From nobody Tue Dec 2 02:19:35 2025 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 D4A5235FF62 for ; Wed, 19 Nov 2025 14:11:30 +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=1763561493; cv=none; b=d6k4XeuhNfPOvxDkx26qLJOMk7nDQthbYuk8UCqt/zmW+bGXAFYYKZsvvorNXXrBsqVNGO1bjv8bioIxil585HvlcLVxgRue+bhwsmsScNZ+CPsW83XFt1B0frukgVz1+8l8NkFBC8Ph/oJN+ck6vP781dq9Snl3D/KWRBnO7Ng= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763561493; c=relaxed/simple; bh=CpE3MEj/x6unXKoMafOZ0/AJs6ykkJuUy8+uEPPju8Q=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=aajNzTPUQFVFCsNaoXkaZc8RvYX1JJfDSQzzL7i37gmhd/O4qaIuX2GgCYr2NaLUf7Oh10hBwGZxBPbXCY0Rnqpvac2dcoIh0QggTTUGb4b5mGl3AJdjr3sRu66TpK/d9Fs699tQm1fXsJQ59+qBQvjP1Li1AHkVWsdnNrZ8304= 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=KJ7HPj6h; arc=none smtp.client-ip=185.67.36.66 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="KJ7HPj6h" Received: from submission (posteo.de [185.67.36.169]) by mout02.posteo.de (Postfix) with ESMTPS id 75AB9240105 for ; Wed, 19 Nov 2025 15:11:23 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=posteo.de; s=2017; t=1763561483; bh=FmzYqryOEGiBbccmVct6HSL/JY7hepGnQ2UHplApjpU=; h=From:Date:Subject:MIME-Version:Content-Type: Content-Transfer-Encoding:Message-Id:To:Cc:Autocrypt:OpenPGP:From; b=KJ7HPj6hjv28C67Nm7Zo3XZwK5bHwsxw6XCwxvhrV+QrmRQpVe/Do0xDSGiet0sWU ImalLiuCLKkpSwNnAgKwPBPSg5S0u5RZNjtFA1sAdb78K7ONV6SUNGtqYPUU69p7cy XTmdVGe9qlXGgJ/6RV6whSOJnI6JhQaMKdRis9WYmmxMPgS4IRGpHk+whFKU+kAXGE w1PhYJ2bi0+8Egg5AaF0EILFeD2VKgkZyo2lD806Xz44L4Rl1HD8TPgfpbO2D4XGyl S2KoZ35pWuzJY1fsz5mOb/gLNMtlsVq3NcpiTPxpWdYDJHdJOml1y09pdwi8UxSaHw gS1Xu9kSAnhvQ== Received: from customer (localhost [127.0.0.1]) by submission (posteo.de) with ESMTPSA id 4dBNgq3pvnz6v1c; Wed, 19 Nov 2025 15:11:19 +0100 (CET) From: Markus Probst Date: Wed, 19 Nov 2025 14:11:21 +0000 Subject: [PATCH v9 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: <20251119-rust_leds-v9-1-86c15da19063@posteo.de> References: <20251119-rust_leds-v9-0-86c15da19063@posteo.de> In-Reply-To: <20251119-rust_leds-v9-0-86c15da19063@posteo.de> To: Lee Jones , Pavel Machek , Greg Kroah-Hartman , Dave Ertman , Ira Weiny , Leon Romanovsky , Miguel Ojeda , Alex Gaynor , Boqun Feng , Gary Guo , =?utf-8?q?Bj=C3=B6rn_Roy_Baron?= , Benno Lossin , Andreas Hindborg , Alice Ryhl , Trevor Gross , Danilo Krummrich , "Rafael J. Wysocki" , Bjorn Helgaas , =?utf-8?q?Krzysztof_Wilczy=C5=84ski?= Cc: rust-for-linux@vger.kernel.org, linux-leds@vger.kernel.org, linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, Markus Probst X-Developer-Signature: v=1; a=openpgp-sha256; l=18717; i=markus.probst@posteo.de; h=from:subject:message-id; bh=CpE3MEj/x6unXKoMafOZ0/AJs6ykkJuUy8+uEPPju8Q=; b=owEBbQKS/ZANAwAIATR2H/jnrUPSAcsmYgBpHdAEgV85h/ryhgmAUS3WwvlesGxwkI4QwkwJo VWSF3C4hi+JAjMEAAEIAB0WIQSCdBjE9KxY53IwxHM0dh/4561D0gUCaR3QBAAKCRA0dh/4561D 0mhhD/9ZG8YIKViUUKghMza20qjE3o/RUg1PP9z29j375oVnqJn5YJ4wR/wW0YEErJ9s8YX+u/t LFKK3xq4kpJntVUV6oNvhgB1e2aTy6bwSiu0+i4q2onUbtoPMpVzw2zY48giWxfotLmbv7jFVNi ZvLXEAC+KxcHsB2gE+UkJMvz0vwwWdyCeGTAvKqiLEVO1eWWg4/rk48h+mYrrQLfzyBbjaPDVZz w7RgypjCh0M/QIlVx+vgaqVtfiJbGGbASyH4+5KdxwgirY94sIe7P5yF54ygVPlBG5TClahE0cg KxRx3DoZwXNo6//Rd8JV3yQSIWFtSCE+bsugJwysQwDjpizKT6Bg+En4yeoNBijhsmyfo8VljcY mbungJ4fXHzGAfClnFlZ2NjhzC1PoCl636oDJF8IiXWCrt/nB11CbaZarAzE9dU6Tw9LWalYKrG 845J6TET0jneb8RsXxSbKZrDv9Y2pUvZhBG3bAOTHf9HLZffFjWqQlb5Q0mrcJfNrrF9cG0TPiu