1.\" Copyright (c) 2013, Luiz Otavio O Souza <loos@FreeBSD.org> 2.\" All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in the 11.\" documentation and/or other materials provided with the distribution. 12.\" 13.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 14.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 15.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 16.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 17.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 18.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 19.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 20.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 21.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 22.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 23.\" SUCH DAMAGE. 24.\" 25.\" $FreeBSD$ 26.\" 27.Dd February 13, 2014 28.Dt GPIOLED 4 29.Os 30.Sh NAME 31.Nm gpioled 32.Nd GPIO led generic device driver 33.Sh SYNOPSIS 34.Cd "device gpio" 35.Cd "device gpioled" 36.Pp 37This driver attaches a 38.Xr led 4 39device to a GPIO pin. 40.Sh DESCRIPTION 41The 42.Em gpioled 43driver provides a glue to attach a 44.Xr led 4 45compatible device to a GPIO pin. 46Each led on the system has a 47.Pa name 48which is used to export a device in 49.Pa /dev/led/<name> . 50The GPIO pin can then be controlled by writing to this device as described 51on 52.Xr led 4 . 53.Pp 54On a hint based system, like 55.Li MIPS , these values are configureable for 56.Nm : 57.Bl -tag -width ".Va hint.gpioiic.%d.atXXX" 58.It Va hint.gpioled.%d.at 59The gpiobus you are attaching to. 60Normally assigned to gpiobus0. 61.It Va hint.gpioled.%d.name 62Arbitrary name of device in 63.Pa /dev/led/ 64to create for 65.Xr led 4 . 66.It Va hint.gpioled.%d.pins 67Which pin on the GPIO interface to map to this instance. 68Please note that this mask should only ever have one bit set 69(any others bits - i.e., pins - will be ignored). 70.El 71.Pp 72On a 73.Xr FDT 4 74based system, like 75.Li ARM , the dts part for a 76.Nm gpioled 77device usually looks like: 78.Bd -literal 79gpio: gpio { 80 81 gpio-controller; 82 ... 83 84 led0 { 85 compatible = "gpioled"; 86 gpios = <&gpio 16 2 0>; /* GPIO pin 16. */ 87 name = "ok"; 88 }; 89 90 led1 { 91 compatible = "gpioled"; 92 gpios = <&gpio 17 2 0>; /* GPIO pin 17. */ 93 name = "user-led1"; 94 }; 95}; 96.Ed 97.Pp 98And optionally, you can choose combine all the leds under a single 99.Dq gpio-leds 100compatible node: 101.Bd -literal 102simplebus0 { 103 104 ... 105 106 leds { 107 compatible = "gpio-leds"; 108 109 led0 { 110 gpios = <&gpio 16 2 0>; 111 name = "ok" 112 }; 113 114 led1 { 115 gpios = <&gpio 17 2 0>; 116 name = "user-led1" 117 }; 118 }; 119}; 120.Ed 121.Pp 122Both methods are equally supported and it is possible to have the leds 123defined with any sort of mix between the methods. 124The only restriction is that a GPIO pin cannot be mapped by two different 125(gpio)leds. 126.Pp 127For more details about the 128.Va gpios 129property, please consult 130.Pa /usr/src/sys/boot/fdt/dts/bindings-gpio.txt . 131.Pp 132The property 133.Va name 134is the arbitrary name of device in 135.Pa /dev/led/ 136to create for 137.Xr led 4 . 138.Sh SEE ALSO 139.Xr fdt 4 , 140.Xr gpio 4 , 141.Xr led 4 , 142.Xr gpioiic 4 143.Sh HISTORY 144The 145.Nm 146manual page first appeared in 147.Fx 11.0 . 148.Sh AUTHORS 149This 150manual page was written by 151.An Luiz Otavio O Souza . 152