Linux I2C slave EEPROM backendΒΆ

by Wolfram Sang <> in 2014-20

This backend simulates an EEPROM on the connected I2C bus. Its memory contents can be accessed from userspace via this file located in sysfs:


The following types are available: 24c02, 24c32, 24c64, and 24c512. Read-only variants are also supported. The name needed for instantiating has the form 'slave-<type>[ro]'. Examples follow:

24c02, read/write, address 0x64:

# echo slave-24c02 0x1064 > /sys/bus/i2c/devices/i2c-1/new_device

24c512, read-only, address 0x42:

# echo slave-24c512ro 0x1042 > /sys/bus/i2c/devices/i2c-1/new_device

You can also preload data during boot if a device-property named 'firmware-name' contains a valid filename (DT or ACPI only).

As of 2015, Linux doesn't support poll on binary sysfs files, so there is no notification when another master changed the content.