[PATCH v2 0/4] rust: i2c: Add basic I2C driver abstractions

[Igor Korotin <igor.korotin.linux@gmail.com>]

This patch series lays the groundwork for writing Linux I2C drivers in Rust by:

 1. Core abstractions 
    Introduce `i2c::Device`, `i2c::Driver` and `i2c::Adapter` built on the
    existing `struct i2c_client` and `struct i2c_driver`, with safe Rust wrappers
    around probe, transfer, and teardown logic.

 2. Manual device creation  
    Provide an API to register an I2C device at runtime from Rust using
    `I2cBoardInfo`, including automatic cleanup when the driver unloads.

 3. Sample driver (legacy table, OF & ACPI)  
    Add `rust_driver_i2c`, a sample that binds to an I2C client via:
      - legacy I2C-ID table,
      - Open Firmware (device-tree) compatible strings, or
      - ACPI IDs.

 4. Sample for manual registration  
    Add `rust_device_i2c`, a sample demonstrating how to create an I²C device
    on a given `I2cAdapterRef`, and how to unregister it automatically.

Together, these four patches:

- Establish the essential Rust traits and types for I2C drivers.
- Enable driver binding via legacy ID table, device-tree (OF), or ACPI
- Enable manual device creation at runtime.
- Ship two samples showing typical usage: one for firmware- or table-based binding,
  and one for manual registration.

Igor Korotin (4):
  rust: i2c: add basic I2C device and driver abstractions
  rust: i2c: add manual I2C device creation abstractions
  samples: rust: add Rust I2C sample driver
  samples: rust: add Rust manual I2C device creation sample

Changelog
---------
v2:
 - Merged separated ACPI support patches since ACPI-table support is 
   merged into driver-core-next.
 - Added I2cAdapterRef and I2cBoardInfo abstractions 
 - Added DeviceState generic parameter which is used for `i2c::Device`
   as a sign if the device is created manually
 - Added `DeviceOwned` abstraction which is a safe reference to a 
   manually created `i2c::Device<Ctx, state::Owned>`. 
 - Added Rust manual I2C device creation sample
 - Link to v1: https://lore.kernel.org/rust-for-linux/20250626174623.904917-1-igor.korotin.linux@gmail.com/

 MAINTAINERS                     |   4 +
 rust/bindings/bindings_helper.h |   1 +
 rust/helpers/helpers.c          |   1 +
 rust/helpers/i2c.c              |  15 +
 rust/kernel/i2c.rs              | 565 ++++++++++++++++++++++++++++++++
 rust/kernel/lib.rs              |   2 +
 samples/rust/Kconfig            |  24 ++
 samples/rust/Makefile           |   2 +
 samples/rust/rust_device_i2c.rs |  50 +++
 samples/rust/rust_driver_i2c.rs |  69 ++++
 10 files changed, 733 insertions(+)
 create mode 100644 rust/helpers/i2c.c
 create mode 100644 rust/kernel/i2c.rs
 create mode 100644 samples/rust/rust_device_i2c.rs
 create mode 100644 samples/rust/rust_driver_i2c.rs


base-commit: b75e1f0619bd707e027812e262af3fbce445e71a
-- 
2.43.0