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-Kernel driver eeprom
-Supported chips:
- * Any EEPROM chip in the designated address range
- Prefix: 'eeprom'
- Addresses scanned: I2C 0x50 - 0x57
- Datasheets: Publicly available from:
- Atmel (,
- Catalyst (,
- Fairchild (,
- Microchip (,
- Philips (,
- Rohm (,
- ST (,
- Xicor (,
- and others.
- Chip Size (bits) Address
- 24C01 1K 0x50 (shadows at 0x51 - 0x57)
- 24C01A 1K 0x50 - 0x57 (Typical device on DIMMs)
- 24C02 2K 0x50 - 0x57
- 24C04 4K 0x50, 0x52, 0x54, 0x56
- (additional data at 0x51, 0x53, 0x55, 0x57)
- 24C08 8K 0x50, 0x54 (additional data at 0x51, 0x52,
- 0x53, 0x55, 0x56, 0x57)
- 24C16 16K 0x50 (additional data at 0x51 - 0x57)
- Sony 2K 0x57
- Atmel 34C02B 2K 0x50 - 0x57, SW write protect at 0x30-37
- Catalyst 34FC02 2K 0x50 - 0x57, SW write protect at 0x30-37
- Catalyst 34RC02 2K 0x50 - 0x57, SW write protect at 0x30-37
- Fairchild 34W02 2K 0x50 - 0x57, SW write protect at 0x30-37
- Microchip 24AA52 2K 0x50 - 0x57, SW write protect at 0x30-37
- ST M34C02 2K 0x50 - 0x57, SW write protect at 0x30-37
- Frodo Looijaard <>,
- Philip Edelbrock <>,
- Jean Delvare <>,
- Greg Kroah-Hartman <>,
- IBM Corp.
-This is a simple EEPROM module meant to enable reading the first 256 bytes
-of an EEPROM (on a SDRAM DIMM for example). However, it will access serial
-EEPROMs on any I2C adapter. The supported devices are generically called
-24Cxx, and are listed above; however the numbering for these
-industry-standard devices may vary by manufacturer.
-This module was a programming exercise to get used to the new project
-organization laid out by Frodo, but it should be at least completely
-effective for decoding the contents of EEPROMs on DIMMs.
-DIMMS will typically contain a 24C01A or 24C02, or the 34C02 variants.
-The other devices will not be found on a DIMM because they respond to more
-than one address.
-DDC Monitors may contain any device. Often a 24C01, which responds to all 8
-addresses, is found.
-Recent Sony Vaio laptops have an EEPROM at 0x57. We couldn't get the
-specification, so it is guess work and far from being complete.
-The Microchip 24AA52/24LCS52, ST M34C02, and others support an additional
-software write protect register at 0x30 - 0x37 (0x20 less than the memory
-location). The chip responds to "write quick" detection at this address but
-does not respond to byte reads. If this register is present, the lower 128
-bytes of the memory array are not write protected. Any byte data write to
-this address will write protect the memory array permanently, and the
-device will no longer respond at the 0x30-37 address. The eeprom driver
-does not support this register.
-Lacking functionality:
-* Full support for larger devices (24C04, 24C08, 24C16). These are not
-typically found on a PC. These devices will appear as separate devices at
-multiple addresses.
-* Support for really large devices (24C32, 24C64, 24C128, 24C256, 24C512).
-These devices require two-byte address fields and are not supported.
-* Enable Writing. Again, no technical reason why not, but making it easy
-to change the contents of the EEPROMs (on DIMMs anyway) also makes it easy
-to disable the DIMMs (potentially preventing the computer from booting)
-until the values are restored somehow.
-After inserting the module (and any other required SMBus/i2c modules), you
-should have some EEPROM directories in /sys/bus/i2c/devices/* of names such
-as "0-0050". Inside each of these is a series of files, the eeprom file
-contains the binary data from EEPROM.