Jonathon, You wrote; <snip> Units don't look right for sampling frequency. Sorry, but that's an abi issue so even if it is fiddly to do the conversion to Hz it needs to be done. </snip> Need some help here. In the tsl2x7x driver sampling frequency is being used for setting "persistence register". It's actually a H/W filter. Here is an abstract from the data sheet: -- Persistence Register (0x0C) The persistence register controls the filtering interrupt capabilities of the device. Configurable filtering is provided to allow interrupts to be generated after each ADC integration cycle or if the ADC integration has produced a result that is outside of the values specified by threshold register for some specified amount of time. Separate filtering is provided for proximity and ALS functions. ALS interrupts are generated using C0DATA. -- The value provided here by the ABI is actually the number of 'consecutive values out of range'. The H/W takes care of counting the consecutive values out of range and issues and interrupt when reached. The timing (or frequency) of these out of range values are based on the ALS or Prox integration time (determined by that respective setting). That being the case a fixed table of sampling "frequencies" cannot be reasonably defined - as the frequency can vary widely, based on other settings. So the register really is set to the desired number of 'values out of range'. To add another slight twist, the value (number of out of range) increases by 1 until 5, then by 5 until 60 - with the caveat that a value of 0 generates an interrupt every ALS or Prox integration cycle . Since the sysfs-bus-iio doc contained a close match with respect to the operation: Description: Some devices have internal clocks. This parameter sets the resulting sampling frequency. In many devices this parameter has an effect on input filters etc rather than simply controlling when the input is sampled. As this effects datardy triggers, hardware buffers and the sysfs direct access interfaces, it may be found in any of the relevant directories. If it effects all of the above then it is to be found in the base device directory. Thus we used "sampling_frequency" - but now I am wondering if it should be something else. If this is better suited for a different ABI please tell me what that would be. Please help! Jon -- 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
