From nobody Tue Aug 25 05:55:01 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 A8F384078F3 for ; Wed, 19 Aug 2026 18:58:46 +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=1787165929; cv=none; b=k7BQQFD5FtGOtcNJsR2Te8+SWOnKkvQ/TC9pdJZL0TXzEV0HlWjEVoakYfzAzzpSwaVRQLtBJXeS0E+m6c+4YrHU9g+iwWIHiZiyV2f8Hoks4UZ/RWs3WsouEB9jKuCpBrsibPiXSOWgdl0Kz5NtClUIYZC7po1+1n53Xc/ULWc= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787165929; c=relaxed/simple; bh=fdGk/gdmV/cdseByoK3a2f3vDhDE4dxg8Ca14hgbA9Y=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=E+W+xEBq+jfrs4A68O0zGCe29AivjWpEH620gqRaB3mt9mR2XKz1diLT/F76eYSt99kVGs5cwMohWEMv34Rr+r+c6s2THCnWdVjzKn+Kdyn+U3uOs7srfKDbmC7ubO0pRCV6UPneHGx/5KHCVcChLWWOfHBAsUExLgK87I2zo1o= 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=mM8n8kNS; 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="mM8n8kNS" Received: from submission (posteo.de [185.67.36.169]) by mout01.posteo.de (Postfix) with ESMTPS id 26075240027 for ; Wed, 19 Aug 2026 20:58:45 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=posteo.de; s=1984.8680eb; t=1787165925; bh=p48Kuv+aM94lHTwtHsul4KgKPZBem/X3NZ8iOmZmqYQ=; h=From:Date:Subject:MIME-Version:Content-Type: Content-Transfer-Encoding:Message-Id:To:Cc:Autocrypt:OpenPGP:From; b=mM8n8kNSGGTiwVhTFYR7sqoHSnhKBvfJe6zA3ocCiNOPxl3m4r0qb0un9XEcfjWhH x04Pk+9snaD4s50iDfEbngdaXVGi6kQ59ym5UDR5do4zCTEAHU8pSCt0HWjOXxELCh mgtPu0izsK+DO4+v9ZJUmh4Gycyld8ksYroWfQ/dOe1jd3rstm3dqEcm6xy5qthWrg aMVeLbr/KZALXhUGjp4s8z7VsHiVfY17OHen/4cgjmAAkUdvWSSEmrcAI4F5cpoTeN zdL4hTGRWQv+IrxgWwFVCVlGWIJBKnWzrZSrNmeJruxDKCRB+V5P0wKlhay7WYiWqG z44TfLUYDyspg== Received: from customer (localhost [127.0.0.1]) by submission (posteo.de) with ESMTPSA id 4hQG7K4cHWz9rxd; Wed, 19 Aug 2026 20:58:37 +0200 (CEST) From: Markus Probst Date: Wed, 19 Aug 2026 18:58:39 +0000 Subject: [PATCH RESEND v23 1/3] rust: leds: add basic led classdev abstractions Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20260819-rust_leds-v23-1-2716a4ef89a4@posteo.de> References: <20260819-rust_leds-v23-0-2716a4ef89a4@posteo.de> In-Reply-To: <20260819-rust_leds-v23-0-2716a4ef89a4@posteo.de> To: Lee Jones , Pavel Machek , Greg Kroah-Hartman , Dave Ertman , Leon Romanovsky , Miguel Ojeda , Alex Gaynor , Gary Guo , =?utf-8?q?Bj=C3=B6rn_Roy_Baron?= , Benno Lossin , Andreas Hindborg , Alice Ryhl , Trevor Gross , Danilo Krummrich , "Rafael J. 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preference=encrypt 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::DeviceBuilder` - the builder for the led class device * `led::Device` - a safe wrapper around `led_classdev` Signed-off-by: Markus Probst --- MAINTAINERS | 8 ++ rust/kernel/led.rs | 288 ++++++++++++++++++++++++++++++++++++++++++= ++++ rust/kernel/led/normal.rs | 230 ++++++++++++++++++++++++++++++++++++ rust/kernel/lib.rs | 1 + 4 files changed, 527 insertions(+) diff --git a/MAINTAINERS b/MAINTAINERS index 806bd2d80d15..70989c4c693c 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -14662,6 +14662,14 @@ F: drivers/leds/ F: include/dt-bindings/leds/ F: include/linux/leds.h =20 +LED SUBSYSTEM [RUST] +M: Markus Probst +L: linux-leds@vger.kernel.org +L: rust-for-linux@vger.kernel.org +S: Maintained +F: rust/kernel/led.rs +F: rust/kernel/led/ + LEGO MINDSTORMS EV3 R: David Lechner S: Maintained diff --git a/rust/kernel/led.rs b/rust/kernel/led.rs new file mode 100644 index 000000000000..596975e103b8 --- /dev/null +++ b/rust/kernel/led.rs @@ -0,0 +1,288 @@ +// 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, + mem::transmute, + ptr::NonNull, // +}; + +use crate::{ + container_of, + device::{ + self, + property::FwNode, + AsBusDevice, + Bound, // + }, + error::{ + from_result, + to_result, + VTABLE_DEFAULT_ERROR, // + }, + macros::vtable, + prelude::*, + str::CStrExt, + sync::aref::ARef, + types::Opaque, // +}; + +mod normal; + +pub use normal::Device; + +/// The name of the led is determined by the driver. +pub enum Named {} +/// The name of the led is determined by its fwnode. +pub enum Unnamed {} + +/// How the name of the led should be determined. +pub trait DeviceBuilderState: private::Sealed {} + +impl DeviceBuilderState for Named {} +impl private::Sealed for Named {} +impl DeviceBuilderState for Unnamed {} +impl private::Sealed for Unnamed {} + +/// The builder to register a led class device. +/// +/// See [`LedOps`]. +pub struct DeviceBuilder<'init, S> { + fwnode: Option>, + name: Option<&'init CStr>, + devicename: Option<&'init CStr>, + devname_mandatory: bool, + initial_brightness: u32, + color: Color, + _p: PhantomData, +} + +impl DeviceBuilder<'static, S> { + /// Creates a new [`DeviceBuilder`]. + #[inline] + #[expect( + clippy::new_without_default, + reason =3D "no need and derive is prevented by S" + )] + pub fn new() -> Self { + Self { + fwnode: None, + name: None, + devicename: None, + devname_mandatory: false, + initial_brightness: 0, + color: Color::default(), + _p: PhantomData, + } + } +} + +impl<'init> DeviceBuilder<'init, Unnamed> { + /// Sets the firmware node. + #[inline] + pub fn fwnode(self, fwnode: Option>) -> Self { + Self { fwnode, ..self } + } + + /// Sets the device name. + #[inline] + pub fn devicename(self, devicename: &'init CStr) -> Self { + Self { + devicename: Some(devicename), + ..self + } + } + + /// Sets if a device name is mandatory. + #[inline] + pub fn devicename_mandatory(self, mandatory: bool) -> Self { + Self { + devname_mandatory: mandatory, + ..self + } + } +} + +impl<'init, S: DeviceBuilderState> DeviceBuilder<'init, S> { + /// Sets the initial brightness value for the led. + /// + /// The default brightness is 0. + /// If [`LedOps::brightness_get`] is implemented, this value will be i= gnored. + #[inline] + pub fn initial_brightness(self, brightness: u32) -> Self { + Self { + initial_brightness: brightness, + ..self + } + } + + /// Sets the color of the led. + /// + /// This value can be overwritten by the "color" fwnode property. + #[inline] + pub fn color(self, color: Color) -> Self { + Self { color, ..self } + } +} + +impl<'init> DeviceBuilder<'init, Named> { + /// Sets the name of the led. + /// + /// Setting this will prevent the fwnode from being used and prevents = automatic name + /// composition. + #[inline] + pub fn name(self, name: &'init CStr) -> Self { + Self { + name: Some(name), + ..self + } + } +} + +/// Trait defining the operations for a LED driver. +/// +/// # Examples +/// ``` +/// use kernel::{ +/// device, +/// devres::Devres, +/// led, +/// macros::vtable, +/// platform, +/// prelude::*, // +/// }; +/// +/// 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<'bound>( +/// &self, +/// _dev: &'bound platform::Device, +/// _classdev: &led::Device<'bound, Self>, +/// _brightness: u32 +/// ) -> Result<()> { +/// // Set the brightness for the led here +/// Ok(()) +/// } +/// } +/// ``` +/// Led drivers must implement this trait in order to register and handle = a [`Device`]. +#[vtable] +pub trait LedOps: Send + Sync + 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<'bound>( + &self, + dev: &'bound Self::Bus, + classdev: &Device<'bound, Self>, + brightness: u32, + ) -> Result<()>; + + /// Gets the current brightness level. + fn brightness_get<'bound>( + &self, + dev: &'bound Self::Bus, + classdev: &Device<'bound, Self>, + ) -> Result { + let _ =3D (dev, classdev); + 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<'bound>( + &self, + dev: &'bound Self::Bus, + classdev: &Device<'bound, Self>, + delay_on: &mut usize, + delay_off: &mut usize, + ) -> Result<()> { + let _ =3D (dev, classdev, delay_on, delay_off); + build_error!(VTABLE_DEFAULT_ERROR) + } +} + +/// Led colors. +#[derive(Copy, Clone, Debug, Default, PartialEq, Eq)] +#[repr(u32)] +#[non_exhaustive] +#[expect( + missing_docs, + reason =3D "it shouldn't be necessary to document each color" +)] +pub enum Color { + #[default] + White =3D bindings::LED_COLOR_ID_WHITE, + Red =3D bindings::LED_COLOR_ID_RED, + Green =3D bindings::LED_COLOR_ID_GREEN, + Blue =3D bindings::LED_COLOR_ID_BLUE, + Amber =3D bindings::LED_COLOR_ID_AMBER, + Violet =3D bindings::LED_COLOR_ID_VIOLET, + Yellow =3D bindings::LED_COLOR_ID_YELLOW, + Ir =3D bindings::LED_COLOR_ID_IR, + Multi =3D bindings::LED_COLOR_ID_MULTI, + Rgb =3D bindings::LED_COLOR_ID_RGB, + Purple =3D bindings::LED_COLOR_ID_PURPLE, + Orange =3D bindings::LED_COLOR_ID_ORANGE, + Pink =3D bindings::LED_COLOR_ID_PINK, + Cyan =3D bindings::LED_COLOR_ID_CYAN, + Lime =3D bindings::LED_COLOR_ID_LIME, +} +static_assert!(bindings::LED_COLOR_ID_MAX =3D=3D 15); + +impl Color { + /// Name of the color + #[inline] + pub fn as_c_str(self) -> &'static CStr { + // SAFETY: + // - `self as u8` is a valid led color id. + // - `led_get_color_name` always returns a valid C string pointer. + unsafe { CStr::from_char_ptr(bindings::led_get_color_name(self as = u8)) } + } +} + +impl TryFrom for Color { + type Error =3D Error; + + fn try_from(value: u32) -> core::result::Result { + if value < bindings::LED_COLOR_ID_MAX { + // SAFETY: + // - `Color` is represented as `u32` + // - the static_assert above guarantees that no additional col= or has been added + // - `value` is guaranteed to be in the color id range + Ok(unsafe { transmute::(value) }) + } else { + Err(EINVAL) + } + } +} + +mod private { + pub trait Sealed {} +} diff --git a/rust/kernel/led/normal.rs b/rust/kernel/led/normal.rs new file mode 100644 index 000000000000..816db7c57689 --- /dev/null +++ b/rust/kernel/led/normal.rs @@ -0,0 +1,230 @@ +// SPDX-License-Identifier: GPL-2.0 + +//! Led mode for the `struct led_classdev`. +//! +//! C header: [`include/linux/leds.h`](srctree/include/linux/leds.h) + +use super::*; + +/// The led class device representation. +/// +/// This structure represents the Rust abstraction for a led class device. +#[pin_data(PinnedDrop)] +pub struct Device<'bound, T: LedOps + 'bound> { + #[pin] + ops: T, + #[pin] + classdev: Opaque, + _p: PhantomData<&'bound ()>, +} + +impl<'init, S: DeviceBuilderState> DeviceBuilder<'init, S> { + /// Registers a new [`Device`]. + pub fn build<'bound: 'init, T: LedOps + 'bound>( + self, + parent: &'bound T::Bus, + ops: impl PinInit + 'init, + ) -> impl PinInit, Error> + 'init { + const_assert!(T::MAX_BRIGHTNESS <=3D i32::MAX.unsigned_abs() || !T= ::HAS_BRIGHTNESS_GET); + + try_pin_init!(Device { + ops <- ops, + classdev <- Opaque::try_ffi_init(|ptr: *mut bindings::led_clas= sdev| { + // SAFETY: `try_ffi_init` guarantees that `ptr` is valid f= or write. + // `led_classdev` gets fully initialized in-place by + // `led_classdev_register_ext` including `mutex` and `list= _head`. + unsafe { + ptr.write(bindings::led_classdev { + brightness_set: (!T::BLOCKING) + .then_some(Adapter::::brightness_set_callba= ck), + brightness_set_blocking: T::BLOCKING + .then_some(Adapter::::brightness_set_blocki= ng_callback), + brightness_get: T::HAS_BRIGHTNESS_GET + .then_some(Adapter::::brightness_get_callba= ck), + blink_set: T::HAS_BLINK_SET.then_some(Adapter::= ::blink_set_callback), + max_brightness: T::MAX_BRIGHTNESS, + brightness: self.initial_brightness, + color: self.color as u32, + name: self.name.map_or(core::ptr::null(), CStrExt:= :as_char_ptr), + ..bindings::led_classdev::default() + }) + }; + + let mut init_data =3D bindings::led_init_data { + fwnode: self + .fwnode + .as_ref() + .map_or(core::ptr::null_mut(), |fwnode| fwnode.as_= raw()), + default_label: core::ptr::null(), + devicename: self + .devicename + .map_or(core::ptr::null(), CStrExt::as_char_ptr), + devname_mandatory: self.devname_mandatory, + }; + + // SAFETY: + // - `parent.as_ref().as_raw()` is guaranteed to be a poin= ter to a valid + // `device`. + // - `ptr` is guaranteed to be a pointer to an initialized= `led_classdev`. + to_result(unsafe { + bindings::led_classdev_register_ext( + parent.as_ref().as_raw(), + ptr, + if self.name.is_none() { + &raw mut init_data + } else { + core::ptr::null_mut() + }, + ) + })?; + + core::mem::forget(self.fwnode); // keep the reference coun= t incremented + + Ok::<_, Error>(()) + }), + _p: PhantomData, + }) + } +} + +impl<'bound, T: LedOps + 'bound> Device<'bound, T> { + /// # Safety + /// `led_cdev` must be a valid pointer to a `led_classdev` embedded wi= thin a + /// `led::Device`. + #[inline] + 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) } + } + + #[inline] + fn parent(&self) -> &'bound device::Device { + // SAFETY: `self.classdev.get()` is guaranteed to be a valid point= er to `led_classdev`. + unsafe { device::Device::from_raw((*(*self.classdev.get()).dev).pa= rent) } + } +} + +// SAFETY: A `led::Device` can be unregistered from any thread. +unsafe impl<'bound, T: LedOps + 'bound + Send> Send for Device<'bound, T> = {} + +// SAFETY: `led::Device` can be shared among threads because all methods o= f `led::Device` +// are thread safe. +unsafe impl<'bound, T: LedOps + 'bound + Sync> Sync for Device<'bound, T> = {} + +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, classdev, 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, classdev, 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()) }; + + // CAST: Resulting value will be casted back to i32 in the led sub= system. + from_result(|| { + classdev + .ops + .brightness_get(parent, classdev) + .inspect(|val| debug_assert!(*val <=3D T::MAX_BRIGHTNESS)) + .and_then(|val| Ok(i32::try_from(val)?)) + }) as u32 + } + + /// # 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, + classdev, + // 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<'bound, T: LedOps + 'bound> PinnedDrop for Device<'bound, T> { + 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 `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::DeviceBuilder::build`. + .