From nobody Sun Feb 8 20:32:56 2026 Received: from mout01.posteo.de (mout01.posteo.de [185.67.36.65]) (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 3C48D347BBF for ; Thu, 23 Oct 2025 17:28:37 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=185.67.36.65 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761240520; cv=none; b=GZJECc9FoLzGfAnEsil9yf/PNsyLVM6ll3sNXaPUCBP1HA3moJAkh2JVtcx8MtB7YTjpbQJEUjMEvkj9C+njyIWjdrlKs98PLQUTHeNG4XOX27PZHie8uNHPEFJozcPXpXVajirKT5toRMo4lKK4GfeEot3Cmd8sHEhpMEdifc8= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761240520; c=relaxed/simple; bh=AHFDoYfjon/4tGZlpCp8TVU857N1RhEo3OW1MemkxkA=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=dYDQnW0fDn4yU88zbq8S7zBbACLX4fgpveu8KB4EWBhbPQlOQ8Gzy4ybkjsPWhHmcsuL58UL01EG05pf4OeMdMMjOezW54BE42745PejSW4S1cI0eEgUAjRP0MZ5gXS7HpOeYes2FHkYUW4s3UQ/Yh7LjelJJlsxtVQ4NAVqj+M= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=posteo.de; spf=pass smtp.mailfrom=posteo.de; dkim=pass (2048-bit key) header.d=posteo.de header.i=@posteo.de header.b=L6PeSDu4; arc=none smtp.client-ip=185.67.36.65 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=posteo.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=posteo.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=posteo.de header.i=@posteo.de header.b="L6PeSDu4" Received: from submission (posteo.de [185.67.36.169]) by mout01.posteo.de (Postfix) with ESMTPS id C072124002A for ; Thu, 23 Oct 2025 19:28:35 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=posteo.de; s=2017; t=1761240515; bh=RrvubjSJi3MqTyvAC8OUUj/Q0ANkEdPC8q50Ec7fUD4=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version: Content-Transfer-Encoding:Autocrypt:OpenPGP:From; b=L6PeSDu498cLmxgdZH3Tw4zBgIQ2BIKdhRVVAWUObtWfbyzHgvYacCyI+ybelf/Eg TNx73NckZBw20Bzp8pTagYuPrgJLL3u7tMWFzptFObfpaIbtFPdS2+bD0xzSpnziyp jh/aDKPEvcgz0lJLtxyILfI44pq3y3AvK5m6EbysPt0reNC2IOv8F+YbWKKF0CxFPD CNVYmHHoP0pxUJc5ASpof6mTEw/WFubTVBd54lKjpPeAn9mnGUdb003YYHtXwZm9mj 0dC6282DRpfydHkeqRGhtBZwD4tE5tcXlRO2S197kCaqvE2nMikEKwIg6ThoXdF+zi Gru+t6w6W29RQ== Received: from customer (localhost [127.0.0.1]) by submission (posteo.de) with ESMTPSA id 4cstKW5tSHz6v2J; Thu, 23 Oct 2025 19:28:15 +0200 (CEST) From: Markus Probst To: Greg Kroah-Hartman , Miguel Ojeda , Alex Gaynor , Danilo Krummrich , "Rafael J. Wysocki" , Lee Jones , Pavel Machek Cc: Dave Ertman , Ira Weiny , Leon Romanovsky , Boqun Feng , Gary Guo , bjorn3_gh@protonmail.com, Benno Lossin , Andreas Hindborg , Alice Ryhl , Trevor Gross , Bjorn Helgaas , =?UTF-8?q?Krzysztof=20Wilczy=C5=84ski?= , Markus Probst , rust-for-linux@vger.kernel.org, linux-leds@vger.kernel.org, linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v6 1/2] rust: Add trait to convert a device reference to a bus device reference Date: Thu, 23 Oct 2025 17:28:18 +0000 Message-ID: <20251023172803.730677-2-markus.probst@posteo.de> In-Reply-To: <20251023172803.730677-1-markus.probst@posteo.de> References: <20251023172803.730677-1-markus.probst@posteo.de> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=5467; i=markus.probst@posteo.de; h=from:subject; bh=AHFDoYfjon/4tGZlpCp8TVU857N1RhEo3OW1MemkxkA=; b=owEBbQKS/ZANAwAIATR2H/jnrUPSAcsmYgBo+mQk7ds/yPGUoEze9yaiY7baeuYuxgf9yNmUC