* [PATCH RESEND v13 1/3] rust: leds: add basic led classdev abstractions
2026-04-11 15:07 [PATCH RESEND v13 0/3] rust: leds: add led classdev abstractions Markus Probst
@ 2026-04-11 15:07 ` Markus Probst
2026-04-11 15:07 ` [PATCH RESEND v13 2/3] rust: leds: add Mode trait Markus Probst
2026-04-11 15:07 ` [PATCH RESEND v13 3/3] rust: leds: add multicolor classdev abstractions Markus Probst
2 siblings, 0 replies; 4+ messages in thread
From: Markus Probst @ 2026-04-11 15:07 UTC (permalink / raw)
To: Lee Jones, Pavel Machek, Greg Kroah-Hartman, Dave Ertman,
Ira Weiny, Leon Romanovsky, Miguel Ojeda, Alex Gaynor, Gary Guo,
Björn Roy Baron, Benno Lossin, Andreas Hindborg, Alice Ryhl,
Trevor Gross, Danilo Krummrich, Rafael J. Wysocki, Bjorn Helgaas,
Krzysztof Wilczyński, Boqun Feng, Boqun Feng
Cc: rust-for-linux, linux-leds, linux-kernel, linux-pci,
Markus Probst
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 <markus.probst@posteo.de>
---
MAINTAINERS | 8 ++
rust/kernel/led.rs | 310 ++++++++++++++++++++++++++++++++++++++++++++++
rust/kernel/led/normal.rs | 223 +++++++++++++++++++++++++++++++++
rust/kernel/lib.rs | 1 +
4 files changed, 542 insertions(+)
diff --git a/MAINTAINERS b/MAINTAINERS
index 7d10988cbc62..83b5a45de729 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -14439,6 +14439,14 @@ F: drivers/leds/
F: include/dt-bindings/leds/
F: include/linux/leds.h
+LED SUBSYSTEM [RUST]
+M: Markus Probst <markus.probst@posteo.de>
+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 <david@lechnology.com>
S: Maintained
diff --git a/rust/kernel/led.rs b/rust/kernel/led.rs
new file mode 100644
index 000000000000..1fba512a804c
--- /dev/null
+++ b/rust/kernel/led.rs
@@ -0,0 +1,310 @@
+// 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, //
+ },
+ devres::Devres,
+ error::{
+ from_result,
+ to_result,
+ VTABLE_DEFAULT_ERROR, //
+ },
+ macros::vtable,
+ prelude::*,
+ str::CStrExt,
+ types::{
+ ARef,
+ 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<'a, S> {
+ fwnode: Option<ARef<FwNode>>,
+ name: Option<&'a CStr>,
+ devicename: Option<&'a CStr>,
+ devname_mandatory: bool,
+ initial_brightness: u32,
+ default_trigger: Option<&'a CStr>,
+ color: Color,
+ _p: PhantomData<S>,
+}
+
+impl<S: DeviceBuilderState> DeviceBuilder<'static, S> {
+ /// Creates a new [`DeviceBuilder`].
+ #[inline]
+ #[expect(
+ clippy::new_without_default,
+ reason = "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,
+ default_trigger: None,
+ color: Color::default(),
+ _p: PhantomData,
+ }
+ }
+}
+
+impl<'a> DeviceBuilder<'a, Unnamed> {
+ /// Sets the firmware node.
+ #[inline]
+ pub fn fwnode(self, fwnode: Option<ARef<FwNode>>) -> Self {
+ Self { fwnode, ..self }
+ }
+
+ /// Sets the device name.
+ #[inline]
+ pub fn devicename(self, devicename: &'a 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<'a, S: DeviceBuilderState> DeviceBuilder<'a, S> {
+ /// Sets the initial brightness value for the led.
+ ///
+ /// The default brightness is 0.
+ /// If [`LedOps::brightness_get`] is implemented, this value will be ignored.
+ #[inline]
+ pub fn initial_brightness(self, brightness: u32) -> Self {
+ Self {
+ initial_brightness: brightness,
+ ..self
+ }
+ }
+
+ /// Set the default led trigger.
+ ///
+ /// This value can be overwritten by the "linux,default-trigger" fwnode property.