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(raw) }; + } +} diff --git a/rust/kernel/lib.rs b/rust/kernel/lib.rs index 9512af7156df..09e4cc7a14db 100644 --- a/rust/kernel/lib.rs +++ b/rust/kernel/lib.rs @@ -90,6 +90,7 @@ pub mod jump_label; #[cfg(CONFIG_KUNIT)] pub mod kunit; +pub mod led; pub mod list; pub mod maple_tree; pub mod miscdevice; --=20 2.54.0 From nobody Tue Aug 25 05:55:01 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 9D8804078FC for ; Wed, 19 Aug 2026 18:58:47 +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=1787165929; cv=none; 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Wed, 19 Aug 2026 20:58:39 +0200 (CEST) From: Markus Probst Date: Wed, 19 Aug 2026 18:58:41 +0000 Subject: [PATCH RESEND v23 2/3] rust: leds: add Mode trait Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20260819-rust_leds-v23-2-2716a4ef89a4@posteo.de> References: <20260819-rust_leds-v23-0-2716a4ef89a4@posteo.de> In-Reply-To: <20260819-rust_leds-v23-0-2716a4ef89a4@posteo.de> To: Lee Jones , Pavel Machek , Greg Kroah-Hartman , Dave Ertman , Leon Romanovsky , Miguel Ojeda , Alex Gaynor , Gary Guo , =?utf-8?q?Bj=C3=B6rn_Roy_Baron?= , Benno Lossin , Andreas Hindborg , Alice Ryhl , Trevor Gross , Danilo Krummrich , "Rafael J. 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Signed-off-by: Markus Probst --- rust/kernel/led.rs | 27 +++++++++++++++++++++++---- rust/kernel/led/normal.rs | 22 +++++++++++++++------- 2 files changed, 38 insertions(+), 11 deletions(-) diff --git a/rust/kernel/led.rs b/rust/kernel/led.rs index 596975e103b8..5d7e6d08ad2a 100644 --- a/rust/kernel/led.rs +++ b/rust/kernel/led.rs @@ -32,7 +32,10 @@ =20 mod normal; =20 -pub use normal::Device; +pub use normal::{ + Device, + Normal, // +}; =20 /// The name of the led is determined by the driver. pub enum Named {} @@ -161,6 +164,7 @@ pub fn name(self, name: &'init CStr) -> Self { /// #[vtable] /// impl led::LedOps for MyLedOps { /// type Bus =3D platform::Device; +/// type Mode =3D led::Normal; /// const BLOCKING: bool =3D false; /// const MAX_BRIGHTNESS: u32 =3D 255; /// @@ -182,6 +186,11 @@ pub trait LedOps: Send + Sync + Sized { #[allow(private_bounds)] type Bus: AsBusDevice; =20 + /// The led mode to use. + /// + /// See [`Mode`]. + type Mode: Mode; + /// 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; @@ -194,7 +203,7 @@ pub trait LedOps: Send + Sync + Sized { fn brightness_set<'bound>( &self, dev: &'bound Self::Bus, - classdev: &Device<'bound, Self>, + classdev: &::Device<'bound, Self>, brightness: u32, ) -> Result<()>; =20 @@ -202,7 +211,7 @@ fn brightness_set<'bound>( fn brightness_get<'bound>( &self, dev: &'bound Self::Bus, - classdev: &Device<'bound, Self>, + classdev: &::Device<'bound, Self>, ) -> Result { let _ =3D (dev, classdev); build_error!(VTABLE_DEFAULT_ERROR) @@ -219,7 +228,7 @@ fn brightness_get<'bound>( fn blink_set<'bound>( &self, dev: &'bound Self::Bus, - classdev: &Device<'bound, Self>, + classdev: &::Device<'bound, Self>, delay_on: &mut usize, delay_off: &mut usize, ) -> Result<()> { @@ -283,6 +292,16 @@ fn try_from(value: u32) -> core::result::Result { } } =20 +/// The led mode. +/// +/// Each led mode has its own led class device type with different capabil= ities. +/// +/// See [`Normal`]. +pub trait Mode: private::Sealed { + /// The class device for the led mode. + type Device<'bound, T: LedOps + 'bound>; +} + mod private { pub trait Sealed {} } diff --git a/rust/kernel/led/normal.rs b/rust/kernel/led/normal.rs index 816db7c57689..25190486a62d 100644 --- a/rust/kernel/led/normal.rs +++ b/rust/kernel/led/normal.rs @@ -6,11 +6,19 @@ =20 use super::*; =20 +/// The led mode for the `struct led_classdev`. Leds with this mode can on= ly have a fixed color. +pub enum Normal {} + +impl Mode for Normal { + type Device<'bound, T: LedOps + 'bound> =3D Device<'bou= nd, T>; +} +impl private::Sealed for Normal {} + /// The led class device representation. /// /// This structure represents the Rust abstraction for a led class device. #[pin_data(PinnedDrop)] -pub struct Device<'bound, T: LedOps + 'bound> { +pub struct Device<'bound, T: LedOps + 'bound> { #[pin] ops: T, #[pin] @@ -20,7 +28,7 @@ pub struct Device<'bound, T: LedOps + 'bound> { =20 impl<'init, S: DeviceBuilderState> DeviceBuilder<'init, S> { /// Registers a new [`Device`]. - pub fn build<'bound: 'init, T: LedOps + 'bound>( + pub fn build<'bound: 'init, T: LedOps + 'bound>( self, parent: &'bound T::Bus, ops: impl PinInit + 'init, @@ -87,7 +95,7 @@ pub fn build<'bound: 'init, T: LedOps + 'bound>( } } =20 -impl<'bound, T: LedOps + 'bound> Device<'bound, T> { +impl<'bound, T: LedOps + 'bound> Device<'bound, T> { /// # Safety /// `led_cdev` must be a valid pointer to a `led_classdev` embedded wi= thin a /// `led::Device`. @@ -107,17 +115,17 @@ fn parent(&self) -> &'bound device::Device { } =20 // SAFETY: A `led::Device` can be unregistered from any thread. -unsafe impl<'bound, T: LedOps + 'bound + Send> Send for Device<'bound, T> = {} +unsafe impl<'bound, T: LedOps + 'bound + Send> Send for D= evice<'bound, T> {} =20 // SAFETY: `led::Device` can be shared among threads because all