i2cget(8) [centos man page]
I2CGET(8) System Manager's Manual I2CGET(8) 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)
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I2CDUMP(8) System Manager's Manual I2CDUMP(8) NAME
i2cdump - examine I2C registers SYNOPSIS
i2cdump [-f] [-r first-last] [-y] i2cbus address [mode [bank [bankreg]]] i2cdump -V DESCRIPTION
i2cdump is a small helper program to examine registers visible through the I2C bus. OPTIONS
-V Display the version and exit. -f Force access to the device even if it is already busy. By default, i2cdump 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 i2cdump to return invalid results. So use at your own risk and only if you know what you're doing. -r first-last Limit the range of registers being accessed. This option is only available with modes b, w, c and W. For mode W, first must be even and last must be odd. -y Disable interactive mode. By default, i2cdump 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. At least two options must be provided to i2cdump. i2cbus indicates the number or name of the I2C bus to be scanned. This number should cor- respond to one of the busses listed by i2cdetect -l. address indicates the address to be scanned on that bus, and is an integer between 0x03 and 0x77. The mode parameter, if specified, is one of the letters b, w, s, or i, corresponding to a read size of a single byte, a 16-bit word, an SMBus block, an I2C block, respectively. The c mode is a little different, it reads all bytes consecutively, and is useful for chips that have an address auto-increment feature, such as EEPROMs. The W mode is also special, it is similar to w except that a read command will only be issued on even register addresses; this is again mainly useful for EEPROMs. A p can also be appended to the mode parameter (except for i and W) to enable PEC. If the mode parameter is omitted, i2cdump defaults to byte access without PEC. The bank and bankreg parameters are useful on the W83781D and similar chips (at the time of writing, all Winbond and Asus chips). bank is an integer between 0 and 7, and bankreg is an integer between 0x00 and 0xFF (default value: 0x4E). The W83781D data sheet has more informa- tion on bank selection. WARNING
i2cdump can be dangerous if used improperly. Most notably, the c mode starts with WRITING a byte to the chip. On most chips it will be stored in the address pointer register, which is OK, but some chips with a single register or no (visible) register at all will most likely see this as a real WRITE, resulting in possible misbehavior or corruption. Do not use i2cdump on random addresses. Anyway, it is of little use unless you have good knowledge of the chip you're working with and an idea of what you are looking for. SEE ALSO
i2cset(8), i2cdetect(8), isadump(8) AUTHOR
Frodo Looijaard, Mark D. Studebaker and Jean Delvare This manual page was originally written by David Z Maze <dmaze@debian.org> for the Debian GNU/Linux system. May 2008 I2CDUMP(8)