* [PATCH v7 1/4] rust: i2c: add basic I2C device and driver abstractions
2025-11-10 11:24 [PATCH v7 0/4] rust: i2c: Add basic I2C driver abstractions Igor Korotin
@ 2025-11-10 11:25 ` Igor Korotin
2025-11-11 8:10 ` Danilo Krummrich
2025-11-10 11:30 ` [PATCH v7 2/4] rust: i2c: add manual I2C device creation abstractions Igor Korotin
` (4 subsequent siblings)
5 siblings, 1 reply; 11+ messages in thread
From: Igor Korotin @ 2025-11-10 11:25 UTC (permalink / raw)
To: Miguel Ojeda, Alex Gaynor, Wolfram Sang
Cc: Boqun Feng, Gary Guo, Björn Roy Baron, 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, rust-for-linux, linux-i2c
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 <igor.korotin.linux@gmail.com>
---
MAINTAINERS | 8 +
rust/bindings/bindings_helper.h | 1 +
rust/kernel/i2c.rs | 425 ++++++++++++++++++++++++++++++++
rust/kernel/lib.rs | 2 +
4 files changed, 436 insertions(+)
create mode 100644 rust/kernel/i2c.rs
diff --git a/MAINTAINERS b/MAINTAINERS
index 46126ce2f968..828f6d8b1c32 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -11737,6 +11737,14 @@ F: include/linux/i2c.h
F: include/uapi/linux/i2c-*.h
F: include/uapi/linux/i2c.h
+I2C SUBSYSTEM [RUST]
+M: Igor Korotin <igor.korotin.linux@gmail.com>
+R: Danilo Krummrich <dakr@kernel.org>
+R: Daniel Almeida <daniel.almeida@collabora.com>
+L: rust-for-linux@vger.kernel.org
+S: Maintained
+F: rust/kernel/i2c.rs
+
I2C SUBSYSTEM HOST DRIVERS
M: Andi Shyti <andi.shyti@kernel.org>
L: linux-i2c@vger.kernel.org
diff --git a/rust/bindings/bindings_helper.h b/rust/bindings/bindings_helper.h
index 2e43c66635a2..a24f9dffed3a 100644
--- a/rust/bindings/bindings_helper.h
+++ b/rust/bindings/bindings_helper.h
@@ -58,6 +58,7 @@
#include <linux/firmware.h>
#include <linux/interrupt.h>
#include <linux/fs.h>
+#include <linux/i2c.h>
#include <linux/ioport.h>
#include <linux/jiffies.h>
#include <linux/jump_label.h>
diff --git a/rust/kernel/i2c.rs b/rust/kernel/i2c.rs
new file mode 100644
index 000000000000..41ef7c65c555
--- /dev/null
+++ b/rust/kernel/i2c.rs
@@ -0,0 +1,425 @@
+// 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<T> = &'static dyn kernel::device_id::IdTable<DeviceId, T>;
+
+/// 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: Driver>(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<T: Driver + 'static> driver::RegistrationOps for Adapter<T> {
+ type RegType = bindings::i2c_driver;
+
+ unsafe fn register(
+ idrv: &Opaque<Self::RegType>,
+ 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<Self::RegType>) {
+ // SAFETY: `idrv` is guaranteed to be a valid `RegType`.
+ unsafe { bindings::i2c_del_driver(idrv.get()) }
+ }
+}
+
+impl<T: Driver + 'static> Adapter<T> {
+ 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::<I2cClient<device::CoreInternal>>() };
+
+ let info =
+ Self::i2c_id_info(idev).or_else(|| <Self as driver::Adapter>::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::<I2cClient<device::CoreInternal>>() };
+
+ // 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<KBox<T>>`.
+ let data = unsafe { idev.as_ref().drvdata_obtain::<Pin<KBox<T>>>() };
+
+ T::unbind(idev, data.as_ref());
+ }
+
+ 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::<I2cClient<device::CoreInternal>>() };
+
+ // 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<KBox<T>>`.
+ let data = unsafe { idev.as_ref().drvdata_obtain::<Pin<KBox<T>>>() };
+
+ T::shutdown(idev, data.as_ref());
+ }
+
+ /// The [`i2c::IdTable`] of the corresponding driver.
+ fn i2c_id_table() -> Option<IdTable<<Self as driver::Adapter>::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 <Self as driver::Adapter>::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::<DeviceId>() };
+
+ Some(table.info(<DeviceId as RawDeviceIdIndex>::index(id)))
+ }
+}
+
+impl<T: Driver + 'static> driver::Adapter for Adapter<T> {
+ type IdInfo = T::IdInfo;
+
+ fn of_id_table() -> Option<of::IdTable<Self::IdInfo>> {
+ T::OF_ID_TABLE
+ }
+
+ fn acpi_id_table() -> Option<acpi::IdTable<Self::IdInfo>> {
+ 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!(<T>, $crate::i2c::Adapter<T>, { $($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,
+/// <MyDriver as i2c::Driver>::IdInfo,
+/// [
+/// (acpi::DeviceId::new(c_str!("LNUXBEEF")), ())
+/// ]
+/// );
+///
+/// kernel::i2c_device_table!(
+/// I2C_TABLE,
+/// MODULE_I2C_TABLE,
+/// <MyDriver as i2c::Driver>::IdInfo,
+/// [
+/// (i2c::DeviceId::new(c_str!("rust_driver_i2c")), ())
+/// ]
+/// );
+///
+/// kernel::of_device_table!(
+/// OF_TABLE,
+/// MODULE_OF_TABLE,
+/// <MyDriver as i2c::Driver>::IdInfo,
+/// [
+/// (of::DeviceId::new(c_str!("test,device")), ())
+/// ]
+/// );
+///
+/// impl i2c::Driver for MyDriver {
+/// type IdInfo = ();
+/// const I2C_ID_TABLE: Option<i2c::IdTable<Self::IdInfo>> = Some(&I2C_TABLE);
+/// const OF_ID_TABLE: Option<of::IdTable<Self::IdInfo>> = Some(&OF_TABLE);
+/// const ACPI_ID_TABLE: Option<acpi::IdTable<Self::IdInfo>> = Some(&ACPI_TABLE);
+///
+/// fn probe(
+/// _idev: &i2c::I2cClient<Core>,
+/// _id_info: Option<&Self::IdInfo>,
+/// ) -> impl PinInit<Self, Error> {
+/// Err(ENODEV)
+/// }
+///
+/// fn shutdown(_idev: &i2c::I2cClient<Core>, 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<IdTable<Self::IdInfo>> = None;
+
+ /// The table of OF device ids supported by the driver.
+ const OF_ID_TABLE: Option<of::IdTable<Self::IdInfo>> = None;
+
+ /// The table of ACPI device ids supported by the driver.
