i2c-tools --------- The i2c-tools package contains a heterogeneous set of I2C tools for Linux: a bus probing tool, a chip dumper, register-level SMBus access helpers, EEPROM decoding scripts, EEPROM programming tools, and a python module for SMBus access. I2CDETECT(8) System Manager's Manual I2CDETECT(8) NAME i2cdetect - detect I2C chips SYNOPSIS i2cdetect [-y] [-a] [-q|-r] i2cbus [first last] i2cdetect -F i2cbus i2cdetect -V i2cdetect -l DESCRIPTION i2cdetect is a userspace program to scan an I2C bus for devices. It outputs a table with the list of detected devices on the specified bus. i2cbus indicates the number or name of the I2C bus to be scanned, and should correspond to one of the busses listed by i2cdetect -l. The optional parameters first and last restrict the scanning range (default: from 0x03 to 0x77). i2cdetect can also be used to query the functionalities of an I2C bus (see option -F.) WARNING This program can confuse your I2C bus, cause data loss and worse! INTERPRETING THE OUTPUT Each cell in the output table will contain one of the following sym- bols: . "--". The address was probed but no chip answered. . "UU". Probing was skipped, because this address is currently in use by a driver. This strongly suggests that there is a chip at this address. . An address number in hexadecimal, e.g. "2d" or "4e". A chip was found at this address. OPTIONS -y Disable interactive mode. By default, i2cdetect 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. -a Force scanning of non-regular addresses. Not recommended. -q Use SMBus "quick write" commands for probing (by default, the command used is the one believed to be the safest for each address). Not recommended. This is known to corrupt the Atmel AT24RF08 EEPROM found on many IBM Thinkpad laptops. -r Use SMBus "read byte" commands for probing (by default, the com- mand used is the one believed to be the safest for each address). Not recommended. This is known to lock SMBus on vari- ous write-only chips (most notably clock chips at address 0x69). -F Display the list of functionalities implemented by the adapter and exit. -V Display the version and exit. -l Output a list of installed busses. SEE ALSO i2cdump(8), sensors-detect(8) AUTHOR Frodo Looijaard, Mark D. Studebaker and Jean Delvare This manual page was originally written by Aurelien Jarno , for the Debian GNU/Linux system. April 2008 I2CDETECT(8) 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 danger- ous, 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 corre- spond 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 EEP- ROMs. 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 information 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 for the Debian GNU/Linux system. May 2008 I2CDUMP(8) 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 danger- ous, 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 regis- ter 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, cor- responding 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 set- ting 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) ------------------------------------------------------------------------------ I2CSET(8) System Manager's Manual I2CSET(8) NAME i2cset - set I2C registers SYNOPSIS i2cset [-f] [-y] [-m mask] [-r] i2cbus chip-address data-address [value] ... [mode] i2cset -V DESCRIPTION i2cset is a small helper program to set 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, i2cset will refuse to access a device which is already under the control of a kernel driver. Using this flag is danger- ous, it can seriously confuse the kernel driver in question. It can also cause i2cset to silently write to the wrong register. So use at your own risk and only if you know what you're doing. -y Disable interactive mode. By default, i2cset 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. -m mask The mask parameter, if specified, describes which bits of value will be actually written to data-address. Bits set to 1 in the mask are taken from value, while bits set to 0 will be read from data-address and thus preserved by the operation. Please note that this parameter assumes that the read and write operations for the specified mode are symmetrical for the device you are accessing. This may or may not be the case, as neither I2C nor SMBus guarantees this. -r Read back the value right after writing it, and compare the result with the value written. This used to be the default behavior. The same limitations apply as those of option -m. There are three required options to i2cset. 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 write to, and is an integer between 0x00 and 0xFF. The value parameter, if specified, is the value to write to that loca- tion on the chip. If this parameter is omitted, then a short write is issued. For most chips, it simply sets an internal pointer to the tar- get location, but doesn't actually write to that location. For a few chips though, in particular simple ones with a single register, this short write is an actual write. If the mode parameter is s or i, multi- ple values can be specified. The mode parameter, if specified, is one of the letters b, w, s, or i, corresponding to a write size of a single byte, a 16-bit word, a SMBus block write, or an I2C block write, respectively. For SMBus and I2C block writes, the write size is determined by the number of value parameters. Except for I2C block writes, a p can also be appended to the mode parameter to enable PEC. If the mode parameter is omitted, i2cset defaults to byte mode without PEC. The value provided must be within range for the specified data type (0x00-0xFF for byte and block writes, 0x0000-0xFFFF for words). Another possible mode is c, which doesn't write any value (so-called short write). You usually don't have to specify this mode, as it is the default when no value is provided, unless you also want to enable PEC. WARNING i2cset can be extremely dangerous if used improperly. It can confuse your I2C bus, cause data loss, or have more serious side effects. Writ- ing to a serial EEPROM on a memory DIMM (chip addresses between 0x50 and 0x57) may DESTROY your memory, leaving your system unbootable! Be extremely careful using this program. SEE ALSO i2cdump(8), isaset(8) AUTHOR Frodo Looijaard, Mark D. Studebaker and Jean Delvare This manual page was originally written by David Z Maze for the Debian GNU/Linux system. November 2008 I2CSET(8) ------------------------------------------------------------------------------