g0US3spVCqJAjMEAAEIAB0WIQSCdBjE9KxY53IwxHM0dh/4561D0gUCaPpkJAAKCRA0dh/4561D 0oo4D/9wbqvRM1QMq4Bwjg9o8KhrhZOjTqksjwkfS93pUsyfugqgkEFh1HIl1ksiikdNlexNb5E VtehOU0vOL3akZTLamwLS5nm5won8MOL8s1Iy+yQsPEGxzwM1kP0u8xBQ6n/0cocR3VImK8LNRG ycnwcHZpj2dfxEjcA+T+dTBPBERZ9XLQdBzSVKX5bfnNsQpaqdoGhAlVrxSv5BsFFY4ou7cbLys zUdoRXjZBHVQe6CVoksy0xJLG2JFYvKyWgKm1rM/N0Mo/juBU2BzO5BKZK6jWLxb6DOjnHAMimo 5aV4E0ybOw0ceGYc7Wzoa1iUoc2L1oS1TQaSNPMn7Z9LcKxn3ZL3xs040Hn8QCF52hj/8fJWi65 ZQ8pl/Waz7NLBlrS88q1PXFNyidycdBhdld0ZxHO22kom7KriwsH7cLbmfstnYw7NmaoSOrTGV5 GzxTSTQ2rorR3rswNsQzeTCWs0aLBLtFO6y5HwxBMfZ0y3/RVogHL4hr6tGryD4GpMXsOa7S4By btPz+fQDWsrRk3VMvY/wlqREjn3TYHIz3vlYSxNMPMYjx/lP4WJCjTLGdWIWP+c7uqpZ+ULu9/S BKjk7knCeDz5XRPEuKfC35WKJtJMdt9L4/8is7bOROV7RDXM8ZD4jJHVJsooeMDXNtlREcH+2li dxqRb9n2I/YLHxA= = X-Developer-Key: i=markus.probst@posteo.de; 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preference=encrypt Content-Type: text/plain; charset="utf-8" Implement the `AsBusDevice` trait for converting a `Device` reference to a bus device reference for all bus devices. The `AsBusDevice` trait allows abstractions to provide the bus device in class device callbacks. It must not be used by drivers and is intended for bus and class device abstractions only. Signed-off-by: Markus Probst --- rust/kernel/auxiliary.rs | 7 +++++++ rust/kernel/device.rs | 30 ++++++++++++++++++++++++++++++ rust/kernel/pci.rs | 7 +++++++ rust/kernel/platform.rs | 7 +++++++ rust/kernel/usb.rs | 6 ++++++ 5 files changed, 57 insertions(+) diff --git a/rust/kernel/auxiliary.rs b/rust/kernel/auxiliary.rs index e11848bbf206..cd1121191137 100644 --- a/rust/kernel/auxiliary.rs +++ b/rust/kernel/auxiliary.rs @@ -15,6 +15,7 @@ }; use core::{ marker::PhantomData, + mem::offset_of, ptr::{addr_of_mut, NonNull}, }; =20 @@ -239,6 +240,12 @@ extern "C" fn release(dev: *mut bindings::device) { } } =20 +// SAFETY: `auxilary::Device` is a transparent wrapper of `struct auxiliar= y_device`. +// The offset is guaranteed to point to a valid device field inside `auxil= ary::Device`. +unsafe impl device::AsBusDevice for Devic= e { + const OFFSET: usize =3D offset_of!(bindings::auxiliary_device, dev); +} + // SAFETY: `Device` is a transparent wrapper of a type that doesn't depend= on `Device`'s generic // argument. kernel::impl_device_context_deref!(unsafe { Device }); diff --git a/rust/kernel/device.rs b/rust/kernel/device.rs index 1321e6f0b53c..d7024c2bb90f 100644 --- a/rust/kernel/device.rs +++ b/rust/kernel/device.rs @@ -511,6 +511,36 @@ impl DeviceContext for Core {} impl DeviceContext for CoreInternal {} impl DeviceContext for Normal {} =20 +/// Bus devices can implement this trait to allow abstractions to provide = the bus device in +/// class device callbacks. +/// +/// This must not be used by drivers and is intended for bus and class dev= ice abstractions only. +/// +/// # Safety +/// +/// `AsBusDevice::OFFSET` must be a offset to a device field in the implem= ented struct. +pub(crate) unsafe trait AsBusDevice: AsRef= > { + /// The relative offset to the device field. + /// + /// Use `offset_of!