Add more details which have either been missing ever since or describe recent additions. Signed-off-by: Wolfram Sang <wsa+renesas@xxxxxxxxxxxxxxxxxxxx> --- Change since v1: add 'help' keyword to the Kconfig explanation Documentation/i2c/slave-eeprom-backend.rst | 22 +++++++++++++++++----- drivers/i2c/Kconfig | 4 ++++ 2 files changed, 21 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@xxxxxxxxxxxxxxxxxxxx> in 2014-15 +by Wolfram Sang <wsa@xxxxxxxxxxxxxxxxxxxx> 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. diff --git a/drivers/i2c/Kconfig b/drivers/i2c/Kconfig index ef39c83aaf33..dbcbb8a6024e 100644 --- a/drivers/i2c/Kconfig +++ b/drivers/i2c/Kconfig @@ -119,6 +119,10 @@ if I2C_SLAVE config I2C_SLAVE_EEPROM tristate "I2C eeprom slave driver" + help + This backend makes Linux behave like an I2C EEPROM. Please read + Documentation/i2c/slave-eeprom-backend.rst for further details. + endif config I2C_DEBUG_CORE -- 2.20.1
