Hi, thank you for the review > On Thu, 22 Nov 2018 11:01:00 +0000 > "Popa, Stefan Serban" <StefanSerban.Popa@xxxxxxxxxx> wrote: > > I think that instead of setting the gain directly, we should use > > the IIO_CHAN_INFO_SCALE attribute. At page 12 of the ad7780 datasheet there > > is a formula from which the output code can be calculated: > > Code = 2^(N − 1) > > × [(AIN × Gain /VREF) + 1]. So, by setting the scale from user space, the > > driver can calculate the correct gain by using the formula above. Also, it > > would be useful to introduce scale available. > > Furthermore, there is a new > > ad7124 adc driver which does this exact thing. Take a look here: https://gi > > thub.com/analogdevicesinc/linux/blob/master/drivers/iio/adc/ad7124.c#L337. We have some questions about the code you provided to us: 1-) What is exactly the inputs for the write_raw function? 2-) Could you give more details about the math around lines 346-348? Is it correct to assume that the multiplication at line 346 won't overflow? (vref is an uint) And regarding our code: 1-) The val in our write_raw function should be, in case of GAIN, a number that best approximate the actual gain value of 1 or 128? For instance, if the user inputs 126, we should default to 128? 2-) In the case of FILTER, is it the same? Is the user sending the value in mHz (milihertz)? Thank you