+ const ACPI_ID_TABLE: Option<acpi::IdTable<Self::IdInfo>> = 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<device::Core>,
+ id_info: Option<&Self::IdInfo>,
+ ) -> impl PinInit<Self, Error>;
+
+ /// 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<device::Core>, 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<Core>` or `&Device<Bound>` 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<device::Core>, 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<Ctx: device::DeviceContext = device::Normal>(
+ Opaque<bindings::i2c_client>,
+ PhantomData<Ctx>,
+);
+
+impl<Ctx: device::DeviceContext> I2cClient<Ctx> {
+ 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<Self>) {
+ // SAFETY: The safety requirements guarantee that the refcount is non-zero.
+ unsafe { bindings::put_device(&raw mut (*obj.as_ref().as_raw()).dev) }
+ }
+}
+
+impl<Ctx: device::DeviceContext> AsRef<device::Device<Ctx>> for I2cClient<Ctx> {
+ fn as_ref(&self) -> &device::Device<Ctx> {
+ 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<Ctx: device::DeviceContext> TryFrom<&device::Device<Ctx>> for &I2cClient<Ctx> {
+ type Error = kernel::error::Error;
+
+ fn try_from(dev: &device::Device<Ctx>) -> Result<Self, Self::Error> {
+ // 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<Normal>) are thread safe.
+unsafe impl Sync for I2cClient {}
diff --git a/rust/kernel/lib.rs b/rust/kernel/lib.rs
index 3dd7bebe7888..8c0070a8029e 100644
--- a/rust/kernel/lib.rs
+++ b/rust/kernel/lib.rs
@@ -94,6 +94,8 @@
pub mod firmware;
pub mod fmt;
pub mod fs;
+#[cfg(CONFIG_I2C = "y")]
+pub mod i2c;
pub mod id_pool;
pub mod init;
pub mod io;
--
2.43.0
^ permalink raw reply related [flat|nested] 11+ messages in thread* Re: [PATCH v7 1/4] rust: i2c: add basic I2C device and driver abstractions
2025-11-10 11:25 ` [PATCH v7 1/4] rust: i2c: add basic I2C device and " Igor Korotin
@ 2025-11-11 8:10 ` Danilo Krummrich
0 siblings, 0 replies; 11+ messages in thread
From: Danilo Krummrich @ 2025-11-11 8:10 UTC (permalink / raw)
To: Igor Korotin
Cc: Miguel Ojeda, Alex Gaynor, Wolfram Sang, Boqun Feng, Gary Guo,
Björn Roy Baron, Benno Lossin, Andreas Hindborg, Alice Ryhl,
Trevor Gross, Greg Kroah-Hartman, Viresh Kumar, Asahi Lina,
Wedson Almeida Filho, Alex Hung, Tamir Duberstein, Xiangfei Ding,
linux-kernel, rust-for-linux, linux-i2c
On Mon Nov 10, 2025 at 10:25 PM AEDT, Igor Korotin wrote:
> diff --git a/rust/kernel/i2c.rs b/rust/kernel/i2c.rs
> new file mode 100644
> index 000000000000..41ef7c65c555
> --- /dev/null
> +++ b/rust/kernel/i2c.rs
> @@ -0,0 +1,425 @@
> +// 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};
Please use kernel "vertical style" [1].
[1] https://docs.kernel.org/rust/coding-guidelines.html#imports
Please also run ./scripts/checkpatch.pl on all patches, there are a few warnings
to address.
> +
> +/// 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() };
You can use pin_init::zeroed() for this.
> + let mut i = 0;
> + while i < src.len() {
> + i2c.name[i] = src[i];
> + i += 1;
> + }
> +
> + Self(i2c)
> + }
> +}
^ permalink raw reply [flat|nested] 11+ messages in thread
* [PATCH v7 2/4] rust: i2c: add manual I2C device creation abstractions
2025-11-10 11:24 [PATCH v7 0/4] rust: i2c: Add basic I2C driver abstractions Igor Korotin
2025-11-10 11:25 ` [PATCH v7 1/4] rust: i2c: add basic I2C device and " Igor Korotin
@ 2025-11-10 11:30 ` Igor Korotin
2025-11-11 8:14 ` Danilo Krummrich
2025-11-10 11:30 ` [PATCH v7 1/4] rust: i2c: add basic I2C device and driver abstractions Igor Korotin
` (3 subsequent siblings)
5 siblings, 1 reply; 11+ messages in thread
From: Igor Korotin @ 2025-11-10 11:30 UTC (permalink / raw)
To: Miguel Ojeda, Alex Gaynor, Wolfram Sang
Cc: Boqun Feng, Gary Guo, Björn Roy Baron, 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, rust-for-linux, linux-i2c
In addition to the basic I2C device support, add rust abstractions
upon `i2c_new_client_device`/`i2c_unregister_device` C functions.
Implement the core abstractions needed for manual creation/deletion
of I2C devices, including:
* `i2c::Registration` — a NonNull pointer created by the function
`i2c_new_client_device`
* `i2c::I2cAdapter` — a ref counted wrapper around `struct i2c_adapter`
* `i2c::I2cBoardInfo` — a safe wrapper around `struct i2c_board_info`
Signed-off-by: Igor Korotin <igor.korotin.linux@gmail.com>
---
rust/kernel/i2c.rs | 153 ++++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 152 insertions(+), 1 deletion(-)
diff --git a/rust/kernel/i2c.rs b/rust/kernel/i2c.rs
index 41ef7c65c555..27f9ee628e2c 100644
--- a/rust/kernel/i2c.rs
+++ b/rust/kernel/i2c.rs
@@ -6,6 +6,7 @@
use crate::{
acpi, container_of, device,
device_id::{RawDeviceId, RawDeviceIdIndex},
+ devres::Devres,
driver,
error::*,
of,
@@ -13,7 +14,12 @@
types::{AlwaysRefCounted, Opaque},
};
-use core::{marker::PhantomData, ptr::NonNull};
+use core::{
+ marker::PhantomData,
+ ptr::{from_ref, NonNull},
+};
+
+use kernel::types::ARef;
/// An I2C device id table.
#[repr(transparent)]
@@ -345,6 +351,101 @@ fn unbind(dev: &I2cClient<device::Core>, this: Pin<&Self>) {
}
}
+/// The i2c adapter representation.
+///
+/// This structure represents the Rust abstraction for a C `struct i2c_adapter`. The
+/// implementation abstracts the usage of an existing C `struct i2c_adapter` that
+/// gets passed from the C side
+///
+/// # Invariants
+///
+/// A [`I2cAdapter`] instance represents a valid `struct i2c_adapter` created by the C portion of
+/// the kernel.