methods o= f `led::Device` // are thread safe. -unsafe impl<'bound, T: LedOps + 'bound + Sync> Sync for Device<'bound, T> = {} +unsafe impl<'bound, T: LedOps + 'bound + Sync> Sync for D= evice<'bound, T> {} =20 struct Adapter { _p: PhantomData, } =20 -impl Adapter { +impl> Adapter { /// # Safety /// `led_cdev` must be a valid pointer to a `led_classdev` embedded wi= thin a /// `led::Device`. @@ -210,7 +218,7 @@ impl Adapter { } =20 #[pinned_drop] -impl<'bound, T: LedOps + 'bound> PinnedDrop for Device<'bound, T> { +impl<'bound, T: LedOps + 'bound> PinnedDrop for Device<'b= ound, T> { 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 --=20 2.54.0 From nobody Tue Aug 25 05:55:01 2026 Received: from mout02.posteo.de (mout02.posteo.de [185.67.36.66]) (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 230443CF054 for ; Wed, 19 Aug 2026 18:58:49 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=185.67.36.66 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787165931; cv=none; b=qwUHNKEfaLRBrcMYQv2Fod7C2njR2Z2eokASC9KLHfNlFLNLClbj4ras0yl6XKiNG6XK/RG3cqpfZ8jQ4RbIH8zAFxis0+ImDfwtAsL69wc66MEGDX85pvSqh9YbsPUUHrEYfgBRryscDPATwhje6Rk2i+ISaWj5uoRNqqY9o9M= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787165931; c=relaxed/simple; bh=XEv168yC49AdqEd5gap66tan9pBN9Wx1zGNT2FdAO68=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; 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bh=w1gM1aFUaXvFjPe7IdGUzdn2DDlN1U7ZkB8JmOeBdik=; h=From:Date:Subject:MIME-Version:Content-Type: Content-Transfer-Encoding:Message-Id:To:Cc:Autocrypt:OpenPGP:From; b=Ysr1L1LewzrUrLfJjOndO8/laR8b1/JqHFJV7JDODWIhHJIulbzfzFVCji82HA4JN 7P+8rzcEK5k8otrqfw9LXDDm+2rw6FkQN7zGJvZe7k3aggU3Ao72Ksfg1slmydBofp jafaAgHSOzfEeDvYz4ZPz5Novx2h+qYZ3yzuRIDzU+nCUYxXrMH9iWDhCb74zAxtQj lxGax9Y01Vk+CHjwkl5vGX9egNSz/cajWcFnrSv+wYi+QRb6Of/bF2S4+m+ztbhW6a r4Ap+51c3nPuBAsjNs9feLhE81bsz8Tue1XSYMMtOuuTy1MMjYo1ucQRCjCxrtzIt3 FAVKRKatXlrdg== Received: from customer (localhost [127.0.0.1]) by submission (posteo.de) with ESMTPSA id 4hQG7P1nSmz9rxh; Wed, 19 Aug 2026 20:58:41 +0200 (CEST) From: Markus Probst Date: Wed, 19 Aug 2026 18:58:42 +0000 Subject: [PATCH RESEND v23 3/3] rust: leds: add multicolor classdev abstractions Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20260819-rust_leds-v23-3-2716a4ef89a4@posteo.de> References: <20260819-rust_leds-v23-0-2716a4ef89a4@posteo.de> In-Reply-To: <20260819-rust_leds-v23-0-2716a4ef89a4@posteo.de> To: Lee Jones , Pavel Machek , Greg Kroah-Hartman , Dave Ertman , Leon Romanovsky , Miguel Ojeda , Alex Gaynor , Gary Guo , =?utf-8?q?Bj=C3=B6rn_Roy_Baron?= , Benno Lossin , Andreas Hindborg , Alice Ryhl , Trevor Gross , Danilo Krummrich , "Rafael J. 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preference=encrypt Implement the abstractions needed for multicolor led class devices, including: * `led::MultiColor` - the led mode implementation * `MultiColorSubLed` - a safe wrapper arround `mc_subled` * `led::MultiColorDevice` - a safe wrapper around `led_classdev_mc` * `led::DeviceBuilder::build_multicolor` - a function to register a new multicolor led class device Signed-off-by: Markus Probst --- rust/bindings/bindings_helper.h | 1 + rust/kernel/led.rs | 34 ++- rust/kernel/led/multicolor.rs | 460 ++++++++++++++++++++++++++++++++++++= ++++ 3 files changed, 494 insertions(+), 1 deletion(-) diff --git a/rust/bindings/bindings_helper.h b/rust/bindings/bindings_helpe= r.h index 1124785e210b..821f539e597e 100644 --- a/rust/bindings/bindings_helper.h +++ b/rust/bindings/bindings_helper.h @@ -68,6 +68,7 @@ #include #include #include +#include #include #include #include diff --git a/rust/kernel/led.rs b/rust/kernel/led.rs index 5d7e6d08ad2a..3aa7cdde78f4 100644 --- a/rust/kernel/led.rs +++ b/rust/kernel/led.rs @@ -30,8 +30,16 @@ types::Opaque, // }; =20 +#[cfg(CONFIG_LEDS_CLASS_MULTICOLOR)] +mod multicolor; mod normal; =20 +#[cfg(CONFIG_LEDS_CLASS_MULTICOLOR)] +pub use multicolor::{ + MultiColor, + MultiColorDevice, + MultiColorSubLed, // +}; pub use normal::{ Device, Normal, // @@ -255,7 +263,24 @@ pub enum Color { Violet =3D bindings::LED_COLOR_ID_VIOLET, Yellow =3D bindings::LED_COLOR_ID_YELLOW, Ir =3D bindings::LED_COLOR_ID_IR, + #[cfg_attr( + CONFIG_LEDS_CLASS_MULTICOLOR, + doc =3D "Use this color for a [`MultiColor`] led." + )] + #[cfg_attr( + not(CONFIG_LEDS_CLASS_MULTICOLOR), + doc =3D "Use this color for a `MultiColor` led." + )] + /// If the led supports RGB, use [`Color::Rgb`] instead. Multi =3D bindings::LED_COLOR_ID_MULTI, + #[cfg_attr( + CONFIG_LEDS_CLASS_MULTICOLOR, + doc =3D "Use this color for a [`MultiColor`] led with rgb support." + )] + #[cfg_attr( + not(CONFIG_LEDS_CLASS_MULTICOLOR), + doc =3D "Use this color