JZvXcsDS4uuBkWzrKFKl4UIKquhu+W1+1Z/0SBGblEft1T/6DAoZIglJIpnUtF+kEZluH6YXlGI f1iUAheWZv8LuZF97Fh0YRFtpyz9GM5Qw2shBFZ8Qcio9WfwARJZA49CiYuj/6yQKGONEkW2TkF A5d0eCRpTqhJrkA== X-Developer-Key: i=markus.probst@posteo.de; 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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::InitData` - data set for the led class device * `led::Device` - a safe wrapper around `led_classdev` Signed-off-by: Markus Probst --- MAINTAINERS | 7 + rust/kernel/led.rs | 472 +++++++++++++++++++++++++++++++++++++++++++++++++= ++++ rust/kernel/lib.rs | 1 + 3 files changed, 480 insertions(+) diff --git a/MAINTAINERS b/MAINTAINERS index b71ea515240a..80cb030911b7 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -14112,6 +14112,13 @@ 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 + 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..fca55f02be8d --- /dev/null +++ b/rust/kernel/led.rs @@ -0,0 +1,472 @@ +// 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, + pin::Pin, + ptr::NonNull, // +}; + +use pin_init::{ + pin_data, + pinned_drop, + PinInit, // +}; + +use crate::{ + build_error, + container_of, + device::{ + self, + property::FwNode, + AsBusDevice, + Bound, // + }, + devres::Devres, + error::{ + code::EINVAL, + from_result, + to_result, + Error, + Result, + VTABLE_DEFAULT_ERROR, // + }, + macros::vtable, + str::CStr, + try_pin_init, + types::{ + ARef, + Opaque, // + }, // +}; + +/// The led class device representation. +/// +/// This structure represents the Rust abstraction for a C `struct led_cla= ssdev`. +#[pin_data(PinnedDrop)] +pub struct Device { + ops: T, + #[pin] + classdev: Opaque, +} + +/// The led init data representation. +/// +/// This structure represents the Rust abstraction for a C `struct led_ini= t_data` with additional +/// fields from `struct led_classdev`. +#[derive(Default)] +pub struct InitData<'a> { + fwnode: Option>, + default_label: Option<&'a CStr>, + devicename: Option<&'a CStr>, + devname_mandatory: bool, + initial_brightness: u32, + default_trigger: Option<&'a CStr>, + color: Color, +} + +impl InitData<'static> { + /// Creates a new [`InitData`] + pub fn new() -> Self { + Self::default() + } +} + +impl<'a> InitData<'a> { + /// Sets the firmware node + pub fn fwnode(self, fwnode: Option>) -> Self { + Self { fwnode, ..self } + } + + /// Sets a default label + pub fn default_label(self, label: &'a CStr) -> Self { + Self { + default_label: Some(label), + ..self + } + } + + /// Sets the device name + pub fn devicename(self, devicename: &'a CStr) -> Self { + Self { + devicename: Some(devicename), + ..self + } + } + + /// Sets if a device name is mandatory + pub fn devicename_mandatory(self, mandatory: bool) -> Self { + Self { + devname_mandatory: mandatory, + ..self + } + } + + /// 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. + 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" fwnod= e property. + 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. + pub fn color(self, color: Color) -> Self { + Self { color, ..self } + } +} + +/// Trait defining the operations for a LED driver. +/// +/// # Examples +/// +///``` +/// # use kernel::{ +/// # c_str, device, devres::Devres, +/// # error::Result, led, +/// # macros::vtable, platform, prelude::*, +/// # }; +/// # use core::pin::Pin; +/// +/// struct MyLedOps; +/// +/// +/// #[vtable] +/// impl led::LedOps for MyLedOps { +/// type Bus =3D platform::Device; +/// const BLOCKING: bool =3D false; +/// const MAX_BRIGHTNESS: u32 =3D 255; +/// +/// fn brightness_set( +/// &self, +/// _dev: &platform::Device, +/// _classdev: &led::Device, +/// _brightness: u32 +/// ) -> Result<()> { +/// // Set the brightness for the led here +/// Ok(()) +/// } +/// } +/// +/// fn register_my_led( +/// parent: &platform::Device, +/// ) -> Result>>>> { +/// KBox::pin_init(led::Device::new( +/// parent, +/// led::InitData::new() +/// .default_label(c_str!