From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 871993ACF1F; Mon, 27 Apr 2026 22:13:55 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777328035; cv=none; b=V/sYwupkKaQ6PZvf6cosQ+3B2JGESY6erwE060Lypj0Cx6mBtLe/lhWMq3rboU8LIxZn+nsqOkGwHgBybjyfAb1vQL22SAxMzHqeBmPXuidDFYlQOE6igSNuhTXGO/ulZINvEI6KCzkJT5s4RA/vLijbjG1uekAwagKIoWNhmo8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777328035; c=relaxed/simple; bh=ru1OCYUc534Gm2mrQq6Ir697MoQdZy8URoT3Gukyl0E=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=bXgB9rx9RyktYFbxqOfz5fjt8sNGXtfj1+agbP4sxcMa6ouaTS6w3KTHK8h3ox4oZD7dnTjvQWKjKtBCC7jQOhTicuhBPQHaCRl1wa0GO9u5C+tlem8MMUkuLfxyXWyQCqEg2sv1S7P35N7UtzkygWj43WlKO/9UMlmL696RUXU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=ttiwFdWh; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="ttiwFdWh" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8C975C19425; Mon, 27 Apr 2026 22:13:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1777328035; bh=ru1OCYUc534Gm2mrQq6Ir697MoQdZy8URoT3Gukyl0E=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ttiwFdWhBUqiITT4H2ptesCXtBZTLIOSXkOjqkaUNBpnmX8TqAYnDHnqcZrKB6jSF 6xSXWLRRNxVcSsdt8ejTnt5ElHsaZj2QoMCQtpGFxR5liHzQwWB6n3IMDkBzuV/Wti VN+CX3lBD76TrQWyEoVstqX5j0Qsiol1zUUYNcQChQACz8OxAhmMR/6bW54GSHCVxf 1nq8mr9aJM0hHV1qmEko9OZZvI15cCtBGIo+4G4lME5WHmlFk3g9G7JFigXbchE1WY LMiJNhgS2trG7+e66OuphvwmYqNSZKdEg7aukBv2DbNcIqN2PuGBtLH0F0NOhVHngW OaIXqKg/qb5fg== From: Danilo Krummrich To: gregkh@linuxfoundation.org, rafael@kernel.org, acourbot@nvidia.com, aliceryhl@google.com, david.m.ertman@intel.com, ira.weiny@intel.com, leon@kernel.org, viresh.kumar@linaro.org, m.wilczynski@samsung.com, ukleinek@kernel.org, bhelgaas@google.com, kwilczynski@kernel.org, abdiel.janulgue@gmail.com, robin.murphy@arm.com, markus.probst@posteo.de, ojeda@kernel.org, boqun@kernel.org, gary@garyguo.net, bjorn3_gh@protonmail.com, lossin@kernel.org, a.hindborg@kernel.org, tmgross@umich.edu Cc: driver-core@lists.linux.dev, linux-kernel@vger.kernel.org, nova-gpu@lists.linux.dev, dri-devel@lists.freedesktop.org, linux-pm@vger.kernel.org, linux-pwm@vger.kernel.org, linux-pci@vger.kernel.org, rust-for-linux@vger.kernel.org, Danilo Krummrich Subject: [PATCH 17/24] rust: i2c: make Driver trait lifetime-parameterized Date: Tue, 28 Apr 2026 00:11:15 +0200 Message-ID: <20260427221155.2144848-18-dakr@kernel.org> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260427221155.2144848-1-dakr@kernel.org> References: <20260427221155.2144848-1-dakr@kernel.org> Precedence: bulk X-Mailing-List: rust-for-linux@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Make i2c::Driver take a lifetime parameter 'a that ties device resources to the binding scope. Internally, Adapter becomes Adapter with a bound for<'a> F::Of<'a>: Driver<'a>; module_i2c_driver! wraps the driver type in ForLt!() so drivers don't have to. Signed-off-by: Danilo Krummrich --- rust/kernel/i2c.rs | 116 +++++++++++++++++++------------- samples/rust/rust_driver_i2c.rs | 18 ++--- 2 files changed, 78 insertions(+), 56 deletions(-) diff --git a/rust/kernel/i2c.rs b/rust/kernel/i2c.rs index 08d310aa9d6b..4464146d6c4d 100644 --- a/rust/kernel/i2c.rs +++ b/rust/kernel/i2c.rs @@ -92,43 +92,57 @@ macro_rules! i2c_device_table { } /// An adapter for the registration of I2C drivers. -pub struct Adapter(T); +/// +/// `F` is a [`ForLt`](trait@ForLt) type that maps lifetimes to the driver's device +/// private data type, i.e. `F::Of<'a>` is the driver struct parameterized by `'a`. The macro +/// `module_i2c_driver!` generates this automatically via `ForLt!