+#[repr(transparent)]
+pub struct I2cAdapter<Ctx: device::DeviceContext = device::Normal>(
+ Opaque<bindings::i2c_adapter>,
+ PhantomData<Ctx>,
+);
+
+impl<Ctx: device::DeviceContext> I2cAdapter<Ctx> {
+ fn as_raw(&self) -> *mut bindings::i2c_adapter {
+ self.0.get()
+ }
+}
+
+impl I2cAdapter {
+ /// Returns the I2C Adapter index.
+ #[inline]
+ pub fn get_nr(&self) -> i32 {
+ // SAFETY: `self.as_raw` is a valid pointer to a `struct i2c_adapter`.
+ unsafe { (*self.as_raw()).nr }
+ }
+ /// Gets pointer to an `i2c_adapter` by index.
+ pub fn get(index: i32) -> Result<ARef<Self>> {
+ // SAFETY: `index` must refer to a valid I2C adapter; the kernel
+ // guarantees that `i2c_get_adapter(index)` returns either a valid
+ // pointer or NULL. `NonNull::new` guarantees the correct check.
+ let adapter = NonNull::new(unsafe { bindings::i2c_get_adapter(index) }).ok_or(ENODEV)?;
+
+ // SAFETY: `adapter` is non-null and points to a live `i2c_adapter`.
+ // `I2cAdapter` is #[repr(transparent)], so this cast is valid.
+ Ok(unsafe { (&*adapter.as_ptr().cast::<I2cAdapter<device::Normal>>()).into() })
+ }
+}
+
+// SAFETY: `I2cAdapter` is a transparent wrapper of a type that doesn't depend on `I2cAdapter`'s generic
+// argument.
+kernel::impl_device_context_deref!(unsafe { I2cAdapter });
+kernel::impl_device_context_into_aref!(I2cAdapter);
+
+// SAFETY: Instances of `I2cAdapter` are always reference-counted.
+unsafe impl crate::types::AlwaysRefCounted for I2cAdapter {
+ fn inc_ref(&self) {
+ // SAFETY: The existence of a shared reference guarantees that the refcount is non-zero.
+ unsafe { bindings::i2c_get_adapter(self.get_nr()) };
+ }
+
+ unsafe fn dec_ref(obj: NonNull<Self>) {
+ // SAFETY: The safety requirements guarantee that the refcount is non-zero.
+ unsafe { bindings::i2c_put_adapter(obj.as_ref().as_raw()) }
+ }
+}
+
+/// The i2c board info representation
+///
+/// This structure represents the Rust abstraction for a C `struct i2c_board_info` structure,
+/// which is used for manual I2C client creation.
+#[repr(transparent)]
+pub struct I2cBoardInfo(bindings::i2c_board_info);
+
+impl I2cBoardInfo {
+ const I2C_TYPE_SIZE: usize = 20;
+ /// Create a new [`I2cBoardInfo`] for a kernel driver.
+ #[inline(always)]
+ pub const fn new(type_: &'static CStr, addr: u16) -> Self {
+ build_assert!(
+ type_.len_with_nul() <= Self::I2C_TYPE_SIZE,
+ "Type exceeds 20 bytes"
+ );
+ let src = type_.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_board_info: bindings::i2c_board_info = unsafe { core::mem::zeroed() };
+ let mut i: usize = 0;
+ while i < src.len() {
+ i2c_board_info.type_[i] = src[i];
+ i += 1;
+ }
+
+ i2c_board_info.addr = addr;
+ Self(i2c_board_info)
+ }
+
+ fn as_raw(&self) -> *const bindings::i2c_board_info {
+ from_ref(&self.0)
+ }
+}
+
/// The i2c client representation.
///
/// This structure represents the Rust abstraction for a C `struct i2c_client`. The
@@ -423,3 +524,53 @@ unsafe impl Send for I2cClient {}
// SAFETY: `I2cClient` can be shared among threads because all methods of `I2cClient`
// (i.e. `I2cClient<Normal>) are thread safe.
unsafe impl Sync for I2cClient {}
+
+/// The registration of an i2c client device.
+///
+/// This type represents the registration of a [`struct i2c_client`]. When an instance of this
+/// type is dropped, its respective i2c client device will be unregistered from the system.
+///
+/// # Invariants
+///
+/// `self.0` always holds a valid pointer to an initialized and registered
+/// [`struct i2c_client`].
+#[repr(transparent)]
+pub struct Registration(NonNull<bindings::i2c_client>);
+
+impl Registration {
+ /// The C `i2c_new_client_device` function wrapper for manual I2C client creation.
+ pub fn new<'a>(
+ i2c_adapter: &I2cAdapter,
+ i2c_board_info: &I2cBoardInfo,
+ parent_dev: &'a device::Device<device::Bound>,
+ ) -> impl PinInit<Devres<Self>, Error> + 'a {
+ Devres::new(parent_dev, Self::try_new(i2c_adapter, i2c_board_info))
+ }
+
+ fn try_new(i2c_adapter: &I2cAdapter, i2c_board_info: &I2cBoardInfo) -> Result<Self> {
+ // SAFETY: the kernel guarantees that `i2c_new_client_device()` returns either a valid
+ // pointer or NULL. `from_err_ptr` separates errors. Following `NonNull::new` checks for NULL.
+ let raw_dev = from_err_ptr(unsafe {
+ bindings::i2c_new_client_device(i2c_adapter.as_raw(), i2c_board_info.as_raw())
+ })?;
+
+ let dev_ptr = NonNull::new(raw_dev).ok_or(ENODEV)?;
+
+ Ok(Self(dev_ptr))
+ }
+}
+
+impl Drop for Registration {
+ fn drop(&mut self) {
+ // SAFETY: `Drop` is only called for a valid `Registration`, which by invariant
+ // always contains a non-null pointer to an `i2c_client`.
+ unsafe { bindings::i2c_unregister_device(self.0.as_ptr()) }
+ }
+}
+
+// SAFETY: A `Registration` of a `struct i2c_client` can be released from any thread.
+unsafe impl Send for Registration {}
+
+// SAFETY: `Registration` offers no interior mutability (no mutation through &self
+// and no mutable access is exposed)
+unsafe impl Sync for Registration {}
--
2.43.0
^ permalink raw reply related [flat|nested] 11+ messages in thread* Re: [PATCH v7 2/4] rust: i2c: add manual I2C device creation abstractions
2025-11-10 11:30 ` [PATCH v7 2/4] rust: i2c: add manual I2C device creation abstractions Igor Korotin
@ 2025-11-11 8:14 ` Danilo Krummrich
0 siblings, 0 replies; 11+ messages in thread
From: Danilo Krummrich @ 2025-11-11 8:14 UTC (permalink / raw)
To: Igor Korotin
Cc: Miguel Ojeda, Alex Gaynor, Wolfram Sang, Boqun Feng, Gary Guo,
Björn Roy Baron, Benno Lossin, Andreas Hindborg, Alice Ryhl,
Trevor Gross, Greg Kroah-Hartman, Viresh Kumar, Asahi Lina,
Wedson Almeida Filho, Alex Hung, Tamir Duberstein, Xiangfei Ding,
linux-kernel, rust-for-linux, linux-i2c
On Mon Nov 10, 2025 at 10:30 PM AEDT, Igor Korotin wrote:
> +impl I2cAdapter {
> + /// Returns the I2C Adapter index.
