Yes, multiple sibling nodes with the same name are not allowed by dtc.
I believe multiple siblings of the same name is legal with
OpenFirmware, but that is at least partially because in OpenFirmware
the @<addr> portion isn't necessarily part of the name. (Imagine
having triplets and naming them sa...@1, sa...@2 and sa...@3!)
I'm not sure how to parse the above because the word "name" seems to be
used somewhat informally.
The Open Firmware situation is this:
a) At a given level of the tree, there can be any number of nodes with
the same value for the "name" property. For example, you could plug in
several PCI Ethernet adapters and each would have "ethernet" as the
value of the "name" property. In general, the "name" property is not
intended as a unique identifier, but rather as a mnemonic for human
convenience. The unique identifier is the first component of the "reg"
property (within the context of the parent node). The whole schema for
reg properties is driven by this uniqueness requirement, along with the
observation that the computer hardware must have some physical means of
addressing specific devices. The "reg" properties mimic physical
addresses on various bus domains.
b) A fully-qualified device specifier component includes both the name
property value and the reg property value (AKA the unit address), for
example "ether...@5".
c) It is possible to have a "wildcard" device node that contains an Open
Firmware driver for a given device, but its bus has not been fully
probed so you don't yet know the addresses (reg properties) for the
actual devices. In that case, you can have a "name" property but no
"reg" property. You can have a wildcard node "disk" and some explicit
nodes "d...@1", "d...@2" as siblings. When searching the device tree,
nodes with reg properties take precedence over wildcard nodes, so the
wildcard node is a "fallback" to use if you can't find an explicit
"n...@reg" match. In principle, you could have several wildcard nodes
with the same name at the same level of the tree, but if so, the search
would find only the most recently defined one, so for all practical
purposes it is as if only one exists.
Wildcard nodes are useful for Open Firmware driver binding, and could
potentially be used for OS driver binding for either hot-plugged or
late-probed devices. Whether or not they fit well into the dtc scheme,
I can't say.
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