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Add support for i2c bus mux hardware.

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An i2c bus can be divided into segments which can be selectively connected
and disconnected from the main bus. This is usually done to enable using
multiple slave devices having the same address, by isolating the devices
onto separate bus segments, only one of which is connected to the main bus
at once.

There are several types of i2c bus muxes, which break down into two general
categories...

 - Muxes which are themselves i2c slaves. These devices respond to i2c
   commands on their upstream bus, and based on those commands, connect
   various downstream buses to the upstream. In newbus terms, they are both
   a child of an iicbus and the parent of one or more iicbus instances.
 - Muxes which are not i2c devices themselves. Such devices are part of the
   i2c bus electrically, but in newbus terms their parent is some other
   bus. The association with the upstream bus must be established by
   separate metadata (such as FDT data).

In both cases, the mux driver has one or more iicbus child instances
representing the downstream buses. The mux driver implements the iicbus_if
interface, as if it were an iichb host bridge/i2c controller driver. It
services the IO requests sent to it by forwarding them to the iicbus
instance representing the upstream bus, after electrically connecting the
upstream bus to the downstream bus that hosts the i2c slave device which
made the IO request.

The net effect is automatic mux switching which is transparent to slaves on
the downstream buses. They just do i2c IO they way they normally do, and the
bus is electrically connected for the duration of the IO and then idled when
it is complete.

The existing iicbus_if callback() method is enhanced so that the parameter
passed to it can be a struct which contains a device_t for the requesting
bus and slave devices. This change is done by adding a flag that indicates
the extra values are present, and making the flags field the first field of
a new args struct. If the flag is set, the iichb or mux driver can recast
the pointer-to-flags into a pointer-to-struct and access the extra
fields. Thus abi compatibility with older drivers is retained (but a mux
cannot exist on the bus with the older iicbus driver in use.)

A new set of core support routines exists in iicbus.c. This code will help
implement mux drivers for any type of mux hardware by supplying all the
boilerplate code that forwards IO requests upstream. It also has code for
parsing metadata and instantiating the child iicbus instances based on it.

Two new hardware mux drivers are added. The ltc430x driver supports the
LTC4305/4306 mux chips which are controlled via i2c commands. The
iic_gpiomux driver supports any mux hardware which is controlled by
manipulating the state of one or more gpio pins.  Test Plan

Tested locally using a variety of mux'd bus configurations involving both
ltc4305 and a homebrew gpio-controlled mux. Tested configurations included
cascaded muxes (unlikely in the real world, but useful to prove that 'it all
just works' in terms of the automatic switching and upstream forwarding of
IO requests).
This commit is contained in:
Ian Lepore 2020-01-02 17:51:49 +00:00
parent 84e404763f
commit 422d05da14
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=356278
18 changed files with 1445 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
share/man/man4/Makefile
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@ -204,8 +204,10 @@ MAN= aac.4 \
ig4.4 \
igmp.4 \
iic.4 \
iic_gpiomux.4 \
iicbb.4 \
iicbus.4 \
iicmux.4 \
iicsmb.4 \
iir.4 \
${_imcsmb.4} \
@ -258,6 +260,7 @@ MAN= aac.4 \
lp.4 \
lpbb.4 \
lpt.4 \
ltc430x.4 \
mac.4 \
mac_biba.4 \
mac_bsdextended.4 \

88
share/man/man4/iic_gpiomux.4 Normal file
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@ -0,0 +1,88 @@
.\"-
.\" SPDX-License-Identifier: BSD-2-Clause
.\"
.\" Copyright (c) 2019 Ian Lepore <ian@freebsd.org>
.\"
.\" 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 AND CONTRIBUTORS ``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 OR CONTRIBUTORS 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 1, 2020
.Dt IIC_GPIOMUX 4
.Os
.Sh NAME
.Nm iic_gpiomux
.Nd driver for I2C mux hardware controlled via GPIO
.Sh SYNOPSIS
To compile this driver into the kernel,
place the following line in your
kernel configuration file:
.Bd -ragged -offset indent
.Cd "device iic_gpiomux"
.Ed
.Pp
Alternatively, to load the driver as a
module at boot time, place the following line in
.Xr loader.conf 5 :
.Bd -literal -offset indent
iic_gpiomux_load="YES"
.Ed
.Sh DESCRIPTION
The
.Nm
driver supports any type of I2C bus multiplexer (mux) hardware that
is controlled by manipulating the state of one or more GPIO pins.
It automatically connects an upstream I2C bus to one of the downstream
buses as needed when slave devices on the downstream buses initiate I/O.
More information on the automatic switching behavior is available in
.Xr iicmux 4 .
.Pp
.Sh FDT CONFIGURATION
On an
.Xr fdt 4
based system, an
.Nm
device node may be defined as a child node of any arbitrary bus
in the FDT data.
The
.Va i2c-parent
property indicates the connection to the upstream I2C bus.
The children of the
.Nm
node are additional i2c buses, which will have their own i2c slave
devices described in their child nodes.
.Pp
The
.Nm
driver conforms to the standard
.Bk -words
.Li i2c/i2c-mux-gpio.txt
.Ek
bindings document.
.Sh SEE ALSO
.Xr iicbus 4 ,
.Xr iicmux 4 ,
.Sh HISTORY
The
.Nm
driver first appeared in
.Fx 13.0 .

