man/man8/i2cadm.8

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.\" Copyright 2025 Oxide Computer Company
.\"
.Dd October 4, 2025
.Dt I2CADM 8
.Os
.Sh NAME
.Nm i2cadm
.Nd I2C administration
.Sh SYNOPSIS
.Nm
.Cm controller
.Cm list
.Op Fl H
.Op Fl o Ar field Ns [,...] Op Fl p
.Op Ar filter Ns ...
.Nm
.Cm controller
.Cm prop
.Cm get
.Op Fl H
.Op Fl o Ar field Ns [,...] Op Fl p
.Ar controller
.Op Ar filter Ns ...
.Nm
.Cm controller
.Cm prop
.Cm set
.Ar controller
.Ar property Ns = Ns Ar value
.Nm
.Cm device
.Cm list
.Op Fl H
.Op Fl o Ar field Ns [,...] Op Fl p
.Op Ar filter Ns ...
.Nm
.Cm device
.Cm addrs
.Op Fl H
.Op Fl o Ar field Ns [,...] Op Fl p
.Op Ar filter Ns ...
.Nm
.Cm device
.Cm add
.Op Fl c Ar compat
.Ar port
.Ar name
.Ar address
.Nm
.Cm device
.Cm remove
.Ar path
.Nm
.Cm mux
.Cm list
.Op Fl H
.Op Fl o Ar field Ns [,...] Op Fl p
.Op Ar filter Ns ...
.Nm
.Cm port
.Cm list
.Op Fl H
.Op Fl o Ar field Ns [,...] Op Fl p
.Op Ar filter Ns ...
.Nm
.Cm port
.Cm map
.Op Fl H
.Op Fl o Ar field Ns [,...] Op Fl p
.Ar port
.Nm
.Cm io
.Op Fl m Ar mode
.Fl d Ar destination
.Op Fl a Ar address
.Op Fl c Ar command
.Op Fl w Ar wlen
.Op Fl r Ar rlen
.Op Fl o Ar output
.Ar data
.Nm
.Cm scan
.Op Fl d Ar device
.Op Fl H
.Op Fl o Ar field Ns [,...] Op Fl p
.Ar port
.Sh DESCRIPTION
The
.Nm
utility is used to enumerate and manipulate I2C and SMBus controllers,
devices, ports, and multiplexors.
.Pp
There are four top-level objects in
.Nm ;
.Bl -tag -width Ds
.It Controllers
These are hardware device that can perform I2C or SMBus operations that
target devices on the bus.
.Nm
provides the ability to list them as well as get and set properties on
specific controllers.
.It Devices
Device represent targets on the I2C bus which provide some functionality
at a given address.
Devices run the gamut including functions like EEPROMs, sensors, GPIO
controllers, voltage regulators, and more.
Many devices will have a corresponding device driver that provides
functionality through a standard system mechanism, but there is no
requirement for a driver.
.It Ports
A port is a logical point on an I2C bus under which one or more devices
can be found.
I2C ports are found directly under controllers and multiplexors.
I2C ports under a controller represent the start of a unique I2C bus and
addresses that are used are specific to that bus.
.Nm
provides the ability to list ports and print information about the
addresses that are in use on the port directly or downstream of it.
.It Multiplexors
Multiplexors provide a means of isolating segments of an I2C bus from
one another, which is generally used to avoid overlapping I2C addresses.
A multiplexor provides a fixed number of ports and the system will
transparently activate and deactivate ports based on I/O requests and
their targets.
At most one port will ever be active on a multiplexor at any given time.
.Nm
provides the ability to discover and list multiplexors.
.El
.Pp
All listing operations leverage the standard illumos output format
library
.Po
.Xr ofmt 3OFMT
.Pc
allowing the selection of specific output fields, the omission of the
header
.Pq Fl H ,
and a parsable mode intended for programmatic consumption
.Pq Fl p .
When requesting parsable output, the colon
.Po
.Do
:
.Dc
.Pc
character is used as a delimiter between fields and any delimiters that
would appear in an output field will be escaped with a backslash
character
.Po
.Do
\e
.Dc
.Pc .
.Pp
Getting information about I2C devices, controllers, ports, and muxes
requires that a process have the
.Brq Dv PRIV_SYS_DEVICES
privilege.
.Ss I2C Paths
All of the different entities that can be found on an I2C bus are
described through a path that indicates the route through the bus to get
to an entity.
Consider the following I2C devices:
.Bd -literal


  +------------+
  |   dwi2c4   |
  |   1 port   |
  | controller |
  +------------+     +------+
         |           | lm75 |
         +---------->| 0x48 |
         |           +------+
         v
   +------------+
   |  pca9548   |
   |    0x72    |
   | 8 port mux |
   +------------+
         |
         * ... port 0, 1-7 not pictured
         |
         v
   +------------+
   |  pca9545   |
   |    0x72    |
   | 4 port mux |
   +------------+
         |
         * ... port 2, 0-1,3 not pictured
         |
         v
    +---------+
    | at24c02 |
    |   0x57  |
    |  EEPROM |
    +---------+
.Ed
.Pp
The following are what different paths refer to for this:
.Bl -tag -width Pa
.It Pa dwi2c4
This refers to the controller itself.
.It Pa dwi2c4/0
This refers to the primary port under a controller.
This could be used for performing device scans, I/O, or manually adding
or removing devices.
.It Pa dwi2c4/0/0x48
This refers to the LM75 temperature sensor that is directly attached to
the controller's port.
.It Pa dwi2c4/0/0x72
This string refers to the 8-port mux directly under the controller's
port.