(bindings, field)` macro to avoid breakage. + const OFFSET: usize; + + /// Convert a reference to [`Device`] into `Self`. + /// + /// # Safety + /// + /// `dev` must be contained in `Self`. + unsafe fn from_device(dev: &Device) -> &Self + where + Self: Sized, + { + let raw =3D dev.as_raw(); + // SAFETY: `raw - Self::OFFSET` is guaranteed by the safety requir= ements + // to be a valid pointer to `Self`. + unsafe { &*raw.byte_sub(Self::OFFSET).cast::() } + } +} + /// # Safety /// /// The type given as `$device` must be a transparent wrapper of a type th= at doesn't depend on the diff --git a/rust/kernel/pci.rs b/rust/kernel/pci.rs index 7fcc5f6022c1..d78f6feeaae9 100644 --- a/rust/kernel/pci.rs +++ b/rust/kernel/pci.rs @@ -19,6 +19,7 @@ }; use core::{ marker::PhantomData, + mem::offset_of, ops::Deref, ptr::{addr_of_mut, NonNull}, }; @@ -593,6 +594,12 @@ pub fn set_master(&self) { } } =20 +// SAFETY: `pci::Device` is a transparent wrapper of `struct pci_dev`. +// The offset is guaranteed to point to a valid device field inside `pci::= Device`. +unsafe impl device::AsBusDevice for Devic= e { + const OFFSET: usize =3D offset_of!(bindings::pci_dev, dev); +} + // SAFETY: `Device` is a transparent wrapper of a type that doesn't depend= on `Device`'s generic // argument. kernel::impl_device_context_deref!(unsafe { Device }); diff --git a/rust/kernel/platform.rs b/rust/kernel/platform.rs index 7205fe3416d3..7197264b5a53 100644 --- a/rust/kernel/platform.rs +++ b/rust/kernel/platform.rs @@ -19,6 +19,7 @@ =20 use core::{ marker::PhantomData, + mem::offset_of, ptr::{addr_of_mut, NonNull}, }; =20 @@ -285,6 +286,12 @@ pub fn io_request_by_name(&self, name: &CStr) -> Optio= n> { } } =20 +// SAFETY: `platform::Device` is a transparent wrapper of `struct platform= _device`. +// The offset is guaranteed to point to a valid device field inside `platf= orm::Device`. +unsafe impl device::AsBusDevice for Devic= e { + const OFFSET: usize =3D offset_of!(bindings::platform_device, dev); +} + macro_rules! define_irq_accessor_by_index { ( $(#[$meta:meta])* $fn_name:ident, diff --git a/rust/kernel/usb.rs b/rust/kernel/usb.rs index 14ddb711bab3..ec21261baf6a 100644 --- a/rust/kernel/usb.rs +++ b/rust/kernel/usb.rs @@ -324,6 +324,12 @@ fn as_raw(&self) -> *mut bindings::usb_interface { } } =20 +// SAFETY: `usb::Interface` is a transparent wrapper of `struct usb_interf= ace`. +// The offset is guaranteed to point to a valid device field inside `usb::= Interface`. +unsafe impl device::AsBusDevice for Inter= face { + const OFFSET: usize =3D offset_of!(bindings::usb_interface, dev); +} + // SAFETY: `Interface` is a transparent wrapper of a type that doesn't dep= end on // `Interface`'s generic argument. kernel::impl_device_context_deref!(unsafe { Interface }); --=20 2.51.0 From nobody Sun Feb 8 20:32:56 2026 Received: from mout01.posteo.de (mout01.posteo.de [185.67.36.65]) (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 C6045347FE2 for ; Thu, 23 Oct 2025 17:28:35 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=185.67.36.65 