+ #[inline]
+ pub fn default_trigger(self, trigger: &'a CStr) -> Self {
+ Self {
+ default_trigger: Some(trigger),
+ ..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<'a> DeviceBuilder<'a, 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: &'a 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 = platform::Device<device::Bound>;
+/// const BLOCKING: bool = false;
+/// const MAX_BRIGHTNESS: u32 = 255;
+///
+/// fn brightness_set(
+/// &self,
+/// _dev: &platform::Device<device::Bound>,
+/// _classdev: &led::Device<Self>,
+/// _brightness: u32
+/// ) -> Result<()> {
+/// // Set the brightness for the led here
+/// Ok(())
+/// }
+/// }
+///
+/// fn register_my_led(
+/// parent: &platform::Device<device::Bound>,
+/// ) -> Result<Pin<KBox<Devres<led::Device<MyLedOps>>>>> {
+/// KBox::pin_init(led::DeviceBuilder::new()
+/// .name(c"white:test")
+/// .build(
+/// parent,
+/// Ok(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<Bound>;
+
+ /// 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,
+ classdev: &Device<Self>,
+ brightness: u32,
+ ) -> Result<()>;
+
+ /// Gets the current brightness level.
+ fn brightness_get(&self, dev: &Self::Bus, classdev: &Device<Self>) -> u32 {
+ let _ = (dev, classdev);
+ build_error!(VTABLE_DEFAULT_ERROR)
+ }
+
+ /// Activates hardware accelerated blinking.
+ ///
+ /// delays are in milliseconds. If both are zero, a sensible default should 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 hardware accelerated
+ /// blinking.
+ ///
+ /// See also [`LedOps::BLOCKING`].
+ fn blink_set(
+ &self,
+ dev: &Self::Bus,
+ classdev: &Device<Self>,
+ delay_on: &mut usize,
+ delay_off: &mut usize,
+ ) -> Result<()> {
+ let _ = (dev, classdev, delay_on, delay_off);
+ build_error!(VTABLE_DEFAULT_ERROR)
+ }
+}
+
+/// Led colors.
+#[derive(Copy, Clone, Debug, Default)]
+#[repr(u32)]
+#[non_exhaustive]
+#[expect(
+ missing_docs,
+ reason = "it shouldn't be necessary to document each color"
+)]
+pub enum Color {
+ #[default]
+ White = bindings::LED_COLOR_ID_WHITE,
+ Red = bindings::LED_COLOR_ID_RED,
+ Green = bindings::LED_COLOR_ID_GREEN,
+ Blue = bindings::LED_COLOR_ID_BLUE,
+ Amber = bindings::LED_COLOR_ID_AMBER,
+ Violet = bindings::LED_COLOR_ID_VIOLET,
+ Yellow = bindings::LED_COLOR_ID_YELLOW,
+ Ir = bindings::LED_COLOR_ID_IR,
+ Multi = bindings::LED_COLOR_ID_MULTI,
+ Rgb = bindings::LED_COLOR_ID_RGB,
+ Purple = bindings::LED_COLOR_ID_PURPLE,
+ Orange = bindings::LED_COLOR_ID_ORANGE,
+ Pink = bindings::LED_COLOR_ID_PINK,
+ Cyan = bindings::LED_COLOR_ID_CYAN,
+ Lime = bindings::LED_COLOR_ID_LIME,
+}
+static_assert!(bindings::LED_COLOR_ID_MAX == 15);
+
+impl Color {
+ /// Name of the color.
+ 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<u32> for Color {
+ type Error = Error;
+
+ fn try_from(value: u32) -> core::result::Result<Self, Self::Error> {
+ if value < bindings::LED_COLOR_ID_MAX {
+ // SAFETY:
+ // - `Color` is represented as `u32`
+ // - the static_assert above guarantees that no additional color has been added
+ // - `value` is guaranteed to be in the color id range
+ Ok(unsafe { transmute::<u32, Color>(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..bd239f186c64
--- /dev/null
+++ b/rust/kernel/led/normal.rs
@@ -0,0 +1,223 @@
+// 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<T: LedOps> {
+ #[pin]
+ ops: T,
+ #[pin]
+ classdev: Opaque<bindings::led_classdev>,
+}
+
+impl<'a, S: DeviceBuilderState> DeviceBuilder<'a, S> {
+ /// Registers a new [`Device`].
+ pub fn build<T: LedOps>(
+ self,
+ parent: &'a T::Bus,
+ ops: impl PinInit<T, Error> + 'a,
+ ) -> impl PinInit<Devres<Device<T>>, Error> + 'a {
+ Devres::new(
+ parent.as_ref(),
+ try_pin_init!(Device {
+ ops <- ops,
+ classdev <- Opaque::try_ffi_init(|ptr: *mut bindings::led_classdev| {
+ // SAFETY: `try_ffi_init` guarantees that `ptr` is valid 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 {
+ brightness_set: (!T::BLOCKING)
+ .then_some(Adapter::<T>::brightness_set_callback),
+ brightness_set_blocking: T::BLOCKING
+ .then_some(Adapter::<T>::brightness_set_blocking_callback),
+ brightness_get: T::HAS_BRIGHTNESS_GET
+ .then_some(Adapter::<T>::brightness_get_callback),
+ blink_set: T::HAS_BLINK_SET.then_some(Adapter::<T>::blink_set_callback),
+ max_brightness: T::MAX_BRIGHTNESS,
+ brightness: self.initial_brightness,
+ default_trigger: self
+ .default_trigger
+ .map_or(core::ptr::null(), CStrExt::as_char_ptr),
+ 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 = 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 pointer 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 count incremented
+
+ Ok::<_, Error>(())
+ }),
+ }),
+ )
+ }
+}
+
+impl<T: LedOps> Device<T> {
+ /// # Safety
+ /// `led_cdev` must be a valid pointer to a `led_classdev` embedded within a
+ /// `led::Device`.