.It Pa dwi2c4/0/0x72/0/0x70/2/0x57
This is a complex string that refers to the AT24C02 EEPROM.
Along the way are all of the devices and ports that are used to get to
it.
A more verbose form of this path would be
.Pa dwi2c4/0/pca9548@0x72/0/pca9545@0x70/2/at24c02@0x57 .
.El
.Pp
When constructing paths, controllers are always referred to by their
name and instance.
Ports are always referred to by their name, which is usually a number
based upon the datasheet.
Devices can be referred to in three ways at their point in the tree.
Using the first mux as an example:
.Bl -enum
.It
Using the device's primary I2C address:
.Ql 0x72 .
.It
Using the device's name and primary address:
.Ql pca9548@0x72 .
.It
Using the device's driver name and instance:
.Ql pca9454x0 .
.El
.Sh SUBCOMMANDS
The following commands are supported by
.Nm :
.Bl -tag -width ""
.It Xo
.Nm
.Cm controller
.Cm list
.Op Fl H
.Op Fl o Ar field Ns [,...] Op Fl p
.Op Ar filter Ns ...
.Xc
List all of the I2C controllers in the system and provide basic
information about them.
.Pp
The following fields are supported:
.Bl -tag -width PROVIDER
.It Sy NAME
This is the name of the I2C controller in the system.
All I2C paths will start with a controller name.
.It Sy TYPE
This is the primary type of the controller, but is not indicative of all
I/O that they can perform.
An SMBus controller may support directly performing I2C.
The valid controller types are:
.Bl -tag -width smbus
.It i2c
An I2C controller.
.It i3c
An I3C controller.
.It smbus
An SMBus controller.
.El
.It Sy SPEED
A string that describe the speed that the bus is operating at, along
with some of the physical capabilities.
The valid speed values are:
.Bl -tag -width fast-plus
.It standard
Standard speed operates the bus at 100 kHz.
.It fast
Fast speed operates the bus at 400 kHz.
.It fast-plus
Fast-plus speed operates the bus at 1 MHz.
.It high
High-speed operate the bus at 3.4 MHz.
.It ultra
Ultra-fast speed operate the bus at 5 MHz.
.El
.It Sy NPORTS
The number of ports that are under the controller.
.It Sy DRIVER
The name of the driver for the controller.
.It Sy INSTANCE
The name of the device driver instance for the controller.
.It Sy PROVIDER
The
.Pa /devices
path to the kernel provider for this controller.
.El
.Pp
The following options are supported:
.Bl -tag -width Fl
.It Fl H
Omit the column header when printing output.
.It Fl o Ar field Ns [,...]
A comma-delineated list of fields to output, selected from the ones
above.
.It Fl p
Displays the output in a machine-parsable format.
When requesting parsable output, the
.Fl o
option is required to specifically control which fields are included.
.El
.Pp
The following operands are supported:
.Bl -tag -width Ar
.It Ar filter
One or more filters may be specified which are used to constrain the
list of controllers that are printed.
Each
.Ar filter
may either match the name of a controller or driver.
.Pp
If any filter is specified and does not match, then that is treated as
an error.
.Pp
Because these are filters, they do not control the order that items are
printed out, only what is printed out.
.El
.It Xo
.Nm
.Cm controller
.Cm prop
.Cm get
.Op Fl H
.Op Fl o Ar field Ns [,...] Op Fl p
.Ar controller
.Op Ar filter Ns ...
.Xc
List all properties, their values, and corresponding metadata on the
specific controller
.Ar controller .
.Pp
The following fields are supported:
.Bl -tag -width PROPERTY
.It Sy PROPERTY
The name of the property.
.It Sy PERM
Indicates whether the property is readable or both readable and
writable.
.It Sy VALUE
The current value of the property.
.It Sy DEFAULT
The default value for the property on the specific instance of the
controller.
This is the value the system will start with assuming no tuning has been
performed.
Some properties may not have a default value.
.It Sy POSSIBLE
A list of possible values that the property might take.
This may be a series of numeric ranges or a list of specific values.
Some properties may not have a set of possible values.
.It Sy TYPE
Indicates the type of the property.
The system has the following I2C property types:
.Bl -tag -width bit32
.It Sy u32
Indicates that the property is a 32-bit unsigned value.
.It Sy bit32
Indicates that the property is a 32-bit unsigned bitfield.
The presence or absence of each bit indicates a specific feature or
property.
.El
.It Sy CONTROLLER
The name of the controller the property is being retrieved from.
.It Sy ID
The system's numeric identifier for the property.
.El
.Pp
The following options are supported:
.Bl -tag -width Fl
.It Fl H
Omit the column header when printing output.
.It Fl o Ar field Ns [,...]
A comma-delineated list of fields to output, selected from the ones
above.
.It Fl p
Displays the output in a machine-parsable format.
When requesting parsable output, the
.Fl o
option is required to specifically control which fields are included.
.El
The following operands are supported:
.Bl -tag -width Ar
.It Ar filter
One or more filters may be specified which are used to constrain the
list of properties that are printed.
Each
.Ar filter
must match the name of a property.
For a list of properties, see the
.Sx PROPERTIES
section.
.Pp
If any filter is specified and does not match, then that is treated as
an error.
.Pp
Because these are filters, they do not control the order that items are
printed out, only what is printed out.
.El
.It Xo
.Nm
.Cm controller
.Cm prop
.Cm set
.Ar controller
.Ar property Ns = Ns Ar value
.Xc
Set the value of a single named
.Ar  property
on the controller,
.Ar controller ,
to the indicated
.Ar value.
