HI Alexander, On 23-02-03, Alexander Stein wrote: > Am Freitag, 3. Februar 2023, 15:12:17 CET schrieb Marco Felsch: > > Hi, > > > > On 23-02-03, Alexander Stein wrote: > > > > ... > > > > > > > > > > + vref-supply: > > > > > > > > + description: External ADC reference voltage supply on VREFH > > > > > > > > pad. > > > > > > > > > > > > > > Please add it to the list of required properties, we can remove it > > > > > > > as > > > > > > > soon as the driver has support for the internal reference > > > > > > > voltages. > > > > > > > > > > > > I was thinking in doing so before as well. But DT describes the > > > > > > hardware, and this ADC apparently would be functioning without a > > > > > > reference voltage on that pad, using a different one. What the > > > > > > driver > > > > > > actual does is a different matter.> > > > > > > > > > > I have also thought about it first but than I checked the RM which > > > > > says > > > > > that "multi-reference selection" is chip dependent. > > > > > > Nice for pointing this out. I wasn't aware that there are differences. > > > > > > > Oh goody. So is it detectable? > > > > > > That's my problem. I didn't find any source of information which chips do > > > support multiple references and which don't. > > > Marco, do you have some information on this? > > > > You can download the RM from the NXP website but you need an account for > > it: > > https://www.nxp.com/products/processors-and-microcontrollers/arm-processors/ > > i-mx-applications-processors/i-mx-8-applications-processors/i-mx-8-family-ar > > m-cortex-a53-cortex-a72-virtualization-vision-3d-graphics-4k-video:i.MX8 > > > > Or is this the wrong model? The naming scheme is quite confusing to me. > > That's i.MX8 (imx8qm), the bindings are for i.MX8X (imx8qxp/imx8dxp). But I > assume the ADC is similar/identical. > > > > > If we are going to stick to a single compatible rather than adding them > > > > for > > > > the variants with and without this feature, should probably add a note > > > > at > > > > least to say it is required for some parts. > > > > > > That's a good idea. I'm okay with that, until there is more information > > > available. > > > > According the RM there is a bit which can be read: Multi Vref > > Implemented (MVI). > > Ah, nice. So there is a hardware feature. From the RM I have available it is > set for both imx8qm and imx8qxp. Given that I will not mark this as required, > but add a comment regarding this feature bit. Can you check the comments about the refsel please? Since this is the important part. Since the RM above states that this bit will indicate a multiref device but it can also the case that, you have a chip with just on ref selection option (external). I can't check this since I don't have the RM for this. @NXP can you give us more information please? Regards, Marco
