This series fixes an fw_devlink supplier-resolution problem reported by
Leonardo Costa while using a Devicetree nexus to describe GPIO and PWM
resources routed through an LVDS connector. Consumers referencing the
nexus could remain deferred because fw_devlink linked them to the nexus
rather than to the providers selected by gpio-map and pwm-map. [1]

GPIO, PWM and clock consumer APIs use of_parse_phandle_with_args_map()
to resolve specifiers through gpio-map, pwm-map and clock-map
properties. The corresponding fw_devlink parsers use direct phandle
parsing instead. Given a consumer which references a nexus, the consumer
API and fw_devlink therefore resolve the reference to different nodes:

  consumer API:  consumer -> nexus -> mapped provider
  fw_devlink:    consumer -> nexus

A nexus is a translation node rather than the resource provider and need
not have a driver. The link to it can consequently remain unresolved and
defer the consumer even though the mapped provider is available.

Make the fw_devlink GPIO, PWM and clock parsers use the same map-aware
resolver as their consumer APIs. The resolver also handles valid direct
references by returning the original provider when no map is present.
Use dedicated exact-name and suffix declaration macros to opt these
bindings into map-aware parsing without changing unrelated property
parsers. Retain GPIO's existing exclusions and compatibility handling.

The regression tests call the OF add_links operation and verify that a
mapped reference creates exactly one link to the final provider, not to
the nexus. They also cover valid direct references. The GPIO tests
exercise all property spellings recognized by fw_devlink, including the
deprecated singular and unprefixed forms.

Tested with:
  - The new CONFIG_OF_UNITTEST fw_devlink cases under QEMU/x86_64 all
    passed
  - W=1 builds on x86_64 and arm64, including the OF unittest data
  - Toradex Verdin iMX8M Plus hardware using a connector nexus for the
    display GPIO and PWM resources: the display probes successfully

[1] https://lore.kernel.org/all/juuc4af7ndbajcl7gzf4tg5qz2q2j5tt3rvql4jbauradujrre@gc5nbdhhixaf/

Signed-off-by: Ernest Van Hoecke <ernest.vanhoecke@toradex.com>

---
Changes in v2:
- Split the unit tests into per-resource follow-up commits
- Added clock nexus as well because the clock nexus series was merged:
  https://lore.kernel.org/all/20260807-schneider-v7-2-rc1-eip201-upstream-v5-0-8785f9531cf0@bootlin.com/
- Link to v1: https://lore.kernel.org/r/20260902-fw-devlink-nexus-ready-v1-0-68fe1996e78a@toradex.com

---
Ernest Van Hoecke (7):
      of: property: fw_devlink: Follow GPIO nexus maps
      of: property: fw_devlink: Report unsupported supplier linking
      of: unittest: Test fw_devlink with GPIO nexus maps
      of: property: fw_devlink: Follow PWM nexus maps
      of: unittest: Test fw_devlink with PWM nexus maps
      of: property: fw_devlink: Follow clock nexus maps
      of: unittest: Test fw_devlink with clock nexus maps

 drivers/of/property.c                       | 53 ++++++++++++++-----
 drivers/of/unittest-data/tests-phandle.dtsi | 63 +++++++++++++++++++++++
 drivers/of/unittest.c                       | 79 +++++++++++++++++++++++++++++
 3 files changed, 182 insertions(+), 13 deletions(-)
---
base-commit: 91b1b8d437abe0cd83210d8f257b785a63047aa9
change-id: 20260901-fw-devlink-nexus-ready-c859706b019d

Best regards,
-- 
Ernest Van Hoecke <ernest.vanhoecke@toradex.com>