[PATCH v8 0/4] rust: leds: add led classdev abstractions

[Markus Probst <markus.probst@posteo.de>]

This patch series has previously been contained in
https://lore.kernel.org/rust-for-linux/20251008181027.662616-1-markus.probst@posteo.de/T/#t
which added a rust written led driver for a microcontroller via i2c.

As the reading and writing to the i2c client via the register!
macro has not been implemented yet [1], the patch series will only
contain the additional abstractions required.

[1] https://lore.kernel.org/rust-for-linux/DDDS2V0V2NVJ.16ZKXCKUA1HUV@kernel.org/

The following changes were made:
* add abstraction to convert a device reference to a bus device
  reference for use in class device callbacks

* add basic led classdev abstractions to register and unregister leds

* add basic led classdev abstractions to register and unregister
  multicolor leds

Changes since v7:
* adjusted import style
* added classdev parameter to callback functions in `LedOps`
* implement `led::Color`
* extend `led::InitData` with
  - initial_brightness
  - default_trigger
  - default_color
* split generic and normal led classdev abstractions up (see patch 3/4)
* add multicolor led class device abstractions (see patch 4/4)
* added MAINTAINERS entry

Changes since v6:
* fixed typos
* improved documentation

Changes since v5:
* rename `IntoBusDevice` trait into `AsBusDevice`
* fix documentation about `LedOps::BLOCKING`
* removed dependency on i2c bindings
* added `AsBusDevice` implementation for `platform::Device`
* removed `device::Device` fallback implementation
* document that `AsBusDevice` must not be used by drivers and is
  intended for bus and class device abstractions only.

Changes since v4:
* add abstraction to convert a device reference to a bus device
  reference
* require the bus device as parent device and provide it in class device
  callbacks
* remove Pin<Vec<_>> abstraction (as not relevant for the led
  abstractions)
* fixed formatting in `led::Device::new`
* fixed `LedOps::BLOCKING` did the inverse effect

Changes since v3:
* fixed kunit tests failing because of example in documentation

Changes since v2:
* return `Devres` on `led::Device` creation
* replace KBox<T> with T in struct definition
* increment and decrement reference-count of fwnode
* make a device parent mandatory for led classdev creation
* rename `led::Handler` to `led::LedOps`
* add optional `brightness_get` function to `led::LedOps`
* use `#[vtable]` instead of `const BLINK: bool`
* use `Opaque::cast_from` instead of casting a pointer
* improve documentation
* improve support for older rust versions
* use `&Device<Bound>` for parent

Changes since v1:
* fixed typos noticed by Onur Özkan

Signed-off-by: Markus Probst <markus.probst@posteo.de>
---
Markus Probst (4):
      rust: Add trait to convert a device reference to a bus device reference
      rust: leds: add basic led classdev abstractions
      rust: leds: split generic and normal led classdev abstractions up
      rust: leds: add multicolor classdev abstractions

 MAINTAINERS                     |   8 +
 rust/bindings/bindings_helper.h |   1 +
 rust/kernel/auxiliary.rs        |   7 +
 rust/kernel/device.rs           |  35 ++-
 rust/kernel/led.rs              | 550 ++++++++++++++++++++++++++++++++++++++++
 rust/kernel/led/multicolor.rs   | 195 ++++++++++++++
 rust/kernel/led/normal.rs       |  39 +++
 rust/kernel/lib.rs              |   1 +
 rust/kernel/pci.rs              |   7 +
 rust/kernel/platform.rs         |   7 +
 rust/kernel/usb.rs              |   6 +
 11 files changed, 855 insertions(+), 1 deletion(-)
---
base-commit: e9a6fb0bcdd7609be6969112f3fbfcce3b1d4a7c
change-id: 20251114-rust_leds-a959f7c2f7f9