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761240518; cv=none; b=jzRyzKMIl4jAdePckQyK7R3zpoC6nAFaG7WIDIA2d3iFj8JZTDUKVE9tRbt+6rPSOJ7OVZbj3es6sSkR6xnrScXc1jMV4Ddf7G8Ttb4CWkRiBrpBqmqJy7l6iopptvjGyI6VLXrMoZ4HuaAypymExOcaAVkmeKS1afDYBtKFnFE= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761240518; c=relaxed/simple; bh=9h+tAmuuvK9EqxjAQukL4RGSRcJTnFax99ceow6JrNs=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=n0fs2dDZ1dyx1f3rkJ36XaheBP78rOMdvOG6JJtjSyO8Z0j7NeXmJq1tYtIkFinhm6ZqNVRNJoxZjEuAt14skf/G4K0ADRAGLLYFqu4ssZJRTvp2K0UaomLF3MZT0Hsv0pxjg0uK3U3+zQqI786KbvaTUNmgH5tRTesgp2IBgEs= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=posteo.de; spf=pass smtp.mailfrom=posteo.de; dkim=pass (2048-bit key) header.d=posteo.de header.i=@posteo.de header.b=NUsZDJjj; arc=none smtp.client-ip=185.67.36.65 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=posteo.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=posteo.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=posteo.de header.i=@posteo.de header.b="NUsZDJjj" Received: from submission (posteo.de [185.67.36.169]) by mout01.posteo.de (Postfix) with ESMTPS id A6BDC240027 for ; Thu, 23 Oct 2025 19:28:33 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=posteo.de; s=2017; t=1761240513; bh=h0DeGFcALHELGR30GG6cngIwx4x0xFLg1HmmpECNVtg=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version: Content-Transfer-Encoding:Autocrypt:OpenPGP:From; b=NUsZDJjjsXM2Gz1kzT2CqqtD6PjzdBrQiblZ3sWj3t1vlz9J9B7XR95Ls/rbLjXQ/ NflEXLZW027oaZspOOCTLYAdnfA2R/bR0e6svPH4cSMOHsFUQnuvZP+kYQtl3ec7ZE wUKVSdaY9GS0GkTml5brQPUvviSk+LTd7F0/nsrAcuEc4T1tPT4w7mPhiJzMd+nHqn Mb2MBnM2pKoMJJBqbxaekmFga4fxQOrgPzUw9Ry6WsYocoIYUZC36+Xyyjas34UJCg NawpsvUjMXj+ZamFfDIHBfzXQuT//bdoMVIYwpL9HxdNSG28soFhcJhQkfBxtOVHHv C/N7s+UugoT8A== Received: from customer (localhost [127.0.0.1]) by submission (posteo.de) with ESMTPSA id 4cstKZ3R4Cz6v2t; Thu, 23 Oct 2025 19:28:18 +0200 (CEST) From: Markus Probst To: Greg Kroah-Hartman , Miguel Ojeda , Alex Gaynor , Danilo Krummrich , "Rafael J. Wysocki" , Lee Jones , Pavel Machek Cc: Dave Ertman , Ira Weiny , Leon Romanovsky , Boqun Feng , Gary Guo , bjorn3_gh@protonmail.com, Benno Lossin , Andreas Hindborg , Alice Ryhl , Trevor Gross , Bjorn Helgaas , =?UTF-8?q?Krzysztof=20Wilczy=C5=84ski?= , Markus Probst , rust-for-linux@vger.kernel.org, linux-leds@vger.kernel.org, linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v6 2/2] rust: leds: add basic led classdev abstractions Date: Thu, 23 Oct 2025 17:28:20 +0000 Message-ID: <20251023172803.730677-3-markus.probst@posteo.de> In-Reply-To: <20251023172803.730677-1-markus.probst@posteo.de> References: <20251023172803.730677-1-markus.probst@posteo.de> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=15201; i=markus.probst@posteo.de; h=from:subject; bh=9h+tAmuuvK9EqxjAQukL4RGSRcJTnFax99ceow6JrNs=; b=owEBbQKS/ZANAwAIATR2H/jnrUPSAcsmYgBo+mQnWaSu8UMraopNwFIpQc/riJ7x5H6IvI+LC 6jkNiSXOvuJAjMEAAEIAB0WIQSCdBjE9KxY53IwxHM0dh/4561D0gUCaPpkJwAKCRA0dh/4561D 0l92D/0amHvZ8ChNdlEzjPhuhVteXsIUiWVBs73lA9bYZRF73731Brw9rKWLBLiCL+vXcfZnNJE vrEpQaQ8Vn5+VCiQ5qtFmDNe/tZI2MsBlMr/leWlIe86SKK3vVWOrxjNoQXu0p7hCQ4vY2zFtnG eJ2M21th3OvD9FBOiCTitFmcq75KPZPf5D7R6idpgTZwPI/Sq6BAlnjyHuvRqjPHPWXVI6yWbxB 2AvxmHeU63LSd8JGik32xtZMjIyexNKoEgBBdOM0hRYROHp4qfHQzgjaZCWjysb/spsWGficbuW /+BxbFYcf8N4K963PYOK6ACBWm/ln8v6wDnVxuP1yubTCglF28zilPG7fNPgDpyCRj5h3VZSrp9 