for a `MultiColor` led with rgb support." + )] Rgb =3D bindings::LED_COLOR_ID_RGB, Purple =3D bindings::LED_COLOR_ID_PURPLE, Orange =3D bindings::LED_COLOR_ID_ORANGE, @@ -296,7 +321,14 @@ fn try_from(value: u32) -> core::result::Result { /// /// Each led mode has its own led class device type with different capabil= ities. /// -/// See [`Normal`]. +#[cfg_attr( + CONFIG_LEDS_CLASS_MULTICOLOR, + doc =3D "See [`Normal`] and [`MultiColor`]." +)] +#[cfg_attr( + not(CONFIG_LEDS_CLASS_MULTICOLOR), + doc =3D "See [`Normal`] and `MultiColor`." +)] pub trait Mode: private::Sealed { /// The class device for the led mode. type Device<'bound, T: LedOps + 'bound>; diff --git a/rust/kernel/led/multicolor.rs b/rust/kernel/led/multicolor.rs new file mode 100644 index 000000000000..82fe96fd5273 --- /dev/null +++ b/rust/kernel/led/multicolor.rs @@ -0,0 +1,460 @@ +// SPDX-License-Identifier: GPL-2.0 + +//! Led mode for the `struct led_classdev_mc`. +//! +//! C header: [`include/linux/led-class-multicolor.h`](srctree/include/lin= ux/led-class-multicolor.h) + +use core::{ + cell::UnsafeCell, + num::NonZero, + ptr, // +}; + +use crate::types::ScopeGuard; + +use super::*; + +/// The led mode for the `struct led_classdev_mc`. Leds with this mode can= have multiple colors. +pub enum MultiColor {} +impl Mode for MultiColor { + type Device<'bound, T: LedOps + 'bound> =3D MultiColorD= evice<'bound, T>; +} +impl private::Sealed for MultiColor {} + +/// The multicolor sub led info representation. +/// +/// This structure represents the Rust abstraction for a C `struct mc_subl= ed`. +#[repr(C)] +#[derive(Debug)] +#[non_exhaustive] +pub struct MultiColorSubLed { + /// The color of the sub led + pub color: Color, + brightness: UnsafeCell, + intensity: UnsafeCell, + /// The maximum supported intensity value. + /// + /// If None the maximum intensity equals to [`LedOps::MAX_BRIGHTNESS`]. + pub max_intensity: Option>, + /// Arbitrary data for the driver to store. + pub channel: u32, +} + +// SAFETY: `MultiColorSubLed` can be shared among threads. +unsafe impl Sync for MultiColorSubLed {} + +impl Clone for MultiColorSubLed { + fn clone(&self) -> Self { + Self { + color: self.color, + brightness: self.brightness().into(), + intensity: self.intensity().into(), + max_intensity: self.max_intensity, + channel: self.channel, + } + } +} + +// We directly pass a reference to the `subled_info` field in `led_classde= v_mc` to the driver via +// `Device::subleds()`. +// We need safeguards to ensure `MultiColorSubLed` and `mc_subled` stay id= entical. +const _: () =3D { + use core::mem::offset_of; + + const fn assert_same_type(_: &T, _: &T) {} + + let rust_zeroed =3D MultiColorSubLed { + color: Color::White, + brightness: UnsafeCell::new(0), + intensity: UnsafeCell::new(0), + max_intensity: None, + channel: 0, + }; + let c_zeroed =3D bindings::mc_subled { + color_index: 0, + brightness: 0, + intensity: 0, + max_intensity: 0, + channel: 0, + }; + + assert!(offset_of!(MultiColorSubLed, color) =3D=3D offset_of!(bindings= ::mc_subled, color_index)); + assert!( + offset_of!(MultiColorSubLed, brightness) =3D=3D offset_of!(binding= s::mc_subled, brightness) + ); + assert!(offset_of!(MultiColorSubLed, intensity) =3D=3D offset_of!(bind= ings::mc_subled, intensity)); + assert!( + offset_of!(MultiColorSubLed, max_intensity) + =3D=3D offset_of!(bindings::mc_subled, max_intensity) + ); + assert!(offset_of!(MultiColorSubLed, channel) =3D=3D offset_of!(bindin= gs::mc_subled, channel)); + + assert_same_type(&0u32, &c_zeroed.color_index); + assert_same_type(&rust_zeroed.brightness.into_inner(), &c_zeroed.brigh= tness); + assert_same_type(&rust_zeroed.intensity.into_inner(), &c_zeroed.intens= ity); + assert!(size_of_val(&rust_zeroed.max_intensity) =3D=3D size_of_val(&c_= zeroed.max_intensity)); + assert_same_type(&rust_zeroed.channel, &c_zeroed.channel); + + assert!(size_of::() =3D=3D size_of::()); +}; + +impl MultiColorSubLed { + /// Create a new multicolor sub led info. + #[inline] + pub const fn new(color: Color) -> Self { + Self { + color, + brightness: UnsafeCell::new(0), + intensity: UnsafeCell::new(0), + max_intensity: None, + channel: 0, + } + } + + /// Set arbitrary data for the driver. + #[inline] + pub const fn channel(mut self, channel: u32) -> Self { + self.channel =3D channel; + self + } + + /// Set the initial intensity of the subled. + #[inline] + pub const fn initial_intensity(mut self, intensity: u32) -> Self { + self.intensity =3D UnsafeCell::new(intensity); + self + } + + /// Set the maximum supported intensity of the subled. + #[inline] + pub const fn max_intensity(mut self, max_intensity: NonZero) -> S= elf { + self.max_intensity =3D Some(max_intensity); + self + } + + /// The intensity of the sub led. + #[inline] + pub const fn intensity(&self) -> u32 { + // SAFETY: + // - `self.intensity.get()` is a valid pointer to `u32`. + // - We don't have exclusive or immutable access to `self.intensit= y`, + // but the alignment should prevent "load tearing". + unsafe { *self.intensity.get() } + } + + /// The brightness of the sub led. + #[inline] + pub const fn brightness(&self) -> u32 { + // SAFETY: + // - `self.brightness.get()` is a valid pointer to `u32`. + // - We don't have exclusive or immutable access to `self.brightne= ss`, + // but the alignment should prevent "load tearing". + unsafe { *self.brightness.get() } + } +} + +/// The multicolor led class device representation. +/// +/// This structure represents the Rust abstraction for a multicolor led cl= ass device. +#[pin_data(PinnedDrop)] +pub struct MultiColorDevice<'bound, T: LedOps + 'boun= d> { + #[pin] + ops: T, + #[pin] + classdev: Opaque, + _p: PhantomData<&'bound ()>, +} + +impl<'init, S: DeviceBuilderState> DeviceBuilder<'init, S> { + /// Registers a new [`MulticolorDevice`]. + pub fn build_multicolor<'bound: 'init, T: LedOps = + 'bound>( + self, + parent: &'bound T::Bus, + ops: impl PinInit + 'init, + subleds: &'init [MultiColorSubLed], + ) -> impl PinInit, Error> + 'init { + const_assert!(T::MAX_BRIGHTNESS <=3D i32::MAX.unsigned_abs() || !T= ::HAS_BRIGHTNESS_GET); + + try_pin_init!(MultiColorDevice { + ops <- ops, + classdev <- Opaque::try_ffi_init(|ptr: *mut bindings::led_clas= sdev_mc| { + let mut colors =3D [false; bindings::LED_COLOR_ID_MAX as u= size]; + for subled in subleds { + if colors[subled.color as usize] { + dev_err!(parent.as_ref(), "duplicate color in mult= icolor led\n"); + return Err(EINVAL); + } + colors[subled.color as usize] =3D true; + } + let subleds_box =3D KBox::pin_slice( + |index| Ok::<_, Error>(subleds[index].clone()), + subleds.len(), + GFP_KERNEL, + )?; + let subleds_box_raw =3D KBox::into_raw(Pin::into_inner(sub= leds_box)); + + let subled_guard =3D ScopeGuard::new(|| { + // SAFETY: `subleds_box_raw` is guaranteed to be a val= id pointer to + // `[MultiColorSubLed]`. + drop(unsafe { >::from_raw(sub= leds_box_raw) }); + }); + + // SAFETY: `try_ffi_init` guarantees that `ptr` is valid f= or write. + // `led_classdev_mc` gets fully initialized in-place by + // `led_classdev_multicolor_register_ext` including `mutex= ` and `list_head`. + unsafe { + ptr.write(bindings::led_classdev_mc { + led_cdev: bindings::led_classdev { + 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), + max_brightness: T::MAX_BRIGHTNESS, + brightness: self.initial_brightness, + color: self.color as u32, + name: self.name.map_or(core::ptr::null(), CStr= Ext::as_char_ptr), + ..bindings::led_classdev::default() + }, + num_colors: u32::try_from(subleds_box_raw.len())?, + // CAST: The safeguards in the const block ensure = that + // `MultiColorSubLed` has an identical layout to `= mc_subled`. + subled_info: subleds_box_raw.cast::(), + }) + }; + + let mut init_data =3D bindings::led_init_data { + fwnode: self + .fwnode + .as_ref() + .map_or(core::ptr::null_mut(), |fwnode| fwnode.as_= raw()), + default_label: core::ptr::null(), + devicename: self + .devicename + .map_or(core::ptr::null(), CStrExt::as_char_ptr), + devname_mandatory: self.devname_mandatory, + }; + + // SAFETY: + // - `parent.as_ref().as_raw()` is guaranteed to be a poin= ter to a valid + // `device`. + // - `ptr` is guaranteed to be a pointer to an initialized= `led_classdev_mc`. + to_result(unsafe { + bindings::led_classdev_multicolor_register_ext( + parent.as_ref().as_raw(), + ptr, + if self.name.is_none() { + &raw mut init_data + } else { + core::ptr::null_mut() + }, + ) + })?; + + subled_guard.dismiss(); + + core::mem::forget(self.fwnode); // keep the reference coun= t incremented + + Ok::<_, Error>(()) + }), + _p: PhantomData, + }) + } +} + +impl<'bound, T: LedOps + 'bound> MultiColorDevice<'bo= und, T> { + /// # Safety + /// `led_cdev` must be a valid pointer to a `led_classdev` embedded wi= thin a + /// `led::MultiColorDevice`. + #[inline] + 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::MultiColorDevice`. `contain= er_of!` can therefore + // safely calculate the address of the containing struct. + let led_mc_cdev =3D unsafe { container_of!(led_cdev, bindings::led= _classdev_mc, led_cdev) }; + + // SAFETY: It is guaranteed that `led_mc_cdev` points to a `led_cl= assdev_mc` + // field embedded within a valid `led::MultiColorDevice`. `contain= er_of!` can therefore + // safely calculate the address of the containing struct. + unsafe { &*container_of!