Please help with I2c on S3c processor

[Guido Piasenza]

Hi everyone,

I tried to look up this topic everywhere but could not find any 
reference to it...

I am writing a software which interfaces a S3C processor to an A/D 
through I2C. I am controlling everything in user mode, i.e. I write a 
strobe and channel selection command to the I2C and I read the results 
with a word read.


The problem is that each read and write operation eats up 10ms. I am not 
sure where these ms come from, I will try to put some traces in the bus 
driver to see where it's lost but I suspect that the calling thread is 
not immediately rescheduled when the interrupt comes and wakes it up. I 
tried setting the scheduler to FIFO and RR, with priority 99, with and 
without preemption in the kernel but nothing changes.


What am I doing wrong ? I checked data with the oscilloscope to see if 
the baud rate is too slow but it seems data get sent out very fast and 
then there is a 10ms delay before further data comes out.


Any help really appreciated !

Thanks

Guido