.Ar value
will be parsed based upon the specific property and its type.
Properties which are translated into strings, can be specified as either
an integer value or the corresponding string.
.Pp
To see the list of properties on a controller use
.Nm
.Cm controller
.Cm prop
.Cm get .
For a list of all properties, see the
.Sx PROPERTIES
section.
.It Xo
.Nm
.Cm device
.Cm list
.Op Fl H
.Op Fl o Ar field Ns [,...] Op Fl p
.Op Ar filter Ns ...
.Xc
Lists basic information about all devices known to the system across all
controllers.
These are devices that have been discovered through a platform-specific
means or explicitly added by an administrator through the
.Nm
.Cm device
.Cm add
command.
.Pp
The following fields are supported:
.Bl -tag -width INSTANCE
.It Sy NAME
The name of the device.
This corresponds to the device tree's node name.
.It Sy ADDR
The primary I2C address that this device has.
This corresponds to the device tree's reg[0] entry.
.It Sy INSTANCE
The driver instance of the device, if any.
.It Sy PATH
The I2C path of the device.
.El
.Pp
The following options are supported:
.Bl -tag -width Fl
.It Fl H
Omit the column header when printing output.
.It Fl o Ar field Ns [,...]
A comma-delineated list of fields to output, selected from the ones
above.
.It Fl p
Displays the output in a machine-parsable format.
When requesting parsable output, the
.Fl o
option is required to specifically control which fields are included.
.El
.Pp
The following operands are supported:
.Bl -tag -width Ar
.It Ar filter
One or more filters may be specified which are used to constrain the
list of properties that are printed.
Each
.Ar filter
may match a device's primary address, a device name, a driver name, a
driver instance, or a portion of the device's I2C path.
.Pp
If any filter is specified and does not match, then that is treated as
an error.
.Pp
Because these are filters, they do not control the order that items are
printed out, only what is printed out.
.El
.It Xo
.Nm
.Cm device
.Cm addrs
.Op Fl H
.Op Fl o Ar field Ns [,...] Op Fl p
.Op Ar filter Ns ...
.Xc
Print the I2C addresses and their sources for device's in the system.
A device's address may come from the platform or it may be an additional
address that the driver itself claims and is either unique to that
device or shared amongst all instance of a particular driver.
.Pp
The following fields are supported:
.Bl -tag -width SOURCE
.It Sy PATH
The I2C path of the device.
.It Sy TYPE
The type of the address.
This is either
.Sy 7-bit
or
.Sy 10-bit .
.It Sy ADDR
The address in question on the device.
.It Sy SOURCE
Indicates how the device was assigned the address.
One of the following values:
.Bl -tag -width platform
.It Sy platform
This address came from information provided by the platform.
This includes firmware sources or addresses assigned as part of an
operator calling
.Nm
.Cm device
.Cm add .
.It Sy claimed
This addresses was claimed exclusively by the device driver.
For example, several EEPROMs require multiple I2C addresses to cover
their entire memory map, but only the base address is often provided by
the platform.
.It Sy shared
This address was claimed by a device driver and is permitted to be used
across all instances of the device driver.
.El
.El
.Pp
The following options are supported:
.Bl -tag -width Fl
.It Fl H
Omit the column header when printing output.
.It Fl o Ar field Ns [,...]
A comma-delineated list of fields to output, selected from the ones
above.
.It Fl p
Displays the output in a machine-parsable format.
When requesting parsable output, the
.Fl o
option is required to specifically control which fields are included.
.El
The following operands are supported:
.Bl -tag -width Ar
.It Ar filter
One or more filters may be specified which are used to constrain the
list of properties that are printed.
Each
.Ar filter
may match a device's particular address, a device name, a driver name, a
driver instance, or a portion of the device's I2C path.
.Pp
If any filter is specified and does not match, then that is treated as
an error.
.Pp
Because these are filters, they do not control the order that items are
printed out, only what is printed out.
.El
.It Xo
.Nm
.Cm device
.Cm add
.Op Fl c Ar compat
.Ar port
.Ar name
.Ar address
.Xc
Add a new device to the system.
The system will attempt to attach a driver to this device; however, even
if there is no driver for the device, it can be created regardless.
.Pp
The following options are supported:
.Bl -tag -width Fl
.It Fl c Ar compat
Add the specified compatibility entry
.Ar compat
to the newly created device node's
.Ql compatible
property.
When the system considers device drivers to attach to an I2C device it
will search for matches against the device's
.Ql compatible
property and then attempt to match the device's name.
.Pp
This property may be specified multiple times in order to add multiple
entries.
The order is meaningful and will reflect the order specified on the
command line.
The matching algorithm walks the list in order and terminates on the
first found match.
More specific entries should be specified first.
.El
.Pp
The following operands are supported:
.Bl -tag -width Ar
.It Ar port
Specifies the I2C path to the port that the device will be created
under.
This may be either a port on a controller or a port under a multiplexor.
Device's under a mux are allowed to have conflicting addresses with
devices on other ports of a given mux.
The mux will be implicitly activated when performing I/O to the device.
.It Ar name
The name of the new device.
This generally should match something about the device itself such as
the part number.
.Pp
Device name's may be at most 31 characters.
The first character must be an upper or lower case letter.
The remaining characters may be upper or lower case letters, numbers, or
one of the following punctuation characters: the comma
.Pq Sq \&, ,
the period
.Pq Sq \&. ,
the hyphen
.Pq Sq - ,
the plus sign
.Pq Sq + ,
and the underscore
.Pq Sq _ .