+ unsafe fn from_raw<'a>(led_cdev: *mut bindings::led_classdev) -> &'a Self {
+ // SAFETY: The function's contract guarantees that `led_cdev` points to a `led_classdev`
+ // field embedded within a valid `led::Device`. `container_of!` can therefore
+ // safely calculate the address of the containing struct.
+ unsafe { &*container_of!(Opaque::cast_from(led_cdev), Self, classdev) }
+ }
+
+ fn parent(&self) -> &device::Device<Bound> {
+ // SAFETY: `self.classdev.get()` is guaranteed to be a valid pointer to `led_classdev`.
+ unsafe { device::Device::from_raw((*(*self.classdev.get()).dev).parent) }
+ }
+}
+
+// SAFETY: A `led::Device` can be unregistered from any thread.
+unsafe impl<T: LedOps + Send> Send for Device<T> {}
+
+// SAFETY: `led::Device` can be shared among threads because all methods of `led::Device`
+// are thread safe.
+unsafe impl<T: LedOps + Sync> Sync for Device<T> {}
+
+struct Adapter<T: LedOps> {
+ _p: PhantomData<T>,
+}
+
+impl<T: LedOps> Adapter<T> {
+ /// # Safety
+ /// `led_cdev` must be a valid pointer to a `led_classdev` embedded within 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 = unsafe { Device::<T>::from_raw(led_cdev) };
+ // SAFETY: `classdev.parent()` is guaranteed to be contained in `T::Bus`.
+ let parent = unsafe { T::Bus::from_device(classdev.parent()) };
+
+ let _ = classdev.ops.brightness_set(parent, classdev, brightness);
+ }
+
+ /// # Safety
+ /// `led_cdev` must be a valid pointer to a `led_classdev` embedded within a
+ /// `led::Device`.
+ /// This function is called on setting the brightness of a led immediately.
+ 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 = unsafe { Device::<T>::from_raw(led_cdev) };
+ // SAFETY: `classdev.parent()` is guaranteed to be contained in `T::Bus`.
+ let parent = 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 within 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 = unsafe { Device::<T>::from_raw(led_cdev) };
+ // SAFETY: `classdev.parent()` is guaranteed to be contained in `T::Bus`.
+ let parent = unsafe { T::Bus::from_device(classdev.parent()) };
+
+ classdev.ops.brightness_get(parent, classdev)
+ }
+
+ /// # Safety
+ /// `led_cdev` must be a valid pointer to a `led_classdev` embedded within a
+ /// `led::Device`.
+ /// `delay_on` and `delay_off` must be valid pointers to `usize` and have
+ /// 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 = unsafe { Device::<T>::from_raw(led_cdev) };
+ // SAFETY: `classdev.parent()` is guaranteed to be contained in `T::Bus`.
+ let parent = 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<T: LedOps> PinnedDrop for Device<T> {
+ fn drop(self: Pin<&mut Self>) {
+ let raw = 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 = unsafe { device::Device::from_raw((*raw).dev) };
+
+ let _fwnode = 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(raw) };
+ }
+}
diff --git a/rust/kernel/lib.rs b/rust/kernel/lib.rs
index d93292d47420..d0e30d3733dd 100644
--- a/rust/kernel/lib.rs
+++ b/rust/kernel/lib.rs
@@ -115,6 +115,7 @@
pub mod jump_label;
#[cfg(CONFIG_KUNIT)]
pub mod kunit;
+pub mod led;
pub mod list;
pub mod maple_tree;
pub mod miscdevice;
--
2.52.0
^ permalink raw reply related [flat|nested] 4+ messages in thread* [PATCH RESEND v13 2/3] rust: leds: add Mode trait
2026-04-11 15:07 [PATCH RESEND v13 0/3] rust: leds: add led classdev abstractions Markus Probst
2026-04-11 15:07 ` [PATCH RESEND v13 1/3] rust: leds: add basic " Markus Probst
@ 2026-04-11 15:07 ` Markus Probst
2026-04-11 15:07 ` [PATCH RESEND v13 3/3] rust: leds: add multicolor classdev abstractions Markus Probst
2 siblings, 0 replies; 4+ messages in thread
From: Markus Probst @ 2026-04-11 15:07 UTC (permalink / raw)
To: Lee Jones, Pavel Machek, Greg Kroah-Hartman, Dave Ertman,
Ira Weiny, Leon Romanovsky, Miguel Ojeda, Alex Gaynor, Gary Guo,
Björn Roy Baron, Benno Lossin, Andreas Hindborg, Alice Ryhl,
Trevor Gross, Danilo Krummrich, Rafael J. Wysocki, Bjorn Helgaas,
Krzysztof Wilczyński, Boqun Feng, Boqun Feng
Cc: rust-for-linux, linux-leds, linux-kernel, linux-pci,
Markus Probst
Add the `led::Mode` trait to allow for other types of led class devices
in `led::LedOps`.