("my_led")), +/// MyLedOps, +/// ), GFP_KERNEL) +/// } +///``` +/// Led drivers must implement this trait in order to register and handle = a [`Device`]. +#[vtable] +pub trait LedOps: Send + 'static + Sized { + /// The bus device required by the implementation. + #[allow(private_bounds)] + type Bus: AsBusDevice; + /// If set true, [`LedOps::brightness_set`] and [`LedOps::blink_set`] = must perform the + /// operation immediately. If set false, they must not sleep. + const BLOCKING: bool; + /// The max brightness level + const MAX_BRIGHTNESS: u32; + + /// Sets the brightness level. + /// + /// See also [`LedOps::BLOCKING`]. + fn brightness_set( + &self, + dev: &Self::Bus, + classdev: &Device, + brightness: u32, + ) -> Result<()>; + + /// Gets the current brightness level. + fn brightness_get(&self, _dev: &Self::Bus, _classdev: &Device) -= > u32 { + build_error!(VTABLE_DEFAULT_ERROR) + } + + /// Activates hardware accelerated blinking. + /// + /// delays are in milliseconds. If both are zero, a sensible default s= hould be chosen. + /// The caller should adjust the timings in that case and if it can't = match the values + /// specified exactly. Setting the brightness to 0 will disable the ha= rdware accelerated + /// blinking. + /// + /// See also [`LedOps::BLOCKING`]. + fn blink_set( + &self, + _dev: &Self::Bus, + _classdev: &Device, + _delay_on: &mut usize, + _delay_off: &mut usize, + ) -> Result<()> { + build_error!(VTABLE_DEFAULT_ERROR) + } +} + +/// Led colors. +#[derive(Copy, Clone, Debug, Default)] +#[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, +} + +impl TryFrom for Color { + type Error =3D Error; + + fn try_from(value: u32) -> core::result::Result { + const _: () =3D { + assert!(bindings::LED_COLOR_ID_MAX =3D=3D 15); + }; + if value < bindings::LED_COLOR_ID_MAX { + // SAFETY: + // - `Color` is represented as `u32` + // - the const block above guarantees that no additional color= has been added + // - `value` is guaranteed to be in the color id range + Ok(unsafe { transmute::(value) }) + } else { + Err(EINVAL) + } + } +} + +// SAFETY: A `led::Device` can be unregistered from any thread. +unsafe impl Send for Device {} + +// SAFETY: `led::Device` can be shared among threads because all methods o= f `led::Device` +// are thread safe. +unsafe impl Sync for Device {} + +impl Device { + /// Registers a new led classdev. + /// + /// The [`Device`] will be unregistered on drop. + pub fn new<'a>( + parent: &'a T::Bus, + init_data: InitData<'a>, + ops: T, + ) -> impl PinInit, Error> + 'a { + Devres::new( + parent.as_ref(), + try_pin_init!