linux/Documentation/i2c/slave-eeprom-backend.rst
Wolfram Sang 59d3d6042d i2c: slave-eeprom: update documentation
Add more details which have either been missing ever since or describe
recent additions.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Reviewed-by: Luca Ceresoli <luca@lucaceresoli.net>
Signed-off-by: Wolfram Sang <wsa@kernel.org>
2020-07-04 08:17:53 +02:00

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Linux I2C slave EEPROM backend
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by Wolfram Sang <wsa@sang-engineering.com> 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::
/sys/bus/i2c/devices/<device-directory>/slave-eeprom
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.