Signed-off-by: Markus Probst <markus.probst@posteo.de>
---
rust/kernel/led.rs | 28 ++++++++++++++++++++++++----
rust/kernel/led/normal.rs | 24 ++++++++++++++++--------
2 files changed, 40 insertions(+), 12 deletions(-)
diff --git a/rust/kernel/led.rs b/rust/kernel/led.rs
index 1fba512a804c..5035563d68a3 100644
--- a/rust/kernel/led.rs
+++ b/rust/kernel/led.rs
@@ -35,7 +35,7 @@
mod normal;
-pub use normal::Device;
+pub use normal::{Device, Normal};
/// The name of the led is determined by the driver.
pub enum Named {}
@@ -177,6 +177,7 @@ pub fn name(self, name: &'a CStr) -> Self {
/// #[vtable]
/// impl led::LedOps for MyLedOps {
/// type Bus = platform::Device<device::Bound>;
+/// type Mode = led::Normal;
/// const BLOCKING: bool = false;
/// const MAX_BRIGHTNESS: u32 = 255;
///
@@ -209,6 +210,11 @@ pub trait LedOps: Send + 'static + Sized {
#[allow(private_bounds)]
type Bus: AsBusDevice<Bound>;
+ /// 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;
@@ -221,12 +227,16 @@ pub trait LedOps: Send + 'static + Sized {
fn brightness_set(
&self,
dev: &Self::Bus,
- classdev: &Device<Self>,
+ classdev: &<Self::Mode as Mode>::Device<Self>,
brightness: u32,
) -> Result<()>;
/// Gets the current brightness level.
- fn brightness_get(&self, dev: &Self::Bus, classdev: &Device<Self>) -> u32 {
+ fn brightness_get(
+ &self,
+ dev: &Self::Bus,
+ classdev: &<Self::Mode as Mode>::Device<Self>,
+ ) -> u32 {
let _ = (dev, classdev);
build_error!(VTABLE_DEFAULT_ERROR)
}
@@ -242,7 +252,7 @@ fn brightness_get(&self, dev: &Self::Bus, classdev: &Device<Self>) -> u32 {
fn blink_set(
&self,
dev: &Self::Bus,
- classdev: &Device<Self>,
+ classdev: &<Self::Mode as Mode>::Device<Self>,
delay_on: &mut usize,
delay_off: &mut usize,
) -> Result<()> {
@@ -305,6 +315,16 @@ fn try_from(value: u32) -> core::result::Result<Self, Self::Error> {
}
}
+/// The led mode.
+///
+/// Each led mode has its own led class device type with different capabilities.
+///
+/// See [`Normal`].
+pub trait Mode: private::Sealed {
+ /// The class device for the led mode.
+ type Device<T: LedOps<Mode = Self>>;
+}
+
mod private {
pub trait Sealed {}
}
diff --git a/rust/kernel/led/normal.rs b/rust/kernel/led/normal.rs
index bd239f186c64..dda247145f25 100644
--- a/rust/kernel/led/normal.rs
+++ b/rust/kernel/led/normal.rs
@@ -6,11 +6,19 @@
use super::*;
+/// The led mode for the `struct led_classdev`. Leds with this mode can only have a fixed color.
+pub enum Normal {}
+
+impl Mode for Normal {
+ type Device<T: LedOps<Mode = Self>> = Device<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<T: LedOps> {
+pub struct Device<T: LedOps<Mode = Normal>> {
#[pin]
ops: T,
#[pin]
@@ -19,7 +27,7 @@ pub struct Device<T: LedOps> {
impl<'a, S: DeviceBuilderState> DeviceBuilder<'a, S> {
/// Registers a new [`Device`].
