1.\" 2.\" SPDX-License-Identifier: BSD-2-Clause 3.\" 4.\" Copyright (c) 2020 Andriy Gapon <avg@FreeBSD.org> 5.\" 6.\" Redistribution and use in source and binary forms, with or without 7.\" modification, are permitted provided that the following conditions 8.\" are met: 9.\" 1. Redistributions of source code must retain the above copyright 10.\" notice, this list of conditions and the following disclaimer. 11.\" 2. Redistributions in binary form must reproduce the above copyright 12.\" notice, this list of conditions and the following disclaimer in the 13.\" documentation and/or other materials provided with the distribution. 14.\" 15.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 16.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 17.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 18.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 19.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 20.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 21.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 22.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 23.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 24.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 25.\" SUCH DAMAGE. 26.\" 27.Dd August 5, 2020 28.Dt GPIOKEYS 4 29.Os 30.Sh NAME 31.Nm gpiokeys 32.Nd GPIO keys device driver 33.Sh SYNOPSIS 34To compile this driver into the kernel, 35place the following lines in your 36kernel configuration file: 37.Bd -ragged -offset indent 38.Cd "options FDT" 39.Cd "device gpio" 40.Cd "device gpiokeys" 41.Ed 42.Pp 43Alternatively, to load the driver as a 44module at boot time, place the following line in 45.Xr loader.conf 5 : 46.Bd -literal -offset indent 47gpiokeys_load="YES" 48.Ed 49.Sh DESCRIPTION 50The 51.Nm 52driver provides a way to represent a set of general purpose inputs as a 53.Xr keyboard 4 54device. 55At the moment the driver supports only 56.Xr FDT 4 57based systems. 58The DTS determines what pins are mapped to buttons and what key codes are 59generated for each virtual button. 60The 61.Xr keyboard 4 62device can be used from userland to monitor for input changes. 63.Pp 64On an 65.Xr FDT 4 66based system 67the DTS part for a 68.Nm 69device usually looks like: 70.Bd -literal 71/ { 72 73 ... 74 75 gpio_keys { 76 compatible = "gpio-keys"; 77 78 btn1 { 79 label = "button1"; 80 linux,code = <KEY_1>; 81 gpios = <&gpio 0 3 GPIO_ACTIVE_LOW> 82 }; 83 84 btn2 { 85 label = "button2"; 86 linux,code = <KEY_2>; 87 gpios = <&gpio 0 4 GPIO_ACTIVE_LOW> 88 }; 89 }; 90}; 91.Ed 92.Pp 93For more details about the 94.Va gpios 95property, please consult 96.Pa /usr/src/sys/dts/bindings-gpio.txt . 97.Pp 98The 99.Nm 100driver supports two properties for specifying a key code. 101.Pp 102The property 103.Va freebsd,code 104specifies a 105.Fx 106native scancode compatible with 107.Xr kbdmap 5 108keyboard maps. 109.Pp 110The property 111.Va linux,code 112specifies an evdev scancode. 113That scancode is internally translated to a native scancode. 114Note that not all evdev scancodes have corresponding native scancodes. 115If a scancode cannot be translated, then a diagnostic message is printed 116and the input is ignored. 117.Pp 118The property 119.Va label 120is a descriptive name of a button. 121It is used for diagnostic messages only. 122This property is optional. 123If not set, the node name is used in its place. 124.Pp 125The property 126.Va autorepeat 127determines whether autorepeat is enabled for a button. 128.Pp 129The property 130.Va debounce-interval 131defines debouncing interval time in milliseconds. 132If not specified the interval defaults to 5. 133.Sh SEE ALSO 134.Xr fdt 4 , 135.Xr gpio 4 , 136.Xr keyboard 4 , 137.Xr kbdmap 5 138.Sh HISTORY 139The 140.Nm 141manual page first appeared in 142.Fx 12.2 . 143.Sh AUTHORS 144The 145.Nm 146driver was written by 147.An Oleksandr Tymoshenko Aq Mt gonzo@FreeBSD.org . 148This 149manual page was written by 150.An Andriy Gapon Aq Mt avg@FreeBSD.org . 151