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rust: i2c: make Driver trait lifetime-parameterized

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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@linux.dev>
Reviewed-by: Alexandre Courbot <acourbot@nvidia.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Gary Guo <gary@garyguo.net>
Link: https://patch.msgid.link/20260525202921.124698-17-dakr@kernel.org
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
This commit is contained in:
Danilo Krummrich
2026-05-25 22:21:03 +02:00
parent a3f09f8e47
commit 71e6b6a80b
2 changed files with 28 additions and 25 deletions
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39
rust/kernel/i2c.rs
View File

@@ -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);
}
}

14
samples/rust/rust_driver_i2c.rs
View File

@@ -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");
}
}