Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 976cf205 authored by Wolfram Sang's avatar Wolfram Sang Committed by Wolfram Sang
Browse files

i2c: slave: docs: be more precise about the prerequsites 



There was some confusion what was needed to utilize the slave support,
so let's be more precise about this. Add an introductory paragraph to
the development section while we are here.

Signed-off-by: default avatarWolfram Sang <wsa+renesas@sang-engineering.com>
Acked-by: default avatarGeert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: default avatarWolfram Sang <wsa@the-dreams.de>
parent 1fb2ad95

Documentation/i2c/slave-interface

+15 −10
Original line number Original line Diff line number Diff line
@@ -3,16 +3,16 @@ Linux I2C slave interface description 




by Wolfram Sang <wsa@sang-engineering.com> in 2014-15

by Wolfram Sang <wsa@sang-engineering.com> in 2014-15





Linux can also be an I2C slave in case I2C controllers have slave support.

Linux can also be an I2C slave if the I2C controller in use has slave

Besides this HW requirement, one also needs a software backend providing the

functionality. For that to work, one needs slave support in the bus driver plus

actual functionality. An example for this is the slave-eeprom driver, which

a hardware independent software backend providing the actual functionality. An

acts as a dual memory driver. While another I2C master on the bus can access it

example for the latter is the slave-eeprom driver, which acts as a dual memory

like a regular EEPROM, the Linux I2C slave can access the content via sysfs and

driver. While another I2C master on the bus can access it like a regular

retrieve/provide information as needed. The software backend driver and the I2C

EEPROM, the Linux I2C slave can access the content via sysfs and handle data as

bus driver communicate via events. Here is a small graph visualizing the data

needed. The backend driver and the I2C bus driver communicate via events. Here

flow and the means by which data is transported. The dotted line marks only one

is a small graph visualizing the data flow and the means by which data is

example. The backend could also use e.g. a character device, be in-kernel

transported. The dotted line marks only one example. The backend could also

only, or something completely different:

use a character device, be in-kernel only, or something completely different:









              e.g. sysfs        I2C slave events        I/O registers

              e.g. sysfs        I2C slave events        I/O registers
@@ -43,6 +43,11 @@ behaviour and setup. 
Developer manual

Developer manual

================

================





First, the events which are used by the bus driver and the backend will be

described in detail. After that, some implementation hints for extending bus

drivers and writing backends will be given.





I2C slave events

I2C slave events

----------------

----------------