> + #[inline]
> + pub fn get_nr(&self) -> i32 {
> + // SAFETY: `self.as_raw` is a valid pointer to a `struct i2c_adapter`.
> + unsafe { (*self.as_raw()).nr }
> + }
Missing empty line. Also, please try to avoid the "get" prefix for functions /
methods that do not increase a reference count. What about just index()?
> + /// Gets pointer to an `i2c_adapter` by index.
> + pub fn get(index: i32) -> Result<ARef<Self>> {
> + // SAFETY: `index` must refer to a valid I2C adapter; the kernel
> + // guarantees that `i2c_get_adapter(index)` returns either a valid
> + // pointer or NULL. `NonNull::new` guarantees the correct check.
> + let adapter = NonNull::new(unsafe { bindings::i2c_get_adapter(index) }).ok_or(ENODEV)?;
> +
> + // SAFETY: `adapter` is non-null and points to a live `i2c_adapter`.
> + // `I2cAdapter` is #[repr(transparent)], so this cast is valid.
> + Ok(unsafe { (&*adapter.as_ptr().cast::<I2cAdapter<device::Normal>>()).into() })
> + }
> +}
> +
> +// SAFETY: `I2cAdapter` is a transparent wrapper of a type that doesn't depend on `I2cAdapter`'s generic
> +// argument.
> +kernel::impl_device_context_deref!(unsafe { I2cAdapter });
> +kernel::impl_device_context_into_aref!(I2cAdapter);
> +
> +// SAFETY: Instances of `I2cAdapter` are always reference-counted.
> +unsafe impl crate::types::AlwaysRefCounted for I2cAdapter {
> + fn inc_ref(&self) {
> + // SAFETY: The existence of a shared reference guarantees that the refcount is non-zero.
> + unsafe { bindings::i2c_get_adapter(self.get_nr()) };
> + }
> +
> + unsafe fn dec_ref(obj: NonNull<Self>) {
> + // SAFETY: The safety requirements guarantee that the refcount is non-zero.
> + unsafe { bindings::i2c_put_adapter(obj.as_ref().as_raw()) }
> + }
> +}
> +
> +/// The i2c board info representation
> +///
> +/// This structure represents the Rust abstraction for a C `struct i2c_board_info` structure,
> +/// which is used for manual I2C client creation.
> +#[repr(transparent)]
> +pub struct I2cBoardInfo(bindings::i2c_board_info);
> +
> +impl I2cBoardInfo {
> + const I2C_TYPE_SIZE: usize = 20;
> + /// Create a new [`I2cBoardInfo`] for a kernel driver.
> + #[inline(always)]
> + pub const fn new(type_: &'static CStr, addr: u16) -> Self {
> + build_assert!(
> + type_.len_with_nul() <= Self::I2C_TYPE_SIZE,
> + "Type exceeds 20 bytes"
> + );
> + let src = type_.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_board_info: bindings::i2c_board_info = unsafe { core::mem::zeroed() };
pin_init::zeroed()
> + let mut i: usize = 0;
> + while i < src.len() {
> + i2c_board_info.type_[i] = src[i];
> + i += 1;
> + }
> +
> + i2c_board_info.addr = addr;
> + Self(i2c_board_info)
> + }
> +
> + fn as_raw(&self) -> *const bindings::i2c_board_info {
> + from_ref(&self.0)
> + }
> +}
^ permalink raw reply [flat|nested] 11+ messages in thread
* [PATCH v7 1/4] rust: i2c: add basic I2C device and driver abstractions
2025-11-10 11:24 [PATCH v7 0/4] rust: i2c: Add basic I2C driver abstractions Igor Korotin
2025-11-10 11:25 ` [PATCH v7 1/4] rust: i2c: add basic I2C device and " Igor Korotin
2025-11-10 11:30 ` [PATCH v7 2/4] rust: i2c: add manual I2C device creation abstractions Igor Korotin
@ 2025-11-10 11:30 ` Igor Korotin
2025-11-10 11:31 ` [PATCH v7 3/4] samples: rust: add Rust I2C sample driver Igor Korotin
` (2 subsequent siblings)
5 siblings, 0 replies; 11+ messages in thread
From: Igor Korotin @ 2025-11-10 11:30 UTC (permalink / raw)
To: Miguel Ojeda, Alex Gaynor, Wolfram Sang
Cc: Boqun Feng, Gary Guo, Björn Roy Baron, 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, rust-for-linux, linux-i2c
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 <igor.korotin.linux@gmail.com>
---
MAINTAINERS | 8 +
rust/bindings/bindings_helper.h | 1 +
rust/kernel/i2c.rs | 425 ++++++++++++++++++++++++++++++++
rust/kernel/lib.rs | 2 +
4 files changed, 436 insertions(+)
create mode 100644 rust/kernel/i2c.rs
diff --git a/MAINTAINERS b/MAINTAINERS
index 46126ce2f968..828f6d8b1c32 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -11737,6 +11737,14 @@ F: include/linux/i2c.h
F: include/uapi/linux/i2c-*.h
F: include/uapi/linux/i2c.h
+I2C SUBSYSTEM [RUST]
+M: Igor Korotin <igor.korotin.linux@gmail.com>
+R: Danilo Krummrich <dakr@kernel.org>
+R: Daniel Almeida <daniel.almeida@collabora.com>
+L: rust-for-linux@vger.kernel.org
+S: Maintained
+F: rust/kernel/i2c.rs
+
I2C SUBSYSTEM HOST DRIVERS
M: Andi Shyti <andi.shyti@kernel.org>
L: linux-i2c@vger.kernel.org
diff --git a/rust/bindings/bindings_helper.h b/rust/bindings/bindings_helper.h
index 2e43c66635a2..a24f9dffed3a 100644
--- a/rust/bindings/bindings_helper.h
+++ b/rust/bindings/bindings_helper.h
@@ -58,6 +58,7 @@
#include <linux/firmware.h>
#include <linux/interrupt.h>
#include <linux/fs.h>
+#include <linux/i2c.h>
#include <linux/ioport.h>
#include <linux/jiffies.h>
#include <linux/jump_label.h>
diff --git a/rust/kernel/i2c.rs b/rust/kernel/i2c.rs
new file mode 100644
index 000000000000..41ef7c65c555
--- /dev/null
+++ b/rust/kernel/i2c.rs
@@ -0,0 +1,425 @@
+// 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<T> = &'static dyn kernel::device_id::IdTable<DeviceId, T>;
+
+/// 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: Driver>(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<T: Driver + 'static> driver::RegistrationOps for Adapter<T> {
+ type RegType = bindings::i2c_driver;
+
+ unsafe fn register(
+ idrv: &Opaque<Self::RegType>,
+ 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<Self::RegType>) {
+ // SAFETY: `idrv` is guaranteed to be a valid `RegType`.
