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)