GPIOKEYS(4) FreeBSD Kernel Interfaces Manual GPIOKEYS(4)
NAME
gpiokeys - GPIO keys device driver
SYNOPSIS
To compile this driver into the kernel, place the following lines in your
kernel configuration file:
options FDT
device gpio
device gpiokeys
Alternatively, to load the driver as a module at boot time, place the
following line in loader.conf(5):
gpiokeys_load="YES"
DESCRIPTION
The gpiokeys driver provides a way to represent a set of general purpose
inputs as a keyboard(4) device. At the moment the driver supports only
FDT(4) based systems. The DTS determines what pins are mapped to buttons
and what key codes are generated for each virtual button. The
keyboard(4) device can be used from userland to monitor for input
changes.
On an FDT(4) based system the DTS part for a gpiokeys device usually
looks like:
/ {
...
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>
};
};
};
For more details about the gpios property, please consult
/usr/src/sys/dts/bindings-gpio.txt.
The gpiokeys driver supports two properties for specifying a key code.
The property freebsd,code specifies a FreeBSD native scancode compatible
with kbdmap(5) keyboard maps.
The property linux,code 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.
The property label 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.
The property autorepeat determines whether autorepeat is enabled for a
button.
The property debounce-interval defines debouncing interval time in
milliseconds. If not specified the interval defaults to 5.
SEE ALSO
fdt(4), gpio(4), keyboard(4), kbdmap(5)
HISTORY
The gpiokeys manual page first appeared in FreeBSD 12.2.
AUTHORS
The gpiokeys driver was written by Oleksandr Tymoshenko
<
[email protected]>. This manual page was written by
Andriy Gapon <
[email protected]>.
FreeBSD 14.1-RELEASE-p8 August 5, 2020 FreeBSD 14.1-RELEASE-p8