[PATCH v5 16/24] rust: i2c: make Driver trait lifetime-parameterized
From: Danilo Krummrich
Date: Mon May 25 2026 - 16:39:19 EST
Add a 'bound lifetime to the associated Data, changing type Data to type
Data<'bound>.
This allows the driver's bus device private data to capture the device /
driver bound lifetime; device resources can be stored directly by
reference rather than requiring Devres.
The probe() and unbind() callbacks thus gain a 'bound lifetime parameter
on the methods themselves; avoiding a global lifetime on the trait impl.
Existing drivers set type Data<'bound> = Self, preserving the current
behavior.
Acked-by: Igor Korotin <igor.korotin@xxxxxxxxx>
Reviewed-by: Alexandre Courbot <acourbot@xxxxxxxxxx>
Reviewed-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Danilo Krummrich <dakr@xxxxxxxxxx>
---
rust/kernel/i2c.rs | 39 ++++++++++++++++++---------------
samples/rust/rust_driver_i2c.rs | 14 ++++++------
2 files changed, 28 insertions(+), 25 deletions(-)
diff --git a/rust/kernel/i2c.rs b/rust/kernel/i2c.rs
index 50feade0fb58..6094d32652e3 100644
--- a/rust/kernel/i2c.rs
+++ b/rust/kernel/i2c.rs
@@ -98,7 +98,7 @@ macro_rules! i2c_device_table {
// - `DEVICE_DRIVER_OFFSET` is the correct byte offset to the embedded `struct device_driver`.
unsafe impl<T: Driver> driver::DriverLayout for Adapter<T> {
type DriverType = bindings::i2c_driver;
- type DriverData<'bound> = T::Data;
+ type DriverData<'bound> = T::Data<'bound>;
const DEVICE_DRIVER_OFFSET: usize = core::mem::offset_of!(Self::DriverType, driver);
}
@@ -176,8 +176,8 @@ extern "C" fn remove_callback(idev: *mut bindings::i2c_client) {
// 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::Data>>`.
- let data = unsafe { idev.as_ref().drvdata_borrow::<T::Data>() };
+ // and stored a `Pin<KBox<T::Data<'_>>>`.
+ let data = unsafe { idev.as_ref().drvdata_borrow::<T::Data<'_>>() };
T::unbind(idev, data);
}
@@ -188,8 +188,8 @@ extern "C" fn shutdown_callback(idev: *mut bindings::i2c_client) {
// 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::Data>>`.
- let data = unsafe { idev.as_ref().drvdata_borrow::<T::Data>() };
+ // and stored a `Pin<KBox<T::Data<'_>>>`.
+ let data = unsafe { idev.as_ref().drvdata_borrow::<T::Data<'_>>() };
T::shutdown(idev, data);
}
@@ -294,19 +294,22 @@ macro_rules! module_i2c_driver {
///
/// impl i2c::Driver for MyDriver {
/// type IdInfo = ();
-/// type Data = Self;
+/// type Data<'bound> = Self;
/// 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::Data, Error> {
+/// fn probe<'bound>(
+/// _idev: &'bound i2c::I2cClient<Core<'_>>,
+/// _id_info: Option<&'bound Self::IdInfo>,
+/// ) -> impl PinInit<Self::Data<'bound>, Error> + 'bound {
/// Err(ENODEV)
/// }
///
-/// fn shutdown(_idev: &i2c::I2cClient<Core<'_>>, this: Pin<&Self::Data>) {
+/// fn shutdown<'bound>(
+/// _idev: &'bound i2c::I2cClient<Core<'_>>,
+/// this: Pin<&Self::Data<'bound>>,
+/// ) {
/// }
/// }
///```
@@ -320,7 +323,7 @@ pub trait Driver {
type IdInfo: 'static;
/// The type of the driver's bus device private data.
- type Data: Send;
+ type Data<'bound>: Send + 'bound;
/// The table of device ids supported by the driver.
const I2C_ID_TABLE: Option<IdTable<Self::IdInfo>> = None;
@@ -335,10 +338,10 @@ pub trait Driver {
///
/// 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::Data, Error>;
+ fn probe<'bound>(
+ dev: &'bound I2cClient<device::Core<'_>>,
+ id_info: Option<&'bound Self::IdInfo>,
+ ) -> impl PinInit<Self::Data<'bound>, Error> + 'bound;
/// I2C driver shutdown.
///
@@ -351,7 +354,7 @@ fn probe(
/// 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 `Drop`.
- fn shutdown(dev: &I2cClient<device::Core<'_>>, this: Pin<&Self::Data>) {
+ fn shutdown<'bound>(dev: &'bound I2cClient<device::Core<'_>>, this: Pin<&Self::Data<'bound>>) {
let _ = (dev, this);
}
@@ -365,7 +368,7 @@ fn shutdown(dev: &I2cClient<device::Core<'_>>, this: Pin<&Self::Data>) {
/// operations to gracefully tear down the device.
///
/// Otherwise, release operations for driver resources should be performed in `Drop`.
- fn unbind(dev: &I2cClient<device::Core<'_>>, this: Pin<&Self::Data>) {
+ fn unbind<'bound>(dev: &'bound I2cClient<device::Core<'_>>, this: Pin<&Self::Data<'bound>>) {
let _ = (dev, this);
}
}
diff --git a/samples/rust/rust_driver_i2c.rs b/samples/rust/rust_driver_i2c.rs
index 171550ea0b6f..ead8263a7d48 100644
--- a/samples/rust/rust_driver_i2c.rs
+++ b/samples/rust/rust_driver_i2c.rs
@@ -35,16 +35,16 @@
impl i2c::Driver for SampleDriver {
type IdInfo = u32;
- type Data = Self;
+ type Data<'bound> = Self;
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> {
+ fn probe<'bound>(
+ idev: &'bound i2c::I2cClient<Core<'_>>,
+ info: Option<&'bound Self::IdInfo>,
+ ) -> impl PinInit<Self, Error> + 'bound {
let dev = idev.as_ref();
dev_info!(dev, "Probe Rust I2C driver sample.\n");
@@ -56,11 +56,11 @@ fn probe(
Ok(Self)
}
- fn shutdown(idev: &i2c::I2cClient<Core<'_>>, _this: Pin<&Self>) {
+ fn shutdown<'bound>(idev: &'bound 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>) {
+ fn unbind<'bound>(idev: &'bound i2c::I2cClient<Core<'_>>, _this: Pin<&Self>) {
dev_info!(idev.as_ref(), "Unbind Rust I2C driver sample.\n");
}
}
--
2.54.0