Implement a nice generalization suggested by Bobby Noelte.
Instead of having a generic #cells key in bindings, have source-specific
*-cells keys. Some examples:
interrupt-cells:
- irq
- priority
- flags
gpio-cells:
- pin
- flags
pwm-cells:
- channel
- period
This makes bindings a bit easier to read, and allows a node to be a
controller for many different 'phandle-array' properties.
The prefix before *-cells is derived from the property name, meaning
there's no fixed set of *-cells keys. This is possible because of the
earlier 'phandle-array' generalization.
The older #cells key is supported for backwards compatibility, but
generates a deprecation warning.
Signed-off-by: Ulf Magnusson <Ulf.Magnusson@nordicsemi.no>
Deprecate 'sub-node:' and add a more general 'child-binding:' mechanism
to bindings. Keep supporting 'sub-node:', but print a deprecation
warning when it's used.
Like 'sub-node:', 'child-binding:' gives a binding to child nodes, but
the binding is required to be a complete binding, and is treated (and
checked) like a normal binding.
'child-binding:' can in turn contain another 'child-binding:', up to any
number of levels. This is automatic from treating it like a normal
binding, and from the code initializing parent Devices before child
Devices.
This lets nodes give bindings to grandchildren.
For example, take this devicetree fragment:
parent {
compatible = "foo";
child-1 {
grandchild-1 {
...
};
grandchild-2 {
...
};
};
child-2 {
grandchild-3 {
...
};
};
};
The binding for 'foo' could provide bindings for grandchild-1/2/3 like
this:
compatible: "foo"
# Binding for children
child-binding:
title: ...
description: ...
...
# Binding for grandchildren
child-binding:
title: ...
description: ...
properties:
...
Due to implementation issues with the old devicetree scripts, only two
levels of 'child-binding:' is supported for now. This limitation will go
away in Zephyr 2.2.
Piggyback shortening 'description:' and 'title:' in some bindings that
provide child bindings. This makes the generated header a bit neater.
Signed-off-by: Ulf Magnusson <Ulf.Magnusson@nordicsemi.no>
Instead of
properties:
compatible:
constraint: "foo"
, just have
compatible: "foo"
at the top level of the binding.
For backwards compatibility, the old 'properties: compatible: ...' form
is still accepted for now, and is treated the same as a single-element
'compatible:'.
The old syntax was inspired by dt-schema (though it isn't
dt-schema-compatible), which is in turn a thin wrapper around
json-schema (the idea is to transform .dts files into YAML and then
verify them).
Maybe the idea was to gradually switch the syntax over to dt-schema and
then be able to use unmodified dt-schema bindings, but dt-schema is
really a different kind of tool (a completely standalone linter), and
works very differently from our stuff (see schemas/dt-core.yaml in the
dt-schema repo to get an idea of just how differently).
Better to keep it simple.
This commit also piggybacks some clarifications to the binding template
re. '#cells:'.
Signed-off-by: Ulf Magnusson <Ulf.Magnusson@nordicsemi.no>
Having backwards compatibility for !include and 'constraint:' is silly
without also having backwards compatibility for 'category:', because
that forces a binding change anyway.
Add backwards compatibility for 'category:', and just print a
deprecation warning when it's used.
Also move tests for deprecated features into a dedicated
test-bindings/deprecated.yaml binding, instead of piggybacking on other
tests.
Signed-off-by: Ulf Magnusson <Ulf.Magnusson@nordicsemi.no>
