Index: head/share/man/man4/man4.arm/bcm283x_pwm.4 =================================================================== --- head/share/man/man4/man4.arm/bcm283x_pwm.4 (revision 338573) +++ head/share/man/man4/man4.arm/bcm283x_pwm.4 (revision 338574) @@ -1,97 +1,110 @@ .\" .\" SPDX-License-Identifier: BSD-2-Clause-FreeBSD .\" .\" Copyright (c) 2017 Poul-Henning Kamp .\" All rights reserved. .\" .\" 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 ``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 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 January 22, 2017 +.Dd September 10, 2018 .Dt BCM283X_PWM 4 .Os .Sh NAME .Nm bcm283x_pwm .Nd bcm283x_pwm - driver for Raspberry Pi 2/3 PWM .Sh SYNOPSIS .Cd "kldload bcm283x_clkman" .Cd "kldload bcm283x_pwm" .Sh DESCRIPTION The .Nm -driver provides access to the PWM engine on GPIO12 of Rpi 2 and 3 hardware. +driver provides access to the PWM engine on GPIO12 of Raspberry Pi 2 and 3 hardware. .Pp The PWM hardware is controlled via the .Xr sysctl 8 interface: .Bd -literal dev.pwm.0.mode: 1 +dev.pwm.0.mode2: 1 dev.pwm.0.freq: 125000000 dev.pwm.0.ratio: 2500 +dev.pwm.0.ratio2: 2500 dev.pwm.0.period: 10000 +dev.pwm.0.period2: 10000 dev.pwm.0.pwm_freq: 12500 +dev.pwm.0.pwm_freq2: 12500 .Ed -.Bl -tag -width ".Va dev.pwm.0.mode" -.It Va dev.pwm.0.mode +.Bl -tag -width ".Va dev.pwm" +.It Va dev.pwm.0.mode , dev.pwm.0.mode2 +PWM Mode for channels 1 and 2. Three modes exist, 0=off, 1=PWM, 2=N/M. The N/M mode is a first order delta-sigma mode, which makes a quite handy DAC output with a trivial RC lowpass filter. .Pp .It Va dev.pwm.0.freq The input frequency to the PWM hardware in Hz. -Minmum frequency is 123 kHz, maximum frequency is 125 MHz. -.It Va dev.pwm.0.period +Applies to both channels 1 and 2. +Minimum frequency is 123 kHz, maximum frequency is 125 MHz. +.It Va dev.pwm.0.period , dev.pwm.0.period2 The period length in cycles. -In PWM mode, the output frequency will be +In PWM mode, the output frequencies will be ( .Va dev.pwm.0.freq / -.Va dev.pwm.0.period . -) -In N/M mode this is the 'M' -.It Va dev.pwm.0.ratio -The "on" period in cycles. +.Va dev.pwm.period +) and ( +.Va dev.pwm.0.freq2 +/ +.Va dev.pwm.0.period2 +). +In N/M mode this is the 'M'. +.It Va dev.pwm.0.ratio , dev.pwm.0.ratio2 +The "on" period in cycles for PWM channels 1 and 2. In PWM mode, to get a 25% dutycycle, set this to 25% of -.Va dev.pwm.0.period . -In N/M mode this is the 'N' -.It Va dev.pwm.0.pwm_freq -The calculated PWM output frequency in PWM mode. +.Va dev.pwm.0.period +or +.Va dev.pwm.0.period2 , +as appropriate. +In N/M mode this is the 'N'. +.It Va dev.pwm.0.pwm_freq , dev.pwm.0.pwm_freq2 +The calculated PWM output frequencies in PWM mode, for channels 1 and 2. .El .Pp .Sh NOTES Currently the .Nm driver ignores the 'status="disabled"' flag in the DTB, assuming that if you load the driver, you want it to work. .Sh SEE ALSO .Xr sysctl 8 .Sh HISTORY The .Nm driver first appeared in .Fx 12.0 . .Sh AUTHORS .An -nosplit The .Nm driver and this manual page were written by .An Poul-Henning Kamp Aq Mt phk@FreeBSD.org .