The binding-template.yaml file has grown organically into something
that's out of control.
It makes too many 'see above' and 'see below' references to be read
comfortably, and we can't cross reference from YAML.
There are also many example DTS and YAML fragments scattered about in
comments, which cannot be syntax highlighted properly.
Fix that by overhauling the documentation into bindings.rst in the DT
guide. This will let us link to individual sections when answering
questions, allows us to cross-reference and use '.. code-block::',
etc.
A couple of things need to go to other pages.
Signed-off-by: Martí Bolívar <marti.bolivar@nordicsemi.no>
Add the ability to filter which properties get imported when we do an
include. We add a new YAML form for this:
include:
- name: other.yaml
property-blocklist:
- prop-to-block
or
include:
- name: other.yaml
property-allowlist:
- prop-to-allow
These lists can intermix simple file names with maps, like:
include:
- foo.yaml
- name: bar.yaml
property-allowlist:
- prop-to-allow
And you can filter from child bindings like this:
include:
- name: bar.yaml
child-binding:
property-allowlist:
- child-prop-to-allow
Signed-off-by: Kumar Gala <kumar.gala@linaro.org>
Signed-off-by: Martí Bolívar <marti.bolivar@nordicsemi.no>
There are some drivers in the tree that support devices on multiple
different buses, although so far this has not been represented in
device tree using the bus concept. In order to convert these drivers &
bindings to refer to a formal bus in device tree we need to be able to
match bindings which lack an explicit "on-bus: ..." value against any
parent bus. This will also be needed for any external bindings, since
those would not be aware of on-bus (as it's a Zephyhr-specific
extension).
The two drivers I'm particularly targeting is the ns16550 UART driver
(drivers/serial/uart_ns16550.c) and the DW I2C driver
(drivers/i2c/i2c_dw.c). They both support devices with a fixed MMIO
address as well as devices connected and discovered over PCIe. The
only issue is that instead of encoding the bus information the proper
DT way these bindings use a special "pcie" property in the DT node
entries to indicate whether the node is on the PCIe bus or not.
Being able to convert the above two drivers to use the DT bus concept
allow the removal of "hacks" like this:
if DT_INST_PROP(0, pcie) || \
DT_INST_PROP(1, pcie) || \
DT_INST_PROP(2, pcie) || \
DT_INST_PROP(3, pcie)
to the more intuitive:
if DT_ANY_INST_ON_BUS_STATUS_OKAY(pcie)
This also has the benefit that the driver doesn't need to make any
arbitrary assumptions of how many matching devices there may be but
works for any number of matches. This is already a problem now since
e.g. the ns16550 driver assumes a maximum of 4 nodes, whereas
dts/x86/elkhart_lake.dtsi defines up to 9 different ns16550 nodes.
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
The YAML binding allows for a default which is used to substitute a
value if one is not explicit in the devicetree source. This feature
is mis-used when defaults are provided that are likely to be
incorrect.
Document concerns with the use of default and provide guidance for
when it can be used, what to do when it shouldn't, and noting the need
to explain the source of the default in the binding documentation.
Signed-off-by: Peter Bigot <peter.bigot@nordicsemi.no>
Add the ability to mark a property as 'deprecated' to get a warning that
it will be removed in the future.
Signed-off-by: Kumar Gala <kumar.gala@linaro.org>
We deprecated a number of aspects of the DTS binding syntax in Zephyr
2.1. Remove the support for the deprecated syntax. Remove from docs
about the deprecated syntax as well.
Removed reference in release-notes-2.1.rst to legacy_binding_syntax
since that anchor doesn't exist anymore.
Signed-off-by: Kumar Gala <kumar.gala@linaro.org>
Remove some deprecated or obsolete functionality:
- the 'title:' key is now deprecated
- more than 2 levels of child-binding are now supported
Signed-off-by: Martí Bolívar <marti.bolivar@nordicsemi.no>
List the details for each type in the order they appear in the summary
of all types. Add the missing 'path' value to the summary.
Signed-off-by: Martí Bolívar <marti.bolivar@nordicsemi.no>
Add binding support for a 'path' property type, for properties that are
assigned node paths. Usually, paths are assigned with path references
like 'foo = &label' (common in /chosen), but plain strings are accepted
as well as long as they're valid paths.