(Self { + ops, + classdev <- Opaque::try_ffi_init(|ptr: *mut bindings::led_= classdev| { + // SAFETY: `try_ffi_init` guarantees that `ptr` is val= id for write. + // `led_classdev` gets fully initialized in-place by + // `led_classdev_register_ext` including `mutex` and `= list_head`. + unsafe { + ptr.write(bindings::led_classdev { + 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: init_data.initial_brightness, + default_trigger: init_data.default_trigger + .map_or(core::ptr::null(), CStr::as_char_p= tr), + color: init_data.color as u32, + ..bindings::led_classdev::default() + }) + }; + + let mut init_data_raw =3D bindings::led_init_data { + fwnode: init_data.fwnode + .as_ref() + .map_or(core::ptr::null_mut(), |fwnode| fwnode= .as_raw()), + default_label: init_data + .default_label + .map_or(core::ptr::null(), CStr::as_char_ptr), + devicename: init_data + .devicename + .map_or(core::ptr::null(), CStr::as_char_ptr), + devname_mandatory: init_data.devname_mandatory, + }; + + // SAFETY: + // - `parent.as_raw()` is guaranteed to be a pointer t= o a valid `device` + // or a null pointer. + // - `ptr` is guaranteed to be a pointer to an initial= ized `led_classdev`. + to_result(unsafe { + bindings::led_classdev_register_ext( + parent.as_ref().as_raw(), + ptr, + &mut init_data_raw, + ) + })?; + + core::mem::forget(init_data.fwnode); // keep the refer= ence count incremented + + Ok::<_, Error>(()) + }), + }), + ) + } + + /// # Safety + /// `led_cdev` must be a valid pointer to a `led_classdev` embedded wi= thin a + /// `led::Device`. + unsafe fn from_raw<'a>(led_cdev: *mut bindings::led_classdev) -> &'a S= elf { + // SAFETY: The function's contract guarantees that `led_cdev` poin= ts to a `led_classdev` + // field embedded within a valid `led::Device`. `container_of!` ca= n therefore + // safely calculate the address of the containing struct. + unsafe { &*container_of!(Opaque::cast_from(led_cdev), Self, classd= ev) } + } + + fn parent(&self) -> &device::Device { + // SAFETY: + // - `self.classdev.get()` is guaranteed to be a valid pointer to = `led_classdev`. + unsafe { device::Device::from_raw((*(*self.classdev.get()).dev).pa= rent) } + } +} + +struct Adapter { + _p: PhantomData, +} + +impl Adapter { + /// # Safety + /// `led_cdev` must be a valid pointer to a `led_classdev` embedded wi= thin a + /// `led::Device`. + /// This function is called on setting the brightness of a led. + unsafe extern "C" fn brightness_set_callback( + led_cdev: *mut bindings::led_classdev, + brightness: u32, + ) { + // SAFETY: The function's contract guarantees that `led_cdev` is a= valid pointer to a + // `led_classdev` embedded within a `led::Device`. + let classdev =3D unsafe { Device::::from_raw(led_cdev) }; + // SAFETY: `classdev.parent()` is guaranteed to be contained in `T= ::Bus`. + let parent =3D unsafe { T::Bus::from_device(classdev.parent()) }; + + let _ =3D classdev.ops.brightness_set(parent, 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()) }; + + classdev.ops.brightness_get(parent, classdev) + } + + /// # 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 PinnedDrop for Device { + fn drop(self: Pin<&mut Self>) { + let raw =3D self.classdev.get(); + // SAFETY: The existence of `self` guarantees that `self.classdev.