On Tue, 30 Jul 2024 12:47:10 +0530 Abhash jha <abhashkumarjha123@xxxxxxxxx> wrote: > On Tue, Jul 30, 2024 at 1:23 AM Jonathan Cameron <jic23@xxxxxxxxxx> wrote: > > > > On Mon, 29 Jul 2024 17:20:54 +0530 > > Abhash Jha <abhashkumarjha123@xxxxxxxxx> wrote: > > > > > Add new ALS channel and allow reading raw and scale values. > > > Also provide gain and resolution configuration for ALS channel. > > > Add automatic mode switching between the UVS and ALS channel > > > based on which channel is being accessed. > > > The default mode in which the sensor start is ALS mode. > > > > > > Signed-off-by: Abhash Jha <abhashkumarjha123@xxxxxxxxx> > > Hi Abhash, > > > > Patch looks good but one quick question. > > Why not present an IIO_LIGHT channel? Needs to be converted > > to be illuminance (with scale / offset applied) rather than IIO_INTENSITY > > which we use when the frequency response is different from the requirements > > to measure Lux (and the units get very vague!) > > > > Looks like what you have here is close, but not quite the right scale > > factor as not including integration time and the mysterious 0.6 on the datasheet. > > Yes, I just noticed it now. I will provide the integration time and > 0.6 as part of the > scale calculation in the next version. > > > > > If we can provide a signal scaled to illuminance that tends to be a lot > > more useful for things like screen brightness control because it should > > be close at least to other light sensors. > > > Hi Jonathan, > It did not occur to me that the IIO_LIGHT channel could be used > directly and hence I > went with the IIO_INTENSITY approach. > Yes we could provide the IIO_LIGHT channel and perform lux calculation > in the driver. > Would that mean forgoing the IIO_INTENSITY channel? Or do we keep both? Expose the scaling as _scale for the light channel and don't expose intensity (as it will be the _raw value anyway). It's rare to see a linear function for intensity to lux transform but I think there are one or two others like this. Mostly the transform is nonlinear and involves multiple intensity channels which is why we normally have those and IIO_LIGHT. Thanks, Jonathan > > Abhash > > > Jonathan