+ unsafe { bindings::i2c_del_driver(idrv.get()) }
+ }
+}
+
+impl<T: Driver + 'static> Adapter<T> {
+ 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::<I2cClient<device::CoreInternal>>() };
+
+ let info =
+ Self::i2c_id_info(idev).or_else(|| <Self as driver::Adapter>::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::<I2cClient<device::CoreInternal>>() };
+
+ // 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<KBox<T>>`.
+ let data = unsafe { idev.as_ref().drvdata_obtain::<Pin<KBox<T>>>() };
+
+ T::unbind(idev, data.as_ref());
+ }
+
+ 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::<I2cClient<device::CoreInternal>>() };
+
+ // 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<KBox<T>>`.
+ let data = unsafe { idev.as_ref().drvdata_obtain::<Pin<KBox<T>>>() };
+
+ T::shutdown(idev, data.as_ref());
+ }
+
+ /// The [`i2c::IdTable`] of the corresponding driver.
+ fn i2c_id_table() -> Option<IdTable<<Self as driver::Adapter>::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 <Self as driver::Adapter>::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::<DeviceId>() };
+
+ Some(table.info(<DeviceId as RawDeviceIdIndex>::index(id)))
+ }
+}
+
+impl<T: Driver + 'static> driver::Adapter for Adapter<T> {
+ type IdInfo = T::IdInfo;
+
+ fn of_id_table() -> Option<of::IdTable<Self::IdInfo>> {
+ T::OF_ID_TABLE
+ }
+
+ fn acpi_id_table() -> Option<acpi::IdTable<Self::IdInfo>> {
+ 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!(<T>, $crate::i2c::Adapter<T>, { $($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,
+/// <MyDriver as i2c::Driver>::IdInfo,
+/// [
+/// (acpi::DeviceId::new(c_str!("LNUXBEEF")), ())
+/// ]
+/// );
+///
+/// kernel::i2c_device_table!(
+/// I2C_TABLE,
+/// MODULE_I2C_TABLE,
+/// <MyDriver as i2c::Driver>::IdInfo,
+/// [
+/// (i2c::DeviceId::new(c_str!("rust_driver_i2c")), ())
+/// ]
+/// );
+///
+/// kernel::of_device_table!(
+/// OF_TABLE,
+/// MODULE_OF_TABLE,
+/// <MyDriver as i2c::Driver>::IdInfo,
+/// [
+/// (of::DeviceId::new(c_str!("test,device")), ())
+/// ]
+/// );
+///
+/// impl i2c::Driver for MyDriver {
+/// type IdInfo = ();
+/// const I2C_ID_TABLE: Option<i2c::IdTable<Self::IdInfo>> = Some(&I2C_TABLE);
+/// const OF_ID_TABLE: Option<of::IdTable<Self::IdInfo>> = Some(&OF_TABLE);
+/// const ACPI_ID_TABLE: Option<acpi::IdTable<Self::IdInfo>> = Some(&ACPI_TABLE);
+///
+/// fn probe(
+/// _idev: &i2c::I2cClient<Core>,
+/// _id_info: Option<&Self::IdInfo>,
+/// ) -> impl PinInit<Self, Error> {
+/// Err(ENODEV)
+/// }
+///
+/// fn shutdown(_idev: &i2c::I2cClient<Core>, 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<IdTable<Self::IdInfo>> = None;
+
+ /// The table of OF device ids supported by the driver.
+ const OF_ID_TABLE: Option<of::IdTable<Self::IdInfo>> = None;
+
+ /// The table of ACPI device ids supported by the driver.
+ const ACPI_ID_TABLE: Option<acpi::IdTable<Self::IdInfo>> = 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<device::Core>,
+ id_info: Option<&Self::IdInfo>,
+ ) -> impl PinInit<Self, Error>;
+
+ /// 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<device::Core>, 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<Core>` or `&Device<Bound>` 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<device::Core>, 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<Ctx: device::DeviceContext = device::Normal>(
+ Opaque<bindings::i2c_client>,
+ PhantomData<Ctx>,
+);
+
+impl<Ctx: device::DeviceContext> I2cClient<Ctx> {
+ 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<Self>) {
+ // SAFETY: The safety requirements guarantee that the refcount is non-zero.
+ unsafe { bindings::put_device(&raw mut (*obj.as_ref().as_raw()).dev) }
+ }
+}
+
+impl<Ctx: device::DeviceContext> AsRef<device::Device<Ctx>> for I2cClient<Ctx> {
+ fn as_ref(&self) -> &device::Device<Ctx> {
+ 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<Ctx: device::DeviceContext> TryFrom<&device::Device<Ctx>> for &I2cClient<Ctx> {
+ type Error = kernel::error::Error;
+
+ fn try_from(dev: &device::Device<Ctx>) -> Result<Self, Self::Error> {
+ // 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<Normal>) are thread safe.
+unsafe impl Sync for I2cClient {}
diff --git a/rust/kernel/lib.rs b/rust/kernel/lib.rs
index 3dd7bebe7888..8c0070a8029e 100644
--- a/rust/kernel/lib.rs
+++ b/rust/kernel/lib.rs
@@ -94,6 +94,8 @@
pub mod firmware;
pub mod fmt;
pub mod fs;
+#[cfg(CONFIG_I2C = "y")]
+pub mod i2c;
pub mod id_pool;
pub mod init;
pub mod io;
--
2.43.0
^ permalink raw reply related [flat|nested] 11+ messages in thread* [PATCH v7 3/4] samples: rust: add Rust I2C sample driver
2025-11-10 11:24 [PATCH v7 0/4] rust: i2c: Add basic I2C driver abstractions Igor Korotin
` (2 preceding siblings ...)
2025-11-10 11:30 ` [PATCH v7 1/4] rust: i2c: add basic I2C device and driver abstractions Igor Korotin
@ 2025-11-10 11:31 ` Igor Korotin
2025-11-11 8:16 ` Danilo Krummrich
2025-11-10 11:31 ` [PATCH v7 4/4] samples: rust: add Rust I2C client registration sample Igor Korotin
2025-11-11 8:05 ` [PATCH v7 0/4] rust: i2c: Add basic I2C driver abstractions Danilo Krummrich
5 siblings, 1 reply; 11+ messages in thread
From: Igor Korotin @ 2025-11-10 11:31 UTC (permalink / raw)
To: Miguel Ojeda, Alex Gaynor, Wolfram Sang
Cc: Boqun Feng, Gary Guo, Björn Roy Baron, 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, rust-for-linux, linux-i2c
Add a new `rust_driver_i2c` sample, showing how to create a new
i2c driver using ACPI/OF/Legacy ID tables.