148
share/man/man4/iicmux.4 Normal file
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@ -0,0 +1,148 @@
.\"-
.\" SPDX-License-Identifier: BSD-2-Clause
.\"
.\" Copyright (c) 2019 Ian Lepore <ian@freebsd.org>
.\"
.\" 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 AND CONTRIBUTORS ``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 OR CONTRIBUTORS 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 1, 2020
.Dt IICMUX 4
.Os
.Sh NAME
.Nm iicmux
.Nd I2C bus mulitiplexer framework
.Sh SYNOPSIS
To compile this driver into the kernel,
place the following line in your
kernel configuration file:
.Bd -ragged -offset indent
.Cd "device iicmux"
.Ed
.Pp
Alternatively, to load the driver as a
module at boot time, place the following line in
.Xr loader.conf 5 :
.Bd -literal -offset indent
iicmux_load="YES"
.Ed
.Pp
Note that it is usually not necessary to explicitly load the
driver module, as it will be loaded automatically along with
the driver for the specific mux hardware in use.
.Sh DESCRIPTION
The
.Nm
framework provides support code to help implement drivers for various
I2C bus multiplexer (mux) hardware.
.Nm
is not a standalone driver,
it is a collection of support functions and driver methods which are
used by individual mux hardware drivers.
It will be loaded automatically when needed by a mux hardware driver.
This manual page provides an overview of the I2C mux framework and its
behavior.
.Pp
Generally speaking, an I2C mux is connected to an upstream I2C bus, and to
one or more downstream I2C buses, and it can be commanded to connect
any one of the downstream buses to the upstream bus.
Some hardware may be able to connect multiple downstream buses at the
same time, but that concept is not supported by
.Nm .
.Pp
The
.Nm
framework operates automatically when I2C slave devices initiate I/O.
It does not require (or even allow for) any external control to select
the active downstream bus.
.Pp
When there is no I/O in progress, the mux is said to be in the
.Dq idle
state.
Some mux hardware has the ability to disconnect all downstream buses
when in an idle state.
Other hardware must always have one of the downstream buses connected.
Individual mux hardware drivers typically provide a way to select which
downstream bus (if any) should be connected while in the idle state.
In the absence of such configuration, whichever downstream bus was
last used remains connected to the upstream bus.
.Pp
When an I2C slave device on a bus downstream of a mux initiates I/O,
it first requests exclusive use of the bus by calling
.Fn iicbus_request_bus .
This request is communicated to the bus's parent, which is the
.Nm
framework
mux driver.
Once exclusive bus ownership is obtained, the mux driver
connects the upstream I2C bus to the downstream bus which hosts the
slave device that requested bus ownership.
The mux hardware maintains that upstream-to-downstream connection until
the slave device calls
.Fn iicbus_release_bus .
Before releasing ownership, the mux driver returns the mux hardware to
the idle state.
.Sh FDT CONFIGURATION
On an
.Xr fdt 4
based system, an I2C mux device node is defined as a child node of its
upstream I2C bus when the mux device is an I2C slave itself.
It may be defined as a child node of any other bus or device in the
system when it is not an I2C slave, in which case the
.Va i2c-parent
property indicates which upstream bus the mux is attached to.
In either case, the children of the mux node are additional I2C buses, which
will have one or more I2C slave devices described in their child nodes.
.Pp
Drivers using the
.Nm
framework conform to the standard
.Bk -words
.Li i2c/i2c-mux.txt
.Ek
bindings document.
.Sh HINTS CONFIGURATION
On a
.Xr device.hints 5
based system, these values are configurable for
.Nm
framework drivers :
.Bl -tag -width indent
.It Va hint.<driver>.<unit>.at
The upstream
.Xr iicbus 4
the
.Nm
instance is attached to.
.El
.Pp
When configured via hints, the driver automatically adds an iicbus
instance for every downstream bus supported by the chip.
There is currently no way to indicate used versus unused downstream buses.
.Sh SEE ALSO
.Xr iicbus 4 ,
.Sh HISTORY
The
.Nm
framework first appeared in
.Fx 13.0 .

112
share/man/man4/ltc430x.4 Normal file
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@ -0,0 +1,112 @@
.\"-
.\" SPDX-License-Identifier: BSD-2-Clause
.\"
.\" Copyright (c) 2019 Ian Lepore <ian@freebsd.org>
.\"
.\" 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 AND CONTRIBUTORS ``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 OR CONTRIBUTORS 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 1, 2020
.Dt LTC430X 4
.Os
.Sh NAME
.Nm ltc430x
.Nd driver for LTC4305 and LTC4306 I2C mux chips
.Sh SYNOPSIS
To compile this driver into the kernel,
place the following line in your
kernel configuration file:
.Bd -ragged -offset indent
.Cd "device ltc430x"
.Ed
.Pp
Alternatively, to load the driver as a
module at boot time, place the following line in
.Xr loader.conf 5 :
.Bd -literal -offset indent
ltc430x_load="YES"
.Ed
.Sh DESCRIPTION
The
.Nm
driver supports the LTC4305 and LTC4306 I2C bus multiplexer (mux) chips.
It automatically connects an upstream I2C bus to one of several downstream
buses as needed when slave devices on the downstream buses initiate I/O.
More information on the automatic switching behavior is available in
.Xr iicmux 4 .
.Sh FDT CONFIGURATION
On an
.Xr fdt 4
based system, an
.Nm
device node is defined as a child node of its upstream i2c bus.
The children of the
.Nm
node are additional i2c buses, which will have their own i2c slave
devices described in their child nodes.
.Pp
The
.Nm
driver conforms to the standard
.Bk -words
.Li i2c/i2c-mux-ltc4306.txt
.Ek
bindings document, except that the following optional properties
are not currently supported and will be ignored if present:
.Bl -bullet -compact -inset -offset indent
.It
enable-gpios
.It
gpio-controller
.It
#gpio-cells
.It
ltc,downstream-accelerators-enable
.It
ltc,upstream-accelerators-enable
.El
.Sh HINTS CONFIGURATION
On a
.Xr device.hints 5
based system, these values are configurable for
.Nm :
.Bl -tag -width indent
.It Va hint.ltc430x.<unit>.at
The upstream
.Xr iicbus 4
the
.Nm
instance is attached to.
.El
.Pp
When configured via hints, the driver automatically adds an iicbus
instance for every downstream bus supported by the chip.
There is currently no way to indicate used versus unused channels.
.Sh SEE ALSO
.Xr iicbus 4 ,
.Xr iicmux 4 ,
.Sh HISTORY
The
.Nm
driver first appeared in
.Fx 13.0 .

