I2C subsystem on Sitara AM335x : where is what

ritu sharma

Hi,

I am trying to understand i2c subsystem in linux by working on a beagle bone black.

As a newbie in linux am a bit perplexed by the vast functionality provided by linux for i2c.

Moreover the terminology : bus driver, adapters, client driver theoretically its clear but I want to look at the sources specific to AM335x and beaglebone black.

Could someone point me to :

1. i2c adapter and algorithm driver sources(in case both are present) or combined implementation.

2. a simple client driver source which is already present on BBB or is easily available would be great.

Any material explaining them wrt AM335X SOC or the client driver also would help.

Cheers

Ritu

over 11 years ago

0 nikunj.rudani over 11 years ago

Expert 1990 points

linux-source/Documentation/i2c/ has lot of the information you'd need. .../writing-clients.txt is a good place to start.

Have a look at the online version:

https://www.kernel.org/doc/Documentation/i2c/writing-clients

There is an okay sort of a tutorial at:

http://renjucnair.blogspot.ca/2012/01/writing-i2c-client-driver.html

Here is a good commentary on someone writing an i2c driver and has a tutorial feel to it:

http://www.embedded-bits.co.uk/2009/i2c-in-the-2632-linux-kernel/

Here is some sample code:

http://code.google.com/p/ldd-templates/source/browse/drivers/i2c/sample-i2c-client.c

0 ritu sharma over 11 years ago in reply to nikunj.rudani

Prodigy 50 points

Hi Nikunj,

Thanks for reply, but I am looking at the bus driver part as I have earlier worked on i2c controller drivers with threadx.

so, I want to know how bus drivers are implemented. specifically for beaglebone black(sitara family) since this is the board I have.

What I have understood from reading at various sources:

1. I2C controller is driven by a) bus driver(present in /drivers/i2c/busses/) and algo driver (/drivers/i2c/algos/)

what i do not understand is where is the adapter driver....

Anyway, so if someone could point me to the sources with classification between bus driver, algo driver and adapter driver would be great.

)

0 ritu sharma over 11 years ago in reply to ritu sharma

Prodigy 50 points

Additionally I do not find any AM33xx related bus driver in /driver/i2c/busses. Only i2c-omap.c is present ???? a I missing something ?

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I2C subsystem on Sitara AM335x : where is what