From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-wr1-f51.google.com (mail-wr1-f51.google.com [209.85.221.51]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id DE19925D1FC for ; Sun, 5 Oct 2025 10:23:33 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.221.51 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1759659816; cv=none; b=LqxR3roolm3luq9O94f/s04u0m/+z9Tb6EK3ux9LlIqVNX74UOv52JLJMDg3GOtQzIznTqWEp5cNU+AqV8vbHuaWxMvVv1yaoiS9YxVn+GgQ6R7eZh0u7Bn7MuYBv5jzgtX7HyETMUgV1VRi38t393SqYBPvzH5MQZIvSKeXoBE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1759659816; c=relaxed/simple; bh=UMDssw2iXEw4kWMyKjYE4jsf/n85NqQORBti+lgd0js=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=lqUdUYzKOApusOqXAkav6Dtvu3yp23nUoXbfot5/u9RGSnqBYcL/K48D7kaRwTNJ4awqxRrp/K4aJL8M0wtvkSQDC/Bm52geJE5O4AFP5+FKSYwyztsELwkxK+KDhrKqyYphYgyowy22T3zbybU3aNRc5Q7HmI0Y4XQd9juCjsw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=lqfiLBNW; arc=none smtp.client-ip=209.85.221.51 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="lqfiLBNW" Received: by mail-wr1-f51.google.com with SMTP id ffacd0b85a97d-4257aafab98so157957f8f.3 for ; Sun, 05 Oct 2025 03:23:33 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1759659812; x=1760264612; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=8zjpsAwvleb0S28WSHkKgjNunUX2sDDBza3LuuidDko=; b=lqfiLBNWriHxboyf4tWvdMj6UTNKsLB0/2NxUzVLcFp8K1QnLN3/sH2tGzYFKtViXJ 4p4KQdky6XET0M7XxbZcE7C/nMRYdRo6Gmy2RPKOwq3bAlnWLdY+QjPpgn7muBfiiDr5 unCPsxeq+s3a7QrbBMV1700lKJ1ygIP/M/v93y0DjEvm2CVunQW6tF8Up2l84iNsGUu9 WLFIfYT6qrvd8utVNlBaXNXQODSSGL8HF8w4kqG9tx23PfFXdZws99mw75wQ2UoITktD j7XFAYmOvhiLO1G1LiDel3wa9ygaPfI0GcdP+i1O9AUGHAcPi5cm8EuOFSTZRqiSd5mY 9nkA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1759659812; x=1760264612; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=8zjpsAwvleb0S28WSHkKgjNunUX2sDDBza3LuuidDko=; b=w0q6UyB/iuucbvn1DQiTUgeBhKEvfsOl8pni3QkuYDouPVLda0vd56m2D25fDVe9+C TjMmuamHRRKskUz+20ORsU0NN4tKpa62JSqbdwnrOlq3YwzzAm7gC8S6czxrd6PE9jex +lRPBRFLB/ICCU1SbceWPv08pL+1qJrGaJ4vHo2Dg8H/AbHr/FOBEj2oQ4djGQ/bo6PY 4/iGCWTuVcRXPqZmGKc2AXTJSuHxH77cug6wSEhnNFmRlu/JTHCdgbXqJALBSVXezhnr Rx595wrWBZC+MMVFceGFv8mpvUHHmHe1uaITl1KCyp+6VT+LSh35me0Bgi6AnvotLJUO x74Q== X-Forwarded-Encrypted: i=1; AJvYcCV3KMeV2Je63xKUA2vBJMlRrmSreW4/oBaXIYSYQ+rozMfR8dyLd/Ew/ckf+2Bp+3jqaKpnVdF188bso7NRkQ==@vger.kernel.org X-Gm-Message-State: AOJu0Yy1N/CmREVYUkyOHc1GwXu3rAbQFRgNr8q3DKtBlYd7ztG8rNru Wj8qwohHKZFVUf19UL6hs9ySNwSi/xyV2oH19FWJwOQBwK6RKCogHQ7g X-Gm-Gg: ASbGncvfjDPkXWJDSqIGlqDQTAXX/nm983uhne7zJKxND1LsnuN4h+VAYg8fS5Eg1sF fk2JDMzqaeIv0PeZZ81S1vo+878XKPRinaL+mh1jcy0r/73UvPQQg71sNF8HZ31nIAZGwtagc7n pd/rxtAJkMU0VneXRJ3bs0YIw0z+t1NHHjUhxHVv9q3SLpiw3Io5WZB7J6Vps8Ys69tO3MZ8x50 uVXJ9ZEAvm4VPtKMATJotNewKFE1+gzs9lXDlJi82i7gcmSg+af+wos4Qct44NMrVjIUwvVnmRU XjRKpw8/Wf+cUyd3JOeQhrPQPD+i9KA9VXaKygsM+YPV2s/XBxzwopr+lA6vwip5eaK6qPOfT/M sZIRkMH+Uk/7SI7qoXpSK/fH2FooIQiHVC0Shk2k8IeYEoq27auPtNpHnBhVdpSyLNGk= X-Google-Smtp-Source: AGHT+IF/LIK7j8Mg0aiNw4WPRoZmVZE1SOgvdXbXKJvrddweYTETJXKjwMOd2BsJmHTvPgGA7Th3GA== X-Received: by 