5
sys/conf/NOTES
View File

@ -2329,6 +2329,11 @@ device iic # userland access to i2c slave devices via ioctl(8)
device iicsmb # smb over i2c bridge
device iicoc # OpenCores I2C controller support
# I2C bus multiplexer (mux) devices
device iicmux # i2c mux core driver
device iic_gpiomux # i2c mux hardware controlled via gpio pins
device ltc430x # LTC4305 and LTC4306 i2c mux chips
# I2C peripheral devices
#
device ad7418 # Analog Devices temp and voltage sensor

4
sys/conf/files
View File

@ -1801,6 +1801,10 @@ dev/iicbus/iicoc_fdt.c optional iicoc fdt
dev/iicbus/iicoc_pci.c optional iicoc pci
dev/iicbus/isl12xx.c optional isl12xx
dev/iicbus/lm75.c optional lm75
dev/iicbus/mux/iicmux.c optional iicmux
dev/iicbus/mux/iicmux_if.m optional iicmux
dev/iicbus/mux/iic_gpiomux.c optional iic_gpiomux fdt
dev/iicbus/mux/ltc430x.c optional ltc430x
dev/iicbus/nxprtc.c optional nxprtc | pcf8563
dev/iicbus/ofw_iicbus.c optional fdt iicbus
dev/iicbus/rtc8583.c optional rtc8583

13
sys/dev/iicbus/iiconf.c
View File

@ -137,6 +137,7 @@ iicbus_poll(struct iicbus_softc *sc, int how)
int
iicbus_request_bus(device_t bus, device_t dev, int how)
{
struct iic_reqbus_data reqdata;
struct iicbus_softc *sc = (struct iicbus_softc *)device_get_softc(bus);
int error = 0;
@ -175,8 +176,11 @@ iicbus_request_bus(device_t bus, device_t dev, int how)
*/
IICBUS_UNLOCK(sc);
/* Ask the underlying layers if the request is ok */
reqdata.dev = dev;
reqdata.bus = bus;
reqdata.flags = how | IIC_REQBUS_DEV;
error = IICBUS_CALLBACK(device_get_parent(bus),
IIC_REQUEST_BUS, (caddr_t)&how);
IIC_REQUEST_BUS, (caddr_t)&reqdata);
IICBUS_LOCK(sc);
if (error != 0) {
@ -201,6 +205,7 @@ iicbus_request_bus(device_t bus, device_t dev, int how)
int
iicbus_release_bus(device_t bus, device_t dev)
{
struct iic_reqbus_data reqdata;
struct iicbus_softc *sc = (struct iicbus_softc *)device_get_softc(bus);
IICBUS_LOCK(sc);
@ -213,7 +218,11 @@ iicbus_release_bus(device_t bus, device_t dev)
if (--sc->owncount == 0) {
/* Drop the lock while informing the low-level driver. */
IICBUS_UNLOCK(sc);
IICBUS_CALLBACK(device_get_parent(bus), IIC_RELEASE_BUS, NULL);
reqdata.dev = dev;
reqdata.bus = bus;
reqdata.flags = IIC_REQBUS_DEV;
IICBUS_CALLBACK(device_get_parent(bus), IIC_RELEASE_BUS,
(caddr_t)&reqdata);
IICBUS_LOCK(sc);
sc->owner = NULL;
wakeup_one(sc);

19
sys/dev/iicbus/iiconf.h
View File

@ -47,6 +47,25 @@
#define IIC_INTR 0x2
#define IIC_INTRWAIT (IIC_INTR | IIC_WAIT)
#define IIC_RECURSIVE 0x4
#define IIC_REQBUS_DEV 0x8 /* See struct iic_reqbus_data, below. */
/*
* The original iicbus->bridge callback api took a pointer to an int containing
* flags. The new api allows a pointer to this struct, with IIC_REQBUS_DEV set
* in the flags to let the implementation know the pointer is actually to this
* struct which has the flags word first, followed by the device_t of the
* requesting bus and device.
*
* Note that the requesting device may not be a i2c slave device which is a
* child of the requested bus -- it may be a mux device which is electrically
* part of the bus hierarchy, but whose driver belongs to some other bus
* hierarchy such as gpio.
*/
struct iic_reqbus_data {
int flags; /* Flags from the set defined above. */
device_t bus; /* The iicbus being requested. */
device_t dev; /* The device requesting the bus. */
};
/*
* i2c modes

