On Fri, Jun 12, 2020 at 02:02:55PM -0600, Rob Herring wrote: > What's the expected property length in these 2 cases?: > > prop = /bits/ 16 <0x1234 0x5678>, <0x9abc 0xdef0>; > prop = /bits/ 16 <0x1234 0x5678 0x9abc 0xdef0>; > > For 32-bit sizes, the <> don't matter. I had assumed /bits/ applied to > the whole property value and the <> don't matter in that case either. > But that's not the case in dtc. In the 1st example, the last 2 values > are 32-bit. In order to make all values in the 1st example 16-bit, we > have to do: > > prop = /bits/ 16 <0x1234 0x5678>, /bits/ 16 <0x9abc 0xdef0>; > > That also means one could do: > > prop = /bits/ 16 <0x1234 0x5678>, /bits/ 8 <0x9a 0xbc 0xde 0xf0>; > > Something we want to support (it already works)? Allowing that was my intention when I added this code. > I don't think such a > thing exists in the wild, Well, arrays of 16-bit or 8-bit values in the tree are pretty rare to begin with. The reason I wanted to allow mixed things here is that properties with mixed types of data absolutely do exist in bindings out there. Note that I suspect there could well be some examples out there with mixed 64-bit and 32-bit values, which could also this form if it's useful to do so. e.g. 'reg' of nodes on a bus with #address-cells = 2 and #size-cells = 1 could be like that. > the kernel's array parsing doesn't expect > it, and I haven't encountered a use for it. Given the non-existent > type information in FDT, that doesn't seem like a great idea. Hrm. To me, it's this way precisely *because* there's no type information. Properties are bytestrings, any internal structure is added by bindings. dtc's job here isn't to impose a structure that doesn't exist onto properties, just to provide tools to let people build those bytestrings in the most convenient possible way. -- David Gibson | I'll have my music baroque, and my code david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_ | _way_ _around_! http://www.ozlabs.org/~dgibson
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