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| author | Wolfram Sang <wsa+renesas@sang-engineering.com> | 2020-06-28 20:54:26 +0200 |
|---|---|---|
| committer | Wolfram Sang <wsa@kernel.org> | 2020-07-04 08:17:53 +0200 |
| commit | 59d3d6042d432f36e206127de0dab7f9319762d5 (patch) | |
| tree | ff8f968810777f6e14b1698fec077b06114a02a7 /Documentation | |
| parent | 5f90786b31fb7d1e199a8999d46c4e3aea672e11 (diff) | |
| download | lwn-59d3d6042d432f36e206127de0dab7f9319762d5.tar.gz lwn-59d3d6042d432f36e206127de0dab7f9319762d5.zip | |
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>
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/i2c/slave-eeprom-backend.rst | 22 |
1 files changed, 17 insertions, 5 deletions
diff --git a/Documentation/i2c/slave-eeprom-backend.rst b/Documentation/i2c/slave-eeprom-backend.rst index 0b8cd83698e0..38d951f10302 100644 --- a/Documentation/i2c/slave-eeprom-backend.rst +++ b/Documentation/i2c/slave-eeprom-backend.rst @@ -1,14 +1,26 @@ ============================== -Linux I2C slave eeprom backend +Linux I2C slave EEPROM backend ============================== -by Wolfram Sang <wsa@sang-engineering.com> in 2014-15 +by Wolfram Sang <wsa@sang-engineering.com> in 2014-20 -This is a proof-of-concept backend which acts like an EEPROM on the connected -I2C bus. The memory contents can be modified from userspace via this file -located in sysfs:: +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. |