Signed-off-by: Igor Korotin <igor.korotin.linux@gmail.com>
---
MAINTAINERS | 1 +
samples/rust/Kconfig | 11 ++++++
samples/rust/Makefile | 1 +
samples/rust/rust_driver_i2c.rs | 69 +++++++++++++++++++++++++++++++++
4 files changed, 82 insertions(+)
create mode 100644 samples/rust/rust_driver_i2c.rs
diff --git a/MAINTAINERS b/MAINTAINERS
index 828f6d8b1c32..641757beb56b 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -11744,6 +11744,7 @@ R: Daniel Almeida <daniel.almeida@collabora.com>
L: rust-for-linux@vger.kernel.org
S: Maintained
F: rust/kernel/i2c.rs
+F: samples/rust/rust_driver_i2c.rs
I2C SUBSYSTEM HOST DRIVERS
M: Andi Shyti <andi.shyti@kernel.org>
diff --git a/samples/rust/Kconfig b/samples/rust/Kconfig
index c376eb899b7a..181466319588 100644
--- a/samples/rust/Kconfig
+++ b/samples/rust/Kconfig
@@ -84,6 +84,17 @@ config SAMPLE_RUST_DEBUGFS_SCOPED
If unsure, say N.
+config SAMPLE_RUST_DRIVER_I2C
+ tristate "I2C Driver"
+ depends on I2C=y
+ help
+ This option builds the Rust I2C driver sample.
+
+ To compile this as a module, choose M here:
+ the module will be called rust_driver_i2c.
+
+ If unsure, say N.
+
config SAMPLE_RUST_DRIVER_PCI
tristate "PCI Driver"
depends on PCI
diff --git a/samples/rust/Makefile b/samples/rust/Makefile
index cf8422f8f219..aec865e2adef 100644
--- a/samples/rust/Makefile
+++ b/samples/rust/Makefile
@@ -7,6 +7,7 @@ obj-$(CONFIG_SAMPLE_RUST_PRINT) += rust_print.o
obj-$(CONFIG_SAMPLE_RUST_DEBUGFS) += rust_debugfs.o
obj-$(CONFIG_SAMPLE_RUST_DEBUGFS_SCOPED) += rust_debugfs_scoped.o
obj-$(CONFIG_SAMPLE_RUST_DMA) += rust_dma.o
+obj-$(CONFIG_SAMPLE_RUST_DRIVER_I2C) += rust_driver_i2c.o
obj-$(CONFIG_SAMPLE_RUST_DRIVER_PCI) += rust_driver_pci.o
obj-$(CONFIG_SAMPLE_RUST_DRIVER_PLATFORM) += rust_driver_platform.o
obj-$(CONFIG_SAMPLE_RUST_DRIVER_USB) += rust_driver_usb.o
diff --git a/samples/rust/rust_driver_i2c.rs b/samples/rust/rust_driver_i2c.rs
new file mode 100644
index 000000000000..79d0055793d7
--- /dev/null
+++ b/samples/rust/rust_driver_i2c.rs
@@ -0,0 +1,69 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Rust I2C driver sample.
+
+use kernel::{acpi, c_str, device::Core, i2c, of, prelude::*, types::ARef};
+
+struct SampleDriver {
+ _idev: ARef<i2c::I2cClient>,
+}
+
+kernel::acpi_device_table! {
+ ACPI_TABLE,
+ MODULE_ACPI_TABLE,
+ <SampleDriver as i2c::Driver>::IdInfo,
+ [(acpi::DeviceId::new(c_str!("LNUXBEEF")), 0)]
+}
+
+kernel::i2c_device_table! {
+ I2C_TABLE,
+ MODULE_I2C_TABLE,
+ <SampleDriver as i2c::Driver>::IdInfo,
+ [(i2c::DeviceId::new(c_str!("rust_driver_i2c")), 0)]
+}
+
+kernel::of_device_table! {
+ OF_TABLE,
+ MODULE_OF_TABLE,
+ <SampleDriver as i2c::Driver>::IdInfo,
+ [(of::DeviceId::new(c_str!("test,rust_driver_i2c")), 0)]
+}
+
+impl i2c::Driver for SampleDriver {
+ type IdInfo = u32;
+
+ const ACPI_ID_TABLE: Option<acpi::IdTable<Self::IdInfo>> = Some(&ACPI_TABLE);
+ const I2C_ID_TABLE: Option<i2c::IdTable<Self::IdInfo>> = Some(&I2C_TABLE);
+ const OF_ID_TABLE: Option<of::IdTable<Self::IdInfo>> = Some(&OF_TABLE);
+
+ fn probe(
+ idev: &i2c::I2cClient<Core>,
+ info: Option<&Self::IdInfo>,
+ ) -> impl PinInit<Self, Error> {
+ let dev = idev.as_ref();
+
+ dev_info!(dev, "Probe Rust I2C driver sample.\n");
+
+ if let Some(info) = info {
+ dev_info!(dev, "Probed with info: '{}'.\n", info);
+ }
+
+ Ok(Self { _idev: idev.into() })
+ }
+
+ fn shutdown(idev: &i2c::I2cClient<Core>, _this: Pin<&Self>) {
+ dev_info!(idev.as_ref(), "Shutdown Rust I2C driver sample.\n");
+ }
+
+ fn unbind(idev: &i2c::I2cClient<Core>, _this: Pin<&Self>) {
+ dev_info!(idev.as_ref(), "Unbind Rust I2C driver sample.\n");
+ }
+}
+
+kernel::module_i2c_driver! {
+ type: SampleDriver,
+ name: "rust_driver_i2c",
+ authors: ["Igor Korotin"],
+ description: "Rust I2C driver",
+ license: "GPL v2",
+}
--
2.43.0
^ permalink raw reply related [flat|nested] 11+ messages in thread* Re: [PATCH v7 3/4] samples: rust: add Rust I2C sample driver
2025-11-10 11:31 ` [PATCH v7 3/4] samples: rust: add Rust I2C sample driver Igor Korotin
@ 2025-11-11 8:16 ` Danilo Krummrich
0 siblings, 0 replies; 11+ messages in thread
From: Danilo Krummrich @ 2025-11-11 8:16 UTC (permalink / raw)
To: Igor Korotin
Cc: Miguel Ojeda, Alex Gaynor, Wolfram Sang, Boqun Feng, Gary Guo,
Björn Roy Baron, Benno Lossin, Andreas Hindborg, Alice Ryhl,
Trevor Gross, Greg Kroah-Hartman, Viresh Kumar, Asahi Lina,
Wedson Almeida Filho, Alex Hung, Tamir Duberstein, Xiangfei Ding,
linux-kernel, rust-for-linux, linux-i2c
On Mon Nov 10, 2025 at 10:31 PM AEDT, Igor Korotin wrote:
> diff --git a/samples/rust/rust_driver_i2c.rs b/samples/rust/rust_driver_i2c.rs
> new file mode 100644
> index 000000000000..79d0055793d7
> --- /dev/null
> +++ b/samples/rust/rust_driver_i2c.rs
> @@ -0,0 +1,69 @@
> +// SPDX-License-Identifier: GPL-2.0
> +
> +//! Rust I2C driver sample.
