I am having problem using the I2C bus. I am using an ARM920T processor, the I2C control register is at 0x54000000. I wrote a new value to I2CCON, but the value is still 0x0, so are the other I2C registers.

I wrote the registers as a user space driver (mmap() the /dev/mem file), and I also setup the SDA and SCL pin in GPIO configuration before this. Could anybody give me some suggestions about what is wrong? Thank you.