AmKts2hz2q21SDV63eQ8hbUmmJljYuxFk938Wl49UTC8CHM//LQyToVYl7EUx3p5YkkojY+FxyY xH8S4tzF9/xB1deiZwjzv+lqRBWg/umhtl8o7s200q6NLs1eUuv//0S1PLnxstOIN7tLdHCqfYs 2P8HPMrAlkA0KoEkp9qNhUgvpHQFxobKJ+lK8+PfOYKMM8wle7s8fV0GfucPor2qLioCQflDVI3 zrX5Q9q1GlNHr34mQE5IoCVFXJv2CAySsQsZz3TJRilzmkKS8yiFbf3d5RS0nGCyPKaO+0dweCF C/0gsLtIxKNVAnA == X-Developer-Key: i=markus.probst@posteo.de; 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preference=encrypt Content-Type: text/plain; charset="utf-8" Implement the core abstractions needed for led class devices, including: * `led::LedOps` - the trait for handling leds, including `brightness_set`, `brightness_get` and `blink_set` * `led::InitData` - data set for the led class device * `led::Device` - a safe wrapper around `led_classdev` Signed-off-by: Markus Probst --- rust/kernel/led.rs | 375 +++++++++++++++++++++++++++++++++++++++++++++ rust/kernel/lib.rs | 1 + 2 files changed, 376 insertions(+) create mode 100644 rust/kernel/led.rs diff --git a/rust/kernel/led.rs b/rust/kernel/led.rs new file mode 100644 index 000000000000..1c1e23a0414c --- /dev/null +++ b/rust/kernel/led.rs @@ -0,0 +1,375 @@ +// SPDX-License-Identifier: GPL-2.0 + +//! Abstractions for the leds driver model. +//! +//! C header: [`include/linux/leds.h`](srctree/include/linux/leds.h) + +use core::{marker::PhantomData, pin::Pin, ptr::NonNull}; + +use pin_init::{pin_data, pinned_drop, PinInit}; + +use crate::{ + build_error, container_of, + device::{self, property::FwNode, Bound, AsBusDevice}, + devres::Devres, + error::{from_result, to_result, Error, Result, VTABLE_DEFAULT_ERROR}, + macros::vtable, + str::CStr, + try_pin_init, + types::{ARef, Opaque}, +}; + +/// The led class device representation. +/// +/// This structure represents the Rust abstraction for a C `struct led_cla= ssdev`. +#[pin_data(PinnedDrop)] +pub struct Device { + ops: T, + #[pin] + classdev: Opaque, +} + +/// The led init data representation. +/// +/// This structure represents the Rust abstraction for a C `struct led_ini= t_data`. +#[derive(Default)] +pub struct InitData<'a> { + fwnode: Option<&'a FwNode>, + default_label: Option<&'a CStr>, + devicename: Option<&'a CStr>, + devname_mandatory: bool, +} + +impl InitData<'static> { + /// Creates a new [`InitData`] + pub fn new() -> Self { + Self::default() + } +} + +impl<'a> InitData<'a> { + /// Sets the firmware node + pub fn fwnode<'b, 'c>(self, fwnode: &'b FwNode) -> InitData<'c> + where + 'a: 'c, + 'b: 'c, + { + InitData { + fwnode: Some(fwnode), + ..self + } + } + + /// Sets a default label + pub fn default_label<'b, 'c>(self, label: &'b CStr) -> InitData<'c> + where + 'a: 'c, + 'b: 'c, + { + InitData { + default_label: Some(label), + ..self + } + } + + /// Sets the device name + pub fn devicename<'b, 'c>(self, devicename: &'b CStr) -> InitData<'c> + where + 'a: 'c, + 'b: 'c, + { + InitData { + devicename: Some(devicename), + ..self + } + } + + /// Sets if a device name is mandatory + pub fn devicename_mandatory(self, mandatory: bool) -> Self { + Self { + devname_mandatory: mandatory, + + ..self + } + } +} + +/// Trait defining the operations for a LED driver. +/// +/// # Examples +/// +///``` +/// # use