9312900f6d
The pwm subsystem consist of API for PWM controllers, pwmbus to register them and a pwm(8) utility to talk to them from userland. Reviewed by: oshgobo (capsicum), bcr (manpage), 0mp (manpage) Differential Revision: https://reviews.freebsd.org/D17938
99 lines
4.1 KiB
Groff
99 lines
4.1 KiB
Groff
.\" Copyright (c) 2018 Emmanuel Vadot <manu@freebsd.org>
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE DEVELOPERS ``AS IS'' AND ANY EXPRESS OR
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.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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.\" IN NO EVENT SHALL THE DEVELOPERS BE LIABLE FOR ANY DIRECT, INDIRECT,
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.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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.\"
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.\" $FreeBSD$
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.\"
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.Dd November 12, 2018
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.Dt PWMBUS 9
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.Os
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.Sh NAME
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.Nm pwmbus ,
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.Nm pwmbus_attach_bus ,
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.Nm PWMBUS_GET_BUS ,
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.Nm PWMBUS_CHANNEL_CONFIG ,
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.Nm PWMBUS_CHANNEL_GET_CONFIG ,
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.Nm PWMBUS_CHANNEL_SET_FLAGS ,
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.Nm PWMBUS_CHANNEL_GET_FLAGS ,
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.Nm PWMBUS_CHANNEL_ENABLE ,
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.Nm PWMBUS_CHANNEL_IS_ENABLED ,
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.Nm PWMBUS_CHANNEL_MAX
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.Nd PWMBUS methods
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.Sh SYNOPSIS
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.Cd "device pwm"
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.In "pwmbus_if.h"
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.Ft device_t
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.Fn pwmbus_attach_bus "device_t dev"
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.Ft int
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.Fn PWMBUS_CHANNEL_CONFIG "device_t bus" "int channel" "uint64_t period" "uint64_t duty"
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.Ft int
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.Fn PWMBUS_CHANNEL_GET_CONFIG "device_t bus" "int channel" "uint64_t *period" "uint64_t *duty"
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.Ft int
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.Fn PWMBUS_CHANNEL_SET_FLAGS "device_t bus" "int channel" "uint32_t flags"
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.Ft int
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.Fn PWMBUS_CHANNEL_GET_FLAGS "device_t bus" "int channel" "uint32_t *flags"
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.Ft int
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.Fn PWMBUS_CHANNEL_ENABLE "device_t bus" "int channel" "bool enable"
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.Ft int
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.Fn PWMBUS_CHANNEL_IS_ENABLED "device_t bus" "int channel" "bool *enabled"
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.Ft int
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.Fn PWMBUS_CHANNEL_MAX "device_t bus" "int channel" "int *nchannel"
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.Sh DESCRIPTION
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The PWMBUS (Pulse-Width Modulation) interface allows the device driver to register to a global
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bus so other devices in the kernel can use them in a generic way
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.Sh INTERFACE
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.Bl -tag -width indent
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.It Fn pwmbus_attach_bus "device_t dev"
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Attach the
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.Nm pwmbus
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to the device driver
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.It Fn PWMBUS_CHANNEL_CONFIG "device_t bus" "int channel" "uint64_t period" "uint64_t duty"
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Configure the period and duty (in nanoseconds) in the PWM controller on the bus for the specified channel.
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Returns 0 on success or
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.Er EINVAL
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is the values are not supported by the controller or
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.Er EBUSY
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is the PWMBUS controller is in use and doesn't support changing the value on the fly.
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.It Fn PWMBUS_CHANNEL_GET_CONFIG "device_t bus" "int channel" "uint64_t *period" "uint64_t *duty"
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Get the current configuration of the period and duty for the specified channel.
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.It Fn PWMBUS_CHANNEL_SET_FLAGS "device_t bus" "int channel" "uint32_t flags"
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Set the flags of the channel (like inverted polarity), if the driver or controller
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doesn't support this a default method is used.
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.It Fn PWMBUS_CHANNEL_GET_FLAGS "device_t bus" "int channel" "uint32_t *flags"
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Get the current flags for the channel, if the driver or controller
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doesn't support this, a default method is used.
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.It Fn PWMBUS_CHANNEL_ENABLE "device_t bus" "int channel" "bool enable"
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Enable the PWM channel.
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.It Fn PWMBUS_CHANNEL_ISENABLED "device_t bus" "int channel" "bool *enable"
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Test if the PWM channel is enabled.
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.It PWMBUS_CHANNEL_MAX "device_t bus" "int channel" "int *nchannel"
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Get the maximum number of channel supported by the controller.
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.El
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.Sh HISTORY
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The
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.Nm pwmbus
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interface first appear in
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.Fx 13.0 .
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The
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.Nm pwmbus
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interface and manual page was written by
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.An Emmanuel Vadot Aq Mt manu@FreeBSD.org .
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