2002:a05:6000:2086:b0:3ea:d9a7:43e4 with SMTP id ffacd0b85a97d-425671c1454mr6535931f8f.53.1759659812029; Sun, 05 Oct 2025 03:23:32 -0700 (PDT) Received: from Vasilio.Home ([2.127.51.206]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-4255d8a6c3esm15973804f8f.1.2025.10.05.03.23.31 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 05 Oct 2025 03:23:31 -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 v6 1/3] rust: i2c: add basic I2C device and driver abstractions Date: Sun, 5 Oct 2025 11:23:28 +0100 Message-ID: <20251005102328.41899-1-igor.korotin.linux@gmail.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20251005102226.41876-1-igor.korotin.linux@gmail.com> References: <20251005102226.41876-1-igor.korotin.linux@gmail.com> Precedence: bulk X-Mailing-List: rust-for-linux@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Implement the core abstractions needed for I2C drivers, including: * `i2c::Driver` — the trait drivers must implement, including `probe` * `i2c::I2cClient` — a safe wrapper around `struct i2c_client` * `i2c::Adapter` — implements `driver::RegistrationOps` to hook into the generic `driver::Registration` machinery * `i2c::DeviceId` — a `RawDeviceIdIndex` implementation for I2C device IDs Signed-off-by: Igor Korotin --- MAINTAINERS | 8 + rust/bindings/bindings_helper.h | 1 + rust/kernel/i2c.rs | 423 ++++++++++++++++++++++++++++++++ rust/kernel/lib.rs | 2 + 4 files changed, 434 insertions(+) create mode 100644 rust/kernel/i2c.rs diff --git a/MAINTAINERS b/MAINTAINERS index fe168477caa4..c44c7ac317b1 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -11516,6 +11516,14 @@ F: include/linux/i2c.h F: include/uapi/linux/i2c-*.h F: include/uapi/linux/i2c.h +I2C SUBSYSTEM [RUST] +M: Igor Korotin +R: Danilo Krummrich +R: Daniel Almeida +L: rust-for-linux@vger.kernel.org +S: Maintained +F: rust/kernel/i2c.rs + I2C SUBSYSTEM HOST DRIVERS M: Andi Shyti L: linux-i2c@vger.kernel.org diff --git a/rust/bindings/bindings_helper.h b/rust/bindings/bindings_helper.h index 84d60635e8a9..81796d5e16e8 100644 --- a/rust/bindings/bindings_helper.h +++ b/rust/bindings/bindings_helper.h @@ -53,6 +53,7 @@ #include #include #include +#include #include #include #include diff --git a/rust/kernel/i2c.rs b/rust/kernel/i2c.rs new file mode 100644 index 000000000000..c5a8a5791523 --- /dev/null +++ b/rust/kernel/i2c.rs @@ -0,0 +1,423 @@ +// SPDX-License-Identifier: GPL-2.0 + +//! I2C Driver subsystem + +// I2C Driver abstractions. +use crate::{ + acpi, container_of, device, + device_id::{RawDeviceId, RawDeviceIdIndex}, + driver, + error::*, + of, + prelude::*, + types::{AlwaysRefCounted, Opaque}, +}; + +use core::{marker::PhantomData, ptr::NonNull}; + +/// An I2C device id table. +#[repr(transparent)] +#[derive(Clone, Copy)] +pub struct DeviceId(bindings::i2c_device_id); + +impl DeviceId { + const I2C_NAME_SIZE: usize = 20; + + /// Create a new device id from an I2C 'id' string. + #[inline(always)] + pub const fn new(id: &'static CStr) -> Self { + build_assert!