diff options
Diffstat (limited to '')
| -rw-r--r-- | Documentation/misc-devices/eeprom.rst | 107 |
1 files changed, 0 insertions, 107 deletions
diff --git a/Documentation/misc-devices/eeprom.rst b/Documentation/misc-devices/eeprom.rst deleted file mode 100644 index 008249675c..0000000000 --- a/Documentation/misc-devices/eeprom.rst +++ /dev/null @@ -1,107 +0,0 @@ -==================== -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 (www.atmel.com), - Catalyst (www.catsemi.com), - Fairchild (www.fairchildsemi.com), - Microchip (www.microchip.com), - Philips (www.semiconductor.philips.com), - Rohm (www.rohm.com), - ST (www.st.com), - Xicor (www.xicor.com), - 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 - ========= ============= ============================================ - - -Authors: - - Frodo Looijaard <frodol@dds.nl>, - - Philip Edelbrock <phil@netroedge.com>, - - Jean Delvare <jdelvare@suse.de>, - - Greg Kroah-Hartman <greg@kroah.com>, - - IBM Corp. - -Description ------------ - -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. - -Use ---- - -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. |