= get()` is a pointer to a + // valid `struct led_classdev`. + let dev: &device::Device =3D unsafe { device::Device::from_raw((*r= aw).dev) }; + + let _fwnode =3D dev + .fwnode() + // SAFETY: the reference count of `fwnode` has previously been + // incremented in `led::Device::new`. + .map(|fwnode| unsafe { ARef::from_raw(NonNull::from(fwnode)) }= ); + + // SAFETY: The existence of `self` guarantees that `self.classdev`= has previously been + // successfully registered with `led_classdev_register_ext`. + unsafe { bindings::led_classdev_unregister(self.classdev.get()) }; + } +} diff --git a/rust/kernel/lib.rs b/rust/kernel/lib.rs index 8c0070a8029e..a8f49ce78f8d 100644 --- a/rust/kernel/lib.rs +++ b/rust/kernel/lib.rs @@ -105,6 +105,7 @@ pub mod jump_label; #[cfg(CONFIG_KUNIT)] pub mod kunit; +pub mod led; pub mod list; pub mod maple_tree; pub mod miscdevice; --=20 2.51.0 From nobody Tue Dec 2 02:19:35 2025 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 4C1C0364E88 for ; Wed, 19 Nov 2025 14:11:33 +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=1763561496; cv=none; b=XSIm3YxIxfjn+VPYADBkhtpY6StpluZSEXZnkS/9iiuFWWUuBGUx725tWB6XVT/zADXBSYGo+G7eJddpgiR2dct9dPoG4SwWLM91tDtZ6PBHfzHCp6n2xEY6bY/0ZawuX3tXsPYR2054I9J+ZkHICba7OhYHY+2weZyv6SoxpK0= ARC-Message-Signature: i=1; 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charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20251119-rust_leds-v9-2-86c15da19063@posteo.de> References: <20251119-rust_leds-v9-0-86c15da19063@posteo.de> In-Reply-To: <20251119-rust_leds-v9-0-86c15da19063@posteo.de> To: Lee Jones , Pavel Machek , Greg Kroah-Hartman , Dave Ertman , Ira Weiny , Leon Romanovsky , Miguel Ojeda , Alex Gaynor , Boqun Feng , 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 --- MAINTAINERS | 1 + rust/kernel/device.rs | 2 +- rust/kernel/led.rs | 128 +++++++++++++++++++++++++++++++++++-------= ---- rust/kernel/led/normal.rs | 39 ++++++++++++++ 4 files changed, 139 insertions(+), 31 deletions(-) diff --git a/MAINTAINERS b/MAINTAINERS index 80cb030911b7..ca11b9064e3f 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -14118,6 +14118,7 @@ L: linux-leds@vger.kernel.org L: rust-for-linux@vger.kernel.org S: Maintained F: rust/kernel/led.rs +F: rust/kernel/led/ =20 LEGO MINDSTORMS EV3 R: David Lechner diff --git a/rust/kernel/device.rs b/rust/kernel/device.rs index 660cb2b48c07..d330248ff2aa 100644 --- a/rust/kernel/device.rs +++ b/rust/kernel/device.rs @@ -333,7 +333,7 @@ pub(crate) fn as_raw(&self) -> *mut bindings::device { } =20 /// Returns a reference to the parent device, if any. - #[cfg_attr(not(CONFIG_AUXILIARY_BUS), expect(dead_code))] + #[cfg_attr(not(any(CONFIG_AUXILIARY_BUS, CONFIG_LEDS_CLASS)), expect(d= ead_code))] pub(crate) fn parent(&self) -> Option<&Device> { // SAFETY: // - By the type invariant `self.as_raw()` is always valid. diff --git a/rust/kernel/led.rs b/rust/kernel/led.rs index fca55f02be8d..d51735322093 100644 --- a/rust/kernel/led.rs +++ b/rust/kernel/led.rs @@ -44,14 +44,18 @@ }, // }; =20 +mod normal; + +pub use normal::Normal; + /// The led class device representation. /// -/// This structure represents the Rust abstraction for a C `struct led_cla= ssdev`. +/// This structure represents the Rust abstraction for a led class device. #[pin_data(PinnedDrop)] pub struct Device { ops: T, #[pin] - classdev: Opaque, + classdev: Opaque<::Type>, } =20 /// The led init data representation. @@ -153,6 +157,7 @@ pub fn color(self, color: Color) -> 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; /// @@ -184,6 +189,12 @@ pub trait LedOps: Send + 'static + Sized { /// The bus device required by the implementation. #[allow(private_bounds)] type Bus: AsBusDevice; + + /// 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; @@ -270,6 +281,42 @@ 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::Mode {} + +impl Mode for T {} + +type