* [PATCH v25 1/4] rust: leds: add basic led classdev abstractions
2026-09-13 16:15 [PATCH v25 0/4] rust: leds: add led classdev abstractions Markus Probst
@ 2026-09-13 16:15 ` Markus Probst
2026-09-13 16:15 ` [PATCH v25 2/4] rust: leds: add Mode trait Markus Probst
` (2 subsequent siblings)
3 siblings, 0 replies; 6+ messages in thread
From: Markus Probst @ 2026-09-13 16:15 UTC (permalink / raw)
To: Lee Jones, Pavel Machek, Greg Kroah-Hartman, Dave Ertman,
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, Daniel Almeida,
Tamir Duberstein, Alexandre Courbot, Onur Özkan, Ira Weiny,
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>
---
rust/kernel/led.rs | 265 ++++++++++++++++++++++++++++++++++++++++++++++
rust/kernel/led/normal.rs | 222 ++++++++++++++++++++++++++++++++++++++
rust/kernel/lib.rs | 1 +
3 files changed, 488 insertions(+)
diff --git a/rust/kernel/led.rs b/rust/kernel/led.rs
new file mode 100644
index 000000000000..deda8cc548a8
--- /dev/null
+++ b/rust/kernel/led.rs
@@ -0,0 +1,265 @@
+// 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,
+ 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<ARef<FwNode>>,
+ name: Option<&'init CStr>,
+ devicename: Option<&'init CStr>,
+ devname_mandatory: bool,
+ initial_brightness: u32,
+ 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,
+ color: Color::default(),
+ _p: PhantomData,
+ }
+ }
+}
+
+impl<'init> DeviceBuilder<'init, 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: &'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 ignored.
+ #[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::{
+/// led,
+/// macros::vtable,
+/// prelude::*, //
+/// };
+///
+/// struct MyLedOps;
+///
+///
+/// #[vtable]
+/// impl led::LedOps for MyLedOps {
+/// const BLOCKING: bool = false;
+/// const MAX_BRIGHTNESS: u32 = 255;
+///
+/// fn brightness_set<'bound>(
+/// self: &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 {
+ /// 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: &Device<'bound, Self>, brightness: u32) -> Result<()>;
+
+ /// Gets the current brightness level.
+ fn brightness_get<'bound>(self: &Device<'bound, Self>) -> Result<u32> {
+ 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<'bound>(
+ self: &Device<'bound, Self>,
+ delay_on: &mut usize,
+ delay_off: &mut usize,
+ ) -> Result<()> {
+ let _ = (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 = "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
+ #[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<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..a22c29cfd262
--- /dev/null
+++ b/rust/kernel/led/normal.rs
@@ -0,0 +1,222 @@
+// 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 core::ops::Deref;
+
+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: 'bound = ()> {
+ #[pin]
+ ops: T,
+ #[pin]
+ classdev: Opaque<bindings::led_classdev>,
+ _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 device::Device<Bound>,
+ ops: impl PinInit<T, Error> + 'init,
+ ) -> impl PinInit<Device<'bound, T>, Error> + 'init {
+ const_assert!(T::MAX_BRIGHTNESS <= i32::MAX.unsigned_abs() || !T::HAS_BRIGHTNESS_GET);
+
+ 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,
+ 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_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_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>(())
+ }),
+ _p: PhantomData,
+ })
+ }
+}
+
+impl<'bound, T: 'bound> Device<'bound, T> {
+ /// # Safety
+ /// `led_cdev` must be a valid pointer to a `led_classdev` embedded within a
+ /// `led::Device`.
+ #[inline]
+ 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) }
+ }
+}
+
+impl<'bound, T: LedOps + 'bound> Deref for Device<'bound, T> {
+ type Target = T;
+
+ fn deref(&self) -> &Self::Target {
+ &self.ops
+ }
+}
+
+// SAFETY: A `led::Device` can be unregistered from any thread.
+unsafe impl<'bound, T: 'bound + Send> Send for Device<'bound, T> {}
+
+// SAFETY: `led::Device` can be shared among threads because all methods of `led::Device`
+// are thread safe.
+unsafe impl<'bound, T: 'bound + Sync> Sync for Device<'bound, 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) };
+
+ let _ = classdev.brightness_set(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) };
+
+ classdev.brightness_set(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) };
+
+ // CAST: Resulting value will be casted back to i32 in the led subsystem.
