437177b028
128 byte reads are much more common than 32 byte reads. The message passing + setup/teardown for a read is much more expensive, in terms of time, than the reading itself. A slightly bigger struct is well worth the time savings. This reduces read times for /dev/eeprom from 57 seconds per 4KB to 14 seconds. Additionally, make sending the page address in the eeprom driver and utility optional. This can save a little time when reading within the same page and allows support for smaller devices that don't support pages (example: chips containing EDID). Change-Id: Ie48087caee40c11fa241d1555fce9309ddd27b43
56 lines
1.6 KiB
Groff
56 lines
1.6 KiB
Groff
.TH EEPROMREAD 1
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.SH NAME
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eepromread \- read data from an EEPROM
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.SH SYNOPSIS
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\fBeepromread\fR [\fB\-i\fR] [\fB\-f\fR \fIdev\fR] [\fB\-a\fR \fIslave_addr\fR]
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[\fB\-n\fR]
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.br
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.de FL
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.TP
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\\fB\\$1\\fR
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\\$2
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..
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.de EX
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.TP 20
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\\fB\\$1\\fR
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# \\$2
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..
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.SH OPTIONS
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.TP 5
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.B \-i
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# interpret the data on the EEPROM and display it as a set of fields.
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.TP 5
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.B \-f
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# Use \fIdevice\fR instead of \fI/dev/i2c-1\fR.
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.TP 5
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.B \-a
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# Use \fIslave_address\fR instead of \fI0x50\fR.
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.TP 5
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.B \-n
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# Do not send the page number when addressing the memory on the EEPROM. Some
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smaller EEPROM chips aren't organized into pages and get confused if a page
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number is sent with the memory address. Use this when reading EDID.
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.SH EXAMPLES
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.TP 20
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.B eepromread -i
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# display the contents of the EEPROM as a list of label:value pairs.
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.TP 20
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.B eepromread
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# display the first 256 bytes of the EEPROM in HEX and ASCII.
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.TP 20
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.B eepromread -f /dev/i2c-3 -a 0x54
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# display the first 256 bytes of the EEPROM on I2C bus 3, slave address 0x54.
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.TP 20
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.B eepromread -f /dev/i2c-3 -n
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# read the EDID info from the display on I2C bus 3 on the BeagleBoard-xM.
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.SH DESCRIPTION
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.PP
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\fIeepromread\fR is a simple tool for viewing the contents of an EEPROM.
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For EEPROM data that is in a specific format that this program knows how to
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detect, \fIeepromread\fR can properly format each of the fields and display
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the information via the \fI-i\fR command line option.
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.SH NOTES
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If the \fIcat24c256\fR driver has claimed the EEPROM device that this
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program is attempting to read from, then this program will fail. Once
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a driver claims an I2C device, the driver has exclusive access.
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