Please help with I2c on S3c processor

[Bill Gatliff]

Is there a kernel thread servicing the i2c peripheral? It would need to go
on the RT scheduler too.

b.g.
---
Bill Gatliff
Embedded Linux Training and Consulting
bgat at billgatliff.com

On May 4, 2010 5:34 AM, "Guido Piasenza" <g.piasenza at fidia.it> wrote:

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


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