249
sys/dev/iicbus/mux/iic_gpiomux.c Normal file
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@ -0,0 +1,249 @@
/*-
* SPDX-License-Identifier: BSD-2-Clause
*
* Copyright (c) 2019 Ian Lepore <ian@freebsd.org>
*
* 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 AND CONTRIBUTORS ``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 OR CONTRIBUTORS 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.
*/
/*
* Driver for i2c bus muxes controlled by one or more gpio pins.
*
* This driver has #ifdef FDT sections in it, as if it supports both fdt and
* hinted attachment, but there is currently no support for hinted attachment.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "opt_platform.h"
#include <sys/param.h>
#include <sys/bus.h>
#include <sys/gpio.h>
#include <sys/kernel.h>
#include <sys/module.h>
#include <sys/systm.h>
#include <dev/gpio/gpiobusvar.h>
#include <dev/iicbus/iicbus.h>
#include <dev/iicbus/mux/iicmux.h>
#ifdef FDT
#include <dev/ofw/ofw_bus.h>
#include <dev/ofw/ofw_bus_subr.h>
#include <dev/ofw/openfirm.h>
static struct ofw_compat_data compat_data[] = {
{"i2c-mux-gpio", true},
{NULL, false}
};
OFWBUS_PNP_INFO(compat_data);
SIMPLEBUS_PNP_INFO(compat_data);
#endif /* FDT */
#include <dev/iicbus/iiconf.h>
#include "iicmux.h"
#include "iicmux_if.h"
struct gpiomux_softc {
struct iicmux_softc mux;
int idleidx;
int numpins;
gpio_pin_t pins[IICMUX_MAX_BUSES];
};
#define IDLE_NOOP (-1) /* When asked to idle the bus, do nothing. */
static int
gpiomux_bus_select(device_t dev, int busidx, struct iic_reqbus_data *rd)
{
struct gpiomux_softc *sc = device_get_softc(dev);
int i;
/*
* The iicmux caller ensures busidx is between 0 and the number of buses
* we passed to iicmux_init_softc(), no need for validation here. The
* bits in the index number are transcribed to the state of the pins,
* except when we're asked to idle the bus. In that case, we transcribe
* sc->idleidx to the pins, unless that is IDLE_NOOP (leave the current
* bus selected), in which case we just bail.
*/
if (busidx == IICMUX_SELECT_IDLE) {
if (sc->idleidx == IDLE_NOOP)
return (0);
busidx = sc->idleidx;
}
for (i = 0; i < sc->numpins; ++i)
gpio_pin_set_active(sc->pins[i], busidx & (1u << i));
return (0);
}
static int
gpiomux_probe(device_t dev)
{
int rv;
rv = ENXIO;
#ifdef FDT
if (ofw_bus_status_okay(dev) &&
ofw_bus_search_compatible(dev, compat_data)->ocd_data)
rv = BUS_PROBE_DEFAULT;
#endif
device_set_desc(dev, "I2C GPIO Mux");
return (rv);
}
static int
gpiomux_attach(device_t dev)
{
struct gpiomux_softc *sc = device_get_softc(dev);
ssize_t len;
device_t busdev;
int err, i, idlebits, numchannels;
pcell_t propval;
phandle_t node;
node = ofw_bus_get_node(dev);
/*
* Locate the gpio pin(s) that control the mux hardware. There can be
* multiple pins, but there must be at least one.
*/
for (i = 0; ; ++i) {
err = gpio_pin_get_by_ofw_propidx(dev, node, "mux-gpios", i,
&sc->pins[i]);
if (err != 0) {
break;
}
}
sc->numpins = i;
if (sc->numpins == 0) {
device_printf(dev, "cannot acquire pins listed in mux-gpios\n");
return ((err == 0) ? ENXIO : err);
}
numchannels = 1u << sc->numpins;
if (numchannels > IICMUX_MAX_BUSES) {
device_printf(dev, "too many mux-gpios pins for max %d buses\n",
IICMUX_MAX_BUSES);
return (EINVAL);
}
/*
* We don't have a parent/child relationship to the upstream bus, we
* have to locate it via the i2c-parent property. Explicitly tell the
* user which upstream we're associated with, since the normal attach
* message is going to mention only our actual parent.
*/
len = OF_getencprop(node, "i2c-parent", &propval, sizeof(propval));
if (len != sizeof(propval)) {
device_printf(dev, "cannot obtain i2c-parent property\n");
return (ENXIO);
}
busdev = OF_device_from_xref((phandle_t)propval);
if (busdev == NULL) {
device_printf(dev,
"cannot find device referenced by i2c-parent property\n");
return (ENXIO);
}
device_printf(dev, "upstream bus is %s\n", device_get_nameunit(busdev));
/*
* If there is an idle-state property, that is the value we set the pins
* to when the bus is idle, otherwise idling the bus is a no-op
* (whichever bus was last accessed remains active).
*/
len = OF_getencprop(node, "idle-state", &propval, sizeof(propval));
if (len == sizeof(propval)) {
if ((int)propval >= numchannels) {
device_printf(dev,
"idle-state property %d exceeds channel count\n",
propval);
}
sc->idleidx = (int)propval;
idlebits = sc->idleidx;
} else {
sc->idleidx = IDLE_NOOP;
idlebits = 0;
}
/* Preset the mux to the idle state to get things started. */
for (i = 0; i < sc->numpins; ++i) {
gpio_pin_setflags(sc->pins[i], GPIO_PIN_OUTPUT);
gpio_pin_set_active(sc->pins[i], idlebits & (1u << i));
}
/* Init the core driver, have it add our child downstream buses. */
if ((err = iicmux_attach(dev, busdev, numchannels)) == 0)
bus_generic_attach(dev);
return (err);
}
static int
gpiomux_detach(device_t dev)
{
struct gpiomux_softc *sc = device_get_softc(dev);
int err, i;
if ((err = iicmux_detach(dev)) != 0)
return (err);
for (i = 0; i < sc->numpins; ++i)
gpio_pin_release(sc->pins[i]);
return (0);
}
static device_method_t gpiomux_methods[] = {
/* device methods */
DEVMETHOD(device_probe, gpiomux_probe),
DEVMETHOD(device_attach, gpiomux_attach),
DEVMETHOD(device_detach, gpiomux_detach),
/* iicmux methods */
DEVMETHOD(iicmux_bus_select, gpiomux_bus_select),
DEVMETHOD_END
};
static devclass_t gpiomux_devclass;
DEFINE_CLASS_1(iic_gpiomux, iic_gpiomux_driver, gpiomux_methods,
sizeof(struct gpiomux_softc), iicmux_driver);
DRIVER_MODULE(iic_gpiomux, simplebus, iic_gpiomux_driver, gpiomux_devclass, 0, 0);
DRIVER_MODULE(iic_gpiomux, ofw_simplebus, iic_gpiomux_driver, gpiomux_devclass, 0, 0);
#ifdef FDT
DRIVER_MODULE(ofw_iicbus, iic_gpiomux, ofw_iicbus_driver, ofw_iicbus_devclass, 0, 0);
#else
DRIVER_MODULE(iicbus, iic_gpiomux, iicbus_driver, iicbus_devclass, 0, 0);
#endif
MODULE_DEPEND(iic_gpiomux, iicmux, 1, 1, 1);
MODULE_DEPEND(iic_gpiomux, iicbus, 1, 1, 1);

