PATCH/RFC [0/3]: Fix suspend and other acceleromter issues

[Werner Almesberger]

Andy Green wrote:
> I read the datasheets (we have two now) for lis302dl again before
> writing that last mail and I did not find an explanation for what clears
> the interrupt source in hardware there.

The description of the LIR bit in FF_WU_CFG_1 suggests what may be the
mechanism:

| Latch Interrupt request into FF_WU_SRC reg with the FF_WU_SRC reg
| cleared by reading FF_WU_SRC_1 reg. Default value: 0

A possible model may be that interrupt-worthy events are signaled as
edges inside the accelerometer, and that LIR has to be set to turn
them into something a level-triggering CPU can digest. If the GPIO
is configured to edge-triggered, it may be interesting to see if
things improve if LIR is cleared.

(That's from the October 2008 data sheet. Didn't check the others.
I think we actually have three - Dkay had a really ancient one ;-)

- Werner