.It Ar address
The address to assign to the device.
Only 7-bit addresses are permitted.
The string will be parsed according to the specified base.
It is recommended to specify addresses in hexadecimal with the leading
.Dq 0x .
.El
.It Xo
.Nm
.Cm device
.Cm remove
.Ar path
.Xc
Attempts to remove the specified device indicated by the I2C path
.Ar path .
This may fail if the device is actively being used.
.It Xo
.Nm
.Cm mux
.Cm list
.Op Fl H
.Op Fl o Ar field Ns [,...] Op Fl p
.Op Ar filter Ns ...
.Xc
List all multiplexors known to the system.
.Pp
The following fields are supported:
.Bl -tag -width INSTANCE
.It Sy DEVICE
The name of the I2C device that implements the multiplexor.
.It Sy NPORTS
The number of ports on the multiplexor.
.It Sy NAME
The name of the multiplexor itself.
.It Sy INSTANCE
The device driver instance that powers the multiplexor.
.It Sy PATH
The I2C path of the multiplexor.
.El
.Pp
The following options are supported:
.Bl -tag -width Fl
.It Fl H
Omit the column header when printing output.
.It Fl o Ar field Ns [,...]
A comma-delineated list of fields to output, selected from the ones
above.
.It Fl p
Displays the output in a machine-parsable format.
When requesting parsable output, the
.Fl o
option is required to specifically control which fields are included.
.El
.Pp
The following operands are supported:
.Bl -tag -width Ar
.It Ar filter
One or more filters may be specified which are used to constrain the
list of multiplexors that are printed.
Each
.Ar filter
may either match the multiplexor name, its device's name, or its
device's driver.
.Pp
If any filter is specified and does not match, then that is treated as
an error.
.Pp
Because these are filters, they do not control the order that items are
printed out, only what is printed out.
.El
.It Xo
.Nm
.Cm port
.Cm list
.Op Fl H
.Op Fl o Ar field Ns [,...] Op Fl p
.Op Ar filter Ns ...
.Xc
List all ports known to the system.
.Pp
The following fields are supported:
.Bl -tag -width PORTNO
.It Sy PATH
The I2C path of the port.
.It Sy TYPE
Indicates the type of port.
One of the following values:
.Bl -tag -width multiplexor
.It Sy controller
The port belongs to a controller.
.It Sy multiplexor
The port belongs to a mux.
.El
.It Sy NAME
The name of the port.
Port names generally follow the datasheet and are either 0-based or
1-based.
.It Sy PORTNO
The 0-based system assigned ID for this port.
.It Sy NDEVS
The number of devices that are directly under this port.
This does not include devices that are under subsequent ports like a
multiplexor.
.It Sy TDEVS
The total number of devices that are under this port, including all
multiplexors.
.El
.Pp
The following options are supported:
.Bl -tag -width Fl
.It Fl H
Omit the column header when printing output.
.It Fl o Ar field Ns [,...]
A comma-delineated list of fields to output, selected from the ones
above.
.It Fl p
Displays the output in a machine-parsable format.
When requesting parsable output, the
.Fl o
option is required to specifically control which fields are included.
.El
.Pp
The following operands are supported:
.Bl -tag -width Ar
.It Ar filter
One or more filters may be specified which are used to constrain the
list of ports that are printed.
Each
.Ar filter
may either match the port's name, its type, or its I2C path.
.Pp
If any filter is specified and does not match, then that is treated as
an error.
.Pp
Because these are filters, they do not control the order that items are
printed out, only what is printed out.
.El
.It Xo
.Nm
.Cm port
.Cm map
.Op Fl H
.Op Fl o Ar field Ns [,...] Op Fl p
.Ar port
.Xc
Prints a map of how addresses are used directly under the specified port
.Ar port
by devices known to the system.
This does not perform I/O to scan for addresses that could be used but
are unknown to the system, instead use
.Nm
.Cm scan
for that.
By default, the command will output a human-oriented table organized
into rows with 16 columns each.
For machine parsable stable, output use the
.Fl p
and
.Fl o
options.
.Pp
The table will use the following characters to indicate specific cases:
.Bl -tag -width Ds
.It L
Indicates that the address corresponds to a device
this port.
.It v
Indicates that the address is used downstream of this port by a device
under a mux port.
The address in question could not be assigned to another device because
of this.
.It S
Indicates that this address is being treated as a shared address across
multiple instances of a device driver.
A list of shared addresses and the corresponding major numbers and
drivers will be printed following the table.
.It -
Indicates that this address is not in use.
.It E
An unexpected error occurred.
.El
.Pp
The following fields are supported:
.Bl -tag -width DRIVER
.It Sy ADDR
The I2C address in question.
The address is printed in decimal.
.It Sy COUNT
The number of devices that are using this address in the port.
.It Sy TYPE
The type of address.
One of the following values:
.Bl -tag -width downstream
.It Sy local
Indicates that this address is in use by a device directly on the port.
.It Sy downstream
Indicates that this address is in use by a device downstream of the
port.
.It Sy shared
Indicates that the address is being actively shared by one or more
instances of a given device driver.
.It Sy none
Indicates that this address is not in use.
.It Sy error
Indicates that information about this addrses is not available because
an error occurred.
.El
.It Sy MAJOR
For shared addresses, indicates the major number of the driver that is
sharing the address.
.It Sy DRIVER
For shared addresses, indicates the name of the device driver that is
sharing the address.
.El
.Pp
The following options are supported:
.Bl -tag -width Fl
.It Fl H
Omit the column header when printing output.