> +
> +use kernel::{acpi, c_str, device::Core, i2c, of, prelude::*, types::ARef};
> +
> +struct SampleDriver {
> + _idev: ARef<i2c::I2cClient>,
> +}
Let's just leave the struct empty if idev isn't used anyways. :)
^ permalink raw reply [flat|nested] 11+ messages in thread
* [PATCH v7 4/4] samples: rust: add Rust I2C client registration sample
2025-11-10 11:24 [PATCH v7 0/4] rust: i2c: Add basic I2C driver abstractions Igor Korotin
` (3 preceding siblings ...)
2025-11-10 11:31 ` [PATCH v7 3/4] samples: rust: add Rust I2C sample driver Igor Korotin
@ 2025-11-10 11:31 ` Igor Korotin
2025-11-11 8:20 ` Danilo Krummrich
2025-11-11 8:05 ` [PATCH v7 0/4] rust: i2c: Add basic I2C driver abstractions Danilo Krummrich
5 siblings, 1 reply; 11+ messages in thread
From: Igor Korotin @ 2025-11-10 11:31 UTC (permalink / raw)
To: Miguel Ojeda, Alex Gaynor, Wolfram Sang
Cc: Boqun Feng, Gary Guo, Björn Roy Baron, 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, rust-for-linux, linux-i2c
Add a new `rust_i2c_client` sample, showing how to create a new
i2c client using `i2c::Registration`
Signed-off-by: Igor Korotin <igor.korotin.linux@gmail.com>
---
samples/rust/Kconfig | 12 +++
samples/rust/Makefile | 1 +
samples/rust/rust_i2c_client.rs | 142 ++++++++++++++++++++++++++++++++
3 files changed, 155 insertions(+)
create mode 100644 samples/rust/rust_i2c_client.rs
diff --git a/samples/rust/Kconfig b/samples/rust/Kconfig
index 181466319588..a952220cdff7 100644
--- a/samples/rust/Kconfig
+++ b/samples/rust/Kconfig
@@ -95,6 +95,18 @@ config SAMPLE_RUST_DRIVER_I2C
If unsure, say N.
+config SAMPLE_RUST_I2C_CLIENT
+ tristate "Manual I2C Client"
+ depends on I2C && I2C_CHARDEV
+ help
+ This option builds the Rust I2C client manual creation
+ sample.
+
+ To compile this as a module, choose M here:
+ the module will be called rust_i2c_client.
+
+ If unsure, say N.
+
config SAMPLE_RUST_DRIVER_PCI
tristate "PCI Driver"
depends on PCI
diff --git a/samples/rust/Makefile b/samples/rust/Makefile
index aec865e2adef..f65885d1d62b 100644
--- a/samples/rust/Makefile
+++ b/samples/rust/Makefile
@@ -8,6 +8,7 @@ obj-$(CONFIG_SAMPLE_RUST_DEBUGFS) += rust_debugfs.o
obj-$(CONFIG_SAMPLE_RUST_DEBUGFS_SCOPED) += rust_debugfs_scoped.o
obj-$(CONFIG_SAMPLE_RUST_DMA) += rust_dma.o
obj-$(CONFIG_SAMPLE_RUST_DRIVER_I2C) += rust_driver_i2c.o
+obj-$(CONFIG_SAMPLE_RUST_I2C_CLIENT) += rust_i2c_client.o
obj-$(CONFIG_SAMPLE_RUST_DRIVER_PCI) += rust_driver_pci.o
obj-$(CONFIG_SAMPLE_RUST_DRIVER_PLATFORM) += rust_driver_platform.o
obj-$(CONFIG_SAMPLE_RUST_DRIVER_USB) += rust_driver_usb.o
diff --git a/samples/rust/rust_i2c_client.rs b/samples/rust/rust_i2c_client.rs
new file mode 100644
index 000000000000..e876a81ffe6e
--- /dev/null
+++ b/samples/rust/rust_i2c_client.rs
@@ -0,0 +1,142 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Rust I2C client registration sample.
+//!
+//! An I2C client in Rust cannot exist on its own. To register a new I2C client,
+//! it must be bound to a parent device. In this sample driver, a platform device
+//! is used as the parent.
+//!
+
+//! ACPI match table test
+//!
+//! This demonstrates how to test an ACPI-based Rust I2C client registration driver
+//! using QEMU with a custom SSDT.
+//!
+//! Steps:
+//!
+//! 1. **Create an SSDT source file** (`ssdt.dsl`) with the following content:
+//!
+//! ```asl
+//! DefinitionBlock ("", "SSDT", 2, "TEST", "VIRTACPI", 0x00000001)
+//! {
+//! Scope (\_SB)
+//! {
+//! Device (T432)
+//! {
+//! Name (_HID, "LNUXBEEF") // ACPI hardware ID to match
+//! Name (_UID, 1)
+//! Name (_STA, 0x0F) // Device present, enabled
+//! Name (_CRS, ResourceTemplate ()
+//! {
+//! Memory32Fixed (ReadWrite, 0xFED00000, 0x1000)
+//! })
+//! }
+//! }
+//! }
+//! ```
+//!
+//! 2. **Compile the table**:
+//!
+//! ```sh
+//! iasl -tc ssdt.dsl
+//! ```
+//!
+//! This generates `ssdt.aml`
+//!
+//! 3. **Run QEMU** with the compiled AML file:
+//!
+//! ```sh
+//! qemu-system-x86_64 -m 512M \
+//! -enable-kvm \
+//! -kernel path/to/bzImage \
+//! -append "root=/dev/sda console=ttyS0" \
+//! -hda rootfs.img \
+//! -serial stdio \
+//! -acpitable file=ssdt.aml
+//! ```
+//!
+//! Requirements:
+//! - The `rust_driver_platform` must be present either:
+//! - built directly into the kernel (`bzImage`), or
+//! - available as a `.ko` file and loadable from `rootfs.img`
+//!
+//! 4. **Verify it worked** by checking `dmesg`:
+//!
+//! ```
+//! rust_driver_platform LNUXBEEF:00: Probed with info: '0'.
+//! ```
+//!
