[PATCH v6 0/6] driver core: remove software node from platform devices on device release

[Bartosz Golaszewski]

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().

In this approach we first provide a fix to an existing problem in v7.1
which requires a specialized release() variant, then address issues in
drivers where a unified approach would cause a regression and then merge
the two release() callbacks into one.

Merging strategy: patch 1 is a self-contained fix and should land in
v7.1. The rest of the commits can wait until patch 1 is upstream.

DRM and platform maintainers: please Ack the two driver patches in this
series.

Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@xxxxxxxxxxxxxxxx>
---
Changes in v6:
- Make patch 1 a minimal fix that can go into v7.1
- Don't provide platform_device_add_software_node(), instead: rework
  drivers in question to use other existing interfaces instead
- Fix life-time issues in the xe_i2c patch and remove unneeded fwnode
  removal
- Fix typos and tweak commit messages
- Link to v5: https://patch.msgid.link/20260512-swnode-remove-on-dev-unreg-v5-0-0035eff63812@xxxxxxxxxxxxxxxx

Changes in v5:
- Provide a helper for users of platform_device_alloc() that wish to
  assign a software node to a platform device
- Rework drivers that could regress after the swnode leak fix
- Split the series into several patches as necessary
- Link to v4: https://patch.msgid.link/20260430-swnode-remove-on-dev-unreg-v4-0-01574da0aed3@xxxxxxxxxxxxxxxx

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@xxxxxxxxxxxxxxxx

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@xxxxxxxxxxxxxxxx

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@xxxxxxxxxxxxxxxx

---
Bartosz Golaszewski (6):
      driver core: platform: remove software node on release()
      platform/surface: gpe: use platform_device_register_full()
      drm/xe/i2c: use device_create_managed_software_node()
      driver core: platform: unify release path
      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 | 166 +++++++++++++++++++++++++++++++
 drivers/gpu/drm/xe/xe_i2c.c              |  22 ++--
 drivers/gpu/drm/xe/xe_i2c.h              |   1 -
 drivers/platform/surface/surface_gpe.c   |  36 ++-----
 include/kunit/fwnode.h                   |  19 ++++
 lib/kunit/Makefile                       |   3 +-
 lib/kunit/fwnode.c                       |  52 ++++++++++
 8 files changed, 276 insertions(+), 42 deletions(-)
---
base-commit: 5d6919055dec134de3c40167a490f33c74c12581
change-id: 20260410-swnode-remove-on-dev-unreg-42bfc4b23ba8

Best regards,
-- 
Bartosz Golaszewski <bartosz.golaszewski@xxxxxxxxxxxxxxxx>