( + id.len_with_nul() <= Self::I2C_NAME_SIZE, + "ID exceeds 20 bytes" + ); + let src = id.as_bytes_with_nul(); + // Replace with `bindings::acpi_device_id::default()` once stabilized for `const`. + // SAFETY: FFI type is valid to be zero-initialized. + let mut i2c: bindings::i2c_device_id = unsafe { core::mem::zeroed() }; + let mut i = 0; + while i < src.len() { + i2c.name[i] = src[i]; + i += 1; + } + + Self(i2c) + } +} + +// SAFETY: `DeviceId` is a `#[repr(transparent)]` wrapper of `i2c_device_id` and does not add +// additional invariants, so it's safe to transmute to `RawType`. +unsafe impl RawDeviceId for DeviceId { + type RawType = bindings::i2c_device_id; +} + +// SAFETY: `DRIVER_DATA_OFFSET` is the offset to the `driver_data` field. +unsafe impl RawDeviceIdIndex for DeviceId { + const DRIVER_DATA_OFFSET: usize = core::mem::offset_of!(bindings::i2c_device_id, driver_data); + + fn index(&self) -> usize { + self.0.driver_data + } +} + +/// IdTable type for I2C +pub type IdTable = &'static dyn kernel::device_id::IdTable; + +/// Create a I2C `IdTable` with its alias for modpost. +#[macro_export] +macro_rules! i2c_device_table { + ($table_name:ident, $module_table_name:ident, $id_info_type: ty, $table_data: expr) => { + const $table_name: $crate::device_id::IdArray< + $crate::i2c::DeviceId, + $id_info_type, + { $table_data.len() }, + > = $crate::device_id::IdArray::new($table_data); + + $crate::module_device_table!("i2c", $module_table_name, $table_name); + }; +} + +/// An adapter for the registration of I2C drivers. +pub struct Adapter(T); + +// SAFETY: A call to `unregister` for a given instance of `RegType` is guaranteed to be valid if +// a preceding call to `register` has been successful. +unsafe impl driver::RegistrationOps for Adapter { + type RegType = bindings::i2c_driver; + + unsafe fn register( + idrv: &Opaque, + name: &'static CStr, + module: &'static ThisModule, + ) -> Result { + build_assert!( + T::ACPI_ID_TABLE.is_some() || T::OF_ID_TABLE.is_some() || T::I2C_ID_TABLE.is_some(), + "At least one of ACPI/OF/Legacy tables must be present when registering an i2c driver" + ); + + let i2c_table = match T::I2C_ID_TABLE { + Some(table) => table.as_ptr(), + None => core::ptr::null(), + }; + + let of_table = match T::OF_ID_TABLE { + Some(table) => table.as_ptr(), + None => core::ptr::null(), + }; + + let acpi_table = match T::ACPI_ID_TABLE { + Some(table) => table.as_ptr(), + None => core::ptr::null(), + }; + + // SAFETY: It's safe to set the fields of `struct i2c_client` on initialization. + unsafe { + (*idrv.get()).driver.name = name.as_char_ptr(); + (*idrv.get()).probe = Some(Self::probe_callback); + (*idrv.get()).remove = Some(Self::remove_callback); + (*idrv.get()).shutdown = Some(Self::shutdown_callback); + (*idrv.get()).id_table = i2c_table; + (*idrv.get()).driver.of_match_table = of_table; + (*idrv.get()).driver.acpi_match_table = acpi_table; + } + + // SAFETY: `idrv` is guaranteed to be a valid `RegType`. + to_result(unsafe { bindings::i2c_register_driver(module.0, idrv.get()) }) + } + + unsafe fn unregister(idrv: &Opaque) { + // SAFETY: `idrv` is guaranteed to be a valid `RegType`. + unsafe { bindings::i2c_del_driver(idrv.get()) } + } +} + +impl Adapter { + extern "C" fn probe_callback(idev: *mut bindings::i2c_client) -> kernel::ffi::c_int { + // SAFETY: The I2C bus only ever calls the probe callback with a valid pointer to a + // `struct i2c_client`. + // + // INVARIANT: `idev` is valid for the duration of `probe_callback()`. + let idev = unsafe { &*idev.cast::>() }; + + let info = + Self::i2c_id_info(idev).or_else(|| ::id_info(idev.as_ref())); + + from_result(|| { + let data = T::probe(idev, info)?; + + idev.as_ref().set_drvdata(data); + Ok(0) + }) + } + + extern "C" fn remove_callback(idev: *mut bindings::i2c_client) { + // SAFETY: `idev` is a valid pointer to a `struct i2c_client`. + let idev = unsafe { &*idev.cast::>() }; + + // SAFETY: `remove_callback` is only ever called after a successful call to + // `probe_callback`, hence it's guaranteed that `I2cClient::set_drvdata()` has been called + // and stored a `Pin>`. + drop(unsafe { idev.as_ref().drvdata_obtain::>>() }); + } + + extern "C" fn shutdown_callback(idev: *mut bindings::i2c_client) { + // SAFETY: `shutdown_callback` is only ever called for a valid `idev` + let idev = unsafe { &*idev.cast::>() }; + + // SAFETY: `shutdown_callback` is only ever called after a successful call to + // `probe_callback`, hence it's guaranteed that `Device::set_drvdata()` has been called + // and stored a `Pin>`. + let data = unsafe { idev.as_ref().drvdata_obtain::>>() }; + + T::shutdown(idev, data.as_ref()); + } + + /// The [`i2c::IdTable`] of the corresponding driver. + fn i2c_id_table() -> Option::IdInfo>> { + T::I2C_ID_TABLE + } + + /// Returns the driver's private data from the matching entry in the [`i2c::IdTable`], if any. + /// + /// If this returns `None`, it means there is no match with an entry in the [`i2c::IdTable`]. + fn i2c_id_info(dev: &I2cClient) -> Option<&'static ::IdInfo> { + let table = Self::i2c_id_table()?; + + // SAFETY: + // - `table` has static lifetime, hence it's valid for reads + // - `dev` is guaranteed to be valid while it's alive, and so is `dev.as_raw()`. + let raw_id = unsafe { bindings::i2c_match_id(table.as_ptr(), dev.as_raw()) }; + + if raw_id.is_null() { + return None; + } + + // SAFETY: `DeviceId` is a `#[repr(transparent)` wrapper of `struct i2c_device_id` and + // does not add additional invariants, so it's safe to transmute. + let id = unsafe { &*raw_id.cast::() }; + + Some(table.info(::index(id))) + } +} + +impl driver::Adapter for Adapter { + type IdInfo = T::IdInfo; + + fn of_id_table() -> Option> { + T::OF_ID_TABLE + } + + fn acpi_id_table() -> Option> { + T::ACPI_ID_TABLE + } +} + +/// Declares a kernel module that exposes a single i2c driver. +/// +/// # Examples +/// +/// ```ignore +/// kernel::module_i2c_driver! { +/// type: MyDriver, +/// name: "Module name", +/// authors: ["Author name"], +/// description: "Description", +/// license: "GPL v2", +/// } +/// ``` +#[macro_export] +macro_rules! module_i2c_driver { + ($($f:tt)*) => { + $crate::module_driver!