- pub fn build<T: LedOps>(
+ pub fn build<T: LedOps<Mode = Normal>>(
self,
parent: &'a T::Bus,
ops: impl PinInit<T, Error> + 'a,
@@ -89,7 +97,7 @@ pub fn build<T: LedOps>(
}
}
-impl<T: LedOps> Device<T> {
+impl<T: LedOps<Mode = Normal>> Device<T> {
/// # Safety
/// `led_cdev` must be a valid pointer to a `led_classdev` embedded within a
/// `led::Device`.
@@ -107,17 +115,17 @@ fn parent(&self) -> &device::Device<Bound> {
}
// SAFETY: A `led::Device` can be unregistered from any thread.
-unsafe impl<T: LedOps + Send> Send for Device<T> {}
+unsafe impl<T: LedOps<Mode = Normal> + Send> Send for Device<T> {}
// SAFETY: `led::Device` can be shared among threads because all methods of `led::Device`
// are thread safe.
-unsafe impl<T: LedOps + Sync> Sync for Device<T> {}
+unsafe impl<T: LedOps<Mode = Normal> + Sync> Sync for Device<T> {}
-struct Adapter<T: LedOps> {
+struct Adapter<T: LedOps<Mode = Normal>> {
_p: PhantomData<T>,
}
-impl<T: LedOps> Adapter<T> {
+impl<T: LedOps<Mode = Normal>> Adapter<T> {
/// # Safety
/// `led_cdev` must be a valid pointer to a `led_classdev` embedded within a
/// `led::Device`.
@@ -203,7 +211,7 @@ impl<T: LedOps> Adapter<T> {
}
#[pinned_drop]
-impl<T: LedOps> PinnedDrop for Device<T> {
+impl<T: LedOps<Mode = Normal>> PinnedDrop for Device<T> {
fn drop(self: Pin<&mut Self>) {
let raw = self.classdev.get();
// SAFETY: The existence of `self` guarantees that `self.classdev.get()` is a pointer to a
--
2.52.0
^ permalink raw reply related [flat|nested] 4+ messages in thread* [PATCH RESEND v13 3/3] rust: leds: add multicolor classdev abstractions
2026-04-11 15:07 [PATCH RESEND v13 0/3] rust: leds: add led classdev abstractions Markus Probst
2026-04-11 15:07 ` [PATCH RESEND v13 1/3] rust: leds: add basic " Markus Probst
2026-04-11 15:07 ` [PATCH RESEND v13 2/3] rust: leds: add Mode trait Markus Probst
@ 2026-04-11 15:07 ` Markus Probst
2 siblings, 0 replies; 4+ messages in thread
From: Markus Probst @ 2026-04-11 15:07 UTC (permalink / raw)
To: Lee Jones, Pavel Machek, Greg Kroah-Hartman, Dave Ertman,
Ira Weiny, Leon Romanovsky, Miguel Ojeda, Alex Gaynor, Gary Guo,
Björn Roy Baron, Benno Lossin, Andreas Hindborg, Alice Ryhl,
Trevor Gross, Danilo Krummrich, Rafael J. Wysocki, Bjorn Helgaas,
Krzysztof Wilczyński, Boqun Feng, Boqun Feng
Cc: rust-for-linux, linux-leds, linux-kernel, linux-pci,
Markus Probst
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 <markus.probst@posteo.de>
---
rust/bindings/bindings_helper.h | 1 +
rust/kernel/led.rs | 30 +++-
rust/kernel/led/multicolor.rs | 387 ++++++++++++++++++++++++++++++++++++++++
3 files changed, 417 insertions(+), 1 deletion(-)
diff --git a/rust/bindings/bindings_helper.h b/rust/bindings/bindings_helper.h
index 083cc44aa952..3171e3e6351c 100644
--- a/rust/bindings/bindings_helper.h
+++ b/rust/bindings/bindings_helper.h
@@ -63,6 +63,7 @@
#include <linux/ioport.h>
#include <linux/jiffies.h>
#include <linux/jump_label.h>
+#include <linux/led-class-multicolor.h>
#include <linux/mdio.h>
#include <linux/mm.h>
#include <linux/miscdevice.h>
diff --git a/rust/kernel/led.rs b/rust/kernel/led.rs
index 5035563d68a3..a862d88cab29 100644
--- a/rust/kernel/led.rs
+++ b/rust/kernel/led.rs
@@ -33,8 +33,12 @@
}, //
};
+#[cfg(CONFIG_LEDS_CLASS_MULTICOLOR)]
+mod multicolor;
mod normal;
+#[cfg(CONFIG_LEDS_CLASS_MULTICOLOR)]
+pub use multicolor::{MultiColor, MultiColorDevice, MultiColorSubLed};
pub use normal::{Device, Normal};
/// The name of the led is determined by the driver.