RegisterFunc =3D + unsafe extern "C" fn(*mut bindings::device, *mut T, *mut bindings::led= _init_data) -> i32; + +type UnregisterFunc =3D unsafe extern "C" fn(*mut T); + +mod private { + pub trait Mode { + type Type; + const REGISTER: super::RegisterFunc; + const UNREGISTER: super::UnregisterFunc; + + /// # Safety + /// `raw` must be a valid pointer to [`Self::Type`]. + unsafe fn device<'a>(raw: *mut Self::Type) -> &'a crate::device::D= evice; + + /// # Safety + /// `led_cdev` must be a valid pointer to `led_classdev` embedded = within [`Self::Type`]. + unsafe fn from_classdev(led_cdev: *mut bindings::led_classdev) -> = *mut Self::Type; + + /// # Safety + /// `raw` must be a valid pointer to [`Self::Type`]. + unsafe fn pre_brightness_set(_raw: *mut Self::Type, _brightness: u= 32) {} + + fn release(_led_cdev: &mut Self::Type) {} + } +} + // SAFETY: A `led::Device` can be unregistered from any thread. unsafe impl Send for Device {} =20 @@ -278,24 +325,22 @@ unsafe impl Send for Device {} unsafe impl Sync for Device {} =20 impl Device { - /// Registers a new led classdev. - /// - /// The [`Device`] will be unregistered on drop. - pub fn new<'a>( + fn __new<'a>( parent: &'a T::Bus, init_data: InitData<'a>, ops: T, + func: impl FnOnce(bindings::led_classdev) -> Result<::Type> + 'a, ) -> impl PinInit, Error> + 'a { Devres::new( parent.as_ref(), try_pin_init!(Self { ops, - classdev <- Opaque::try_ffi_init(|ptr: *mut bindings::led_= classdev| { + classdev <- Opaque::try_ffi_init(|ptr: *mut ::Type| { // SAFETY: `try_ffi_init` guarantees that `ptr` is val= id for write. - // `led_classdev` gets fully initialized in-place by - // `led_classdev_register_ext` including `mutex` and `= list_head`. + // `T::Mode::Type` (and the embedded led_classdev) get= s fully initialized + // in-place by `T::Mode::REGISTER` including `mutex` a= nd `list_head`. unsafe { - ptr.write(bindings::led_classdev { + ptr.write((func)(bindings::led_classdev { brightness_set: (!T::BLOCKING) .then_some(Adapter::::brightness_set_ca= llback), brightness_set_blocking: T::BLOCKING @@ -309,7 +354,7 @@ pub fn new<'a>( .map_or(core::ptr::null(), CStr::as_char_p= tr), color: init_data.color as u32, ..bindings::led_classdev::default() - }) + })?) }; =20 let mut init_data_raw =3D bindings::led_init_data { @@ -326,11 +371,11 @@ pub fn new<'a>( }; =20 // SAFETY: - // - `parent.as_raw()` is guaranteed to be a pointer t= o a valid `device` - // or a null pointer. - // - `ptr` is guaranteed to be a pointer to an initial= ized `led_classdev`. + // - `parent.as_ref().as_raw()` is guaranteed to be a = pointer to a valid + // `device`. + // - `ptr` is guaranteed to be a pointer to an initial= ized `T::Mode::Type`. to_result(unsafe { - bindings::led_classdev_register_ext( + (::REGISTER)( parent.as_ref().as_raw(), ptr, &mut init_data_raw, @@ -350,15 +395,22 @@ pub fn new<'a>( /// `led::Device`. unsafe fn from_raw<'a>(led_cdev: *mut bindings::led_classdev) -> &'a S= elf { // SAFETY: The function's contract guarantees that `led_cdev` poin= ts to a `led_classdev` - // field embedded within a valid `led::Device`. `container_of!` ca= n therefore - // safely calculate the address of the containing struct. - unsafe { &*container_of!(Opaque::cast_from(led_cdev), Self, classd= ev) } + // embedded within a `led::Device` and thus is embedded within `T:= :Mode::Type`. + let raw =3D unsafe { ::from_classdev(led= _cdev) }; + + // SAFETY: The function's contract guarantees that `raw` points to= a `led_classdev` field + // embedded within a valid `led::Device`. `container_of!