The 'path' type is mostly for completeness at this point, but might be
useful for https://github.com/zephyrproject-rtos/zephyr/issues/21623.
The support is there already in dtlib.
Signed-off-by: Ulf Magnusson <Ulf.Magnusson@nordicsemi.no>
I keep mixing these up, so that's probably a sign that the names are
bad. The root of the problem is that "parent-bus" can be read as both
"this is the parent bus" and as "the parent bus is this".
Use 'bus:' for the bus "provider" and 'on-bus:' for nodes on the bus
instead, which is less confusing.
Support the old keys for backwards compatibility, along with a
deprecation warning.
Signed-off-by: Ulf Magnusson <Ulf.Magnusson@nordicsemi.no>
Most bindings look something like this:
title: Foo
description: This binding provides a base representation of Foo
That kind of description doesn't add any useful information, as it's
just the title along with some copy-pasted text. I'm not sure what "base
representation" was supposed to mean originally either.
Many bindings also put something that's closer to a description in the
title, because it's not clear what's expected or how the title is used.
In reality, the title isn't used anywhere. 'description:' on the other
hand shows up as a comment in the generated header.
Deprecate 'title:' and generate a long informative warning if it shows
up in a binding.
Next commits will clean up the 'description:' strings (bringing them
closer to 'title:' in most cases) and remove 'title:' from all bindings.
Signed-off-by: Ulf Magnusson <Ulf.Magnusson@nordicsemi.no>
Explain how 'include:' works in some more detail and mention base.yaml,
along with an example of how it can be used.
This was adapted from
https://github.com/zephyrproject-rtos/zephyr/pull/19846.
Signed-off-by: Ulf Magnusson <Ulf.Magnusson@nordicsemi.no>
Do
description: |
instead of
description: >
in the example, to preserve internal newlines in the string. Also link
to https://yaml-multiline.info/, which is handy.
Signed-off-by: Ulf Magnusson <Ulf.Magnusson@nordicsemi.no>
The int, array, string, and string-array property types were not
documented together with the other types, for whatever reason (might've
been too focused on the more complex types and overlooked it). Add
documentation for them.
Also do some minor cleanup on the descriptions, e.g. to make them more
consistent.
Signed-off-by: Ulf Magnusson <Ulf.Magnusson@nordicsemi.no>
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>
Generating generic information for 'type: phandle-array' properties in
edtlib was difficult due to defining phandle-array as just a list of
phandles and numbers. To make sense of a phandle-array property like
'pwms', you have to know that #pwm-cells is expected to appear on
each referenced controller, and that the binding for the controller has
a #cells.
Because of this, handling of various 'type: phandle-array' properties
was previously hardcoded in edtlib and exposed through properties like
Node.pwms, instead of through the generic Node.props (though with a lot
of shared code).
In practice, it turns out that all 'type: phandle-array' properties in
Zephyr work exactly the same way: They all have names that end in -s,
the 's' is removed to derive the name of related properties, and they
all look up #cells in the binding for the controller, which gives names
to the data values.
Strengthen the definition of 'type: phandle-array' to mean a property
that works exactly like the existing phandle-array properties (which
also means requiring that the name ends in -s). This removes a ton of
hardcoding from edtlib and allows new 'type: phandle-array' properties
to be added without making any code changes.
If we ever need a property type that's a list of phandles and numbers
but that doesn't follow this scheme, then we could add a separate type
for it. We should check if the standard scheme is fine first though.
The only property type for which no information is generated is now
'compound'.
There's some inconsistency in how we generate identifiers for clocks
compared to other 'type: phandle-array' properties, so keep
special-casing them for now in gen_defines.py (see the comment in
write_clocks()).
This change also enabled a bunch of other simplifications, like reusing
the ControllerAndData class for interrupts.
Piggyback generalization of *-map properties so that they work for any
phandle-array properties. It's now possible to have things like
'io-channel-map', if you need to.
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
child:
bus: foo
parent:
bus: bar
, have
child-bus: foo
parent-bus: bar
'bus' is the only key that ever appears under 'child' and 'parent'.
Support the old keys for backwards compatibility, with a deprecation
warning if they're used.