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/*-
* SPDX-License-Identifier: BSD-2-Clause
*
* Copyright (c) 2019 Ian Lepore <ian@freebsd.org>
*
* 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 AND CONTRIBUTORS ``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 OR CONTRIBUTORS 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.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "opt_platform.h"
#include <sys/param.h>
#include <sys/bus.h>
#include <sys/kernel.h>
#include <sys/module.h>
#include <sys/sysctl.h>
#ifdef FDT
#include <dev/ofw/ofw_bus.h>
#include <dev/ofw/ofw_bus_subr.h>
#include <dev/ofw/openfirm.h>
#endif
#include <dev/iicbus/iiconf.h>
#include "iicbus_if.h"
#include "iicmux_if.h"
#include "iicmux.h"
/*------------------------------------------------------------------------------
* iicbus methods, called by the iicbus functions in iiconf.c.
*
* All these functions return an IIC adapter-layer error code (because we are
* pretending to be a host bridge/i2c controller). Standard errno values
* returned from these must be encoded using iic2errno().
*----------------------------------------------------------------------------*/
static int
iicmux_callback(device_t dev, int index, caddr_t data)
{
struct iicmux_softc *sc = device_get_softc(dev);
struct iic_reqbus_data *rd;
int err, i;
/* If it's not one of the operations we know about, bail early. */
if (index != IIC_REQUEST_BUS && index != IIC_RELEASE_BUS)
return (iic2errno(EOPNOTSUPP));
/*
* Ensure that the data passed to us includes the device_t of the child
* bus and device. If missing, someone bypassed iicbus_request_bus()
* and called this method directly using the old calling standard. If
* present, find the index of the child bus that called us.
*/
rd = (struct iic_reqbus_data *)data;
if (!(rd->flags & IIC_REQBUS_DEV))
return (iic2errno(EINVAL));
for (i = 0; i <= sc->maxbus && sc->childdevs[i] != rd->bus; ++i)
continue;
if (i > sc->maxbus)
return (iic2errno(ENOENT));
/*
* If the operation is a release it "cannot fail". Idle the downstream
* bus, then release exclusive use of the upstream bus, and we're done.
*/
if (index == IIC_RELEASE_BUS) {
if (sc->debugmux > 0) {
device_printf(dev, "idle the bus for %s on bus %s\n",
device_get_nameunit(rd->dev),
device_get_nameunit(rd->bus));
}
IICMUX_BUS_SELECT(dev, IICMUX_SELECT_IDLE, rd);
iicbus_release_bus(sc->busdev, dev);
return (IIC_NOERR);
}
if (sc->debugmux > 0) {
device_printf(dev, "select bus idx %d for %s on bus %s\n", i,
device_get_nameunit(rd->dev), device_get_nameunit(rd->bus));
}
/*
* The operation is a request for exclusive use. First we have to
* request exclusive use of our upstream bus. If multiple slave devices
* from our different child buses attempt to do IO at the same time,
* this is what ensures that they don't switch the bus out from under
* each other. The first one in proceeds and others wait here (or get an
* EWOULDBLOCK return if they're using IIC_DONTWAIT).
*/
if ((err = iicbus_request_bus(sc->busdev, dev, rd->flags)) != 0)
return (err); /* Already an IIC error code. */
/*
* Now that we own exclusive use of the upstream bus, connect it to the
* downstream bus where the request came from.
*/
if ((err = IICMUX_BUS_SELECT(dev, i, rd)) != 0)
iicbus_release_bus(sc->busdev, dev);
return (err);
}
static u_int
iicmux_get_frequency(device_t dev, u_char speed)
{
struct iicmux_softc *sc = device_get_softc(dev);
return (IICBUS_GET_FREQUENCY(sc->busdev, speed));
}
#ifdef FDT
static phandle_t
iicmux_get_node(device_t dev, device_t child)
{
struct iicmux_softc *sc = device_get_softc(dev);
int i;
for (i = 0; i <= sc->maxbus; ++i) {
if (sc->childdevs[i] == child)
return (sc->childnodes[i]);
}
return (0); /* null handle */
}
#endif
static int
iicmux_intr(device_t dev, int event, char *buf)
{
struct iicmux_softc *sc = device_get_softc(dev);
/* XXX iicbus_intr() in iiconf.c should return status. */
iicbus_intr(sc->busdev, event, buf);
return (0);
}
static int
iicmux_read(device_t dev, char *buf, int len, int *bytes, int last, int delay)
{
struct iicmux_softc *sc = device_get_softc(dev);
return (iicbus_read(sc->busdev, buf, len, bytes, last, delay));
}
static int
iicmux_repeated_start(device_t dev, u_char slave, int timeout)
{
struct iicmux_softc *sc = device_get_softc(dev);
return (iicbus_repeated_start(sc->busdev, slave, timeout));
}
static int
iicmux_reset(device_t dev, u_char speed, u_char addr, u_char *oldaddr)
{
struct iicmux_softc *sc = device_get_softc(dev);
return (iicbus_reset(sc->busdev, speed, addr, oldaddr));
}
static int
iicmux_start(device_t dev, u_char slave, int timeout)
{
