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<table class="head">
<tr>
<td class="head-ltitle">GPIOKEYS(4)</td>
<td class="head-vol">Device Drivers Manual</td>
<td class="head-rtitle">GPIOKEYS(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">gpiokeys</code> — <span class="Nd">GPIO
keys device driver</span></p>
</section>
<section class="Sh">
<h1 class="Sh" id="SYNOPSIS"><a class="permalink" href="#SYNOPSIS">SYNOPSIS</a></h1>
<p class="Pp">To compile this driver into the kernel, place the following lines
in your kernel configuration file:</p>
<div class="Bd Pp Bd-indent"><code class="Cd">options FDT</code>
<br/>
<code class="Cd">device gpio</code>
<br/>
<code class="Cd">device gpiokeys</code></div>
<p class="Pp">Alternatively, to load the driver as a module at boot time, place
the following line in <a class="Xr">loader.conf(5)</a>:</p>
<div class="Bd Pp Bd-indent Li">
<pre>gpiokeys_load="YES"</pre>
</div>
</section>
<section class="Sh">
<h1 class="Sh" id="DESCRIPTION"><a class="permalink" href="#DESCRIPTION">DESCRIPTION</a></h1>
<p class="Pp">The <code class="Nm">gpiokeys</code> driver provides a way to
represent a set of general purpose inputs as a <a class="Xr">keyboard(4)</a>
device. At the moment the driver supports only <a class="Xr">FDT(4)</a>
based systems. The DTS determines what pins are mapped to buttons and what
key codes are generated for each virtual button. The
<a class="Xr">keyboard(4)</a> device can be used from userland to monitor
for input changes.</p>
<p class="Pp">On an <a class="Xr">FDT(4)</a> based system the DTS part for a
<code class="Nm">gpiokeys</code> device usually looks like:</p>
<div class="Bd Pp Li">
<pre>/ {
...
gpio_keys {
compatible = "gpio-keys";
btn1 {
label = "button1";
linux,code = <KEY_1>;
gpios = <&gpio 0 3 GPIO_ACTIVE_LOW>
};
btn2 {
label = "button2";
linux,code = <KEY_2>;
gpios = <&gpio 0 4 GPIO_ACTIVE_LOW>
};
};
};</pre>
</div>
<p class="Pp">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">The <code class="Nm">gpiokeys</code> driver supports two
properties for specifying a key code.</p>
<p class="Pp">The property <var class="Va">freebsd,code</var> specifies a
<span class="Ux">FreeBSD</span> native scancode compatible with
<a class="Xr">kbdmap(5)</a> keyboard maps.</p>
<p class="Pp">The property <var class="Va">linux,code</var> specifies an evdev
scancode. That scancode is internally translated to a native scancode. Note
that not all evdev scancodes have corresponding native scancodes. If a
scancode cannot be translated, then a diagnostic message is printed and the
input is ignored.</p>
<p class="Pp">The property <var class="Va">label</var> is a descriptive name of
a button. It is used for diagnostic messages only. This property is
optional. If not set, the node name is used in its place.</p>
<p class="Pp">The property <var class="Va">autorepeat</var> determines whether
autorepeat is enabled for a button.</p>
<p class="Pp">The property <var class="Va">debounce-interval</var> defines
debouncing interval time in milliseconds. If not specified the interval
defaults to 5.</p>
</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">fdt(4)</a>, <a class="Xr">gpio(4)</a>,
<a class="Xr">keyboard(4)</a>, <a class="Xr">kbdmap(5)</a></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">gpiokeys</code> manual page first appeared in
<span class="Ux">FreeBSD 12.2</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">gpiokeys</code> driver was written by
<span class="An">Oleksandr Tymoshenko</span>
<<a class="Mt" href="mailto:gonzo@FreeBSD.org">gonzo@FreeBSD.org</a>>.
This manual page was written by
<br/>
<span class="An">Andriy Gapon</span>
<<a class="Mt" href="mailto:avg@FreeBSD.org">avg@FreeBSD.org</a>>.</p>
</section>
</div>
<table class="foot">
<tr>
<td class="foot-date">August 5, 2020</td>
<td class="foot-os">FreeBSD 15.0</td>
</tr>
</table>
|