` can ther= efore safely calculate + // the address of the containing struct. + unsafe { &*container_of!(Opaque::cast_from(raw), Self, classdev) } } =20 fn parent(&self) -> &device::Device { - // SAFETY: - // - `self.classdev.get()` is guaranteed to be a valid pointer to = `led_classdev`. - unsafe { device::Device::from_raw((*(*self.classdev.get()).dev).pa= rent) } + // SAFETY: `self.classdev.get()` is guaranteed to be a valid point= er to `T::Mode::Type`. + let device =3D unsafe { ::device(self.cl= assdev.get()) }; + // SAFETY: `led::Device::__new` doesn't allow to register a class = device without an parent. + let parent =3D unsafe { device.parent().unwrap_unchecked() }; + // SAFETY: the existence of `self` guarantees that `parent` is bou= nd to a driver. + unsafe { parent.as_bound() } } } =20 @@ -376,11 +428,17 @@ impl Adapter { brightness: u32, ) { // SAFETY: The function's contract guarantees that `led_cdev` is a= valid pointer to a - // `led_classdev` embedded within a `led::Device`. + // `T::Mode::Type` 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()) }; =20 + // SAFETY: `classdev.classdev.get()` is guaranteed to be a valid p= ointer to a + // `T::Mode::Type`. + unsafe { + ::pre_brightness_set(classdev.classd= ev.get(), brightness); + } + let _ =3D classdev.ops.brightness_set(parent, classdev, brightness= ); } =20 @@ -394,11 +452,17 @@ impl Adapter { ) -> 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`. + // `T::Mode::Type` 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())= }; =20 + // SAFETY: `classdev.classdev.get()` is guaranteed to be a val= id pointer to a + // `T::Mode::Type`. + unsafe { + ::pre_brightness_set(classdev.cl= assdev.get(), brightness); + } + classdev.ops.brightness_set(parent, classdev, brightness)?; Ok(0) }) @@ -410,7 +474,7 @@ impl Adapter { /// 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`. + // `T::Mode::Type` 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()) }; @@ -431,7 +495,7 @@ impl Adapter { ) -> 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`. + // `T::Mode::Type` 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())= }; @@ -456,17 +520,21 @@ impl PinnedDrop for Device { fn drop(self: Pin<&mut Self>) { let raw =3D self.classdev.get(); // SAFETY: The existence of `self` guarantees that `self.classdev.= get()` is a pointer to a - // valid `struct led_classdev`. - let dev: &device::Device =3D unsafe { device::Device::from_raw((*r= aw).dev) }; + // valid `T::Mode::Type`. + let dev: &device::Device =3D unsafe { ::= device(raw) }; =20 let _fwnode =3D dev .fwnode() // SAFETY: the reference count of `fwnode` has previously been - // incremented in `led::Device::new`. + // incremented in `led::Device::__new`. .map(|fwnode| unsafe { ARef::from_raw(NonNull::from(fwnode)) }= ); =20 // SAFETY: The existence of `self` guarantees that `self.classdev`= has previously been - // successfully registered with `led_classdev_register_ext`. - unsafe { bindings::led_classdev_unregister(self.classdev.get()) }; + // successfully registered with `T::Mode::REGISTER`. + unsafe { (::UNREGISTER)(raw) }; + + // SAFETY: The existence of `self` guarantees that `self.classdev.