1.\" 2.\" Copyright (C) 2008-2009 Semihalf, Michal Hajduk and Bartlomiej Sieka 3.\" All rights reserved. 4.\" 5.\" Redistribution and use in source and binary forms, with or without 6.\" modification, are permitted provided that the following conditions 7.\" are met: 8.\" 1. Redistributions of source code must retain the above copyright 9.\" notice, this list of conditions and the following disclaimer. 10.\" 2. Redistributions in binary form must reproduce the above copyright 11.\" notice, this list of conditions and the following disclaimer in the 12.\" documentation and/or other materials provided with the distribution. 13.\" 14.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 15.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17.\" ARE DISCLAIMED. IN NO EVENT SHALL AUTHOR OR CONTRIBUTORS BE LIABLE 18.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24.\" SUCH DAMAGE. 25.\" 26.\" $FreeBSD$ 27.\" 28.Dd May 22, 2019 29.Dt I2C 8 30.Os 31.Sh NAME 32.Nm i2c 33.Nd test I2C bus and slave devices 34.Sh SYNOPSIS 35.Nm 36.Cm -a Ar address 37.Op Fl f Ar device 38.Op Fl d Ar r|w 39.Op Fl w Ar 0|8|16|16LE|16BE 40.Op Fl o Ar offset 41.Op Fl c Ar count 42.Op Fl m Ar tr|ss|rs|no 43.Op Fl b 44.Op Fl v 45.Nm 46.Cm -h 47.Nm 48.Cm -i 49.Op Fl v 50.Op Ar cmd ... 51.Op Ar - 52.Nm 53.Cm -r 54.Op Fl f Ar device 55.Op Fl v 56.Nm 57.Cm -s 58.Op Fl f Ar device 59.Op Fl n Ar skip_addr 60.Op Fl v 61.Sh DESCRIPTION 62The 63.Nm 64utility can be used to perform raw data transfers (read or write) to devices 65on an I2C bus. 66It can also scan the bus for available devices and reset the I2C controller. 67.Pp 68The options are as follows: 69.Bl -tag -width ".Fl d Ar direction" 70.It Fl a Ar address 717-bit address on the I2C device to operate on (hex). 72.It Fl b 73binary mode - when performing a read operation, the data read from the device 74is output in binary format on stdout. 75.It Fl c Ar count 76number of bytes to transfer (decimal). 77.It Fl d Ar r|w 78transfer direction: r - read, w - write. 79Data to be written is read from stdin as binary bytes. 80.It Fl f Ar device 81I2C bus to use (default is /dev/iic0). 82.It Fl i 83Interpreted mode 84.It Fl h 85Help 86.It Fl m Ar tr|ss|rs|no 87addressing mode, i.e., I2C bus operations performed after the offset for the 88transfer has been written to the device and before the actual read/write 89operation. 90.Bl -tag -compact -offset indent 91.It Va tr 92complete-transfer 93.It Va ss 94stop then start 95.It Va rs 96repeated start 97.It Va no 98none 99.El 100Some I2C bus hardware does not provide control over the individual start, 101repeat-start, and stop operations. 102Such hardware can only perform a complete transfer of the offset and the 103data as a single operation. 104The 105.Va tr 106mode creates control structures describing the transfer and submits them 107to the driver as a single complete transaction. 108This mode works on all types of I2C hardware. 109.It Fl n Ar skip_addr 110address(es) to be skipped during bus scan. 111One or more addresses ([0x]xx) or ranges of addresses 112([0x]xx-[0x]xx or [0x]xx..[0x]xx) separated by commas or colons. 113.It Fl o Ar offset 114offset within the device for data transfer (hex). 115The default is zero. 116Use 117.Dq -w 0 118to disable writing of the offset to the slave. 119.It Fl r 120reset the controller. 121.It Fl s 122scan the bus for devices. 123.It Fl v 124be verbose. 125.It Fl w Ar 0|8|16|16LE|16BE 126device offset width (in bits). 127This is used to determine how to pass 128.Ar offset 129specified with 130.Fl o 131to the slave. 132Zero means that the offset is ignored and not passed to the slave at all. 133The endianess defaults to little-endian. 134.El 135.Sh INTERPRETED MODE 136When started with 137.Fl i 138any remaining arguments are interpreted as commands, and 139if the last argument is '-', or there are no arguments, 140commands will (also) be read from stdin. 141.Pp 142Available commands: 143.Bl -tag -compact 144.It 'r' bus address [0|8|16|16LE|16BE] offset count 145Read command, count bytes are read and hexdumped to stdout. 146.It 'w' bus address [0|8|16|16LE|16BE] offset hexstring 147Write command, hexstring (white-space is allowed) is written to device. 148.It 'p' anything 149Print command, the entire line is printed to stdout. (This can be used 150for synchronization.) 151.El 152.Pp 153All numeric fields accept canonical decimal/octal/hex notation. 154.Pp 155Without the 156.Fl v 157option, all errors are fatal with non-zero exit status. 158.Pp 159With the 160.Fl v 161option, no errors are fatal, and all commands will return 162either "OK\en" or "ERROR\en" on stdout. 163In case of error, detailed diagnostics will precede that on stderr. 164.Pp 165Blank lines and lines starting with '#' are ignored. 166.Sh EXAMPLES 167.Bl -bullet 168.It 169Scan the default bus (/dev/iic0) for devices: 170.Pp 171i2c -s 172.It 173Scan the default bus (/dev/iic0) for devices and skip addresses 1740x45 to 0x47 (inclusive) and 0x56. 175.Pp 176i2c -s -n 0x56,45-47 177.It 178Read 8 bytes of data from device at address 0x56 (e.g., an EEPROM): 179.Pp 180i2c -a 0x56 -d r -c 8 181.It 182Write 16 bytes of data from file data.bin to device 0x56 at offset 0x10: 183.Pp 184i2c -a 0x56 -d w -c 16 -o 0x10 -b < data.bin 185.It 186Copy 4 bytes between two EEPROMs (0x56 on /dev/iic1 to 0x57 on /dev/iic0): 187.Pp 188i2c -a 0x56 -f /dev/iic1 -d r -c 0x4 -b | i2c -a 0x57 -f /dev/iic0 -d w -c 4 -b 189.It 190Reset the controller: 191.Pp 192i2c -f /dev/iic1 -r 193.It 194Read 8 bytes at address 24 in an EEPROM: 195.Pp 196i2c -i 'r 0 0x50 16BE 24 8' 197.It 198Read 2x8 bytes at address 24 and 48 in an EEPROM: 199.Pp 200echo 'r 0 0x50 16BE 48 8' | i2c -i 'r 0 0x50 16BE 24 8' - 201.El 202.Sh WARNING 203Many systems store critical low-level information in I2C memories, and 204may contain other I2C devices, such as temperature or voltage sensors. 205Reading these can disturb the firmware's operation and writing to them 206can "brick" the hardware. 207.Sh SEE ALSO 208.Xr iic 4 , 209.Xr iicbus 4 210.Xr smbus 4 211.Sh HISTORY 212The 213.Nm 214utility appeared in 215.Fx 8.0 . 216.Sh AUTHORS 217.An -nosplit 218The 219.Nm 220utility and this manual page were written by 221.An Bartlomiej Sieka Aq Mt tur@semihalf.com 222and 223.An Michal Hajduk Aq Mt mih@semihalf.com . 224.Pp 225.An Poul-Henning Kamp Aq Mt phk@FreeBSD.org 226added interpreted mode. 227