Document established Devicetree bindings maintainers review practice:
1. Device node names should not be treated as an ABI, unless for
children of a device when documented.
There were many patches posted using of_find_node_by_name() or
of_node_name_eq() for accessing siblings or completely different
nodes. These cases were introducing undocumented ABI, so they are
discouraged.
2. 'simple-mfd' means children do not depend on parent device resources.
'simple-bus' is so simple, that even 'reg' properties are not
applicable.
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20250818132534.120217-2-krzysztof.kozlowski@linaro.org
Signed-off-by: Rob Herring (Arm) <robh@kernel.org>
devices only need child nodes when the child nodes have their own DT
resources. A single node can be multiple providers (e.g. clocks and resets).
+- DON'T treat device node names as a stable ABI, but instead use phandles or
+ compatibles to find sibling devices. Exception: sub-nodes of given device
+ could be treated as ABI, if explicitly documented in the bindings.
+
- DON'T use 'syscon' alone without a specific compatible string. A 'syscon'
hardware block should have a compatible string unique enough to infer the
register layout of the entire block (at a minimum).
+- DON'T use 'simple-mfd' compatible for non-trivial devices, where children
+ depend on some resources from the parent. Similarly, 'simple-bus' should not
+ be used for complex buses and even 'regs' property means device is not
+ a simple bus.
+
Properties
==========
projects / thirdparty / kernel / stable.git / commitdiff
