On 9/20/2010 11:08 AM, Nori, Sekhar wrote:

> Hi Michael,
> 
> On Sat, Sep 18, 2010 at 18:38:13, Michael Williamson wrote:
>>
>> * I'm not sure I understand why there is a "intr_line" field in the platform
>> data and then a possibility to configure an "io_type" as interrupt or polled 
>> at
>> the chip select level.  I got burned by setting the "io_type" to 
>> SPI_IO_TYPE_INTR
>> and not setting "intr_line" to non-zero.  The probe just hung because it was
>> trying to use interrupts but never setting SPILVL register.  These fields 
>> aren't
>> mutually exclusive.  Is the intent to support a configuration with one chip 
>> select
>> running in polled mode and another in interrupt mode?  If so, then it seems 
>> the SPILVL
>> register logic needs some attention during each transfer.
> 
> The intr_line to be set is constant for the SoC. So, irrespective of what the
> individual devices on a given board choose to operate (interrupted, polled or 
> DMA)
> the SoC code (da850.c) should setup the intr_line according to how the SPI 
> interrupt
> is wired within the SoC. Can you clarify what you mean by "needs some 
> attention during
> each transfer"?
> 


Ah... OK.  Thank you.  I now see that the SPILVL can be INT0 or INT1 for other 
davinci
SoCs like the DM644x.  For the da850 (OMAP-L138), SPILVL is valid only for 
INT1.  So 
pretty much, if your using a da850 (at least), intr_line has to be 1.  On other 
platforms,
it carries a lot more meaning...

Please ignore my ignorance...

Let me know if you want testing on the DMA portion of the patch (when your 
ready, of course).  

-Mike




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