On 12/23/24 5:40 AM, Jonathan Cameron wrote: > On Fri, 20 Dec 2024 14:01:33 +0200 > Antoniu Miclaus <antoniu.miclaus@xxxxxxxxxx> wrote: > >> Add devicetree bindings for ad485x family. >> >> Reviewed-by: Conor Dooley <conor.dooley@xxxxxxxxxxxxx> >> Signed-off-by: Antoniu Miclaus <antoniu.miclaus@xxxxxxxxxx> > Mixed single end and differential channel devices that have per channel > child nodes need a more complex description to avoid reg have different > and possibly clashing meanings for the two types of channel. > > See inline. > ... >> +patternProperties: >> + "^channel(@[0-7])?$": >> + $ref: adc.yaml >> + type: object >> + description: Represents the channels which are connected to the ADC. >> + >> + properties: >> + reg: >> + description: The channel number in single-ended mode. > > And what is it in differential mode? (usually just an index). > Which is a problem if you have a mix. That's why we added > single-channel. This chip isn't a mix-and match like many chips with muxes that use this binding so I think it should just be diff-channels = <0 0>; similar to adi,ad7606. The pins on the chip are labeled IN0+ and IN0- so it makes sense that both the positive and negative inputs to be 0. So, this should be fine with or without a single-channel property since reg should always have the same number as diff-channels and single-channel. > > So for devices where reg isn't enough, you can use: > reg: index of channel, not real meaning just makes them unique. > single-channel: The channel number for single ended. > diff-channels: The channel numbers for differential channels. > >> + minimum: 0 >> + maximum: 7 >> + >> + diff-channels: true > > Should be constraints / information on the values possible. > I've no idea what the 8 is in your example for instance. >