@@ -279,7 +283,24 @@ pub enum Color {
Violet = bindings::LED_COLOR_ID_VIOLET,
Yellow = bindings::LED_COLOR_ID_YELLOW,
Ir = bindings::LED_COLOR_ID_IR,
+ #[cfg_attr(
+ CONFIG_LEDS_CLASS_MULTICOLOR,
+ doc = "Use this color for a [`MultiColor`] led."
+ )]
+ #[cfg_attr(
+ not(CONFIG_LEDS_CLASS_MULTICOLOR),
+ doc = "Use this color for a `MultiColor` led."
+ )]
+ /// If the led supports RGB, use [`Color::Rgb`] instead.
Multi = bindings::LED_COLOR_ID_MULTI,
+ #[cfg_attr(
+ CONFIG_LEDS_CLASS_MULTICOLOR,
+ doc = "Use this color for a [`MultiColor`] led with rgb support."
+ )]
+ #[cfg_attr(
+ not(CONFIG_LEDS_CLASS_MULTICOLOR),
+ doc = "Use this color for a `MultiColor` led with rgb support."
+ )]
Rgb = bindings::LED_COLOR_ID_RGB,
Purple = bindings::LED_COLOR_ID_PURPLE,
Orange = bindings::LED_COLOR_ID_ORANGE,
@@ -319,7 +340,14 @@ fn try_from(value: u32) -> core::result::Result<Self, Self::Error> {
///
/// Each led mode has its own led class device type with different capabilities.
///
-/// See [`Normal`].
+#[cfg_attr(
+ CONFIG_LEDS_CLASS_MULTICOLOR,
+ doc = "See [`Normal`] and [`MultiColor`]."
+)]
+#[cfg_attr(
+ not(CONFIG_LEDS_CLASS_MULTICOLOR),
+ doc = "See [`Normal`] and `MultiColor`."
+)]
pub trait Mode: private::Sealed {
/// The class device for the led mode.
type Device<T: LedOps<Mode = Self>>;
diff --git a/rust/kernel/led/multicolor.rs b/rust/kernel/led/multicolor.rs
new file mode 100644
index 000000000000..726fdaf068cb
--- /dev/null
+++ b/rust/kernel/led/multicolor.rs
@@ -0,0 +1,387 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Led mode for the `struct led_classdev_mc`.
+//!
+//! C header: [`include/linux/led-class-multicolor.h`](srctree/include/linux/led-class-multicolor.h)
+
+use crate::alloc::KVec;
+
+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<T: LedOps<Mode = Self>> = MultiColorDevice<T>;
+}
+impl private::Sealed for MultiColor {}
+
+/// The multicolor sub led info representation.
+///
+/// This structure represents the Rust abstraction for a C `struct mc_subled`.
+#[repr(C)]
+#[derive(Copy, Clone, Debug)]
+#[non_exhaustive]
+pub struct MultiColorSubLed {
+ /// the color of the sub led
+ pub color: Color,
+ /// the brightness of the sub led.
+ ///
+ /// The value will be automatically calculated.
+ /// See `MultiColor::pre_brightness_set`.
+ pub brightness: u32,
+ /// the intensity of the sub led.
+ pub intensity: u32,
+ /// arbitrary data for the driver to store.
+ pub channel: u32,
+}
+
+// We directly pass a reference to the `subled_info` field in `led_classdev_mc` to the driver via
+// `Device::subleds()`.
+// We need safeguards to ensure `MultiColorSubLed` and `mc_subled` stay identical.
+const _: () = {
+ use core::mem::offset_of;
+
+ const fn assert_same_type<T>(_: &T, _: &T) {}
+
+ let rust_zeroed = MultiColorSubLed {
+ color: Color::White,
+ brightness: 0,
+ intensity: 0,
+ channel: 0,
+ };
+ let c_zeroed = bindings::mc_subled {
+ color_index: 0,
+ brightness: 0,
+ intensity: 0,
+ channel: 0,
+ };
+
+ assert!(offset_of!(MultiColorSubLed, color) == offset_of!(bindings::mc_subled, color_index));
+ assert_same_type(&0u32, &c_zeroed.color_index);
+
+ assert!(
+ offset_of!(MultiColorSubLed, brightness) == offset_of!(bindings::mc_subled, brightness)
+ );
+ assert_same_type(&rust_zeroed.brightness, &c_zeroed.brightness);
+
+ assert!(offset_of!(MultiColorSubLed, intensity) == offset_of!(bindings::mc_subled, intensity));
+ assert_same_type(&rust_zeroed.intensity, &c_zeroed.intensity);
+
+ assert!(offset_of!(MultiColorSubLed, channel) == offset_of!(bindings::mc_subled, channel));
+ assert_same_type(&rust_zeroed.channel, &c_zeroed.channel);
+
+ assert!(size_of::<MultiColorSubLed>() == size_of::<bindings::mc_subled>());
+};
+
+impl MultiColorSubLed {
+ /// Create a new multicolor sub led info.