()`. +pub struct Adapter(PhantomData); // SAFETY: // - `bindings::i2c_driver` is a C type declared as `repr(C)`. -// - `T` is the type of the driver's device private data. +// - `F::Of<'static>` is the stored type of the driver's device private data. // - `struct i2c_driver` embeds a `struct device_driver`. // - `DEVICE_DRIVER_OFFSET` is the correct byte offset to the embedded `struct device_driver`. -unsafe impl driver::DriverLayout for Adapter { +unsafe impl driver::DriverLayout for Adapter +where + F: ForLt + 'static, + for<'a> F::Of<'a>: Driver<'a>, +{ type DriverType = bindings::i2c_driver; - type DriverData = ForLt!(T); + type DriverData = F; const DEVICE_DRIVER_OFFSET: usize = core::mem::offset_of!(Self::DriverType, driver); } // SAFETY: A call to `unregister` for a given instance of `DriverType` is guaranteed to be valid if // a preceding call to `register` has been successful. -unsafe impl driver::RegistrationOps for Adapter { +unsafe impl driver::RegistrationOps for Adapter +where + F: ForLt + 'static, + for<'a> F::Of<'a>: Driver<'a>, +{ 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(), + as Driver<'static>>::ACPI_ID_TABLE.is_some() + || as Driver<'static>>::OF_ID_TABLE.is_some() + || as Driver<'static>>::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 { + let i2c_table = match as Driver<'static>>::I2C_ID_TABLE { Some(table) => table.as_ptr(), None => core::ptr::null(), }; - let of_table = match T::OF_ID_TABLE { + let of_table = match as Driver<'static>>::OF_ID_TABLE { Some(table) => table.as_ptr(), None => core::ptr::null(), }; - let acpi_table = match T::ACPI_ID_TABLE { + let acpi_table = match as Driver<'static>>::ACPI_ID_TABLE { Some(table) => table.as_ptr(), None => core::ptr::null(), }; @@ -154,7 +168,11 @@ unsafe fn unregister(idrv: &Opaque) { } } -impl Adapter { +impl Adapter +where + F: ForLt + 'static, + for<'a> F::Of<'a>: Driver<'a>, +{ 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`. @@ -162,13 +180,12 @@ extern "C" fn probe_callback(idev: *mut bindings::i2c_client) -> kernel::ffi::c_ // 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); + let info = Self::i2c_id_info(idev) + .or_else(|| >::id_info(idev.as_ref())); + let data = as Driver<'_>>::probe(idev, info); - idev.as_ref().set_drvdata::(data)?; + idev.as_ref().set_drvdata::(data)?; Ok(0) }) } @@ -178,11 +195,10 @@ extern "C" fn remove_callback(idev: *mut bindings::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>`. - let data = unsafe { idev.as_ref().drvdata_borrow::() }; + // `probe_callback`, hence it's guaranteed that drvdata has been set. + let data = unsafe { idev.as_ref().drvdata_borrow::() }; - T::unbind(idev, data); + as Driver<'_>>::unbind(idev, data); } extern "C" fn shutdown_callback(idev: *mut bindings::i2c_client) { @@ -190,23 +206,22 @@ extern "C" fn shutdown_callback(idev: *mut bindings::i2c_client) { 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_borrow::() }; + // `probe_callback`, hence it's guaranteed that drvdata has been set. + let data = unsafe { idev.as_ref().drvdata_borrow::() }; - T::shutdown(idev, data); + as Driver<'_>>::shutdown(idev, data); } /// The [`i2c::IdTable`] of the corresponding driver. - fn i2c_id_table() -> Option>::IdInfo>> { - T::I2C_ID_TABLE + fn i2c_id_table<'a>() -> Option as Driver<'a>>::IdInfo>> { + as Driver<'a>>::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()?; + fn i2c_id_info<'a>(dev: &I2cClient) -> Option<&'a as Driver<'a>>::IdInfo> { + let table = Self::i2c_id_table::<'a>()?; // SAFETY: // - `table` has static lifetime, hence it's valid for reads @@ -225,15 +240,19 @@ fn i2c_id_info(dev: &I2cClient) -> Option<&'static driver::Adapter<'a> for Adapter { - type IdInfo = T::IdInfo; +impl<'a, F> driver::Adapter<'a> for Adapter +where + F: ForLt + 'static, + F::Of<'a>: Driver<'a>, +{ + type IdInfo = as Driver<'a>>::IdInfo; fn of_id_table() -> Option> { - T::OF_ID_TABLE + as Driver<'a>>::OF_ID_TABLE } fn acpi_id_table() -> Option> { - T::ACPI_ID_TABLE + as Driver<'a>>::ACPI_ID_TABLE } } @@ -252,8 +271,11 @@ fn acpi_id_table() -> Option> { /// ``` #[macro_export] macro_rules! module_i2c_driver { - ($($f:tt)*) => { - $crate::module_driver!