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 <gonzo@FreeBSD.org>.  This manual
     page was written by
     Andriy Gapon <avg@FreeBSD.org>.