struct iicmux_softc *sc = device_get_softc(dev);
return (iicbus_start(sc->busdev, slave, timeout));
}
static int
iicmux_stop(device_t dev)
{
struct iicmux_softc *sc = device_get_softc(dev);
return (iicbus_stop(sc->busdev));
}
static int
iicmux_transfer( device_t dev, struct iic_msg *msgs, uint32_t nmsgs)
{
struct iicmux_softc *sc = device_get_softc(dev);
return (iicbus_transfer(sc->busdev, msgs, nmsgs));
}
static int
iicmux_write(device_t dev, const char *buf, int len, int *bytes, int timeout)
{
struct iicmux_softc *sc = device_get_softc(dev);
return (iicbus_write(sc->busdev, buf, len, bytes, timeout));
}
/*------------------------------------------------------------------------------
* iicmux helper functions, called by hardware-specific drivers.
* All these functions return a standard errno value.
*----------------------------------------------------------------------------*/
int
iicmux_add_child(device_t dev, device_t child, int busidx)
{
struct iicmux_softc *sc = device_get_softc(dev);
KASSERT(busidx < sc->numbuses,
("iicmux_add_child: bus idx %d too big", busidx));
KASSERT(sc->childdevs[busidx] == NULL,
("iicmux_add_child: bus idx %d already added", busidx));
sc->childdevs[busidx] = child;
if (sc->maxbus < busidx)
sc->maxbus = busidx;
return (0);
}
int
iicmux_attach(device_t dev, device_t busdev, int numbuses)
{
struct iicmux_softc *sc = device_get_softc(dev);
int i, numadded;
/*
* Init the softc...
*/
KASSERT(numbuses <= IICMUX_MAX_BUSES,
("iicmux_attach: numbuses %d exceeds max %d\n",
numbuses, IICMUX_MAX_BUSES));
sc->dev = dev;
sc->busdev = busdev;
sc->numbuses = numbuses;
SYSCTL_ADD_UINT(device_get_sysctl_ctx(sc->dev),
SYSCTL_CHILDREN(device_get_sysctl_tree(sc->dev)), OID_AUTO,
"debugmux", CTLFLAG_RWTUN, &sc->debugmux, 0, "debug mux operations");
/*
* Add children...
*/
numadded = 0;
#ifdef FDT
phandle_t child, node, parent;
pcell_t idx;
/*
* Find our FDT node. Child nodes within our node will become our
* iicbus children.
*/
if((node = ofw_bus_get_node(sc->dev)) == 0) {
device_printf(sc->dev, "cannot find FDT node\n");
return (ENOENT);
}
/*
* First we have to see if there is a child node named "i2c-mux". If it
* exists, all children of that node are buses, else all children of the
* device node are buses.
*/
if ((parent = ofw_bus_find_child(node, "i2c-mux")) == 0)
parent = node;
/*
* Attach the children represented in the device tree.
*/
for (child = OF_child(parent); child != 0; child = OF_peer(child)) {
if (OF_getencprop(child, "reg", &idx, sizeof(idx)) == -1) {
device_printf(dev,
"child bus missing required 'reg' property\n");
continue;
}
if (idx >= sc->numbuses) {
device_printf(dev,
"child bus 'reg' property %d exceeds the number "
"of buses supported by the device (%d)\n",
idx, sc->numbuses);
continue;
}
sc->childdevs[idx] = device_add_child(sc->dev, "iicbus", -1);
sc->childnodes[idx] = child;
if (sc->maxbus < idx)
sc->maxbus = idx;
++numadded;
}
#endif /* FDT */
/*
* If we configured anything using FDT data, we're done. Otherwise add
* an iicbus child for every downstream bus supported by the mux chip.
*/
if (numadded > 0)
return (0);
for (i = 0; i < sc->numbuses; ++i) {
sc->childdevs[i] = device_add_child(sc->dev, "iicbus", -1);
if (sc->maxbus < i)
sc->maxbus = i;
}
return (0);
}
int
iicmux_detach(device_t dev)
{
struct iicmux_softc *sc = device_get_softc(dev);
int err, i;
/* Delete only the children we added in iicmux_add* functions. */
for (i = 0; i <= sc->maxbus; ++i) {
if (sc->childdevs[i] == NULL)
continue;
if ((err = device_delete_child(dev, sc->childdevs[i])) != 0)
return (err);
sc->childdevs[i] = NULL;
}
return (0);
}
static device_method_t iicmux_methods [] = {
/* iicbus_if methods */
DEVMETHOD(iicbus_intr, iicmux_intr),
DEVMETHOD(iicbus_callback, iicmux_callback),
DEVMETHOD(iicbus_repeated_start, iicmux_repeated_start),
DEVMETHOD(iicbus_start, iicmux_start),
DEVMETHOD(iicbus_stop, iicmux_stop),
DEVMETHOD(iicbus_read, iicmux_read),
DEVMETHOD(iicbus_write, iicmux_write),
DEVMETHOD(iicbus_reset, iicmux_reset),
DEVMETHOD(iicbus_transfer, iicmux_transfer),
DEVMETHOD(iicbus_get_frequency, iicmux_get_frequency),
#ifdef FDT
/* ofwbus_if methods */
DEVMETHOD(ofw_bus_get_node, iicmux_get_node),
#endif
DEVMETHOD_END
};
static int
iicmux_modevent(module_t mod, int type, void *unused)
{
switch (type) {
case MOD_LOAD:
return 0;
case MOD_UNLOAD:
return 0;
}
return EINVAL;
}
static moduledata_t iicmux_mod = {
"iicmux",
iicmux_modevent,
0
};
DEFINE_CLASS_0(iicmux, iicmux_driver, iicmux_methods,
sizeof(struct iicmux_softc));
DECLARE_MODULE(iicmux, iicmux_mod, SI_SUB_DRIVERS, SI_ORDER_ANY);
MODULE_VERSION(iicmux, 1);
MODULE_DEPEND(iicmux, iicbus, 1, 1, 1);

