ident</structfield> will contain
	<constant>V4L2_IDENT_AMBIGUOUS</constant>. In all these cases the
	<structfield>revision</structfield> field remains unchanged.</para>

	<para>This ioctl is optional, not all drivers may support it. It
	was introduced in Linux 2.6.21, but the API was changed to the
	one described here in 2.6.29.</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="ident-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="ident-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-ident">
	<title>struct <structname>v4l2_dbg_chip_ident</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="ident-v4l2-dbg-match" />.</entry>
	</row>
	<row>
	<entry>__u32</entry>
	<entry><structfield>ident</structfield></entry>
	<entry>A chip identifier as defined in the Linux
	<filename>media/v4l2-chip-ident.h</filename> header file, or one of
	the values from <xref linkend="chip-ids" />.</entry>
	</row>
	<row>
	<entry>__u32</entry>
	<entry><structfield>revision</structfield></entry>
	<entry>A chip revision, chip and driver specific.</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="ident-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.</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.</entry>
	</row>
	<row>
	<entry><constant>V4L2_CHIP_MATCH_AC97</constant></entry>
	<entry>3</entry>
	<entry>Match the nth anciliary AC97 chip.</entry>
	</row>
	<row>
	<entry><constant>V4L2_CHIP_MATCH_SUBDEV</constant></entry>
	<entry>4</entry>
	<entry>Match the nth sub-device. Can't be used with this ioctl.</entry>
	</row>
	</tbody>
	</tgroup>
	</table>

	<!-- This is an anonymous enum in media/v4l2-chip-ident.h. -->
	<table pgwide="1" frame="none" id="chip-ids">
	<title>Chip Identifiers</title>
	<tgroup cols="3">
	&cs-def;
	<tbody valign="top">
	<row>
	<entry><constant>V4L2_IDENT_NONE</constant></entry>
	<entry>0</entry>
	<entry>No chip matched.</entry>
	</row>
	<row>
	<entry><constant>V4L2_IDENT_AMBIGUOUS</constant></entry>
	<entry>1</entry>
	<entry>Multiple chips matched.</entry>
	</row>
	<row>
	<entry><constant>V4L2_IDENT_UNKNOWN</constant></entry>
	<entry>2</entry>
	<entry>A chip is present at this address, but the driver
	could not identify it.</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.</para>
	</listitem>
	</varlistentry>
	</variablelist>
	</refsect1>
	</refentry>