<p>Is there a kernel thread servicing the i2c peripheral? It would need to go on the RT scheduler too.</p>
<p>b.g.<br>
---<br>
Bill Gatliff<br>
Embedded Linux Training and Consulting<br>
<a href="mailto:bgat@billgatliff.com">bgat@billgatliff.com</a><br>
</p>
<p><blockquote type="cite">On May 4, 2010 5:34 AM, "Guido Piasenza" <<a href="mailto:g.piasenza@fidia.it">g.piasenza@fidia.it</a>> wrote:<br><br>Hi everyone,<br>
<br>
I tried to look up this topic everywhere but could not find any reference to it...<br>
<br>
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.<br>
<br>
<br>
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.<br>
<br>
<br>
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.<br>
<br>
<br>
Any help really appreciated !<br>
<br>
Thanks<br>
<br>
Guido<br>
<br>
<br>
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