[PATCH v16 0/3] rust: add basic serial device bus abstractions

[Markus Probst]

This patch series adds the serdev device bus rust abstraction into the
kernel.

This abstraction will be used by a driver,
which targets the MCU devices in Synology devices.

Kari Argillander also messaged me, stating that he wants to write a
watchdog driver with this abstraction (needing initial device data).

This series depends on [1].

[1] https://lore.kernel.org/rust-for-linux/20260530132736.3298549-1-dakr@xxxxxxxxxx/

Signed-off-by: Markus Probst <markus.probst@xxxxxxxxx>
---
Changes in v16:
- use `Jiffies` instead of `impl Into<Jiffies>`, until `Jiffies` is a
  newtype
- Link to v15: https://patch.msgid.link/20260718-rust_serdev-v15-0-208ed2e6ec15@xxxxxxxxx

Changes in v15:
- fix documentation typo
- add documentation for `PrivateData::active`
- adding missing `#[inline]` attributes
- replace `serdev::Timeout` with the use of `impl Into<Jiffies>`
- This replaces https://lore.kernel.org/rust-for-linux/20260718-rust_serdev_fixes-v1-0-35433b6dce0f@xxxxxxxxx/
- Link to v14: https://patch.msgid.link/20260715-rust_serdev-v14-0-b4ed5c93606f@xxxxxxxxx

Changes in v14:
- fix issues reported by Sashiko:
  - fix missing Sync
  - fix write buffers allowed with data.len() > i32::MAX
  - fix sample driver possibly stalling on full tx buffer
- Link to v13: https://patch.msgid.link/20260712-rust_serdev-v13-0-2c4060bc8e30@xxxxxxxxx

Changes in v13:
- Added Acked-by trailer from Rob. Consider this a RESEND.
- Link to v12: https://patch.msgid.link/20260603-rust_serdev-v12-0-3400ffb88b12@xxxxxxxxx

Changes in v12:
- fix CoreInternal instead of BoundInternal
- Link to v11: https://patch.msgid.link/20260531-rust_serdev-v11-0-dee8e0d830f1@xxxxxxxxx

Changes in v11:
- redo changes from v9 with the following fixes:
  - fix memory leak on probe failure
  - fix possible access of dropped drvdata from receive_buf
- Link to v10: https://patch.msgid.link/20260530-rust_serdev-v10-0-65d1d5db876c@xxxxxxxxx

Changes in v10:
- revert everything from v9, except BoundInternal
- use mutex to ensure receive_buf won't be called on a dropped drvdata.
- Link to v9: https://patch.msgid.link/20260530-rust_serdev-v9-0-f8b5fccb49c3@xxxxxxxxx

Changes in v9:
- make use of BoundInternal
- use PrivateData wrapper and drop rust_private_data field
- use non-devm version of serdev_device_open
- Link to v8: https://patch.msgid.link/20260530-rust_serdev-v8-0-2a95f1da22a7@xxxxxxxxx

Changes in v8:
- adapted to driver-lifetime v5 patch series
- add MAINTAINERS file patch
- Link to v7: https://patch.msgid.link/20260429-rust_serdev-v7-0-0d89c791b5c8@xxxxxxxxx

Changes in v7:
- adapted to driver-lifetime patch series
- Link to v6: https://patch.msgid.link/20260427-rust_serdev-v6-0-173798d5e1a3@xxxxxxxxx

Changes in v6:
- rebased onto v7.1-rc1
- Link to v5: https://patch.msgid.link/20260420-rust_serdev-v5-0-57e8ba0519f3@xxxxxxxxx

Changes in v5:
- fix typo in documentation
- Link to v4: https://lore.kernel.org/r/20260411-rust_serdev-v4-0-845e960c6627@xxxxxxxxx

Changes in v4:
- fixed not selecting rust serdev abstraction in sample
- Link to v3: https://lore.kernel.org/r/20260313-rust_serdev-v3-0-c9a3af214f7f@xxxxxxxxx

Changes in v3:
- fix vertical import style
- add Kconfig entry for the rust abstraction
- fix documentation in include/linux/serdev.h
- rename private_data to rust_private_data
- fix `complete_all` <-> `wait_for_completion` typo
- move drvdata_borrow call after the completion
- Link to v2: https://lore.kernel.org/r/20260306-rust_serdev-v2-0-e9b23b42b255@xxxxxxxxx

Changes in v2:
- fix documentation in `serdev::Driver::write` and
  `serdev::Driver::write_all`
- remove use of `dev_info` in probe from the sample
- remove `properties_parse` from the sample
- add optional `baudrate` property to the sample
- remove 1. patch
- remove `TryFrom<&device::Device<Ctx>> for &serdev::Device<Ctx>`
  implementation
- fix import style
- add patch to return reference in `devres::register` to fix safety
  issue
- add patch to add private data to serdev_device, to fix
  `Device.drvdata()` from failing
- simplify abstraction by removing ability to receive the initial
  transmission. It may be added later in a separate patch series if
  needed.
- Link to v1: https://lore.kernel.org/r/20251220-rust_serdev-v1-0-e44645767621@xxxxxxxxx

---
Markus Probst (3):
      rust: add basic serial device bus abstractions
      samples: rust: add Rust serial device bus sample device driver
      MAINTAINERS: serdev: Add self for serdev

 MAINTAINERS                        |   5 +-
 drivers/tty/serdev/Kconfig         |   7 +
 rust/bindings/bindings_helper.h    |   1 +
 rust/helpers/helpers.c             |   1 +
 rust/helpers/serdev.c              |  22 ++
 rust/kernel/lib.rs                 |   2 +
 rust/kernel/serdev.rs              | 605 +++++++++++++++++++++++++++++++++++++
 samples/rust/Kconfig               |  11 +
 samples/rust/Makefile              |   1 +
 samples/rust/rust_driver_serdev.rs |  90 ++++++
 10 files changed, 744 insertions(+), 1 deletion(-)
---
base-commit: 4e63c0582e2aef7284a2cc7c62215f245003e775
change-id: 20251217-rust_serdev-ee5481e9085c