pca954x: driver for PCA954x / TCA954x I2C switches
At the moment only PCA9548A is supported and has been tested. MFC after: 2 weeks
This commit is contained in:
Andriy Gapon
parent
01e3492337
commit
c0525ab1d1
@ -418,6 +418,7 @@ MAN= aac.4 \
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owc.4 \
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${_padlock.4} \
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pass.4 \
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pca954x.4 \
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pccard.4 \
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pccbb.4 \
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pcf.4 \
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119
share/man/man4/pca954x.4
Normal file
119
share/man/man4/pca954x.4
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@ -0,0 +1,119 @@
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.\"
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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 November 13, 2021
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.Dt PCA954X 4
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.Os
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.Sh NAME
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.Nm pca954x
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.Nd driver for PCA9548A I2C switch
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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 pca954x"
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.Cd "device iicmux"
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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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pca954x_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 supports the PCA9548A I2C bus switch and compatible chips such as
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TCA9548A.
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It automatically connects an upstream I2C bus to one of several downstream
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buses as needed when slave devices on the downstream buses initiate I/O.
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More information on the automatic switching behavior is available in
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.Xr iicmux 4 .
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.Sh FDT CONFIGURATION
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On an
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.Xr FDT 4
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based system, an
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.Nm
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device node is defined as a child node of its upstream I2C bus.
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The children of the
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.Nm
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node are additional I2C buses, which will have their own I2C slave
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devices described in their child nodes.
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.Pp
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The
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.Nm
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driver attaches to nodes where the
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.Va compatible
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property is set to one of
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.Bl -bullet
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.It
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.Qq nxp,pca9548
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.El
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.Pp
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The
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.Nm
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driver supports the following optional properties in addition to the standard
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I2C mux properties:
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.Bl -tag -width i2c-mux-idle-disconnect
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.It Va i2c-mux-idle-disconnect
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if defined, forces the switch to disconnect all children in idle state.
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.El
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.Sh HINTS CONFIGURATION
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On a
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.Xr device.hints 5
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based system, these values are configurable for
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.Nm :
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.Bl -tag -width hint.pca954x.<unit>.chip_type
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.It Va hint.pca954x.<unit>.at
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The upstream
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.Xr iicbus 4
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the
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.Nm
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instance is attached to.
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.It Va hint.pca954x.<unit>.chip_type
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The type of the chip.
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At present, only
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.Qq pca9548
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is supported.
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.El
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.Pp
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When configured via hints, the driver automatically adds an
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.Xr iicbus 4
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instance for every downstream bus supported by the chip.
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There is currently no way to indicate used versus unused channels.
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.Sh SEE ALSO
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.Xr iicbus 4 ,
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.Xr iicmux 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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@ -1855,6 +1855,7 @@ dev/iicbus/mux/iicmux.c optional iicmux
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dev/iicbus/mux/iicmux_if.m optional iicmux
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dev/iicbus/mux/iic_gpiomux.c optional iic_gpiomux fdt
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dev/iicbus/mux/ltc430x.c optional ltc430x
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dev/iicbus/mux/pca954x.c optional pca954x
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dev/iicbus/nxprtc.c optional nxprtc | pcf8563
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dev/iicbus/ofw_iicbus.c optional fdt iicbus
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dev/iicbus/pcf8574.c optional pcf8574
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214
sys/dev/iicbus/mux/pca954x.c
Normal file
214
sys/dev/iicbus/mux/pca954x.c
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@ -0,0 +1,214 @@
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/*-
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* SPDX-License-Identifier: BSD-2-Clause
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*
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* Copyright (c) Andriy Gapon
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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 FOR
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* 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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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include "opt_platform.h"
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#include <sys/param.h>
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#include <sys/bus.h>
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#include <sys/kernel.h>
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#include <sys/module.h>
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#include <sys/systm.h>
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#ifdef FDT
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#include <dev/ofw/ofw_bus.h>
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#include <dev/ofw/ofw_bus_subr.h>
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#include <dev/ofw/openfirm.h>
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#endif
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#include <dev/iicbus/iicbus.h>
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#include <dev/iicbus/iiconf.h>
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#include "iicbus_if.h"
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#include "iicmux_if.h"
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#include <dev/iicbus/mux/iicmux.h>
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struct pca954x_descr {
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const char *partname;
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const char *description;
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int numchannels;
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};
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static struct pca954x_descr pca9548_descr = {
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.partname = "pca9548",
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.description = "PCA9548A I2C Mux",
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.numchannels = 8,
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};
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#ifdef FDT
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static struct ofw_compat_data compat_data[] = {
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{ "nxp,pca9548", (uintptr_t)&pca9548_descr },
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{ NULL, 0 },
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};
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#else
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static struct pca954x_descr *part_descrs[] = {
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&pca9548_descr,
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};
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#endif
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struct pca954x_softc {
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struct iicmux_softc mux;
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uint8_t addr;
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bool idle_disconnect;
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};
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static int
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pca954x_bus_select(device_t dev, int busidx, struct iic_reqbus_data *rd)
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{
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struct iic_msg msg;
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struct pca954x_softc *sc = device_get_softc(dev);
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uint8_t busbits;
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int error;
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/*
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* The iicmux caller ensures busidx is between 0 and the number of buses
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* we passed to iicmux_init_softc(), no need for validation here. If
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* the fdt data has the idle_disconnect property we idle the bus by
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* selecting no downstream buses, otherwise we just leave the current
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* bus active.
