On Jo, 2018-11-08 at 10:34 -0600, Rob Herring wrote: > On Thu, Nov 8, 2018 at 9:02 AM Popa, Stefan Serban > <StefanSerban.Popa@xxxxxxxxxx> wrote: > > > > > > On Sb, 2018-11-03 at 12:16 +0000, Jonathan Cameron wrote: > > > > > > On Mon, 29 Oct 2018 18:38:31 +0200 > > > Stefan Popa <stefan.popa@xxxxxxxxxx> wrote: > > > > > > > > > > > > > > > The ad7124-4 and ad7124-8 are a family of 4 and 8 channel sigma- > > > > delta > > > > ADCs > > > > with 24-bit precision and reference. > > > > > > > > Three power modes are available which in turn affect the output > > > > data > > > > rate: > > > > * Full power: 9.38 SPS to 19,200 SPS > > > > * Mid power: 2.34 SPS to 4800 SPS > > > > * Low power: 1.17 SPS to 2400 SPS > > > > > > > > The ad7124-4 can be configured to have four differential inputs, > > > > while > > > > ad7124-8 can have 8. Moreover, ad7124 also supports per channel > > > > configuration. Each configuration consists of gain, reference > > > > source, > > > > output data rate and bipolar/unipolar configuration. > > > > > > > > Datasheets: > > > > Link: http://www.analog.com/media/en/technical-documentation/data-s > > > > heet > > > > s/AD7124-4.pdf > > > > Link: http://www.analog.com/media/en/technical-documentation/data-s > > > > heet > > > > s/ad7124-8.pdf > > > > > > > > Signed-off-by: Stefan Popa <stefan.popa@xxxxxxxxxx> > > > Hi Stefan, > > > > > > The discussion around the DT binding has gotten me looking at bit > > > more closely at that for this version. > > > > > > Some most comments in that section. Also a really minor ordering > > > issue > > > in > > > remove which I'd just have fixed if we weren't going around again for > > > the binding. > > > > > > Main binding thing is I don't think the odr value belongs in DT. > > > Gain is more marginal (unless the part can actually be damaged by > > > a wrong value - which I hope it can't!). I'm not that fussed > > > as there are definitely reasons to specify a default scale to > > > cover the reasonable range on a pin. > > > > > > Thanks, > > > > > > Jonathan > > Hi Jonathan, > > > > Thank you for the review! So, how should I proceed? > > > > First, we need an adc.txt file where "bipolar" and something like > > "diff- > > channels" should be documented. Should the file be placed under > > Documentation/devicetree/bindings/iio/adc? > Yes. > > > > > Regarding the "odr-hz" property, it totally makes sense to remove it > > from > > the DT. How about the "gain"? Should we leave it in the DT and also add > > the > > possibility to be configured from user space? > Look at other bindings. I think there are others having gain. If not, > then it probably should only be user space configurable. If so, then > can it be a common property too. > > Rob > Hi Rob, I found only a couple of examples using gain in other bindings, so I guess it's not common practice. I will remove the gain as well from the DT and set it with the default of 1. @Jonathan: I think that IIO_CHAN_INFO_HARDWAREGAIN is the attribute that can be used in user space? Thank you! -Stefan