+
+use kernel::{acpi, c_str, device, devres, i2c, of, platform, prelude::*, sync::aref::ARef};
+
+#[pin_data(PinnedDrop)]
+struct SampleDriver {
+ parent_dev: ARef<platform::Device>,
+ #[pin]
+ idev: devres::Devres<i2c::Registration>,
+}
+
+kernel::of_device_table!(
+ OF_TABLE,
+ MODULE_OF_TABLE,
+ <SampleDriver as platform::Driver>::IdInfo,
+ [(of::DeviceId::new(c_str!("test,rust-device")), ())]
+);
+
+kernel::acpi_device_table!(
+ ACPI_TABLE,
+ MODULE_ACPI_TABLE,
+ <SampleDriver as platform::Driver>::IdInfo,
+ [(acpi::DeviceId::new(c_str!("LNUXBEEF")), ())]
+);
+
+const SAMPLE_I2C_CLIENT_ADDR: u16 = 0x30;
+const SAMPLE_I2C_ADAPTER_INDEX: i32 = 0;
+const BOARD_INFO: i2c::I2cBoardInfo =
+ i2c::I2cBoardInfo::new(c_str!("rust_driver_i2c"), SAMPLE_I2C_CLIENT_ADDR);
+
+impl platform::Driver for SampleDriver {
+ type IdInfo = ();
+ const OF_ID_TABLE: Option<of::IdTable<Self::IdInfo>> = Some(&OF_TABLE);
+ const ACPI_ID_TABLE: Option<acpi::IdTable<Self::IdInfo>> = Some(&ACPI_TABLE);
+
+ fn probe(
+ pdev: &platform::Device<device::Core>,
+ _info: Option<&Self::IdInfo>,
+ ) -> impl PinInit<Self, Error> {
+ pin_init::pin_init_scope(move || {
+ dev_info!(
+ pdev.as_ref(),
+ "Probe Rust I2C Client registration sample.\n"
+ );
+
+ Ok(kernel::try_pin_init!( Self {
+ parent_dev: pdev.into(),
+
+ idev <- {
+ let adapter = i2c::I2cAdapter::get(SAMPLE_I2C_ADAPTER_INDEX)?;
+
+ i2c::Registration::new(&adapter, &BOARD_INFO, pdev.as_ref())
+ }
+ }))
+ })
+ }
+}
+
+#[pinned_drop]
+impl PinnedDrop for SampleDriver {
+ fn drop(self: Pin<&mut Self>) {
+ dev_info!(
+ self.parent_dev.as_ref(),
+ "Remove Rust Platform driver for I2C Client registration sample.\n"
+ );
+ }
+}
+
+kernel::module_platform_driver! {
+ type: SampleDriver,
+ name: "rust_device_i2c",
+ authors: ["Danilo Krummrich", "Igor Korotin"],
+ description: "Rust Platform driver",
+ license: "GPL v2",
+}
--
2.43.0
^ permalink raw reply related [flat|nested] 11+ messages in thread* Re: [PATCH v7 4/4] samples: rust: add Rust I2C client registration sample
2025-11-10 11:31 ` [PATCH v7 4/4] samples: rust: add Rust I2C client registration sample Igor Korotin
@ 2025-11-11 8:20 ` Danilo Krummrich
0 siblings, 0 replies; 11+ messages in thread
From: Danilo Krummrich @ 2025-11-11 8:20 UTC (permalink / raw)
To: Igor Korotin
Cc: Miguel Ojeda, Alex Gaynor, Wolfram Sang, Boqun Feng, Gary Guo,
Björn Roy Baron, Benno Lossin, Andreas Hindborg, Alice Ryhl,
Trevor Gross, Greg Kroah-Hartman, Viresh Kumar, Asahi Lina,
Wedson Almeida Filho, Alex Hung, Tamir Duberstein, Xiangfei Ding,
linux-kernel, rust-for-linux, linux-i2c
On Mon Nov 10, 2025 at 10:31 PM AEDT, Igor Korotin wrote:
> +impl platform::Driver for SampleDriver {
> + type IdInfo = ();
> + const OF_ID_TABLE: Option<of::IdTable<Self::IdInfo>> = Some(&OF_TABLE);
> + const ACPI_ID_TABLE: Option<acpi::IdTable<Self::IdInfo>> = Some(&ACPI_TABLE);
> +
> + fn probe(
> + pdev: &platform::Device<device::Core>,
> + _info: Option<&Self::IdInfo>,
> + ) -> impl PinInit<Self, Error> {
> + pin_init::pin_init_scope(move || {
We probably don't need pin_init_scope() here.
> + dev_info!(
> + pdev.as_ref(),
> + "Probe Rust I2C Client registration sample.\n"
> + );
> +
> + Ok(kernel::try_pin_init!( Self {
> + parent_dev: pdev.into(),
> +
> + idev <- {
> + let adapter = i2c::I2cAdapter::get(SAMPLE_I2C_ADAPTER_INDEX)?;
> +
> + i2c::Registration::new(&adapter, &BOARD_INFO, pdev.as_ref())
> + }
> + }))
> + })
> + }
> +}
> +
> +#[pinned_drop]
> +impl PinnedDrop for SampleDriver {
> + fn drop(self: Pin<&mut Self>) {
> + dev_info!(
> + self.parent_dev.as_ref(),
> + "Remove Rust Platform driver for I2C Client registration sample.\n"
> + );
> + }
Let's use unbind() here as well.
(Yes, the existing samples need to be updated. :)
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH v7 0/4] rust: i2c: Add basic I2C driver abstractions
2025-11-10 11:24 [PATCH v7 0/4] rust: i2c: Add basic I2C driver abstractions Igor Korotin
` (4 preceding siblings ...)
2025-11-10 11:31 ` [PATCH v7 4/4] samples: rust: add Rust I2C client registration sample Igor Korotin
@ 2025-11-11 8:05 ` Danilo Krummrich
5 siblings, 0 replies; 11+ messages in thread
From: Danilo Krummrich @ 2025-11-11 8:05 UTC (permalink / raw)
To: Igor Korotin
Cc: Miguel Ojeda, Alex Gaynor, Wolfram Sang, Boqun Feng, Gary Guo,
Björn Roy Baron, Benno Lossin, Andreas Hindborg, Alice Ryhl,
Trevor Gross, Greg Kroah-Hartman, Viresh Kumar, Asahi Lina,
Wedson Almeida Filho, Alex Hung, Tamir Duberstein, Xiangfei Ding,
linux-kernel, rust-for-linux, linux-i2c
On Mon Nov 10, 2025 at 10:24 PM AEDT, Igor Korotin wrote:
> v7:
> - Rebase and update `i2c::Driver::probe` function based on patch
> series [1].
Can you please rebase onto driver-core-next from [1].
[1] https://git.kernel.org/pub/scm/linux/kernel/git/driver-core/driver-core.git/log/?h=driver-core-next
There are a few more nits I'd usually fix up on apply, but since you have to
resend anyways, please find a few comments on the patches.
^ permalink raw reply [flat|nested] 11+ messages in thread