NAME

       i2cget - read from I2C/SMBus chip registers

SYNOPSIS

       i2cget [-f] [-y] i2cbus chip-address [data-address [mode]]
       i2cget -V

DESCRIPTION

       i2cget is a small helper program to read registers visible through the I2C bus (or SMBus).

OPTIONS

       -V     Display the version and exit.

       -f     Force  access to the device even if it is already busy. By default, i2cget will refuse to access a
              device which is already under the control of a kernel driver. Using this flag is dangerous, it can
              seriously  confuse  the  kernel  driver in question. It can also cause i2cget to return an invalid
              value. So use at your own risk and only if you know what you're doing.

       -y     Disable interactive mode. By default, i2cget will wait for a confirmation  from  the  user  before
              messing  with the I2C bus. When this flag is used, it will perform the operation directly. This is
              mainly meant to be used in scripts. Use with caution.

       There are two required options to i2cget. i2cbus indicates the number or  name  of  the  I2C  bus  to  be
       scanned.   This  number  should  correspond  to  one  of  the busses listed by i2cdetect -l. chip-address
       specifies the address of the chip on that bus, and is an integer between 0x03 and 0x77.

       data-address specifies the address on that chip to read from, and is an integer between 0x00 and 0xFF. If
       omitted, the currently active register will be read (if that makes sense for the considered chip).

       The  mode  parameter, if specified, is one of the letters b, w or c, corresponding to a read byte data, a
       read word data or a write byte/read byte transaction, respectively. A p can also be appended to the  mode
       parameter  to  enable  PEC.  If  the  mode  parameter  is  omitted,  i2cget  defaults to a read byte data
       transaction, unless data-address is also omitted, in which case the default (and only valid)  transaction
       is a single read byte.

WARNING

       i2cget  can  be  extremely dangerous if used improperly. I2C and SMBus are designed in such a way that an
       SMBus read transaction can be seen as a write transaction by certain chips. This is particularly true  if
       setting mode to cp (write byte/read byte with PEC). Be extremely careful using this program.

SEE ALSO

       i2cdump(8), i2cset(8)

AUTHOR

       Jean Delvare

       This manual page was strongly inspired from those written by David Z Maze for i2cset.

                                                    May 2008                                           I2CGET(8)