Hi Rob, I am splitting this message out as a separate thread because the original one Cced lots of people and lists mainly because it touched lots of subsystems. This discussion is more focussed on device tree side of things. On 15/06/21 01:15PM, Rob Herring wrote: > If a property has an 'items' list, then a 'minItems' or 'maxItems' with the > same size as the list is redundant and can be dropped. Note that is DT > schema specific behavior and not standard json-schema behavior. The tooling > will fixup the final schema adding any unspecified minItems/maxItems. Please understand that things like this have a hidden cost involved. For example, I was thoroughly confused a couple weeks back when I was looking at the binding for spi/cdns,qspi-nor.yaml. It has 4 properties for the subnode: 'cdns,read-delay', 'cdns,tshsl-ns', 'cdns,tsd2d-ns', and 'cdns,tslch-ns'. The latter three are fine with just a description and need nothing else to define their types. The first one needs a $ref to uint32. I could not figure out why. I even looked at the processed JSON schema and came out none the wiser. After banging my head on the table for some time, I finally came across the dt-schema repo's property-units.yaml file which makes every property ending in "-ns" a uint32-array. This is a neat feature and makes writing bindings slightly easier if you know about it. But it makes reading bindings a very difficult process if you don't know about it. The same applies to every little thing that the tooling does in the background in the name of convenience. You are very familiar with the entire ecosystem so these things are obvious for you. They aren't as obvious for most other developers who don't deal with bindings or yaml or JSON schema on a regular basis. I don't know enough about the ecosystem to prescribe whether this or some other hidden behaviour is good or not. But I want you to keep this in mind. The more things tooling does in the background, the more things the average developer needs to know, and the harder it becomes to read and write bindings. > > This condition is partially checked with the meta-schema already, but > only if both 'minItems' and 'maxItems' are equal to the 'items' length. > An improved meta-schema is pending. -- Regards, Pratyush Yadav Texas Instruments Inc.