+ pub const fn new(color: Color) -> Self {
+ Self {
+ color,
+ brightness: 0,
+ intensity: 0,
+ channel: 0,
+ }
+ }
+
+ /// Set arbitrary data for the driver.
+ pub const fn channel(mut self, channel: u32) -> Self {
+ self.channel = channel;
+ self
+ }
+
+ /// Set the initial intensity of the subled.
+ pub const fn initial_intensity(mut self, intensity: u32) -> Self {
+ self.intensity = intensity;
+ self
+ }
+}
+
+/// The multicolor led class device representation.
+///
+/// This structure represents the Rust abstraction for a multicolor led class device.
+#[pin_data(PinnedDrop)]
+pub struct MultiColorDevice<T: LedOps<Mode = MultiColor>> {
+ #[pin]
+ ops: T,
+ #[pin]
+ classdev: Opaque<bindings::led_classdev_mc>,
+}
+
+impl<'a, S: DeviceBuilderState> DeviceBuilder<'a, S> {
+ /// Registers a new [`MulticolorDevice`].
+ pub fn build_multicolor<T: LedOps<Mode = MultiColor>>(
+ self,
+ parent: &'a T::Bus,
+ ops: impl PinInit<T, Error> + 'a,
+ subleds: &'a [MultiColorSubLed],
+ ) -> impl PinInit<Devres<MultiColorDevice<T>>, Error> + 'a {
+ Devres::new(
+ parent.as_ref(),
+ try_pin_init!(MultiColorDevice {
+ ops <- ops,
+ classdev <- Opaque::try_ffi_init(|ptr: *mut bindings::led_classdev_mc| {
+ let mut used = 0;
+ if subleds.iter().any(|subled| {
+ let bit = 1 << (subled.color as u32);
+ if (used & bit) != 0 {
+ true
+ } else {
+ used |= bit;
+ false
+ }
+ }) {
+ dev_err!(parent.as_ref(), "duplicate color in multicolor led\n");
+ return Err(EINVAL);
+ }
+ let mut subleds_vec = KVec::new();
+ subleds_vec.extend_from_slice(subleds, GFP_KERNEL)?;
+ let (subled_info, num_colors, capacity) = subleds_vec.into_raw_parts();
+ debug_assert_eq!(num_colors, capacity);
+
+ // SAFETY: `try_ffi_init` guarantees that `ptr` is valid for 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::<T>::brightness_set_callback),
+ brightness_set_blocking: T::BLOCKING
+ .then_some(Adapter::<T>::brightness_set_blocking_callback),
+ brightness_get: T::HAS_BRIGHTNESS_GET
+ .then_some(Adapter::<T>::brightness_get_callback),
+ blink_set: T::HAS_BLINK_SET
+ .then_some(Adapter::<T>::blink_set_callback),
+ max_brightness: T::MAX_BRIGHTNESS,
+ brightness: self.initial_brightness,
+ default_trigger: self
+ .default_trigger
+ .map_or(core::ptr::null(), CStrExt::as_char_ptr),
+ color: self.color as u32,
+ name: self.name.map_or(core::ptr::null(), CStrExt::as_char_ptr),
+ ..bindings::led_classdev::default()
+ },
+ num_colors: u32::try_from(num_colors)?,
+ // CAST: The safeguards in the const block ensure that
+ // `MultiColorSubLed` has an identical layout to `mc_subled`.
+ subled_info: subled_info.cast::<bindings::mc_subled>(),
+ })
+ };
+
+ let mut init_data = 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 pointer 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()
+ },
+ )
+ })
+ .inspect_err(|_err| {
+ // SAFETY: `subled_info` is guaranteed to be a valid array pointer to
+ // `mc_subled` with the length and capacity of `num_colors`.
+ drop(unsafe { KVec::from_raw_parts(subled_info, num_colors, num_colors) });
+ })?;
+
+ core::mem::forget(self.fwnode); // keep the reference count incremented
+
+ Ok::<_, Error>(())
+ }),
+ }),
+ )
+ }
+}
+
+impl<T: LedOps<Mode = MultiColor>> MultiColorDevice<T> {
+ /// # Safety
+ /// `led_cdev` must be a valid pointer to a `led_classdev` embedded within a
+ /// `led::MultiColorDevice`.
+ unsafe fn from_raw<'a>(led_cdev: *mut bindings::led_classdev) -> &'a Self {
+ // SAFETY: The function's contract guarantees that `led_cdev` points to a `led_classdev`
+ // field embedded within a valid `led::MultiColorDevice`. `container_of!` can therefore
+ // safely calculate the address of the containing struct.