.It Fl o Ar field Ns [,...]
A comma-delineated list of fields to output, selected from the ones
above.
.It Fl p
Displays the output in a machine-parsable format.
When requesting parsable output, the
.Fl o
option is required to specifically control which fields are included.
.El
.Pp
The following operands are required:
.Bl -tag -width Ar
.It Ar port
The I2C path of the port to print information about.
.El
.It Xo
.Nm
.Cm io
.Op Fl m Ar mode
.Fl d Ar destination
.Op Fl a Ar address
.Op Fl c Ar command
.Op Fl w Ar wlen
.Op Fl r Ar rlen
.Op Fl o Ar output
.Ar data
.Xc
Perform arbitrary I/O to a specific device or address on the I2C bus.
This will perform a single transaction based on the type specified by
the
.Ar mode
argument, which defaults to I2C.
Transmitted data will be taken from the positional arguments and
received data will be output in a hexdump if
.Fl o
is not specified.
.Pp
Care should be taken when performing I/O to arbitrary devices.
If a kernel device driver is attached this can potentially confuse the
driver.
If the device is modified, this can potentially lead to an unbootable or
unsable system.
For example, modifying the EERPOM on a DRAM device could lead to DRAM
training failures.
The following options are supported:
.Bl -tag -width Fl
.It Fl a Ar address
A string that indicates the numeric 7-bit address to send the I/O to.
.It Fl c Ar command
An SMBus command to send.
This option is only valid when using an SMBus mode with
.Fl m
that requires a command to be specified.
.It Fl d Ar destination
An I2C path that indicates where the I/O should target.
If this is a port, then an address must be specified with the
.Fl a
option.
If the path includes mux ports, they will be implicitly activated as
part of performing this operation.
If the path ends at a device, the device's primary address
.Pq reg[0]
will be used.
.It Fl m Ar mode
Specifies the type of I/O request that should be sent.
The following types are supported:
.Bl -tag -width write-block-i2c
.It i2c
Perform a general I2C transaction.
One or both of
.Fl r
and
.Fl w
must be used and non-zero.
.It quick-read
Perform an SMBus quick read.
No data arguments may be specified or are required.
.It quick-write
Perform an SMBus quick write.
No data arguments may be specified or are required.
.It recv-u8
Receive a single byte.
No data arguments may be specified or are required.
.It read-u8
Perform the SMBus read byte operation.
An SMBus command must be specified with
.Fl c .
.It read-u16
Perform the SMBus read word operation.
An SMBus command must be specified with
.Fl c .
.It read-u32
Perform the SMBus read u32 operation.
An SMBus command must be specified with
.Fl c .
.It read-u64
Perform the SMBus read u64 operation.
An SMBus command must be specified with
.Fl c .
.It read-block-i2c
Perform an SMBus I2C block read operation.
An SMBus command must be specified with
.Fl c .
A read length must be specified with
.Fl r .
It will not be sent on the wire, unlike a traditional SMBus block read.
.It send-u8
Transmit a single byte.
.It write-u8
Perform the SMBus write byte operation.
An SMBus command must be specified with
.Fl c
and a single data operand must be specified.
.It write-u16
Perform the SMBus write word operation.
An SMBus command must be specified with
.Fl c
and a single data operand must be specified.
.It write-u32
Perform the SMBus write u32 operation.
An SMBus command must be specified with
.Fl c
and a single data operand must be specified.
.It write-u64
Perform the SMBus write u64 operation.
An SMBus command must be specified with
.Fl c
and a single data operand must be specified.
.It write-block
Perform an SMBus write block operation.
SMBus block write with command and length
An SMBus command must be specified with
.Fl c
and the number of byte to write must be specified with
.Fl w .
Both the command and the write length will be sent on the wire.
There must be a single-byte positional argument for each byte indicated
with
.Fl w .
.It write-block-i2c
Operates as per write-block above, but the byte length is not sent on
the wire.
.It call
Performs the SMBus process call operation.
An SMBus command must be specified with
.Fl c
and a single positional data argument must be specified.
Process call transmits and then reads a u16.
.El
.It Fl o Ar output
Send received binary data to the file
.Ar output
rather than performing a hexadecimal dump to standard out.
.It Fl r Ar rlen
Specifies the number of bytes that should be read from the device.
.It Fl w Ar wlen
Specifies the number of bytes that should be transmitted to the device.
There must be one positional argument for each byte that should be
transmitted.
.El
.It Xo
.Nm
.Cm scan
.Op Fl d Ar device
.Op Fl H
.Op Fl o Ar field Ns [,...] Op Fl p
.Ar port
.Xc
Scan the specified I2C
.Ar port
for devices.
This works by attempting to perform I/O to every non-reserved address on
the bus.
If the port belongs to a mux, then all of the appropriate mux segments
will be enabled prior to performing the scan.
The command will output a human-oriented table by default organized into
rows with 16 columns each.
For machine parsable, stable output use the
.Fl p
and
.Fl o
options.
.Pp
The table will use the following characters to indicate specific cases:
.Bl -tag -width Ds
.It @
Indicates that a device was found at the address.
.It -
Indicates that no device was found at the address.
.It S
Indicates that the address was skipped as the
.Fl d
option was used and the address in question wasn't listed.
.It R
Indicates that the address is considered reserved and therefore was not
scanned.
.It X
Indicates that a time out occurred.
.It Err
Indicates that an error occurred.
Following the table, a list of address-specific errors will be printed.
.El
.Pp
Unfortunately, the only way to determine if a device is there is by
attempting to do I/O to it.