kernel::{ +/// # c_str, device, devres::Devres, +/// # error::Result, led, +/// # macros::vtable, platform, prelude::*, +/// # }; +/// # use core::pin::Pin; +/// +/// struct MyLedOps; +/// +/// +/// #[vtable] +/// impl led::LedOps for MyLedOps { +/// type Bus =3D platform::Device; +/// const BLOCKING: bool =3D false; +/// const MAX_BRIGHTNESS: u32 =3D 255; +/// +/// fn brightness_set( +/// &self, +/// _dev: &platform::Device, +/// _brightness: u32 +/// ) -> Result<()> { +/// // Set the brightness for the led here +/// Ok(()) +/// } +/// } +/// +/// fn register_my_led( +/// parent: &platform::Device, +/// ) -> Result>>>> { +/// KBox::pin_init(led::Device::new( +/// parent, +/// led::InitData::new() +/// .default_label(c_str!("my_led")), +/// MyLedOps, +/// ), GFP_KERNEL) +/// } +///``` +/// Led drivers must implement this trait in order to register and handle = a [`Device`]. +#[vtable] +pub trait LedOps: Send + 'static + Sized { + /// The bus device required by the implementation. + #[allow(private_bounds)] + type Bus: AsBusDevice; + /// If set true, [`LedOps::brightness_set`] and [`LedOps::blink_set`] = must perform the + /// operation immediately. If set false, they must not sleep. + const BLOCKING: bool; + /// The max brightness level + const MAX_BRIGHTNESS: u32; + + /// Sets the brightness level. + /// + /// See also [`LedOps::BLOCKING`] + fn brightness_set(&self, dev: &Self::Bus, brightness: u32) -> Result<(= )>; + + /// Gets the current brightness level. + fn brightness_get(&self, _dev: &Self::Bus) -> u32 { + build_error!(VTABLE_DEFAULT_ERROR) + } + + /// Activates hardware accelerated blinking. + /// + /// delays are in milliseconds. If both are zero, a sensible default s= hould be chosen. + /// The caller should adjust the timings in that case and if it can't = match the values + /// specified exactly. Setting the brightness to 0 will disable the ha= rdware accelerated + /// blinking. + /// + /// See also [`LedOps::BLOCKING`] + fn blink_set( + &self, + _dev: &Self::Bus, + _delay_on: &mut usize, + _delay_off: &mut usize, + ) -> Result<()> { + build_error!(VTABLE_DEFAULT_ERROR) + } +} + +// SAFETY: A `led::Device` can be unregistered from any thread. +unsafe impl Send for Device {} + +// SAFETY: `led::Device` can be shared among threads because all methods o= f `led::Device` +// are thread safe. +unsafe impl Sync for Device {} + +impl Device { + /// Registers a new led classdev. + /// + /// The [`Device`] will be unregistered on drop. + pub fn new<'a>( + parent: &'a T::Bus, + init_data: InitData<'a>, + ops: T, + ) -> impl PinInit, Error> + 'a { + Devres::new( + parent.as_ref(), + try_pin_init!(Self { + ops, + classdev <- Opaque::try_ffi_init(|ptr: *mut bindings::led_= classdev| { + // SAFETY: `try_ffi_init` guarantees that `ptr` is val= id for write. + // `led_classdev` gets fully initialized in-place by + // `led_classdev_register_ext` including `mutex` and `= list_head`. + unsafe { + ptr.write(bindings::led_classdev { + max_brightness: T::MAX_BRIGHTNESS, + brightness_set: (!T::BLOCKING) + .then_some(Adapter::::brightness_set_ca= llback), + brightness_set_blocking: T::BLOCKING + .then_some(Adapter::::brightness_set_bl= ocking_callback), + brightness_get: T::HAS_BRIGHTNESS_GET + .then_some(Adapter::::brightness_get_ca= llback), + blink_set: T::HAS_BLINK_SET.then_some(Adapter:= :::blink_set_callback), + ..bindings::led_classdev::default() + }) + }; + + let fwnode =3D init_data.fwnode.map(ARef::from); + + let mut init_data =3D bindings::led_init_data { + fwnode: fwnode + .as_ref() + .map_or(core::ptr::null_mut(), |fwnode| fwnode= .as_raw()), + default_label: init_data + .default_label + .map_or(core::ptr::null(), CStr::as_char_ptr), + devicename: init_data + .devicename + .map_or(core::ptr::null(), CStr::as_char_ptr), + devname_mandatory: init_data.devname_mandatory, + }; + + // SAFETY: + // - `parent.as_raw()` is guaranteed to be a pointer t= o a valid `device` + // or a null pointer. + // - `ptr` is guaranteed to be a pointer to an initial= ized `led_classdev`. + to_result(unsafe { + bindings::led_classdev_register_ext( + parent.as_ref().as_raw(), + ptr, + &mut init_data, + ) + })?; + + core::mem::forget(fwnode); // keep the reference count= incremented + + Ok::<_, Error>(()) + }), + }), + ) + } + + /// # Safety + /// `led_cdev` must be a valid pointer to a `led_classdev` embedded wi= thin a + /// `led::Device`. + unsafe fn from_raw<'a>(led_cdev: *mut bindings::led_classdev) -> &'a S= elf { + // SAFETY: The function's contract guarantees that `led_cdev` poin= ts to a `led_classdev` + // field embedded within a valid `led::Device`. `container_of!` ca= n therefore + // safely calculate the address of the containing struct. + unsafe { &*container_of!(Opaque::cast_from(led_cdev), Self, classd= ev) } + } + + fn parent(&self) -> &device::Device { + // SAFETY: + // - `self.classdev.get()` is guaranteed to be a valid pointer to = `led_classdev`. + unsafe { device::Device::from_raw((*(*self.classdev.get()).dev).pa= rent) } + } +} + +struct Adapter { + _p: PhantomData, +} + +impl Adapter { + /// # Safety + /// `led_cdev` must be a valid pointer to a `led_classdev` embedded wi= thin a + /// `led::Device`. + /// This function is called on setting the brightness of a led. + unsafe extern "C" fn brightness_set_callback( + led_cdev: *mut bindings::led_classdev, + brightness: u32, + ) { + // SAFETY: The function's contract guarantees that `led_cdev` is a= valid pointer to a + // `led_classdev` embedded within a `led::Device`. + let classdev =3D unsafe { Device::::from_raw(led_cdev) }; + // SAFETY: `classdev.parent()` is guaranteed to be contained in `T= ::Bus`. + let parent =3D unsafe { T::Bus::from_device(classdev.parent()) }; + + let _ =3D classdev.ops.brightness_set(parent, brightness); + } + + /// # Safety + /// `led_cdev` must be a valid pointer to a `led_classdev` embedded wi= thin a + /// `led::Device`. + /// This function is called on setting the brightness of a led immedia= tely. + unsafe extern "C" fn brightness_set_blocking_callback( + led_cdev: *mut bindings::led_classdev, + brightness: u32, + ) -> i32 { + from_result(|| { + // SAFETY: The function's contract guarantees that `led_cdev` = is a valid pointer to a + // `led_classdev` embedded within a `led::Device`. + let classdev =3D unsafe { Device::::from_raw(led_cdev) }; + // SAFETY: `classdev.parent()` is guaranteed to be contained i= n `T::Bus`. + let parent =3D unsafe { T::Bus::from_device(classdev.parent())= }; + + classdev.ops.brightness_set(parent, brightness)?; + Ok(0) + }) + } + + /// # Safety + /// `led_cdev` must be a valid pointer to a `led_classdev` embedded wi= thin a + /// `led::Device`. + /// This function is called on getting the brightness of a led. + unsafe extern "C" fn brightness_get_callback(led_cdev: *mut bindings::= led_classdev) -> u32 { + // SAFETY: The function's contract guarantees that `led_cdev` is a= valid pointer to a + // `led_classdev` embedded within a `led::Device`. + let classdev =3D unsafe { Device::::from_raw(led_cdev) }; + // SAFETY: `classdev.parent()` is guaranteed to be contained in `T= ::Bus`. + let parent =3D unsafe { T::Bus::from_device(classdev.parent()) }; + + classdev.ops.brightness_get(parent) + } + + /// # Safety + /// `led_cdev` must be a valid pointer to a `led_classdev` embedded wi= thin a + /// `led::Device`. + /// `delay_on` and `delay_off` must be valid pointers to `usize` and h= ave + /// exclusive access for the period of this function. + /// This function is called on enabling hardware accelerated blinking. + unsafe extern "C" fn blink_set_callback( + led_cdev: *mut bindings::led_classdev, + delay_on: *mut usize, + delay_off: *mut usize, + ) -> i32 { + from_result(|| { + // SAFETY: The function's contract guarantees that `led_cdev` = is a valid pointer to a + // `led_classdev` embedded within a `led::Device`. + let classdev =3D unsafe { Device::::from_raw(led_cdev) }; + // SAFETY: `classdev.parent()` is guaranteed to be contained i= n `T::Bus`. + let parent =3D unsafe { T::Bus::from_device(classdev.parent())= }; + + classdev.ops.blink_set( + parent, + // SAFETY: The function's contract guarantees that `delay_= on` points to a `usize` + // and is exclusive for the period of this function. + unsafe { &mut *delay_on }, + // SAFETY: The function's contract guarantees that `delay_= off` points to a `usize` + // and is exclusive for the period of this function. + unsafe { &mut *delay_off }, + )?; + Ok(0) + }) + } +} + +#[pinned_drop] +impl PinnedDrop for Device { + fn drop(self: Pin<&mut Self>) { + let raw =3D self.classdev.get(); + // SAFETY: The existence of `self` guarantees that `self.classdev.= get()` is a pointer to a + // valid `struct led_classdev`. + let dev: &device::Device =3D unsafe { device::Device::from_raw((*r= aw).dev) }; + + let _fwnode =3D dev + .fwnode() + // SAFETY: the reference count of `fwnode` has previously been + // incremented in `led::Device::new`. + .map(|fwnode| unsafe { ARef::from_raw(NonNull::from(fwnode)) }= ); + + // SAFETY: The existence of `self` guarantees that `self.classdev`= has previously been + // successfully registered with `led_classdev_register_ext`. + unsafe { bindings::led_classdev_unregister(self.classdev.get()) }; + } +} diff --git a/rust/kernel/lib.rs b/rust/kernel/lib.rs index 3dd7bebe7888..c03b7b242a2b 100644 --- a/rust/kernel/lib.rs +++ b/rust/kernel/lib.rs @@ -103,6 +103,7 @@ pub mod jump_label; #[cfg(CONFIG_KUNIT)] pub mod kunit; +pub mod led; pub mod list; pub mod maple_tree; pub mod miscdevice; --=20 2.51.0