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Thu, 11 Sep 2025 08:47:45 -0700 (PDT) Received: from localhost.localdomain ([152.37.120.249]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-45e03729c76sm28250545e9.6.2025.09.11.08.47.42 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 11 Sep 2025 08:47:44 -0700 (PDT) From: Igor Korotin To: Miguel Ojeda , Alex Gaynor , Wolfram Sang Cc: Boqun Feng , Gary Guo , =?UTF-8?q?Bj=C3=B6rn=20Roy=20Baron?= , Benno Lossin , Andreas Hindborg , Alice Ryhl , Trevor Gross , Danilo Krummrich , Greg Kroah-Hartman , Viresh Kumar , Asahi Lina , Wedson Almeida Filho , Alex Hung , Tamir Duberstein , Xiangfei Ding , linux-kernel@vger.kernel.org, rust-for-linux@vger.kernel.org, linux-i2c@vger.kernel.org Subject: [PATCH v5 0/3] rust: i2c: Add basic I2C driver abstractions Date: Thu, 11 Sep 2025 16:47:17 +0100 Message-ID: <20250911154717.96637-1-igor.korotin.linux@gmail.com> X-Mailer: git-send-email 2.43.0 Precedence: bulk X-Mailing-List: linux-i2c@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit This patch series lays the groundwork for writing Linux I2C drivers in Rust by: 1. Core abstractions Introduce `i2c::I2cClient`, `i2c::I2cAdapter`, `i2c::Driver` and built on the existing `struct i2c_client`, `struct i2c_adapter` 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` and `I2cAdapter`, including automatic cleanup when the driver unloads. 3. Sample driver (legacy table, OF & ACPI) Add `rust_driver_i2c`, a sample that: - creates an I2C client device using `i2c::Registration::new()` - binds to an I2C client via: - legacy I2C-ID table, - Open Firmware (device-tree) compatible strings, or - ACPI IDs. - destroyes the I2C client device on exit. Together, these three 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 a samples showing typical usage Igor Korotin (3): rust: i2c: add basic I2C device and driver abstractions rust: i2c: add manual I2C device creation abstractions samples: rust: add Rust I2C sample driver Changelog --------- v5: - Rename missed pdev variables to idev (thanks to Daniel). - Import `crate::device_id::RawDeviceIdIndex` and `crate::types::AlwaysRefCounted` in i2c.rs. - Switch dev_dbg to dev_info in the sample I2C driver messages. - Make `I2cAdapter::get()` return `ARef` instead of `&I2cAdapter`. - Remove `TryFrom> for I2cAdapter` (unused; to be reintroduced in a later I2C series). - Remove `AsRef> for I2cAdapter` (unused; to be reintroduced in a later I2C series). - Add `AsRef for I2cAdapter`. - Use i2c_get/put_adapter instead of get/put_device for `AlwaysRefCounted`. - Update safety comment for `unsafe impl Sync for Registration {}`. - Tweak comment for `I2cBoardInfo::new`. - Adjust build-time assertion message in `Adapter::register`. - Link to v4: https://lore.kernel.org/rust-for-linux/20250820151427.1812482-1-igor.korotin.linux@gmail.com/ v4: - Renamed `i2c::I2cAdapterRef` to `i2c::I2cAdapter`. - Renamed `i2c::Device` to `i2c::I2cClient` for consistency with `i2c::I2cAdapter` and to avoid confusion with `i2c::Adapter` - Reworked `i2c::I2cAdapter` to be an Opaque around `i2c_adapter` struct - Implemented AlwaysRefCounted trait for `i2c::I2cAdapter`. - Fixed numerous comment mistakes and typos all over the code, thanks to Danilo and Daniel - Got rid of all unwrap() use-cases in i2c.rs and rust_driver_i2c.rs. This covers 0-day kernel panic <202508071027.8981cbd4-lkp@intel.com> - Removed unnecessary casts. - Replaced all addr_of_mut! macros to &raw mut. - In `i2c::Adapter::register` method build assert if all ID tables are None. - Renamed all pdrv and pdev instances to idrv and idev respectivly - Implemented an ealry return in `i2c::Adapter::i2c_id_info` - Added all missing Safety comments. - Removed `unsafe impl crate::types::AlwaysRefCounted for Device` implementation which came to v3 from v2 by mistake. - Added more details regarding i2c-stub driver usage in rust_driver_i2c comment. - Changed `i2c::I2cAdapter::get` return type from `Option` to `Result<&'static Self>`. - Added Daniel Almeida as a reviewer to the "I2C Subsystem [RUST]" entry in MAINTAINERS, per his offer. - Link to v3: https://lore.kernel.org/rust-for-linux/20250801153742.13472-1-igor.korotin.linux@gmail.com/ v3: - removed unnecessary i2c_get_clientdata and i2c_set_clientdata rust helpers. Using generic accessors implemented in [1] instead. - Reimplemented i2c::DeviceId based on changes in [2]. - Using from_result in i2c::Adapter::probe_callback - Using explicit drop() for i2c client private data in `i2c::Adapter::remove_callback` - replaced device::Device::as_ref() with device::Device::from_raw in `i2c::Device::as_ref()`. It is renamed in device::Device. - Build Rust I2C only if I2C is built-in - Reimplement overcomplicated trait i2c::DeviceOwned the same way it is implemented in auxiliary [3]. - Merge rust_device_i2c and rust_driver_i2c samples. Resulting rust_driver_i2c creates pined i2c_client using i2c::Registration::new and probes newly created i2c_client. - Created a new entry in MAINTAINERS file containing i2c.rs and rust_driver_i2c.rs in it. - Link to v2: [4] [1] https://lore.kernel.org/lkml/20250621195118.124245-3-dakr@kernel.org/ [2] https://lore.kernel.org/rust-for-linux/20250711040947.1252162-1-fujita.tomonori@gmail.com/ [3] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/rust/kernel/auxiliary.rs?h=v6.16-rc4#n299 [4] https://lore.kernel.org/rust-for-linux/20250704153332.1193214-1-igor.korotin.linux@gmail.com/ 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`. - 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 | 9 + rust/bindings/bindings_helper.h | 1 + rust/kernel/i2c.rs | 547 ++++++++++++++++++++++++++++++++ rust/kernel/lib.rs | 2 + samples/rust/Kconfig | 11 + samples/rust/Makefile | 1 + samples/rust/rust_driver_i2c.rs | 128 ++++++++ 7 files changed, 699 insertions(+) create mode 100644 rust/kernel/i2c.rs create mode 100644 samples/rust/rust_driver_i2c.rs base-commit: 8f5ae30d69d7543eee0d70083daf4de8fe15d585 -- 2.43.0