Re: I2C

[arasv@xxxxxxxxxxxxxx]

> Dear All,
>
> I'm still trying to get the I2C working on my AT91RM9200. What's the
> current state of the driver?

It's been working for quite some time. I don't think it has changed in
ages except for the GPIO driver being accepted as necessary for the
at91rm9200.

Which kernel are you looking at?


> Which driver should I use (soft or the TWI
> HW)? Any kernel version dependency?

If you can live with the slight overhead, the GPIO driver will work with
all i2c transfer methods (such as block/page transfers to/from i2c
EEPROMs). If you are only ever doing byte-by-byte transfers then the TWI
driver is quite fine.

I use the GPIO method in a mass produced product for its main
configuration. That was kernel 2.6.16.

I just tested the i2c on the 2.6.26.3 kernel for a new product, and it
looked good, ran at about 125KHz as the default speed.


> The wierdest thing is, that I'm not having any i2c-0 nodes in /dev,
> however, the kernel recognises the I2C. Any ideas?

Did you select the i2c-dev module?

Are you running udev? Try running 'udevadm monitor' and insmod the i2c
drivers and see what it says.

Have you tried creating the nodes by hand?

Aras


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