(Opaque::cast_from(led_mc_cdev), Self, cla= ssdev) } + } + + #[inline] + fn parent(&self) -> &'bound device::Device { + // SAFETY: `self.classdev.get()` is guaranteed to be a valid point= er to `led_classdev_mc`. + unsafe { device::Device::from_raw((*(*self.classdev.get()).led_cde= v.dev).parent) } + } + + /// Returns the subleds passed to [`Device::new_multicolor`]. + #[inline] + pub fn subleds(&self) -> &[MultiColorSubLed] { + // SAFETY: The existence of `self` guarantees that `self.classdev.= get()` is a pointer to a + // valid `led_classdev_mc`. + let raw =3D unsafe { &*self.classdev.get() }; + // SAFETY: `raw.subled_info` is a valid pointer to `mc_subled[num_= colors]`. + // CAST: The safeguards in the const block ensure that `MultiColor= SubLed` has an identical + // layout to `mc_subled`. + unsafe { + core::slice::from_raw_parts( + raw.subled_info.cast::(), + // CAST: It is guaranteed that `num_colors` fits into an `= usize`. + raw.num_colors as usize, + ) + } + } +} + +// SAFETY: A `led::MultiColorDevice` can be unregistered from any thread. +unsafe impl<'bound, T: LedOps + 'bound + Send> Send + for MultiColorDevice<'bound, T> +{ +} + +// SAFETY: `led::MultiColorDevice` can be shared among threads because all= methods of `led::Device` +// are thread safe. +unsafe impl<'bound, T: LedOps + 'bound + Sync> Sync + for MultiColorDevice<'bound, T> +{ +} + +struct Adapter> { + _p: PhantomData, +} + +impl> Adapter { + /// # Safety + /// `led_cdev` must be a valid pointer to a `led_classdev` embedded wi= thin a + /// `led::MultiColorDevice`. + /// 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::MultiColorDevice`. + let classdev =3D unsafe { MultiColorDevice::::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()) }; + + // SAFETY: `classdev.classdev.get()` is guaranteed to be a pointer= to a valid + // `led_classdev_mc`. + unsafe { bindings::led_mc_calc_color_components(classdev.classdev.= get(), brightness) }; + + let _ =3D classdev.ops.brightness_set(parent, classdev, brightness= ); + } + + /// # Safety + /// `led_cdev` must be a valid pointer to a `led_classdev` embedded wi= thin a + /// `led::MultiColorDevice`. + /// 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::MultiColorDevice`. + let classdev =3D unsafe { MultiColorDevice::::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())= }; + + // SAFETY: `classdev.classdev.get()` is guaranteed to be a poi= nter to a valid + // `led_classdev_mc`. + unsafe { bindings::led_mc_calc_color_components(classdev.class= dev.get(), brightness) }; + + classdev.ops.brightness_set(parent, classdev, brightness)?; + Ok(0) + }) + } + + /// # Safety + /// `led_cdev` must be a valid pointer to a `led_classdev` embedded wi= thin a + /// `led::MultiColorDevice`. + /// 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::MultiColorDevice`. + let classdev =3D unsafe { MultiColorDevice::::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()) }; + + // CAST: Resulting value will be casted back to i32 in the led sub= system. + from_result(|| { + classdev + .ops + .brightness_get(parent, classdev) + .inspect(|val| debug_assert!(*val <=3D T::MAX_BRIGHTNESS)) + .and_then(|val| Ok(i32::try_from(val)?)) + }) as u32 + } + + /// # Safety + /// `led_cdev` must be a valid pointer to a `led_classdev` embedded wi= thin a + /// `led::MultiColorDevice`. + /// `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::MultiColorDevice`. + let classdev =3D unsafe { MultiColorDevice::::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, + classdev, + // 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<'bound, T: LedOps + 'bound> PinnedDrop for Multi= ColorDevice<'bound, T> { + 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 `led_classdev_mc`. + let dev: &device::Device =3D unsafe { device::Device::from_raw((*r= aw).led_cdev.dev) }; + + let _fwnode =3D dev + .fwnode() + // SAFETY: the reference count of `fwnode` has previously been + // incremented in `led::DeviceBuilder::build_multicolor`. + .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_multicolor_register_= ext`. + unsafe { bindings::led_classdev_multicolor_unregister(raw) }; + + // SAFETY: `raw` is guaranteed to be a valid pointer to `led_class= dev_mc`. + let led_cdev =3D unsafe { &*raw }; + + // SAFETY: `led_cdev.subled_info` is guaranteed to be a valid poin= ter to + // `[MultiColorSubLed]` with length of `led_cdev.num_colors`. + // See `led::DeviceBuilder::build_multicolor`. + drop(unsafe { + KBox::from_raw(ptr::slice_from_raw_parts_mut( + led_cdev.subled_info.cast::(), + // CAST: `num_colors` was originally converted from a `usi= ze` in + // `DeviceBuilder::build_multicolor`. Thus it is guarantee= d that + // `num_colors` fits into an usize. + led_cdev.num_colors as usize, + )) + }); + } +} --=20 2.54.0