dts: dtlib/edtlib: Add phandle and phandle+nums array types

Add two new type-checked property types 'phandles' and 'phandle-array'
to edtlib.

'phandles' is for pure lists of phandles, with no other data, like

    foo = < &bar &baz ... >

'phandle-array' is for lists of phandles and (possibly) numbers, like

    foo = < &bar 1 2 &baz 3 4 ... >

dt-schema also has the 'phandle-array' type.

Property.val (in edtlib) is set to an array of Device objects for the
'phandles' type.

For the 'phandle-array' type, no Property object is created. This type
is only used for type checking.

Also refactor how types that do not create a Property object
('phandle-array' and 'compound') are handled. Have _prop_val() return
None for them.

The new types are implemented with two new TYPE_PHANDLES and
TYPE_PHANDLES_AND_NUMS types at the dtlib level. There is also a new
Property.to_nodes() functions for fetching the Nodes for an array of
phandles, with type checking.

Signed-off-by: Ulf Magnusson <Ulf.Magnusson@nordicsemi.no>
7 files changed