The scan defaults to performing a single byte read.
Note, there is no safe way to scan for devices and it is quite possible
for system damage to occur from scanning!
.Pp
The following fields are supported when using machine parsable output:
.Bl -tag -width RESULT
.It Sy ADDR
The I2C address that was scanned, printed in hexadecimal.
.It Sy RESULT
A string that describes the result.
Valid strings include:
.Dq found ,
.Dq missing ,
.Dq reserved ,
.Dq timeout ,
.Dq error ,
and
.Dq skipped .
.It Sy ERROR
A string that includes information about the error that occurred.
This is only valid if the
.Sy RESULT
field is error.
.El
The following options are supported:
.Bl -tag -width Fl
.It Fl d Ar device
Restrict the scan to the specified I2C address.
This may be specified multiple times to only scan a subset of devices.
.It Fl H
Omit the column header when printing output.
.It Fl o Ar field Ns [,...]
A comma-delineated list of fields to output, selected from the ones
above.
.It Fl p
Displays the output in a machine-parsable format.
When requesting parsable output, the
.Fl o
option is required to specifically control which fields are included.
.El
.Pp
The following operands are required:
.Bl -tag -width Ar
.It Ar port
An I2C path that terminates at a port.
If the port is downstream of a multiplexor, all of the segments required
to send to that port will be enabled, allowing the results to be
included in the scan.
Otherwise, multiplexors will be disabled during the scan.
.El
.El
.Sh PROPERTIES
The system supports a number of named I2C properties.
Properties are consider either read-only or read-write.
Some properties may be read-write on one controller and then read-only
or possibly even unsupported on another controller.
Whether a property is supported, is writable, and the valid values a
property can take will vary from one controller to another.
.Pp
There are some properties which control timing parameters on the I2C
bus.
These properties often have a single instance for each speed that the
I2C bus can operate at.
This allows for one to set the tuning properties to the correct value
before changing the speed without impacting the current operation.
.Pp
Properties have a specific type which is either the
.Sy u32
or
.Sy bit32
which are 32-bit integers that represent a single value or a bitfield
where each bit conveys its own meaning respectively.
A few properties such as
.Em speed ,
.Em type ,
and
.Em smbus-ops
have well known string values that correspond to fields.
By default the tools print the stable human-readable strings for these.
Properties with these are called out in the property table.
.Pp
The following properties are supported:
.Bl -tag -width clock-Thigh-high
.It speed
Describes the frequency of the bus.
This is a
.Sy u32
that is translated to the following string values:
.Bl -tag -width fast-plus
.It Sy standard
100 kHz standard operation.
.It Sy fast
400 kHz fast-mode operation.
.It Sy fast-plus
1 MHz fast-mode plus operation.
.It Sy high
3.4 MHz high-speed operation.
.It Sy ultra
5 MHz ultra-fast operation.
.El
.It ports
A
.Sy u32
property that indicates the number of ports under the controller.
This property is always read-only and generally will be 1.
.It type
Describes the type of controller.
This is always read-only
.Sy u32
property that is translated to the following string values:
.Bl -tag -width smbus
.It i2c
Indicates that this is an I2C controller.
.It i3c
Indicates that this is an I3C controller.
.It smbus
Indicates that this is an SMBus controller.
.El
.Pp
Some controllers can support more than one I/O command request.
For example, all I3C controllers support operating as an I2C controller.
Similarly some SMBus controllers support first-class I2C operation.
This property only indicates the primary mode of the controller.
.It smbus-ops
Describes the set of SMBus operations that the controller supports.
This is a read-only
.Sy bit32
property that is translated to the following string values:
.Bl -tag -width write-i2c-block
.It Sy quick
The controller supports the SMBus quick read and write operation.
.It Sy send-byte
The controller supports the SMBus send byte operation.
.It Sy recv-byte
The controller supports the SMBus receive byte operation.
.It Sy write-byte
The controller supports the SMBus write byte operation.
.It Sy read-byte
The controller supports the SMBus read byte operation.
.It Sy write-word
The controller supports the SMBus write word
.Pq 16-bit
operation.
.It Sy read-word
The controller supports the SMBus read word
.Pq 16-bit
operation.
.It Sy process-call
The controller supports the SMBus process call operation which transmits
a 16-bit value and then reads back a 16-bit value.
.It Sy write-block
The controller supports the SMBus write block operation which transmits
the SMBus command, the byte length, and all the bytes.
.It Sy read-block
The controller supports the SMBus read block operation which reads a
variable number of bytes that are indicated by the target.
.It Sy host-notify
The controller supports sending out the host notification command.
This is generally only used for SMBus targets and not controllers.
.It Sy block-call
The controller supports the SMBus block call operation which transmits
and then receives a variable number of bytes.
.It Sy write-u32
The controller supports the SMBus write 32-bit operation.
.It Sy read-u32
The controller supports the SMBus read 32-bit operation.
.It Sy write-u64
The controller supports the SMBus write 64-bit operation.
.It Sy read-u64
The controller supports the SMBus read 64-bit operation.
.It Sy write-i2c-block
The controller supports a variant of the write block operation that is
compatible with I2C by not transmitting the number of bytes that the
controller will send.
.It Sy read-i2c-block
The controller supports a variant of the read block operation that is
compatible with I2C by explicitly reading a fixed number of bytes.
The number of bytes is not transmitted on the wire.
.El
.It i2c-max-read
This is a read-only
.Sy u32
property that indicates the largest I2C read the controller can
receive in one operation.
