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 July 30, 2016 28.Dt GPIOLED 4 29.Os 30.Sh NAME 31.Nm gpioled 32.Nd GPIO LED generic 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 "device gpio" 39.Cd "device gpioled" 40.Ed 41.Sh DESCRIPTION 42The 43.Nm 44driver provides glue to attach a 45.Xr led 4 46compatible device to a GPIO pin. 47Each LED in the system has a 48.Pa name 49which is used to export a device as 50.Pa /dev/led/<name> . 51The GPIO pin can then be controlled by writing to this device as described 52in 53.Xr led 4 . 54.Pp 55On a 56.Xr device.hints 5 57based system, like 58.Li MIPS , 59these values are configurable for 60.Nm : 61.Bl -tag -width ".Va hint.gpioiic.%d.atXXX" 62.It Va hint.gpioled.%d.at 63The gpiobus you are attaching to. 64Normally assigned to gpiobus0. 65.It Va hint.gpioled.%d.name 66Arbitrary name of device in 67.Pa /dev/led/ 68to create for 69.Xr led 4 . 70.It Va hint.gpioled.%d.pins 71Which pin on the GPIO interface to map to this instance. 72Please note that this mask should only ever have one bit set 73(any other bits - i.e., pins - will be ignored). 74.It Va hint.gpioled.%d.invert 75If set to 1, the pin will be set to 0 to light the LED, and 1 to clear it. 76.El 77.Pp 78On a 79.Xr FDT 4 80based system, like 81.Li ARM , 82the DTS part for a 83.Nm gpioled 84device usually looks like: 85.Bd -literal 86gpio: gpio { 87 88 gpio-controller; 89 ... 90 91 led0 { 92 compatible = "gpioled"; 93 gpios = <&gpio 16 2 0>; /* GPIO pin 16. */ 94 name = "ok"; 95 }; 96 97 led1 { 98 compatible = "gpioled"; 99 gpios = <&gpio 17 2 0>; /* GPIO pin 17. */ 100 name = "user-led1"; 101 }; 102}; 103.Ed 104.Pp 105Optionally, you can choose to combine all the LEDs under a single 106.Dq gpio-leds 107compatible node: 108.Bd -literal 109simplebus0 { 110 111 ... 112 113 leds { 114 compatible = "gpio-leds"; 115 116 led0 { 117 gpios = <&gpio 16 2 0>; 118 name = "ok" 119 }; 120 121 led1 { 122 gpios = <&gpio 17 2 0>; 123 name = "user-led1" 124 }; 125 }; 126}; 127.Ed 128.Pp 129Both methods are equally supported and it is possible to have the LEDs 130defined with any sort of mix between the methods. 131The only restriction is that a GPIO pin cannot be mapped by two different 132(gpio)leds. 133.Pp 134For more details about the 135.Va gpios 136property, please consult 137.Pa /usr/src/sys/dts/bindings-gpio.txt . 138.Pp 139The property 140.Va name 141is the arbitrary name of the device in 142.Pa /dev/led/ 143to create for 144.Xr led 4 . 145.Sh SEE ALSO 146.Xr fdt 4 , 147.Xr gpio 4 , 148.Xr gpioiic 4 , 149.Xr led 4 150.Sh HISTORY 151The 152.Nm 153manual page first appeared in 154.Fx 10.1 . 155.Sh AUTHORS 156This 157manual page was written by 158.An Luiz Otavio O Souza . 159