[PATCH 1/2]: export-irq-functionality.patch
andy at openmoko.com
Sat Nov 15 19:37:56 CET 2008
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Somebody in the thread at some point said:
|>> But it's a problem to solve if and when we concentrate on getting
|>> lis302dl upstream, difficult as that may anyway be, so I sent both of
|>> these on stable-tracking.
|> Thanks. I'm also slightly worried about the upstreaming. Although I'm
|> hardy an expert, I really see no other way than extending the SPI
|> interface with some "raw" interface that can be used from interrupt
|> context. That looks to me like a daunting task.
| I don't know it if this could be usefull but there's been a submission
| of an accelerometer driver (ST LIS3LV02Dx) for mainline inclusion, see
|  - http://lkml.org/lkml/2008/10/18/144
Thanks for the tip... I guess this explains why that driver doesn't have
the difficulty around SPI IO in interrupt context...
''* Andrew Morton asked to investigate using interrupt-based sensor
reading (instead of timer-based): it turns out not useful because the
sensor generate interrupts even if the data has not changed, so we end
up waking up at 40Hz''
I think it is useful alright to have a reliably constant period between
samples, it just makes trouble for IO subsystem that can't operate in
interrupt context; the threshold stuff can help with the absolute amount
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