On Wed, 6 Jan 2021 21:23:53 +0000 Jyoti Bhayana <jbhayana@xxxxxxxxxx> wrote: > Hi Jonathan, > > Instead of adding IIO_VAL_INT_H32_L32, I am thinking of adding IIO_VAL_FRACTIONAL_LONG > or IIO_VAL_FRACTIONAL_64 as the scale/exponent used for min/max range can be different > than the one used in resolution according to specification. That's somewhat 'odd'. Given min/max are inherently values the sensor is supposed to be able to return why give them different resolutions? Can you point me at a specific section of the spec? The axis_min_range_low etc fields don't seem to have units specified but I assumed they were in sensor units and so same scale factors? > > I am planning to use read_avail for IIO_CHAN_INFO_PROCESSED using IIO_AVAIL_RANGE > and this new IIO_VAL_FRACTIONAL_64 for min range,max range and resolution. > Instead of two values used in IIO_VAL_FRACTIONAL, IIO_VAL_FRACTIONAL_64 will use 4 values > val_high,val_low,and val2_high and val2_low. I'm not keen on the changing that internal kernel interface unless we absolutely have to. read_avail() is called from consumer drivers and they won't know anything about this new variant. > > Let me know if that is an acceptable solution. Hmm. It isn't a standard use of the ABI given the value in the buffer is (I assume) raw (needs scale applied). However, it isn't excluded by the ABI docs. Whether a standard userspace is going to expect it is not clear to me. I don't want to end up in a position where we end up with available being generally added for processed when what most people care about is what the value range they might get from a polled read is (rather than via a buffer). So I'm not that keen on this solution but if we can find a way to avoid it. Jonathan > > > Thanks, > Jyoti >