+ let led_mc_cdev = unsafe { container_of!(led_cdev, bindings::led_classdev_mc, led_cdev) };
+
+ // SAFETY: It is guaranteed that `led_mc_cdev` points to a `led_classdev_mc`
+ // field embedded within a valid `led::MultiColorDevice`. `container_of!` can therefore
+ // safely calculate the address of the containing struct.
+ unsafe { &*container_of!(Opaque::cast_from(led_mc_cdev), Self, classdev) }
+ }
+
+ fn parent(&self) -> &device::Device<Bound> {
+ // SAFETY: `self.classdev.get()` is guaranteed to be a valid pointer to `led_classdev_mc`.
+ unsafe { device::Device::from_raw((*(*self.classdev.get()).led_cdev.dev).parent) }
+ }
+
+ /// Returns the subleds passed to [`Device::new_multicolor`].
+ 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 = 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 `MultiColorSubLed` has an identical
+ // layout to `mc_subled`.
+ unsafe {
+ core::slice::from_raw_parts(
+ raw.subled_info.cast::<MultiColorSubLed>(),
+ raw.num_colors as usize,
+ )
+ }
+ }
+}
+
+// SAFETY: A `led::MultiColorDevice` can be unregistered from any thread.
+unsafe impl<T: LedOps<Mode = MultiColor> + Send> Send for MultiColorDevice<T> {}
+
+// SAFETY: `led::MultiColorDevice` can be shared among threads because all methods of `led::Device`
+// are thread safe.
+unsafe impl<T: LedOps<Mode = MultiColor> + Sync> Sync for MultiColorDevice<T> {}
+
+struct Adapter<T: LedOps<Mode = MultiColor>> {
+ _p: PhantomData<T>,
+}
+
+impl<T: LedOps<Mode = MultiColor>> Adapter<T> {
+ /// # Safety
+ /// `led_cdev` must be a valid pointer to a `led_classdev` embedded within 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 = unsafe { MultiColorDevice::<T>::from_raw(led_cdev) };
+ // SAFETY: `classdev.parent()` is guaranteed to be contained in `T::Bus`.
+ let parent = 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 _ = classdev.ops.brightness_set(parent, classdev, brightness);
+ }
+
+ /// # Safety
+ /// `led_cdev` must be a valid pointer to a `led_classdev` embedded within a
+ /// `led::MultiColorDevice`.
+ /// This function is called on setting the brightness of a led immediately.
+ 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 = unsafe { MultiColorDevice::<T>::from_raw(led_cdev) };
+ // SAFETY: `classdev.parent()` is guaranteed to be contained in `T::Bus`.
+ let parent = 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) };
+
+ classdev.ops.brightness_set(parent, classdev, brightness)?;
+ Ok(0)
+ })
+ }
+
+ /// # Safety
+ /// `led_cdev` must be a valid pointer to a `led_classdev` embedded within 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 = unsafe { MultiColorDevice::<T>::from_raw(led_cdev) };
+ // SAFETY: `classdev.parent()` is guaranteed to be contained in `T::Bus`.
+ let parent = unsafe { T::Bus::from_device(classdev.parent()) };
+
+ classdev.ops.brightness_get(parent, classdev)
+ }
+
+ /// # Safety
+ /// `led_cdev` must be a valid pointer to a `led_classdev` embedded within a
+ /// `led::MultiColorDevice`.
+ /// `delay_on` and `delay_off` must be valid pointers to `usize` and have
+ /// 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 = unsafe { MultiColorDevice::<T>::from_raw(led_cdev) };
+ // SAFETY: `classdev.parent()` is guaranteed to be contained in `T::Bus`.
+ let parent = 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<T: LedOps<Mode = MultiColor>> PinnedDrop for MultiColorDevice<T> {
+ fn drop(self: Pin<&mut Self>) {
+ let raw = 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 = unsafe { device::Device::from_raw((*raw).led_cdev.dev) };
+
+ let _fwnode = 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_multicolor_register_ext`.
+ unsafe { bindings::led_classdev_multicolor_unregister(raw) };
+
+ // SAFETY: `raw` is guaranteed to be a valid pointer to `led_classdev_mc`.
+ let led_cdev = unsafe { &*raw };
+
+ // SAFETY: `subled_info` is guaranteed to be a valid array pointer to `mc_subled` with the
+ // length and capacity of `led_cdev.num_colors`. See `led::MulticolorDevice::new`.
+ drop(unsafe {
+ KVec::from_raw_parts(
+ led_cdev.subled_info,
+ led_cdev.num_colors as usize,
+ led_cdev.num_colors as usize,
+ )
+ });
+ }
+}
--
2.52.0
^ permalink raw reply related [flat|nested] 4+ messages in thread