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*/
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if (busidx == IICMUX_SELECT_IDLE) {
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if (sc->idle_disconnect)
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busbits = 0;
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else
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return (0);
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} else {
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busbits = 1u << busidx;
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}
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msg.slave = sc->addr;
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msg.flags = IIC_M_WR;
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msg.len = 1;
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msg.buf = &busbits;
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error = iicbus_transfer(dev, &msg, 1);
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return (error);
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}
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static const struct pca954x_descr *
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pca954x_find_chip(device_t dev)
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{
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#ifdef FDT
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const struct ofw_compat_data *compat;
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compat = ofw_bus_search_compatible(dev, compat_data);
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if (compat == NULL)
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return (NULL);
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return ((const struct pca954x_descr *)compat->ocd_data);
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#else
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const char *type;
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int i;
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if (resource_string_value(device_get_name(dev), device_get_unit(dev),
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"chip_type", &type) == 0) {
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for (i = 0; i < nitems(part_descrs) - 1; ++i) {
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if (strcasecmp(type, part_descrs[i]->partname) == 0)
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return (part_descrs[i]);
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}
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}
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return (NULL);
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#endif
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}
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static int
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pca954x_probe(device_t dev)
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{
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const struct pca954x_descr *descr;
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descr = pca954x_find_chip(dev);
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if (descr == NULL)
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return (ENXIO);
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device_set_desc(dev, descr->description);
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return (BUS_PROBE_DEFAULT);
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}
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static int
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pca954x_attach(device_t dev)
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{
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#ifdef FDT
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phandle_t node;
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#endif
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struct pca954x_softc *sc;
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const struct pca954x_descr *descr;
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int err;
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sc = device_get_softc(dev);
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sc->addr = iicbus_get_addr(dev);
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#ifdef FDT
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node = ofw_bus_get_node(dev);
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sc->idle_disconnect = OF_hasprop(node, "i2c-mux-idle-disconnect");
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#endif
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descr = pca954x_find_chip(dev);
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err = iicmux_attach(dev, device_get_parent(dev), descr->numchannels);
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if (err == 0)
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bus_generic_attach(dev);
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return (err);
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}
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static int
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pca954x_detach(device_t dev)
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{
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int err;
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err = iicmux_detach(dev);
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return (err);
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}
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static device_method_t pca954x_methods[] = {
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/* device methods */
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DEVMETHOD(device_probe, pca954x_probe),
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DEVMETHOD(device_attach, pca954x_attach),
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DEVMETHOD(device_detach, pca954x_detach),
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/* iicmux methods */
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DEVMETHOD(iicmux_bus_select, pca954x_bus_select),
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DEVMETHOD_END
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};
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static devclass_t pca954x_devclass;
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DEFINE_CLASS_1(pca9548, pca954x_driver, pca954x_methods,
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sizeof(struct pca954x_softc), iicmux_driver);
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DRIVER_MODULE(pca9548, iicbus, pca954x_driver, pca954x_devclass, 0, 0);
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#ifdef FDT
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DRIVER_MODULE(ofw_iicbus, pca9548, ofw_iicbus_driver, ofw_iicbus_devclass, 0, 0);
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#else
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DRIVER_MODULE(iicbus, pca9548, iicbus_driver, iicbus_devclass, 0, 0);
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#endif
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MODULE_DEPEND(pca9548, iicmux, 1, 1, 1);
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MODULE_DEPEND(pca9548, iicbus, IICBUS_MINVER, IICBUS_PREFVER, IICBUS_MAXVER);
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MODULE_VERSION(pca9548, 1);
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#ifdef FDT
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IICBUS_FDT_PNP_INFO(compat_data);
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#endif
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@ -3,6 +3,7 @@
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SUBDIR = \
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iicmux \
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ltc430x \
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pca954x \
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.if !empty(OPT_FDT)
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SUBDIR+= iic_gpiomux
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20
sys/modules/i2c/mux/pca954x/Makefile
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20
sys/modules/i2c/mux/pca954x/Makefile
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@ -0,0 +1,20 @@
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# $FreeBSD$
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.PATH: ${SRCTOP}/sys/dev/iicbus/mux
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KMOD= pca954x
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SRCS= pca954x.c
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SRCS+= \
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bus_if.h \
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device_if.h \
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iicbus_if.h \
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iicmux_if.h \
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opt_platform.h \
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.if !empty(OPT_FDT)
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SRCS+= ofw_bus_if.h
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.endif
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.include <bsd.kmod.mk>
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