(, $crate::i2c::Adapter, { $($f)* }); + }; +} + +/// The i2c driver trait. +/// +/// Drivers must implement this trait in order to get a i2c driver registered. +/// +/// # Example +/// +///``` +/// # use kernel::{acpi, bindings, c_str, device::Core, i2c, of}; +/// +/// struct MyDriver; +/// +/// kernel::acpi_device_table!( +/// ACPI_TABLE, +/// MODULE_ACPI_TABLE, +/// ::IdInfo, +/// [ +/// (acpi::DeviceId::new(c_str!("LNUXBEEF")), ()) +/// ] +/// ); +/// +/// kernel::i2c_device_table!( +/// I2C_TABLE, +/// MODULE_I2C_TABLE, +/// ::IdInfo, +/// [ +/// (i2c::DeviceId::new(c_str!("rust_driver_i2c")), ()) +/// ] +/// ); +/// +/// kernel::of_device_table!( +/// OF_TABLE, +/// MODULE_OF_TABLE, +/// ::IdInfo, +/// [ +/// (of::DeviceId::new(c_str!("test,device")), ()) +/// ] +/// ); +/// +/// impl i2c::Driver for MyDriver { +/// type IdInfo = (); +/// const I2C_ID_TABLE: Option> = Some(&I2C_TABLE); +/// const OF_ID_TABLE: Option> = Some(&OF_TABLE); +/// const ACPI_ID_TABLE: Option> = Some(&ACPI_TABLE); +/// +/// fn probe( +/// _idev: &i2c::I2cClient, +/// _id_info: Option<&Self::IdInfo>, +/// ) -> Result>> { +/// Err(ENODEV) +/// } +/// +/// fn shutdown(_idev: &i2c::I2cClient, this: Pin<&Self>) { +/// } +/// } +///``` +pub trait Driver: Send { + /// The type holding information about each device id supported by the driver. + // TODO: Use `associated_type_defaults` once stabilized: + // + // ``` + // type IdInfo: 'static = (); + // ``` + type IdInfo: 'static; + + /// The table of device ids supported by the driver. + const I2C_ID_TABLE: Option> = None; + + /// The table of OF device ids supported by the driver. + const OF_ID_TABLE: Option> = None; + + /// The table of ACPI device ids supported by the driver. + const ACPI_ID_TABLE: Option> = None; + + /// I2C driver probe. + /// + /// Called when a new i2c client is added or discovered. + /// Implementers should attempt to initialize the client here. + fn probe( + dev: &I2cClient, + id_info: Option<&Self::IdInfo>, + ) -> Result>>; + + /// I2C driver shutdown. + /// + /// Called by the kernel during system reboot or power-off to allow the [`Driver`] to bring the + /// [`Device`] into a safe state. Implementing this callback is optional. + /// + /// Typical actions include stopping transfers, disabling interrupts, or resetting the hardware + /// to prevent undesired behavior during shutdown. + /// + /// This callback is distinct from final resource cleanup, as the driver instance remains valid + /// after it returns. Any deallocation or teardown of driver-owned resources should instead be + /// handled in `Self::drop`. + fn shutdown(dev: &I2cClient, this: Pin<&Self>) { + let _ = (dev, this); + } + + /// I2C driver unbind. + /// + /// Called when a [`Device`] is unbound from its bound [`Driver`]. Implementing this callback + /// is optional. + /// + /// This callback serves as a place for drivers to perform teardown operations that require a + /// `&Device` or `&Device` reference. For instance, drivers may try to perform I/O + /// operations to gracefully tear down the device. + /// + /// Otherwise, release operations for driver