| 1 | .TH I2CGET 8 "May 2008" |
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| 2 | .SH "NAME" |
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| 3 | i2cget \- read from I2C/SMBus chip registers |
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| 4 | |
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| 5 | .SH SYNOPSIS |
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| 6 | .B i2cget |
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| 7 | .RB [ -f ] |
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| 8 | .RB [ -y ] |
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| 9 | .I i2cbus |
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| 10 | .I chip-address |
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| 11 | .RI [ "data-address " [ mode ]] |
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| 12 | .br |
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| 13 | .B i2cget |
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| 14 | .B -V |
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| 15 | |
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| 16 | .SH DESCRIPTION |
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| 17 | i2cget is a small helper program to read registers visible through the I2C |
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| 18 | bus (or SMBus). |
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| 19 | |
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| 20 | .SH OPTIONS |
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| 21 | .TP |
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| 22 | .B -V |
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| 23 | Display the version and exit. |
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| 24 | .TP |
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| 25 | .B -f |
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| 26 | Force access to the device even if it is already busy. By default, i2cget |
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| 27 | will refuse to access a device which is already under the control of a |
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| 28 | kernel driver. Using this flag is dangerous, it can seriously confuse the |
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| 29 | kernel driver in question. It can also cause i2cget to return an invalid |
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| 30 | value. So use at your own risk and only if you know what you're doing. |
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| 31 | .TP |
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| 32 | .B -y |
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| 33 | Disable interactive mode. By default, i2cget will wait for a confirmation |
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| 34 | from the user before messing with the I2C bus. When this flag is used, it |
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| 35 | will perform the operation directly. This is mainly meant to be used in |
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| 36 | scripts. Use with caution. |
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| 37 | .PP |
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| 38 | There are two required options to i2cget. \fIi2cbus\fR indicates the number |
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| 39 | or name of the I2C bus to be scanned. This number should correspond to one of |
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| 40 | the busses listed by \fIi2cdetect -l\fR. \fIchip-address\fR specifies the |
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| 41 | address of the chip on that bus, and is an integer between 0x03 and 0x77. |
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| 42 | .PP |
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| 43 | \fIdata-address\fR specifies the address on that chip to read from, and is |
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| 44 | an integer between 0x00 and 0xFF. If omitted, the currently active register |
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| 45 | will be read (if that makes sense for the considered chip). |
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| 46 | .PP |
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| 47 | The \fImode\fR parameter, if specified, is one of the letters \fBb\fP, |
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| 48 | \fBw\fP or \fBc\fP, corresponding to a read byte data, a read word data or a |
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| 49 | write byte/read byte transaction, respectively. A \fBp\fP can also be appended |
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| 50 | to the \fImode\fR parameter to enable PEC. If the \fImode\fR parameter is omitted, |
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| 51 | i2cget defaults to a read byte data transaction, unless \fIdata-address\fR is |
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| 52 | also omitted, in which case the default (and only valid) transaction is a |
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| 53 | single read byte. |
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| 54 | |
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| 55 | .SH WARNING |
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| 56 | i2cget can be extremely dangerous if used improperly. I2C and SMBus are designed |
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| 57 | in such a way that an SMBus read transaction can be seen as a write transaction by |
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| 58 | certain chips. This is particularly true if setting \fImode\fR to \fBcp\fP (write byte/read |
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| 59 | byte with PEC). Be extremely careful using this program. |
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| 60 | |
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| 61 | .SH SEE ALSO |
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| 62 | i2cdump(8), i2cset(8) |
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| 63 | |
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| 64 | .SH AUTHOR |
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| 65 | Jean Delvare |
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| 66 | |
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| 67 | This manual page was strongly inspired from those written by David Z Maze |
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| 68 | for i2cset. |
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