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/*-
* SPDX-License-Identifier: BSD-2-Clause
*
* Copyright (c) 2019 Ian Lepore <ian@freebsd.org>
*
* 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 AND CONTRIBUTORS ``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 OR CONTRIBUTORS 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.
*
* $FreeBSD$
*/
#ifndef __IICMUX_H
#define __IICMUX_H
#define IICMUX_MAX_BUSES 16 /* More than any available mux chip. */
/*
* IICMUX_SELECT_IDLE instructs the mux hardware driver to do whatever it is
* configured to do when the downstream buses are idle. Hardware has varying
* capabilities; it may disconnect all downstream buses, or connect a specific
* bus, or just leave whatever bus was last used connected. Hardware which is
* capable of various choices will have some mechanism to configure the choice
* which is handled outside of the iicmux framework.
*/
#define IICMUX_SELECT_IDLE (-1)
/*
* The iicmux softc; chip drivers should embed one of these as the first member
* variable of their own softc struct, and must call iicmux_attach() to
* initialize it before calling any other iicmux functions.
*/
struct iicmux_softc {
device_t busdev; /* Upstream i2c bus (may not be our parent). */
device_t dev; /* Ourself. */
int maxbus; /* Index of highest populated busdevs slot. */
int numbuses; /* Number of buses supported by the chip. */
int debugmux; /* Write debug messages when > 0. */
device_t childdevs[IICMUX_MAX_BUSES]; /* Child bus instances. */
#ifdef FDT
phandle_t childnodes[IICMUX_MAX_BUSES]; /* Child bus fdt nodes. */
#endif
};
DECLARE_CLASS(iicmux_driver);
/*
* Helpers to call from attach/detach functions of chip-specific drivers.
*
* The iicmux_attach() function initializes the core driver's portion of the
* softc, and creates child iicbus instances for any children it can identify
* using hints and FDT data. If a chip driver does its own device_add_child()
* calls to add other downstream buses that participate in the mux switching, it
* must call iicmux_add_child() to inform the core driver of the downstream
* busidx<->device_t relationship.
*/
int iicmux_add_child(device_t dev, device_t child, int busidx);
int iicmux_attach(device_t dev, device_t busdev, int numbuses);
int iicmux_detach(device_t dev);
#endif

