[PATCH v4 0/3] driver core: remove software node from platform devices on device release

[Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com>]

This fixes an issue in platform device code where, if we specify a
software node for a platform device using struct platform_device_info,
it will not be removed on device .release().

The second patch adds a new kunit helper which is used in patch 3/3 that
adds a test-case that can be used to reproduce the problem and prove that
the fix works as well as another making sure a corner case of using a
software node as the primary firmware node works too.

Merging strategy: patch 1/3 should go into v7.1. Once it's upstream, the
first tag containing it should be pulled into the driver core tree and
the remaining patches applied on top with an ack from the kunit
maintainers.

Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com>
---
Changes in v4:
- Drop redundant !pdevinfo->swnode check in
  platform_device_register_full()
- Handle all three combinations with which two software nodes can be
  assigned to a platform device
- Extend the new kunit test to verify all three combinations
- Link to v3: https://patch.msgid.link/20260428-swnode-remove-on-dev-unreg-v3-0-533bdc71b22e@oss.qualcomm.com

Changes in v3:
- Make sure the reference of the primary software node we possibly take,
  is always released by moving the get() before calls that may fail
- Don't allow passing two software nodes
- Add a test case for that situation
- Link to v2: https://patch.msgid.link/20260423-swnode-remove-on-dev-unreg-v2-0-0e5213cde2ed@oss.qualcomm.com

Changes in v2:
- Change the order between removing the software node and dropping the
  reference to the device's OF node
- Address a situation where a software node is used as the primary
  firmware node
- Add a patch adding a new kunit helper
- Add another test case
- Link to v1: https://patch.msgid.link/20260410-swnode-remove-on-dev-unreg-v1-0-cd7d305f3db2@oss.qualcomm.com

---
Bartosz Golaszewski (3):
      driver core: platform: remove software node on release()
      kunit: provide kunit_software_node_register()
      driver core: platform: tests: add test cases for correct swnode removal

 drivers/base/platform.c                  |  19 +++-
 drivers/base/test/platform-device-test.c | 168 +++++++++++++++++++++++++++++++
 include/kunit/fwnode.h                   |  19 ++++
 lib/kunit/Makefile                       |   3 +-
 lib/kunit/fwnode.c                       |  52 ++++++++++
 5 files changed, 259 insertions(+), 2 deletions(-)
---
base-commit: 254f49634ee16a731174d2ae34bc50bd5f45e731
change-id: 20260410-swnode-remove-on-dev-unreg-42bfc4b23ba8

Best regards,
-- 
Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com>