91 lines
2.9 KiB
Groff
91 lines
2.9 KiB
Groff
.\"
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.\" Copyright (c) 2018 Ian Lepore <ian@freebsd.org>
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.\" All rights reserved.
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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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.\"
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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 ``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 AUTHOR 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 July 9, 2018
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.Dt IMX_SPI 4
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.Os
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.Sh NAME
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.Nm imx_spi
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.Nd device driver for the NXP i.MX family Serial Peripheral Interface (SPI)
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.Sh SYNOPSIS
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To compile this driver into the kernel,
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place the following line in your
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kernel configuration file:
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.Bd -ragged -offset indent
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.Cd "device imx_spi"
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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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imx_spi_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 the
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.Sq ECSPI
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(Enhanced Configurable SPI) hardware present on the NXP i.MX family
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of processors.
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While the ECSPI hardware supports both master and slave mode,
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this driver currently operates only in master mode.
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.Pp
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Due to hardware quirks, the
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.Nm
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driver requires that all chip select pins be configured as GPIO pins.
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Use the FDT property
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.Sq cs-gpios
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to specify which pins to use as chip selects.
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You may use any GPIO pins, including the ones that the hardware would
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normally use as SPI select pins; just configure them as GPIO in the
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.Xr fdt_pinctrl 4
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data.
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.Pp
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.Sh SYSCTL VARIABLES
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The following variables are available via
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.Xr sysctl 8 ,
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and as
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.Xr loader 8
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tunables:
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.Bl -tag -width indent
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.It Va dev.imx_spi.%d.debug
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Output debugging info when non-zero.
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A value of 1 displays information about bus transfers,
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2 adds information about bus clock frequency and chip select activity,
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and 3 adds information about interrupt handling.
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.El
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.Sh SEE ALSO
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.Xr fdt 4 ,
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.Xr fdt_pinctrl 4 ,
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.Xr sysctl 8
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.Sh HISTORY
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The
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.Nm
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driver first appeared in
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.Fx 12.0 .
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