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#-
# SPDX-License-Identifier: BSD-2-Clause
#
# Copyright (c) 2019 Ian Lepore <ian@freebsd.org>
#
# 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 AND CONTRIBUTORS ``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 OR CONTRIBUTORS 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.
#
# $FreeBSD$
#
#include <sys/bus.h>
INTERFACE iicmux;
HEADER {
struct iic_reqbus_data;
}
#
# iicmux_bus_select(device_t dev, int busidx, struct iic_reqbus_data *rd)
# Do whatever the mux hardware requires to connect the downstream
# bus selected by busidx to the upstream bus. This must return
# an IIC adapter-layer error code; standard errno values returned
# from this must be encoded using iic2errno().
#
METHOD int bus_select {
device_t dev;
int busidx;
struct iic_reqbus_data *rd;
};

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/*-
* SPDX-License-Identifier: BSD-2-Clause
*
* Copyright (c) 2019 Ian Lepore <ian@freebsd.org>
*
* 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 AND CONTRIBUTORS ``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 OR CONTRIBUTORS 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.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "opt_platform.h"
#include <sys/param.h>
#include <sys/bus.h>
#include <sys/kernel.h>
#include <sys/module.h>
#include <sys/systm.h>
#include <dev/iicbus/iicbus.h>
#include <dev/iicbus/iiconf.h>
#include "iicbus_if.h"
#include "iicmux_if.h"
static struct chip_info {
const char *partname;
const char *description;
int numchannels;
} chip_infos[] = {
{"ltc4305", "LTC4305 I2C Mux", 2},
{"ltc4306", "LTC4306 I2C Mux", 4},
};
#define CHIP_NONE (-1)
#define CHIP_LTC4305 0
#define CHIP_LTC4306 1
#ifdef FDT
#include <dev/ofw/ofw_bus.h>
#include <dev/ofw/ofw_bus_subr.h>
#include <dev/ofw/openfirm.h>
static struct ofw_compat_data compat_data[] = {
{"lltc,ltc4305", CHIP_LTC4305},
{"lltc,ltc4306", CHIP_LTC4306},
{NULL, CHIP_NONE}
};
IICBUS_FDT_PNP_INFO(compat_data);
#endif
#include <dev/iicbus/mux/iicmux.h>
struct ltc430x_softc {
struct iicmux_softc mux;
bool idle_disconnect;
};
/*
* The datasheet doesn't name the registers, it calls them control register 0-3.
*/
#define LTC430X_CTLREG_0 0
#define LTC430X_CTLREG_1 1
#define LTC430X_CTLREG_2 2
#define LTC430X_CTLREG_3 3
static int
ltc430x_bus_select(device_t dev, int busidx, struct iic_reqbus_data *rd)
{
struct ltc430x_softc *sc = device_get_softc(dev);
uint8_t busbits;
/*
* The iicmux caller ensures busidx is between 0 and the number of buses
* we passed to iicmux_init_softc(), no need for validation here. If
* the fdt data has the idle_disconnect property we idle the bus by
* selecting no downstream buses, otherwise we just leave the current
* bus active. The upper bits of control register 3 activate the
* downstream buses; bit 7 is the first bus, bit 6 the second, etc.
*/
if (busidx == IICMUX_SELECT_IDLE) {
if (sc->idle_disconnect)
busbits = 0;
else
return (0);
} else {
busbits = 1u << (7 - busidx);
}
/*
* We have to add the IIC_RECURSIVE flag because the iicmux core has
* already reserved the bus for us, and iicdev_writeto() is going to try
* to reserve it again, which is allowed with the recursive flag.
*/
return (iicdev_writeto(dev, LTC430X_CTLREG_3, &busbits, sizeof(busbits),
rd->flags | IIC_RECURSIVE));
}
static int
ltc430x_find_chiptype(device_t dev)
{
#ifdef FDT
return (ofw_bus_search_compatible(dev, compat_data)->ocd_data);
#else
const char *type;
int i;
if (resource_string_value(device_get_name(dev), device_get_unit(dev),
"chip_type", &type) == 0) {
for (i = 0; i < nitems(chip_infos); ++i) {
if (strcasecmp(type, chip_infos[i].partname) == 0) {
return (i);
}
}
}
return (CHIP_NONE);
#endif
}
static int
ltc430x_probe(device_t dev)
{
int type;
#ifdef FDT
if (!ofw_bus_status_okay(dev))
return (ENXIO);
#endif
type = ltc430x_find_chiptype(dev);
if (type == CHIP_NONE)
return (ENXIO);
device_set_desc(dev, chip_infos[type].description);
return (BUS_PROBE_DEFAULT);
}
static int
ltc430x_attach(device_t dev)
{
struct ltc430x_softc *sc __unused;
int chip, err, numchan;
sc = device_get_softc(dev);
#ifdef FDT
phandle_t node;
node = ofw_bus_get_node(dev);
sc->idle_disconnect = OF_hasprop(node, "i2c-mux-idle-disconnect");
#endif
/* We found the chip type when probing, so now it "can't fail". */
if ((chip = ltc430x_find_chiptype(dev)) == CHIP_NONE) {
device_printf(dev, "impossible: can't identify chip type\n");
return (ENXIO);
}
numchan = chip_infos[chip].numchannels;
if ((err = iicmux_attach(dev, device_get_parent(dev), numchan)) == 0)
bus_generic_attach(dev);
return (err);
}
static int
ltc430x_detach(device_t dev)
{
int err;
if ((err = iicmux_detach(dev)) != 0)
return (err);
return (0);
}
static device_method_t ltc430x_methods[] = {
/* device methods */
DEVMETHOD(device_probe, ltc430x_probe),
DEVMETHOD(device_attach, ltc430x_attach),
DEVMETHOD(device_detach, ltc430x_detach),
/* iicmux methods */
DEVMETHOD(iicmux_bus_select, ltc430x_bus_select),
DEVMETHOD_END
};
static devclass_t ltc430x_devclass;
DEFINE_CLASS_1(ltc430x, ltc430x_driver, ltc430x_methods,
sizeof(struct ltc430x_softc), iicmux_driver);
DRIVER_MODULE(ltc430x, iicbus, ltc430x_driver, ltc430x_devclass, 0, 0);
#ifdef FDT
DRIVER_MODULE(ofw_iicbus, ltc430x, ofw_iicbus_driver, ofw_iicbus_devclass, 0, 0);
#else
DRIVER_MODULE(iicbus, ltc430x, iicbus_driver, iicbus_devclass, 0, 0);
#endif
MODULE_DEPEND(ltc430x, iicmux, 1, 1, 1);
MODULE_DEPEND(ltc430x, iicbus, 1, 1, 1);

1
sys/modules/i2c/Makefile
View File

@ -17,6 +17,7 @@ SUBDIR = \
isl \
isl12xx \
jedec_dimm \
mux \
nxprtc \
rtc8583 \
s35390a \

11
sys/modules/i2c/mux/Makefile Normal file
View File

@ -0,0 +1,11 @@
# $FreeBSD$
SUBDIR = \
iicmux \
ltc430x \
.if !empty(OPT_FDT)
SUBDIR+= iic_gpiomux
.endif
.include <bsd.subdir.mk>

20
sys/modules/i2c/mux/iic_gpiomux/Makefile Normal file
View File

@ -0,0 +1,20 @@
# $FreeBSD$
.PATH: ${SRCTOP}/sys/dev/iicbus/mux
KMOD= iic_gpiomux
SRCS= iic_gpiomux.c
SRCS+= \
bus_if.h \
device_if.h \
gpio_if.h \
iicbus_if.h \
iicmux_if.h \
opt_platform.h \
.if !empty(OPT_FDT)
SRCS+= ofw_bus_if.h
.endif
.include <bsd.kmod.mk>

19
sys/modules/i2c/mux/iicmux/Makefile Normal file
View File

@ -0,0 +1,19 @@
# $FreeBSD$
.PATH: ${SRCTOP}/sys/dev/iicbus/mux
KMOD= iicmux
SRCS= iicmux.c iicmux_if.c
SRCS+= \
bus_if.h \
device_if.h \
iicbus_if.h \
iicmux_if.h \
opt_platform.h \
.if !empty(OPT_FDT)
SRCS+= ofw_bus_if.h
.endif
.include <bsd.kmod.mk>

20
sys/modules/i2c/mux/ltc430x/Makefile Normal file
View File

@ -0,0 +1,20 @@
# $FreeBSD$
.PATH: ${SRCTOP}/sys/dev/iicbus/mux
KMOD= ltc430x
SRCS= ltc430x.c
SRCS+= \
bus_if.h \
device_if.h \
iicbus_if.h \
iicmux_if.h \
opt_platform.h \
.if !empty(OPT_FDT)
SRCS+= ofw_bus_if.h
.endif
.include <bsd.kmod.mk>