From 75050aa9af786305be9e70a1ac79cdcc031641f5 Mon Sep 17 00:00:00 2001 From: Andriy Gapon Date: Wed, 5 Aug 2020 11:38:33 +0000 Subject: [PATCH] gpiokeys: add a basic manual page Reviewed by: manu, bjk, 0mp MFC after: 1 week Differential Revision: https://reviews.freebsd.org/D25939 --- share/man/man4/gpiokeys.4 | 152 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 152 insertions(+) create mode 100644 share/man/man4/gpiokeys.4 diff --git a/share/man/man4/gpiokeys.4 b/share/man/man4/gpiokeys.4 new file mode 100644 index 000000000000..5af11cedb7e0 --- /dev/null +++ b/share/man/man4/gpiokeys.4 @@ -0,0 +1,152 @@ +.\" +.\" SPDX-License-Identifier: BSD-2-Clause-FreeBSD +.\" +.\" Copyright (c) 2020 Andriy Gapon +.\" +.\" Redistribution and use in source and binary forms, with or without +.\" modification, are permitted provided that the following conditions +.\" are met: +.\" 1. Redistributions of source code must retain the above copyright +.\" notice, this list of conditions and the following disclaimer. +.\" 2. Redistributions in binary form must reproduce the above copyright +.\" notice, this list of conditions and the following disclaimer in the +.\" documentation and/or other materials provided with the distribution. +.\" +.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND +.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE +.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE +.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE +.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL +.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS +.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) +.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT +.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY +.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF +.\" SUCH DAMAGE. +.\" +.\" $FreeBSD$ +.\" +.Dd August 5, 2020 +.Dt GPIOKEYS 4 +.Os +.Sh NAME +.Nm gpiokeys +.Nd GPIO keys device driver +.Sh SYNOPSIS +To compile this driver into the kernel, +place the following lines in your +kernel configuration file: +.Bd -ragged -offset indent +.Cd "options FDT" +.Cd "device gpio" +.Cd "device gpiokeys" +.Ed +.Pp +Alternatively, to load the driver as a +module at boot time, place the following line in +.Xr loader.conf 5 : +.Bd -literal -offset indent +gpiokeys_load="YES" +.Ed +.Sh DESCRIPTION +The +.Nm +driver provides a way to represent a set of general purpose inputs as a +.Xr keyboard 4 +device. +At the moment the driver supports only +.Xr FDT 4 +based systems. +The DTS determines what pins are mapped to buttons and what key codes are +generated for each virtual button. +The +.Xr keyboard 4 +device can be used from userland to monitor for input changes. +.Pp +On an +.Xr FDT 4 +based system +the DTS part for a +.Nm +device usually looks like: +.Bd -literal +/ { + + ... + + gpio_keys { + compatible = "gpio-keys"; + + btn1 { + label = "button1"; + linux,code = ; + gpios = <&gpio 0 3 GPIO_ACTIVE_LOW> + }; + + btn2 { + label = "button2"; + linux,code = ; + gpios = <&gpio 0 4 GPIO_ACTIVE_LOW> + }; + }; +}; +.Ed +.Pp +For more details about the +.Va gpios +property, please consult +.Pa /usr/src/sys/dts/bindings-gpio.txt . +.Pp +The +.Nm +driver supports two properties for specifying a key code. +.Pp +The property +.Va freebsd,code +specifies a +.Fx +native scancode compatible with +.Xr kbdmap 5 +keyboard maps. +.Pp +The property +.Va 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. +.Pp +The property +.Va 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. +.Pp +The property +.Va autorepeat +determines whether autorepeat is enabled for a button. +.Pp +The property +.Va debounce-interval +defines debouncing interval time in milliseconds. +If not specified the interval defaults to 5. +.Sh SEE ALSO +.Xr fdt 4 , +.Xr gpio 4 , +.Xr keyboard 4 , +.Xr kbdmap 5 +.Sh HISTORY +The +.Nm +manual page first appeared in +.Fx 12.2 . +.Sh AUTHORS +The +.Nm +driver was written by +.An Oleksandr Tymoshenko Aq Mt gonzo@FreeBSD.org . +This +manual page was written by +.An Andriy Gapon Aq Mt avg@FreeBSD.org .