+ from_result(|| {
+ classdev
+ .brightness_get()
+ .inspect(|val| debug_assert!(*val <= 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 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) };
+
+ classdev.blink_set(
+ // 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: 'bound> PinnedDrop for Device<'bound, 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::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 4d5c96ddc49c..748788ad131b 100644
--- a/rust/kernel/lib.rs
+++ b/rust/kernel/lib.rs
@@ -96,6 +96,7 @@
pub mod jump_label;
#[cfg(CONFIG_KUNIT)]
pub mod kunit;
+pub mod led;
pub mod list;
pub mod maple_tree;
pub mod miscdevice;
--
2.55.0
^ permalink raw reply related [flat|nested] 6+ messages in thread* [PATCH v25 2/4] rust: leds: add Mode trait
2026-09-13 16:15 [PATCH v25 0/4] rust: leds: add led classdev abstractions Markus Probst
2026-09-13 16:15 ` [PATCH v25 1/4] rust: leds: add basic " Markus Probst
@ 2026-09-13 16:15 ` Markus Probst
2026-09-13 16:24 ` Markus Probst
2026-09-13 16:15 ` [PATCH v25 3/4] rust: leds: add multicolor classdev abstractions Markus Probst
2026-09-13 16:15 ` [PATCH v25 4/4] MAINTAINERS: rust: leds: Add rust abstraction entry Markus Probst
3 siblings, 1 reply; 6+ messages in thread
From: Markus Probst @ 2026-09-13 16:15 UTC (permalink / raw)
To: Lee Jones, Pavel Machek, Greg Kroah-Hartman, Dave Ertman,
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, Daniel Almeida,
Tamir Duberstein, Alexandre Courbot, Onur Özkan, Ira Weiny,
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 | 37 ++++++++++++++++++++++++++-----------
rust/kernel/led/normal.rs | 12 ++++++++++--
2 files changed, 36 insertions(+), 13 deletions(-)
diff --git a/rust/kernel/led.rs b/rust/kernel/led.rs
index deda8cc548a8..7cd8f0504649 100644
--- a/rust/kernel/led.rs
+++ b/rust/kernel/led.rs
@@ -4,11 +4,7 @@
//!
//! C header: [`include/linux/leds.h`](srctree/include/linux/leds.h)
-use core::{
- marker::PhantomData,
- mem::transmute,
- ptr::NonNull, //
-};
+use core::{marker::PhantomData, mem::transmute, ops::Deref, ptr::NonNull};
use crate::{
container_of,
@@ -31,7 +27,10 @@
mod normal;
-pub use normal::Device;
+pub use normal::{
+ Device,
+ Normal, //
+};
/// The name of the led is determined by the driver.
pub enum Named {}
@@ -156,6 +155,7 @@ pub fn name(self, name: &'init CStr) -> Self {
///
/// #[vtable]
/// impl led::LedOps for MyLedOps {
+/// type Mode = led::Normal;
/// const BLOCKING: bool = false;
/// const MAX_BRIGHTNESS: u32 = 255;
///
@@ -176,16 +176,21 @@ pub trait LedOps: Send + Sync + Sized {
const BLOCKING: bool;
/// The max brightness level.
const MAX_BRIGHTNESS: u32;
-
/// Sets the brightness level.
///
/// See also [`LedOps::BLOCKING`].
- fn brightness_set<'bound>(self: &Device<'bound, Self>, brightness: u32) -> Result<()>;
-
+ fn brightness_set<'bound>(
+ self: &<Self::Mode as Mode>::Device<'bound, Self>,
+ brightness: u32,
+ ) -> Result<()>;
/// Gets the current brightness level.
- fn brightness_get<'bound>(self: &Device<'bound, Self>) -> Result<u32> {
+ fn brightness_get<'bound>(self: &<Self::Mode as Mode>::Device<'bound, Self>) -> Result<u32> {
build_error!(VTABLE_DEFAULT_ERROR)
}
+ /// The led mode to use.
+ ///
+ /// See [`Mode`].
+ type Mode: Mode;
/// Activates hardware accelerated blinking.