resources should be performed in `Self::drop`. + fn unbind(dev: &I2cClient, this: Pin<&Self>) { + let _ = (dev, this); + } +} + +/// The i2c client representation. +/// +/// This structure represents the Rust abstraction for a C `struct i2c_client`. The +/// implementation abstracts the usage of an existing C `struct i2c_client` that +/// gets passed from the C side +/// +/// # Invariants +/// +/// A [`I2cClient`] instance represents a valid `struct i2c_client` created by the C portion of +/// the kernel. +#[repr(transparent)] +pub struct I2cClient( + Opaque, + PhantomData, +); + +impl I2cClient { + fn as_raw(&self) -> *mut bindings::i2c_client { + self.0.get() + } +} + +// SAFETY: `I2cClient` is a transparent wrapper of a type that doesn't depend on `I2cClient`'s generic +// argument. +kernel::impl_device_context_deref!(unsafe { I2cClient }); +kernel::impl_device_context_into_aref!(I2cClient); + +// SAFETY: Instances of `I2cClient` are always reference-counted. +unsafe impl AlwaysRefCounted for I2cClient { + fn inc_ref(&self) { + // SAFETY: The existence of a shared reference guarantees that the refcount is non-zero. + unsafe { bindings::get_device(self.as_ref().as_raw()) }; + } + + unsafe fn dec_ref(obj: NonNull) { + // SAFETY: The safety requirements guarantee that the refcount is non-zero. + unsafe { bindings::put_device(&raw mut (*obj.as_ref().as_raw()).dev) } + } +} + +impl AsRef> for I2cClient { + fn as_ref(&self) -> &device::Device { + let raw = self.as_raw(); + // SAFETY: By the type invariant of `Self`, `self.as_raw()` is a pointer to a valid + // `struct i2c_client`. + let dev = unsafe { &raw mut (*raw).dev }; + + // SAFETY: `dev` points to a valid `struct device`. + unsafe { device::Device::from_raw(dev) } + } +} + +impl TryFrom<&device::Device> for &I2cClient { + type Error = kernel::error::Error; + + fn try_from(dev: &device::Device) -> Result { + // SAFETY: By the type invariant of `Device`, `dev.as_raw()` is a valid pointer to a + // `struct device`. + if unsafe { bindings::i2c_verify_client(dev.as_raw()).is_null() } { + return Err(EINVAL); + } + + // SAFETY: We've just verified that the type of `dev` equals to + // `bindings::i2c_client_type`, hence `dev` must be embedded in a valid + // `struct i2c_client` as guaranteed by the corresponding C code. + let idev = unsafe { container_of!(dev.as_raw(), bindings::i2c_client, dev) }; + + // SAFETY: `idev` is a valid pointer to a `struct i2c_client`. + Ok(unsafe { &*idev.cast() }) + } +} + +// SAFETY: A `I2cClient` is always reference-counted and can be released from any thread. +unsafe impl Send for I2cClient {} + +// SAFETY: `I2cClient` can be shared among threads because all methods of `I2cClient` +// (i.e. `I2cClient) are thread safe. +unsafe impl Sync for I2cClient {} diff --git a/rust/kernel/lib.rs b/rust/kernel/lib.rs index ed53169e795c..a5e97a9b1546 100644 --- a/rust/kernel/lib.rs +++ b/rust/kernel/lib.rs @@ -89,6 +89,8 @@ pub mod firmware; pub mod fmt; pub mod fs; +#[cfg(CONFIG_I2C = "y")] +pub mod i2c; pub mod init; pub mod io; pub mod ioctl; -- 2.43.0