.It i2c-max-write
This is a read-only
.Sy u32
property that indicates the largest I2C write the controller can
transmit in one operation.
.It smbus-max-block
This is a read-only
.Sy u32
property that indicates the largest SMBus block operation the controller
can perform.
.It clock-Thigh-std
This property indicates the high period of the I2C clock.
It is a
.Sy u32
property that is counted in terms of clock cycles.
This property only applies when the bus is operating at standard speed.
.It clock-Tlow-std
This property indicates the low period of the I2C clock.
It is a
.Sy u32
property that is counted in terms of clock cycles.
This property only applies when the bus is operating at standard speed.
.It clock-Thigh-fast
This property indicates the high period of the I2C clock.
It is a
.Sy u32
property that is counted in terms of clock cycles.
This property only applies when the bus is operating at fast-mode and
fast-mode plus speeds.
.It clock-Tlow-fast
This property indicates the low period of the I2C clock.
It is a
.Sy u32
property that is counted in terms of clock cycles.
This property only applies when the bus is operating at fast-mode and
fast-mode plus speeds.
.It clock-Thigh-high
This property indicates the high period of the I2C clock.
It is a
.Sy u32
property that is counted in terms of clock cycles.
This property only applies when the bus is operating at fast-mode and
high speed.
.It clock-Tlow-high
This property indicates the low period of the I2C clock.
It is a
.Sy u32
property that is counted in terms of clock cycles.
This property only applies when the bus is operating at fast-mode and
high speed.
.El
.Sh EXIT STATUS
The
.Nm
utility exits 0 on success.
If an error occurs, it exits 1, and provides additional details about
the underlying cause of the error.
If there was an invalid or missing command line options, then
.Nm
exits 2.
.Pp
When performing a listing operation, if no items are listed or if a filter
is specified but is not matched, then these conditions are all treated as
errors and
.Nm
exits 1.
.Sh EXAMPLES
.Sy Example 1
Listing Controllers
.Pp
This example shows how to discover I2C and SMBus controllers in the
system.
.Bd -literal -offset indent
# i2cadm controller list
NAME        TYPE      SPEED       NPORTS  PROVIDER
ismt0       smbus     standard    1       /pci@0,0/pci8086,7270@f/i2cnex@ismt0
pchsmbus0   smbus     standard    1       /pci@0,0/pci8086,7270@1f,
                                          4/i2cnex@pchsmbus0
.Ed
.Pp
The controller information can be changed by requesting specific fields
or adding a filter:
.Bd -literal -offset indent
# i2cadm controller list -o name,speed ismt
NAME        SPEED
ismt0       standard
.Ed
.Pp
.Sy Example 2
Listing Devices
.Pp
This example shows how to discover the I2C devices that the system knows
about.
.Bd -literal -offset indent
# i2cadm device list
NAME        ADDR        INSTANCE        PATH
at24c32     0x50        at24c0          ismt0/0/0x50
pca9548     0x72        pca954x0        pchsmbus0/0/0x72
pca9548     0x73        pca954x1        pchsmbus0/0/0x73
pca9548     0x74        pca954x2        pchsmbus0/0/0x74
pca9548     0x75        pca954x3        pchsmbus0/0/0x75
pca9548     0x76        pca954x4        pchsmbus0/0/0x76
tmp431      0x4c        tmp43x0         pchsmbus0/0/0x72/6/0x4c
lm75        0x48        lm7x0           pchsmbus0/0/0x73/1/0x48
lm75        0x49        lm7x1           pchsmbus0/0/0x73/1/0x49
lm75        0x4a        lm7x2           pchsmbus0/0/0x73/1/0x4a
lm75        0x4b        lm7x3           pchsmbus0/0/0x73/1/0x4b
lm75        0x4c        lm7x4           pchsmbus0/0/0x73/1/0x4c
lm75        0x4d        lm7x5           pchsmbus0/0/0x73/1/0x4d
lm75        0x4e        lm7x6           pchsmbus0/0/0x73/1/0x4e
lm75        0x4f        lm7x7           pchsmbus0/0/0x73/1/0x4f
.Ed
.Pp
One can also print out a subset of devices in a parsable form:
.Bd -literal -offset indent
# i2cadm device list -Hpo name,path lm75
lm75:pchsmbus0/0/0x73/1/0x48
lm75:pchsmbus0/0/0x73/1/0x49
lm75:pchsmbus0/0/0x73/1/0x4a
lm75:pchsmbus0/0/0x73/1/0x4b
lm75:pchsmbus0/0/0x73/1/0x4c
lm75:pchsmbus0/0/0x73/1/0x4d
lm75:pchsmbus0/0/0x73/1/0x4e
lm75:pchsmbus0/0/0x73/1/0x4f
.Ed
.Pp
.Sy Example 3
Adding a Device
.Pp
This example shows how we would add an AT24C32 EEPROM that is at
address 0x50.
