88 lines
3.0 KiB
Groff
88 lines
3.0 KiB
Groff
.\"
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.\" SPDX-License-Identifier: BSD-2-Clause-FreeBSD
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.\"
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.\" Copyright (c) 2020 Andriy Gapon <avg@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 AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" $FreeBSD$
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.\"
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.Dd August 12, 2020
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.Dt CP2112 4
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.Os
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.Sh NAME
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.Nm cp2112
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.Nd driver for a USB GPIO and I2C peripheral device
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.Sh SYNOPSIS
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To compile this driver into the kernel,
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place the following lines in your
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kernel configuration file:
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.Bd -ragged -offset indent
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.Cd "device cp2112"
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.Cd "device usb"
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.Cd "device gpio"
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.Cd "device iicbus"
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.Ed
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.Pp
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Alternatively, to load the driver as a
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module at boot time, place the following line in
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.Xr loader.conf 5 :
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.Bd -literal -offset indent
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cp2112_load="YES"
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.Ed
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.Sh DESCRIPTION
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The
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.Nm
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driver provides support for Silicon Labs CP2112 device.
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The device has 8 general purpose I/O pins and an I2C controller that supports
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a subset of the I2C protocol.
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.Pp
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All pins support both input and output modes.
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An output pin can be configured either for open-drain or push-pull operation.
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Pins 0, 1 and 7 support special functions: I2C transmit indication,
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I2C receive indication and clock output respectively.
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At the moment the
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.Nm
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driver does not provide a way to enable and configure the special functions.
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.Pp
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The I2C controller supports read transactions with up to 512 bytes of data,
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write transactions with up to 61 bytes of data and a write followed by
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the repeated start followed by a read transactions where the write can be
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up to 16 bytes and the read can be up to 512 bytes.
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Zero length transfers are not supported.
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The
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.Nm
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driver creates a
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.Xr gpio 4
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and
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.Xr iicbus 4
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child buses to expose the respective functions.
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.Sh SEE ALSO
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.Xr gpio 4 ,
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.Xr iicbus 4 ,
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.Xr usb 4
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.Sh HISTORY
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The
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.Nm
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driver and this manual page was written by
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.An Andriy Gapon Aq Mt avg@FreeBSD.org .
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