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<html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=ANSI_X3.4-1968" /><title>PCI Entries</title><meta name="generator" content="DocBook XSL Stylesheets V1.75.2" /><link rel="home" href="index.html" title="Writing an ALSA Driver" /><link rel="up" href="ch04.html" title="Chapter 4. PCI Resource Management" /><link rel="prev" href="ch04s04.html" title="Registration of Device Struct" /><link rel="next" href="ch05.html" title="Chapter 5. PCM Interface" /></head><body><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">PCI Entries</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="ch04s04.html">Prev</a> </td><th width="60%" align="center">Chapter 4. PCI Resource Management</th><td width="20%" align="right"> <a accesskey="n" href="ch05.html">Next</a></td></tr></table><hr /></div><div class="section" title="PCI Entries"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a id="pci-resource-entries"></a>PCI Entries</h2></div></div></div><p>
So far, so good. Let's finish the missing PCI
stuff. At first, we need a
<span class="structname">pci_device_id</span> table for this
chipset. It's a table of PCI vendor/device ID number, and some
masks.
</p><p>
For example,
</p><div class="informalexample"><pre class="programlisting">
static struct pci_device_id snd_mychip_ids[] = {
{ PCI_VENDOR_ID_FOO, PCI_DEVICE_ID_BAR,
PCI_ANY_ID, PCI_ANY_ID, 0, 0, 0, },
....
{ 0, }
};
MODULE_DEVICE_TABLE(pci, snd_mychip_ids);
</pre></div><p>
</p><p>
The first and second fields of
the <span class="structname">pci_device_id</span> structure are the vendor and
device IDs. If you have no reason to filter the matching
devices, you can leave the remaining fields as above. The last
field of the <span class="structname">pci_device_id</span> struct contains
private data for this entry. You can specify any value here, for
example, to define specific operations for supported device IDs.
Such an example is found in the intel8x0 driver.
</p><p>
The last entry of this list is the terminator. You must
specify this all-zero entry.
</p><p>
Then, prepare the <span class="structname">pci_driver</span> record:
</p><div class="informalexample"><pre class="programlisting">
static struct pci_driver driver = {
.name = "My Own Chip",
.id_table = snd_mychip_ids,
.probe = snd_mychip_probe,
.remove = __devexit_p(snd_mychip_remove),
};
</pre></div><p>
</p><p>
The <em class="structfield"><code>probe</code></em> and
<em class="structfield"><code>remove</code></em> functions have already
been defined in the previous sections.
The <em class="structfield"><code>remove</code></em> function should
be defined with the
<code class="function">__devexit_p()</code> macro, so that it's not
defined for built-in (and non-hot-pluggable) case. The
<em class="structfield"><code>name</code></em>
field is the name string of this device. Note that you must not
use a slash <span class="quote">“<span class="quote">/</span>”</span> in this string.
</p><p>
And at last, the module entries:
</p><div class="informalexample"><pre class="programlisting">
static int __init alsa_card_mychip_init(void)
{
return pci_register_driver(&driver);
}
static void __exit alsa_card_mychip_exit(void)
{
pci_unregister_driver(&driver);
}
module_init(alsa_card_mychip_init)
module_exit(alsa_card_mychip_exit)
</pre></div><p>
</p><p>
Note that these module entries are tagged with
<em class="parameter"><code>__init</code></em> and
<em class="parameter"><code>__exit</code></em> prefixes, not
<em class="parameter"><code>__devinit</code></em> nor
<em class="parameter"><code>__devexit</code></em>.
</p><p>
Oh, one thing was forgotten. If you have no exported symbols,
you need to declare it in 2.2 or 2.4 kernels (it's not necessary in 2.6 kernels).
</p><div class="informalexample"><pre class="programlisting">
EXPORT_NO_SYMBOLS;
</pre></div><p>
That's all!
</p></div><div class="navfooter"><hr /><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="ch04s04.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="ch04.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="ch05.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">Registration of Device Struct </td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top"> Chapter 5. PCM Interface</td></tr></table></div></body></html>