///
@@ -196,7 +201,7 @@ fn brightness_get<'bound>(self: &Device<'bound, Self>) -> Result<u32> {
///
/// See also [`LedOps::BLOCKING`].
fn blink_set<'bound>(
- self: &Device<'bound, Self>,
+ self: &<Self::Mode as Mode>::Device<'bound, Self>,
delay_on: &mut usize,
delay_off: &mut usize,
) -> Result<()> {
@@ -260,6 +265,16 @@ 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<'bound, T: LedOps<Mode = Self> + 'bound>: Deref<Target = T>;
+}
+
mod private {
pub trait Sealed {}
}
diff --git a/rust/kernel/led/normal.rs b/rust/kernel/led/normal.rs
index a22c29cfd262..992353319522 100644
--- a/rust/kernel/led/normal.rs
+++ b/rust/kernel/led/normal.rs
@@ -8,6 +8,14 @@
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<'bound, T: LedOps<Mode = Self> + 'bound> = Device<'bound, T>;
+}
+impl private::Sealed for Normal {}
+
/// The led class device representation.
///
/// This structure represents the Rust abstraction for a led class device.
@@ -22,7 +30,7 @@ pub struct Device<'bound, T: 'bound = ()> {
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<Mode = Normal> + 'bound>(
self,
parent: &'bound device::Device<Bound>,
ops: impl PinInit<T, Error> + 'init,
@@ -120,7 +128,7 @@ struct Adapter<T: LedOps> {
_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`.
--
2.55.0
^ permalink raw reply related [flat|nested] 6+ messages in thread* Re: [PATCH v25 2/4] rust: leds: add Mode trait
2026-09-13 16:15 ` [PATCH v25 2/4] rust: leds: add Mode trait Markus Probst
@ 2026-09-13 16:24 ` Markus Probst
0 siblings, 0 replies; 6+ messages in thread
From: Markus Probst @ 2026-09-13 16:24 UTC (permalink / raw)
To: Lee Jones, Pavel Machek, Greg Kroah-Hartman, Dave Ertman,
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, Daniel Almeida,
Tamir Duberstein, Alexandre Courbot, Onur Özkan, Ira Weiny
Cc: rust-for-linux, linux-leds, linux-kernel, linux-pci
[-- Attachment #1: Type: text/plain, Size: 896 bytes --]
On Sun, 2026-09-13 at 16:15 +0000, Markus Probst wrote:
> 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 | 37 ++++++++++++++++++++++++++-----------
> rust/kernel/led/normal.rs | 12 ++++++++++--
> 2 files changed, 36 insertions(+), 13 deletions(-)
>
> diff --git a/rust/kernel/led.rs b/rust/kernel/led.rs
> index deda8cc548a8..7cd8f0504649 100644
> --- a/rust/kernel/led.rs
> +++ b/rust/kernel/led.rs
> @@ -4,11 +4,7 @@
> //!
> //! C header: [`include/linux/leds.h`](srctree/include/linux/leds.h)
>
> -use core::{
> - marker::PhantomData,
> - mem::transmute,
> - ptr::NonNull, //
> -};
> +use core::{marker::PhantomData, mem::transmute, ops::Deref, ptr::NonNull};
supposed to be vertical.
Thanks
- Markus Probst
[-- Attachment #2: This is a digitally signed message part --]
[-- Type: application/pgp-signature, Size: 870 bytes --]
^ permalink raw reply [flat|nested] 6+ messages in thread
* [PATCH v25 3/4] rust: leds: add multicolor classdev abstractions
2026-09-13 16:15 [PATCH v25 0/4] rust: leds: add led classdev abstractions Markus Probst
2026-09-13 16:15 ` [PATCH v25 1/4] rust: leds: add basic " Markus Probst
2026-09-13 16:15 ` [PATCH v25 2/4] rust: leds: add Mode trait Markus Probst
@ 2026-09-13 16:15 ` Markus Probst
2026-09-13 16:15 ` [PATCH v25 4/4] MAINTAINERS: rust: leds: Add rust abstraction entry Markus Probst
3 siblings, 0 replies; 6+ messages in thread
From: Markus Probst @ 2026-09-13 16:15 UTC (permalink / raw)
To: Lee Jones, Pavel Machek, Greg Kroah-Hartman, Dave Ertman,
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, Daniel Almeida,
Tamir Duberstein, Alexandre Courbot, Onur Özkan, Ira Weiny,
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 | 34 ++-
rust/kernel/led/multicolor.rs | 445 ++++++++++++++++++++++++++++++++++++++++
3 files changed, 479 insertions(+), 1 deletion(-)
diff --git a/rust/bindings/bindings_helper.h b/rust/bindings/bindings_helper.h
index 4b31aa7f432f..81a03985322a 100644
--- a/rust/bindings/bindings_helper.h
+++ b/rust/bindings/bindings_helper.h
@@ -69,6 +69,7 @@
#include <linux/iosys-map.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 7cd8f0504649..b25a6f992a62 100644
--- a/rust/kernel/led.rs
+++ b/rust/kernel/led.rs
@@ -25,8 +25,16 @@
types::Opaque, //
};
+#[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, //
@@ -228,7 +236,24 @@ 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,
@@ -269,7 +294,14 @@ 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<'bound, T: LedOps<Mode = Self> + 'bound>: Deref<Target = T>;
diff --git a/rust/kernel/led/multicolor.rs b/rust/kernel/led/multicolor.rs
new file mode 100644
index 000000000000..309487bdf38a
--- /dev/null
+++ b/rust/kernel/led/multicolor.rs
@@ -0,0 +1,445 @@
+// 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 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<Mode = Self> + 'bound> = MultiColorDevice<'bound, 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(Debug)]
+#[non_exhaustive]
+pub struct MultiColorSubLed {
+ /// The color of the sub led
+ pub color: Color,
+ brightness: UnsafeCell<u32>,
+ intensity: UnsafeCell<u32>,
+ /// The maximum supported intensity value.