Also add 'child/parent-bus' tests to the edtlib test suite. It was
untested before.
I also considered putting more stuff under 'child' and 'parent', but
there's not much point when there's just a few keys I think. Top-level
stuff is cleaner and easier to read.
I'm planning to add a 'child-binding' key a bit later (like 'sub-node',
but more flexible), and child-* is consistent with that.
Also add an unrelated test-bindings/grandchild-3.yaml that was
accidentally left out earlier.
Signed-off-by: Ulf Magnusson <Ulf.Magnusson@nordicsemi.no>
When foo.yaml set some property 'required: true' and bar.yaml set the
same property 'required: false', the check for changing
'required: false' to 'required: true' would raise an error for
include: [bar.yaml, foo.yaml]
(with that particular order due to implementation details).
The order files are included in shouldn't matter. To fix it, change the
logic so that 'required' values are ORed together between included files
(so that 'required: true' is always respected), and remove the
'required' true-to-false check when merging included files.
Keep the true-to-false check when merging the (merged) included files
into the main binding (the binding with the 'include:' in it). This
might give a good organization, and the old scripts do it too.
Piggyback two fixes/cleanups:
- 'compatible' should be allowed to appear in included files
- No need to allow an 'inherits' key in _check_binding(), because
it has been removed before then, when merging bindings
Signed-off-by: Ulf Magnusson <Ulf.Magnusson@nordicsemi.no>
It's a bit subtle in that it's the only type where a property can
generate output even if it doesn't exist.
Signed-off-by: Ulf Magnusson <Ulf.Magnusson@nordicsemi.no>
For missing optional properties, it can be handy to generate a default
value instead of no value, to cut down on #ifdefs.
Allow a default value to be specified in the binding, via a new
'default: <default value>' setting for properties in bindings.
Defaults are supported for both scalar and array types. YAML arrays are
used to specify the value for array types.
'default:' also appears in json-schema, with the same meaning.
Include misc. sanity checks, like the 'default' value matching 'type'.
The documentation changes in binding-template.yaml explain the syntax.
Suggested by Peter A. Bigot in
https://github.com/zephyrproject-rtos/zephyr/issues/17829.
Fixes: #17829
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>
Have
include: foo.dts
include: [foo.dts, bar.dts]
instead of
inherits:
!include foo.dts
inherits:
!include [foo.dts, bar.dts]
This is a nicer and shorter and less cryptic syntax, and will make it
possible to get rid of the custom PyYAML constructor for '!include'
later.
'inherits: !include ...' is still supported for backwards compatibility
for now. Later on, I'm planning to mass-replace it, add a deprecation
warning if it's used, and document 'include:'. Then the '!include'
implementation can be removed a bit later.
'!include' has caused issues in the past (see the comment above the
add_constructor() call), gets iffy with multiple EDT instances, and
makes the code harder to follow.
I'm guessing '!include' might've been intended to be useful outside of
'inherits:' originally, but that's the only place where it's used. It's
undocumented that it's possible to put it elsewhere.
To implement the backwards compatibility, the code just transforms
inherits:
!include foo.dts
into
inherits:
- foo.dts
and treats 'inherits:' similarly to 'include:'. Previously, !include
inserted the contents of the included file instead.
Some more sanity checks for 'include:'/'inherits:' are included as well.
Signed-off-by: Ulf Magnusson <Ulf.Magnusson@nordicsemi.no>
The 'category: required/optional' setting for properties is just a
yes/no thing. Using a boolean makes it clearer, so have
'required: true/false' instead.
Print a clear error when 'category:' is used:
edtlib.EDTError: please put 'required: true' instead of 'category:
required' in 'properties: foo: ...' in
test-bindings/sub-node-parent.yaml - 'category' has been removed
The old scripts in scripts/dts/ ignore this setting, and only print a
warning if 'category: required' in an inherited binding is changed to
'category: optional'. Remove that code, since the new scripts already
have the same check.
The replacement was done with
git ls-files 'dts/bindings/*.yaml' | xargs sed -i \
-e 's/category:\s*required/required: true/' \
-e 's/category:\s*optional/required: false/'
dts/binding-template.yaml is updated as well.
Signed-off-by: Ulf Magnusson <Ulf.Magnusson@nordicsemi.no>
