> I agree with your understanding. It's a rising threshold, just that the input > will only reflect high frequency changes in the signal. Thank you for the clarification. I am hoping this gets merged in the next window if no other issues. Thanks, Hari On Sun, Sep 3, 2017 at 12:24 PM, Jonathan Cameron <jic23@xxxxxxxxxx> wrote: > On Tue, 29 Aug 2017 23:01:16 -0400 > harinath Nampally <harinath922@xxxxxxxxx> wrote: > >> > We should never say "transient is for rising >> > direction" or "ff_mt is for falling direction". any combination is fine. >> >> Ok I agree that there is no hard and fast rule that "transient is for rising >> direction" or "ff_mt is for falling direction". >> But in our case, datasheet for these chips define these events based on >> acceleration magnitude rising or falling below a set threshold value. >> >> For quick reference, below excerpts are from fxls8471 datasheet: >> Motion Event: "When the acceleration exceeds a set threshold for a set >> amount of time, >> the motion interrupt is asserted." >> >> Freefall event: "The detection of “Freefall” involves the monitoring >> of the X, Y, and Z axes >> for the condition where the acceleration magnitude is below a >> user-specified threshold >> for a user-definable amount of time" >> >> Transient event: "When the high-pass filter is bypassed, the >> functionality becomes >> similar to the motion-detection function; in this mode, acceleration >> greater than >> a programmable threshold is detected (along an axis)." >> >> Therefore I think in this driver freefall event is defined as >> 'falling' event type and >> motion event is defined as 'rising' event type and Transient is also defined as >> 'rising' event type. >> As you might already know that mma8562 and mma8563 doesn't have >> transient event support >> but they do have freefall and motion event support which are defined >> as 'fall' and 'rise' >> event types respectively. Please note in this driver, motion event is >> enabled/configured only >> for mma8652 and mma8653. >> Therefore if I read/write sysfs node for 'rise' it should use the >> FF_MT registers for mma8652 and mma853, but for all others like >> mma8451, mma8452 and >> mma8453 which has transient event support it picks the Transient >> registers if enabled. Also please >> note transient event is enabled(but not motion event) for mma8451, >> mma8452 and mma8453. >> The problem seems like we have two different events(motion and >> transient) that are defined >> as same event type 'rising' but in fact both motion and transient are >> pretty much similar as they >> both raise interrupt flag when the acceleration magnitude rises above >> the threshold. >> Only difference is transient event has its own event config registers >> with High pass filter. >> If HPF bypassed using config register transient event acts like motion >> detection event. > >> >> That was my understanding but please correct me if I am wrong. > > I agree with your understanding. It's a rising threshold, just that the input > will only reflect high frequency changes in the signal. > >> >> > Only freefall mode needs one fix: remembering to which set of registers to fall back when >> > disabling it. >> >> I don't quite understand what you mean by 'to fall back when disabling >> it'. Please elaborate. I would >> appreciate if you could suggest your logic in the form of pseudo-code. >> Thanks for your time >> > ... -- To unsubscribe from this list: send the line "unsubscribe linux-iio" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