+ ///
+ /// If None the maximum intensity equals to [`LedOps::MAX_BRIGHTNESS`].
+ pub max_intensity: Option<NonZero<u32>>,
+ /// 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_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: UnsafeCell::new(0),
+ intensity: UnsafeCell::new(0),
+ max_intensity: None,
+ channel: 0,
+ };
+ let c_zeroed = bindings::mc_subled {
+ color_index: 0,
+ brightness: 0,
+ intensity: 0,
+ max_intensity: 0,
+ channel: 0,
+ };
+
+ assert!(offset_of!(MultiColorSubLed, color) == offset_of!(bindings::mc_subled, color_index));
+ assert!(
+ offset_of!(MultiColorSubLed, brightness) == offset_of!(bindings::mc_subled, brightness)
+ );
+ assert!(offset_of!(MultiColorSubLed, intensity) == offset_of!(bindings::mc_subled, intensity));
+ assert!(
+ offset_of!(MultiColorSubLed, max_intensity)
+ == offset_of!(bindings::mc_subled, max_intensity)
+ );
+ assert!(offset_of!(MultiColorSubLed, channel) == offset_of!(bindings::mc_subled, channel));
+
+ assert_same_type(&0u32, &c_zeroed.color_index);
+ assert_same_type(&rust_zeroed.brightness.into_inner(), &c_zeroed.brightness);
+ assert_same_type(&rust_zeroed.intensity.into_inner(), &c_zeroed.intensity);
+ assert!(size_of_val(&rust_zeroed.max_intensity) == size_of_val(&c_zeroed.max_intensity));
+ 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.
+ #[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 = channel;
+ self
+ }
+
+ /// Set the initial intensity of the subled.
+ #[inline]
+ pub const fn initial_intensity(mut self, intensity: u32) -> Self {
+ self.intensity = UnsafeCell::new(intensity);
+ self
+ }
+
+ /// Set the maximum supported intensity of the subled.
+ #[inline]
+ pub const fn max_intensity(mut self, max_intensity: NonZero<u32>) -> Self {
+ self.max_intensity = 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.intensity`,
+ // 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.brightness`,
+ // 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 class device.
+#[pin_data(PinnedDrop)]
+pub struct MultiColorDevice<'bound, T: 'bound = ()> {
+ #[pin]
+ ops: T,
+ #[pin]
+ classdev: Opaque<bindings::led_classdev_mc>,
+ _p: PhantomData<&'bound ()>,
+}
+
+impl<'init, S: DeviceBuilderState> DeviceBuilder<'init, S> {
+ /// Registers a new [`MulticolorDevice`].
