1.\" Copyright (c) 2018 Emmanuel Vadot <manu@freebsd.org> 2.\" 3.\" Redistribution and use in source and binary forms, with or without 4.\" modification, are permitted provided that the following conditions 5.\" are met: 6.\" 1. Redistributions of source code must retain the above copyright 7.\" notice, this list of conditions and the following disclaimer. 8.\" 2. Redistributions in binary form must reproduce the above copyright 9.\" notice, this list of conditions and the following disclaimer in the 10.\" documentation and/or other materials provided with the distribution. 11.\" 12.\" THIS SOFTWARE IS PROVIDED BY THE DEVELOPERS ``AS IS'' AND ANY EXPRESS OR 13.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 14.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 15.\" IN NO EVENT SHALL THE DEVELOPERS BE LIABLE FOR ANY DIRECT, INDIRECT, 16.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 17.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 18.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 19.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 20.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 21.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 22.\" 23.\" $FreeBSD$ 24.\" 25.Dd June 17, 2019 26.Dt PWM 8 27.Os 28.Sh NAME 29.Nm pwm 30.Nd configure PWM (Pulse Width Modulation) hardware 31.Sh SYNOPSIS 32.Nm 33.Op Fl f Ar device 34.Fl C 35.Nm 36.Op Fl f Ar device 37.Op Fl D | Fl E 38.Op Fl p Ar period 39.Op Fl d Ar duty 40.Sh DESCRIPTION 41The 42.Nm 43utility can be used to configure pwm hardware. 44.Nm 45uses a 46.Xr pwmc 4 47device to communicate with the hardware. 48Some PWM hardware supports multiple output channels within a single 49controller block; each 50.Xr pwmc 4 51instance controls a single PWM channel. 52.Pp 53.Xr pwmc 4 54devices are named 55.Pa /dev/pwm/pwmcX.Y , 56where 57.Va X 58is the controller unit number and 59.Va Y 60is the channel number within that unit. 61.Pp 62The options are as follows: 63.Bl -tag -width "-f device" 64.It Fl f Ar device 65Device to operate on. 66If not specified, 67.Pa /dev/pwm/pwmc0.0 68is used. 69If an unqualified name is provided, 70.Pa /dev/pwm 71is automatically prepended. 72.It Fl C 73Show the configuration of the PWM channel. 74.It Fl D 75Disable the PWM channel. 76.It Fl d Ar duty 77Configure the duty cycle (in nanoseconds or percentage) of the PWM channel. 78Duty is the portion of the 79.Ar period 80during which the signal is asserted. 81.It Fl E 82Enable the PWM channel. 83.It Fl p Ar period 84Configure the period (in nanoseconds) of the PWM channel. 85.El 86.Sh EXAMPLES 87.Bl -bullet 88.It 89Show the configuration of the PWM channel: 90.Bd -literal 91pwm -f /dev/pwm/pwmc0.1 -C 92.Ed 93.It 94Configure a 50000 ns period and a 25000 ns duty cycle 95and enable the channel: 96.Bd -literal 97pwm -f pwmc1.1 -E -p 50000 -d 25000 98.Ed 99.It 100Configure a 50% duty cycle on the device and channel which 101were configured in 102.Xr pwmc 4 103to have the label 104.Pa backlight : 105.Bd -literal 106pwm -f backlight -d 50% 107.Ed 108.El 109.Sh SEE ALSO 110.Xr pwm 9 , 111.Xr pwmbus 9 112.Sh HISTORY 113The 114.Nm 115utility appeared in 116.Fx 13.0 . 117.Sh AUTHORS 118.An -nosplit 119The 120.Nm 121utility and this manual page were written by 122.An Emmanuel Vadot Aq Mt manu@FreeBSD.org . 123