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<table class="head">
<tr>
<td class="head-ltitle">OWC(4)</td>
<td class="head-vol">Device Drivers Manual</td>
<td class="head-rtitle">OWC(4)</td>
</tr>
</table>
<div class="manual-text">
<section class="Sh">
<h1 class="Sh" id="NAME"><a class="permalink" href="#NAME">NAME</a></h1>
<p class="Pp"><code class="Nm">owc</code> — <span class="Nd">Dallas
Semiconductor 1-Wire Controller</span></p>
</section>
<section class="Sh">
<h1 class="Sh" id="SYNOPSIS"><a class="permalink" href="#SYNOPSIS">SYNOPSIS</a></h1>
<p class="Pp"><code class="Cd">device owc</code></p>
</section>
<section class="Sh">
<h1 class="Sh" id="DESCRIPTION"><a class="permalink" href="#DESCRIPTION">DESCRIPTION</a></h1>
<p class="Pp">The <code class="Nm">owc</code> module implements Dallas
Semiconductor 1-Wire signaling. It attaches the <a class="Xr">ow(4)</a>
driver 1-Wire bus protocol. The <code class="Nm">owc</code> device
implements the Link Layer of the 1-Wire bus protocol stack.</p>
<p class="Pp">Bit banging a pin on a <a class="Xr">gpiobus(4)</a> is the only
supported controller. Both standard and overdrive transfer timings are
implemented. Strong pull-up functionality needed to support parasitic mode
is not implemented.</p>
<p class="Pp">To enable 1-Wire for FDT systems requires modifying the DTS for
your board to add something like:</p>
<div class="Bd Pp Li">
<pre>/ {
...
onewire {
compatible = "w1-gpio";
gpios = <&gpio 4 1>;
};
...
};</pre>
</div>
<p class="Pp">The gpios property describes the GPIO pin the 1-Wire bus is
connected to. For more details about the <var class="Va">gpios</var>
property, please consult
<span class="Pa">/usr/src/sys/dts/bindings-gpio.txt</span>.</p>
<p class="Pp">On a <a class="Xr">device.hints(5)</a> based system these values
are required for the <code class="Nm">owc</code>:</p>
<dl class="Bl-tag">
<dt id="hint.owc._d.at"><var class="Va">hint.owc.%d.at</var></dt>
<dd>The <code class="Nm">gpiobus</code> you are attaching to.</dd>
<dt id="hint.owc._d.pins"><var class="Va">hint.owc.%d.pins</var></dt>
<dd>This is a bitmask that defines a pin on the
<code class="Nm">gpiobus</code> that is to be used for the 1-Wire bus. For
instance, to configure pin 10, use the bitmask of 0x400. Please note that
this mask should have only one bit set (any other bits - i.e., pins - will
be ignored).</dd>
</dl>
</section>
<section class="Sh">
<h1 class="Sh" id="SEE_ALSO"><a class="permalink" href="#SEE_ALSO">SEE
ALSO</a></h1>
<p class="Pp"><a class="Xr">gpiobus(4)</a>, <a class="Xr">ow(4)</a>,
<a class="Xr">ow_temp(4)</a>, <a class="Xr">owll(9)</a>,
<a class="Xr">own(9)</a></p>
</section>
<section class="Sh">
<h1 class="Sh" id="LEGAL"><a class="permalink" href="#LEGAL">LEGAL</a></h1>
<p class="Pp">1-Wire is a registered trademark of Maxim Integrated Products,
Inc.</p>
</section>
<section class="Sh">
<h1 class="Sh" id="HISTORY"><a class="permalink" href="#HISTORY">HISTORY</a></h1>
<p class="Pp">The <code class="Nm">owc</code> driver first appeared in
<span class="Ux">FreeBSD 11.0</span>.</p>
</section>
<section class="Sh">
<h1 class="Sh" id="AUTHORS"><a class="permalink" href="#AUTHORS">AUTHORS</a></h1>
<p class="Pp">The <code class="Nm">owc</code> device driver and this manual page
were written by <span class="An">Warner Losh</span>.</p>
</section>
<section class="Sh">
<h1 class="Sh" id="CAVEATS"><a class="permalink" href="#CAVEATS">CAVEATS</a></h1>
<p class="Pp">The gpio driver implements timing by busy waiting, which can cause
a high load on slower systems.</p>
</section>
<section class="Sh">
<h1 class="Sh" id="BUGS"><a class="permalink" href="#BUGS">BUGS</a></h1>
<p class="Pp">Overdrive mode has not actually been tested.</p>
</section>
</div>
<table class="foot">
<tr>
<td class="foot-date">June 26, 2019</td>
<td class="foot-os">FreeBSD 15.0</td>
</tr>
</table>
|