+ pub fn build_multicolor<'bound: 'init, T: LedOps<Mode = MultiColor> + 'bound>(
+ self,
+ parent: &'bound device::Device<Bound>,
+ ops: impl PinInit<T, Error> + 'init,
+ subleds: &'init [MultiColorSubLed],
+ ) -> impl PinInit<MultiColorDevice<'bound, T>, Error> + 'init {
+ const_assert!(T::MAX_BRIGHTNESS <= i32::MAX.unsigned_abs() || !T::HAS_BRIGHTNESS_GET);
+
+ try_pin_init!(MultiColorDevice {
+ ops <- ops,
+ classdev <- Opaque::try_ffi_init(|ptr: *mut bindings::led_classdev_mc| {
+ let mut colors = [false; bindings::LED_COLOR_ID_MAX as usize];
+ for subled in subleds {
+ if colors[subled.color as usize] {
+ dev_err!(parent.as_ref(), "duplicate color in multicolor led\n");
+ return Err(EINVAL);
+ }
+ colors[subled.color as usize] = true;
+ }
+ let subleds_box = KBox::pin_slice(
+ |index| Ok::<_, Error>(subleds[index].clone()),
+ subleds.len(),
+ GFP_KERNEL,
+ )?;
+ let subleds_box_raw = KBox::into_raw(Pin::into_inner(subleds_box));
+
+ let subled_guard = ScopeGuard::new(|| {
+ // SAFETY: `subleds_box_raw` is guaranteed to be a valid pointer to
+ // `[MultiColorSubLed]`.
+ drop(unsafe { <KBox<[MultiColorSubLed]>>::from_raw(subleds_box_raw) });
+ });
+
+ // 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,
+ 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(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::<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()
+ },
+ )
+ })?;
+
+ subled_guard.dismiss();
+
+ core::mem::forget(self.fwnode); // keep the reference count incremented
+
+ Ok::<_, Error>(())
+ }),
+ _p: PhantomData,
+ })
+ }
+}
+
+impl<'bound, T: 'bound> MultiColorDevice<'bound, T> {
+ /// # Safety
+ /// `led_cdev` must be a valid pointer to a `led_classdev` embedded within a
+ /// `led::MultiColorDevice`.
+ #[inline]
+ 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) }
+ }
+
+ /// 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 = 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>(),
+ // CAST: It is guaranteed that `num_colors` fits into an `usize`.
+ raw.num_colors as usize,
+ )
+ }
+ }
+}
+
+impl<'bound, T: LedOps + 'bound> Deref for MultiColorDevice<'bound, T> {
+ type Target = T;
+
+ fn deref(&self) -> &Self::Target {
+ &self.ops
+ }
+}
+
+// SAFETY: A `led::MultiColorDevice` can be unregistered from any thread.
+unsafe impl<'bound, T: '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: 'bound + Sync> Sync for MultiColorDevice<'bound, 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.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.brightness_set(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.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.brightness_set(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) };
+
+ // CAST: Resulting value will be casted back to i32 in the led subsystem.
+ from_result(|| {
+ classdev
+ .brightness_get()
+ .inspect(|val| debug_assert!(*val <= 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 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) };
+
+ classdev.blink_set(
+ // 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: 'bound> PinnedDrop for MultiColorDevice<'bound, 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::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_classdev_mc`.
+ let led_cdev = unsafe { &*raw };
+
+ // SAFETY: `led_cdev.subled_info` is guaranteed to be a valid pointer 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::<MultiColorSubLed>(),
+ // CAST: `num_colors` was originally converted from a `usize` in
+ // `DeviceBuilder::build_multicolor`. Thus it is guaranteed that
+ // `num_colors` fits into an usize.
+ led_cdev.num_colors as usize,
+ ))
+ });
+ }
+}
--
2.55.0
^ permalink raw reply related [flat|nested] 6+ messages in thread* [PATCH v25 4/4] MAINTAINERS: rust: leds: Add rust abstraction entry
2026-09-13 16:15 [PATCH v25 0/4] rust: leds: add led classdev abstractions Markus Probst
` (2 preceding siblings ...)
2026-09-13 16:15 ` [PATCH v25 3/4] rust: leds: add multicolor classdev abstractions Markus Probst
@ 2026-09-13 16:15 ` Markus Probst
3 siblings, 0 replies; 6+ messages in thread
From: Markus Probst @ 2026-09-13 16:15 UTC (permalink / raw)
To: Lee Jones, Pavel Machek, Greg Kroah-Hartman, Dave Ertman,
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, Daniel Almeida,
Tamir Duberstein, Alexandre Courbot, Onur Özkan, Ira Weiny,
Boqun Feng
Cc: rust-for-linux, linux-leds, linux-kernel, linux-pci,
Markus Probst
Add self as maintainer.
Signed-off-by: Markus Probst <markus.probst@posteo.de>
---
MAINTAINERS | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/MAINTAINERS b/MAINTAINERS
index 3a19da74d00c..54931e850570 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -14795,6 +14795,14 @@ 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
--
2.55.0
^ permalink raw reply related [flat|nested] 6+ messages in thread