(, $crate::i2c::Adapter, { $($f)* }); + (type: $type:ty, $($rest:tt)*) => { + $crate::module_driver!(, $crate::i2c::Adapter, { + type: $crate::types::ForLt!($type), + $($rest)* + }); }; } @@ -271,7 +293,7 @@ macro_rules! module_i2c_driver { /// kernel::acpi_device_table!( /// ACPI_TABLE, /// MODULE_ACPI_TABLE, -/// ::IdInfo, +/// >::IdInfo, /// [ /// (acpi::DeviceId::new(c"LNUXBEEF"), ()) /// ] @@ -280,7 +302,7 @@ macro_rules! module_i2c_driver { /// kernel::i2c_device_table!( /// I2C_TABLE, /// MODULE_I2C_TABLE, -/// ::IdInfo, +/// >::IdInfo, /// [ /// (i2c::DeviceId::new(c"rust_driver_i2c"), ()) /// ] @@ -289,30 +311,30 @@ macro_rules! module_i2c_driver { /// kernel::of_device_table!( /// OF_TABLE, /// MODULE_OF_TABLE, -/// ::IdInfo, +/// >::IdInfo, /// [ /// (of::DeviceId::new(c"test,device"), ()) /// ] /// ); /// -/// impl i2c::Driver for MyDriver { +/// impl<'a> i2c::Driver<'a> 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>, -/// ) -> impl PinInit { +/// _idev: &'a i2c::I2cClient, +/// _id_info: Option<&'a Self::IdInfo>, +/// ) -> impl PinInit + 'a { /// Err(ENODEV) /// } /// -/// fn shutdown(_idev: &i2c::I2cClient, this: Pin<&Self>) { +/// fn shutdown(_idev: &'a i2c::I2cClient, _this: Pin<&'a Self>) { /// } /// } ///``` -pub trait Driver: Send { +pub trait Driver<'a>: Send { /// The type holding information about each device id supported by the driver. // TODO: Use `associated_type_defaults` once stabilized: // @@ -335,9 +357,9 @@ pub trait Driver: Send { /// 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>, - ) -> impl PinInit; + dev: &'a I2cClient, + id_info: Option<&'a Self::IdInfo>, + ) -> impl PinInit + 'a; /// I2C driver shutdown. /// @@ -350,7 +372,7 @@ 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 `Self::drop`. - fn shutdown(dev: &I2cClient, this: Pin<&Self>) { + fn shutdown(dev: &'a I2cClient, this: Pin<&'a Self>) { let _ = (dev, this); } @@ -364,7 +386,7 @@ fn shutdown(dev: &I2cClient, this: Pin<&Self>) { /// 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>) { + fn unbind(dev: &'a I2cClient, this: Pin<&'a Self>) { let _ = (dev, this); } } diff --git a/samples/rust/rust_driver_i2c.rs b/samples/rust/rust_driver_i2c.rs index 6be79f9e9fb5..f86c1cf7c786 100644 --- a/samples/rust/rust_driver_i2c.rs +++ b/samples/rust/rust_driver_i2c.rs @@ -15,25 +15,25 @@ kernel::acpi_device_table! { ACPI_TABLE, MODULE_ACPI_TABLE, - ::IdInfo, + >::IdInfo, [(acpi::DeviceId::new(c"LNUXBEEF"), 0)] } kernel::i2c_device_table! { I2C_TABLE, MODULE_I2C_TABLE, - ::IdInfo, + >::IdInfo, [(i2c::DeviceId::new(c"rust_driver_i2c"), 0)] } kernel::of_device_table! { OF_TABLE, MODULE_OF_TABLE, - ::IdInfo, + >::IdInfo, [(of::DeviceId::new(c"test,rust_driver_i2c"), 0)] } -impl i2c::Driver for SampleDriver { +impl<'a> i2c::Driver<'a> for SampleDriver { type IdInfo = u32; const ACPI_ID_TABLE: Option> = Some(&ACPI_TABLE); @@ -41,9 +41,9 @@ impl i2c::Driver for SampleDriver { const OF_ID_TABLE: Option> = Some(&OF_TABLE); fn probe( - idev: &i2c::I2cClient, - info: Option<&Self::IdInfo>, - ) -> impl PinInit { + idev: &'a i2c::I2cClient, + info: Option<&'a Self::IdInfo>, + ) -> impl PinInit + 'a { let dev = idev.as_ref(); dev_info!(dev, "Probe Rust I2C driver sample.\n"); @@ -55,11 +55,11 @@ fn probe( Ok(Self) } - fn shutdown(idev: &i2c::I2cClient, _this: Pin<&Self>) { + fn shutdown(idev: &'a i2c::I2cClient, _this: Pin<&'a Self>) { dev_info!(idev.as_ref(), "Shutdown Rust I2C driver sample.\n"); } - fn unbind(idev: &i2c::I2cClient, _this: Pin<&Self>) { + fn unbind(idev: &'a i2c::I2cClient, _this: Pin<&'a Self>) { dev_info!(idev.as_ref(), "Unbind Rust I2C driver sample.\n"); } } -- 2.54.0