.Bd -literal -offset indent
# i2cadm device add ismt0/0 at24c32 0x50
# i2cadm device list at24c32
NAME        ADDR        INSTANCE        PATH
at24c32     0x50        at24c0          ismt0/0/0x50
.Ed
.Pp
Let's say we now wanted to add a TMP431 with 7-bit address address 0x4c
that is under port 6 of an 8-port PCA9548 at 0x72:
.Bd -literal -offset indent
# i2cadm mux list pca954x0
DEVICE      NPORTS      NAME        INSTANCE        PATH
pca9548     8           pca954x0    pca954x0        pchsmbus0/0/0x72
# i2cadm device add pchsmbus0/0/0x72/6 tmp431 0x4c
# i2cadm device list tmp431
NAME        ADDR        INSTANCE        PATH
tmp431      0x4c        tmp43x0         pchsmbus0/0/0x72/6/0x4c
.Ed
.Pp
.Sy Example 4
Scanning an I2C bus
.Pp
This shows
.Bd -literal
# i2cadm scan pchsmbus0/0
Device scan on pchsmbus0/0:

        - = No Device      @ = Device Found
        R = Reserved       S = Skipped
        X = Timed Out    Err = Error

ADDR    0x0 0x1 0x2 0x3 0x4 0x5 0x6 0x7 0x8 0x9 0xa 0xb 0xc 0xd 0xe 0xf
0x00      R   R   R   R   R   R   R   R   -   -   -   -   -   -   -   -
0x10      -   -   -   -   -   -   -   -   -   -   -   -   -   -   -   -
0x20      -   -   -   -   -   -   -   -   -   -   -   -   -   -   -   -
0x30      -   -   -   -   -   -   -   -   -   -   -   -   -   -   -   -
0x40      -   -   -   -   @   -   -   -   -   -   -   -   -   -   -   -
0x50      -   -   -   -   -   -   -   -   -   -   -   -   -   -   -   -
0x60      -   -   -   -   -   -   -   -   @   -   -   -   -   -   -   -
0x70      -   -   @   @   @   @   @   -   R   R   R   R   R   R   R   R
.Ed
.Pp
To instead scan on a port of a given mux, you would change the path to
indicate that.
For example:
.Bd -literal
# i2cadm scan pchsmbus0/0/0x72/6
Device scan on pchsmbus0/0/0x72/6:

        - = No Device      @ = Device Found
        R = Reserved       S = Skipped
        X = Timed Out    Err = Error

ADDR    0x0 0x1 0x2 0x3 0x4 0x5 0x6 0x7 0x8 0x9 0xa 0xb 0xc 0xd 0xe 0xf
0x00      R   R   R   R   R   R   R   R   -   -   -   -   -   -   -   -
0x10      -   -   -   -   -   -   -   -   -   -   -   -   -   -   -   -
0x20      -   -   -   -   -   -   -   -   -   -   -   -   -   -   -   -
0x30      -   -   -   -   -   -   -   -   -   -   -   -   -   -   -   -
0x40      -   -   -   -   @   -   -   -   -   -   -   -   @   -   -   -
0x50      -   -   -   -   -   -   -   -   -   -   -   -   -   -   -   -
0x60      -   -   -   -   -   -   -   -   @   -   -   -   -   -   -   -
0x70      -   -   @   @   @   @   @   -   R   R   R   R   R   R   R   R
.Ed
.Pp
.Sy Example 5
Printing a Port Address Map
.Pp
The following shows how to see a list of addresses that are in use on a
given port according to the system.
This may not be every device that is present on the bus as the system
may not have been told about them.
.Bd -literal
# i2cadm port map pchsmbus0/0
Address map for pchsmbus0/0:

        - = No Device      L = Local Device
        S = Shared         v = Downstream
                           E = Error

ADDR    0x0 0x1 0x2 0x3 0x4 0x5 0x6 0x7 0x8 0x9 0xa 0xb 0xc 0xd 0xe 0xf
0x00      -   -   -   -   -   -   -   -   -   -   -   -   -   -   -   -
0x10      -   -   -   -   -   -   -   -   -   -   -   -   -   -   -   -
0x20      -   -   -   -   -   -   -   -   -   -   -   -   -   -   -   -
0x30      -   -   -   -   -   -   -   -   -   -   -   -   -   -   -   -
0x40      -   -   -   -   -   -   -   -  1v  1v  1v  1v  2v  1v  1v  1v
0x50      -   -   -   -   -   -   -   -   -   -   -   -   -   -   -   -
0x60      -   -   -   -   -   -   -   -   -   -   -   -   -   -   -   -
0x70      -   -   L   L   L   L   L   -   -   -   -   -   -   -   -   -
.Ed
.Pp
In this case there are a number of downstream devices on this port that
are below the muxes.
If we then ask for the map of everything on a given mux port that most
of those are on we'd instead see:
.Bd -literal
# i2cadm port map pchsmbus0/0/0x73/1
Address map for pchsmbus0/0/0x73/1:

        - = No Device      L = Local Device
        S = Shared         v = Downstream
                           E = Error

ADDR    0x0 0x1 0x2 0x3 0x4 0x5 0x6 0x7 0x8 0x9 0xa 0xb 0xc 0xd 0xe 0xf
0x00      -   -   -   -   -   -   -   -   -   -   -   -   -   -   -   -
0x10      -   -   -   -   -   -   -   -   -   -   -   -   -   -   -   -
0x20      -   -   -   -   -   -   -   -   -   -   -   -   -   -   -   -
0x30      -   -   -   -   -   -   -   -   -   -   -   -   -   -   -   -
0x40      -   -   -   -   -   -   -   -   L   L   L   L   L   L   L   L
0x50      -   -   -   -   -   -   -   -   -   -   -   -   -   -   -   -
0x60      -   -   -   -   -   -   -   -   -   -   -   -   -   -   -   -
0x70      -   -   -   -   -   -   -   -   -   -   -   -   -   -   -   -
.Ed
.Sh INTERFACE STABILITY
The command line interface of
.Nm
is
.Sy Evolving .
The output of
.Nm
is
.Sy Not-An-Interface
and may change at any time.
.Sh SEE ALSO
.Xr ofmt 3OFMT