= get()` is a pointer to a + // valid `T::Mode::Type`. + ::release(unsafe { &mut *raw }); } } diff --git a/rust/kernel/led/normal.rs b/rust/kernel/led/normal.rs new file mode 100644 index 000000000000..13feeb3256f3 --- /dev/null +++ b/rust/kernel/led/normal.rs @@ -0,0 +1,39 @@ +// 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 mode for the `struct led_classdev`. Leds with this mode can on= ly have a fixed color. +pub enum Normal {} + +impl private::Mode for Normal { + type Type =3D bindings::led_classdev; + const REGISTER: RegisterFunc =3D bindings::led_classdev_re= gister_ext; + const UNREGISTER: UnregisterFunc =3D bindings::led_classde= v_unregister; + + unsafe fn device<'a>(raw: *mut Self::Type) -> &'a device::Device { + // SAFETY: + // - The function's contract guarantees that `raw` is a valid poin= ter to `led_classdev`. + unsafe { device::Device::from_raw((*raw).dev) } + } + + unsafe fn from_classdev(led_cdev: *mut bindings::led_classdev) -> *mut= Self::Type { + led_cdev + } +} + +impl> Device { + /// Registers a new led classdev. + /// + /// The [`Device`] will be unregistered on drop. + pub fn new<'a>( + parent: &'a T::Bus, + init_data: InitData<'a>, + ops: T, + ) -> impl PinInit, Error> + 'a { + Self::__new(parent, init_data, ops, Ok) + } +} --=20 2.51.0 From nobody Tue Dec 2 02:19:35 2025 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 9B6F3364021 for ; Wed, 19 Nov 2025 14:11:35 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=185.67.36.65 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763561499; cv=none; b=AuPqSO5Rl8eAFM+ggsKkm/Olmsgos3s//hwO2a80fO1kjRtdPZOp5k6oT6DoDTd8HpCN1hx7m3dwu4bJUBzFJh8mQSGRtUZUPC18R5CVjk7pZbZcmQLV4E36owB7IDGaXBfRg0QTBWVAFgrsKZk0npyMs4jCftcfQYBW1aNPopg= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763561499; c=relaxed/simple; bh=DY3Bm4NtAYa457ryVSDZmJmWwlLWDBAI1VLaFfmXsF8=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=VjMwNBxLfPacKpwy4VRxCM5qVkg9pPyJfQWaPbAYx0n5195q+nsud0e6rDs03T/wYz1UVImKF+2hQiAVwzILqxpw6myLmhBY9gRAv5UcdUM4sIoH9ujyD1Bs4eFzsJVJaIxz7vuy8U9keHQQu9cD6f6i8rzjQXziYOTWVR+2dCA= 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=T9s+5sNJ; 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="T9s+5sNJ" Received: from submission (posteo.de [185.67.36.169]) by mout01.posteo.de (Postfix) with ESMTPS id DD731240027 for ; Wed, 19 Nov 2025 15:11:27 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=posteo.de; s=2017; t=1763561487; bh=2sINMZR+Orb1e0bIRwpcjQBgTeoK31kcru61/G6qYSE=; h=From:Date:Subject:MIME-Version:Content-Type: Content-Transfer-Encoding:Message-Id:To:Cc:Autocrypt:OpenPGP:From; b=T9s+5sNJsvVqhcIx9hnG4w3R9ao42HMDT6S6TlOh5CfFMd1lxjG8TO6JGIMrxpION T8px82F96vBUQi5ZyZ5q/3zTIlDookWY6xxNOie9MbjVxLAegJYAGnWgG4dEibPGmO vqSAZU/HDO0ME1dmpGE6FtXow3kranS0QssufJ7ww1Y2L01Hf0BEajyqcATDHRzh1X HvthiCY/xCIN4bhJf6OySR8M3l3h8XhSpfjaTjZRT9e3YxDxUkF+vpyRLWlM4h5jvr 40rkZwO/8WQktEAqgs4uZGcdbGGM1y4PQDvTJEirVcgoS+kJexyw9KrK9bbycR/5LP BeFMEqUW8opdg== Received: from customer (localhost [127.0.0.1]) by submission (posteo.de) with ESMTPSA id 4dBNgw4QZgz6v2f; Wed, 19 Nov 2025 15:11:24 +0100 (CET) From: Markus Probst Date: Wed, 19 Nov 2025 14:11:26 +0000 Subject: [PATCH v9 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: <20251119-rust_leds-v9-3-86c15da19063@posteo.de> References: <20251119-rust_leds-v9-0-86c15da19063@posteo.de> In-Reply-To: <20251119-rust_leds-v9-0-86c15da19063@posteo.de> To: Lee Jones , Pavel Machek , Greg Kroah-Hartman , Dave Ertman , Ira Weiny , Leon Romanovsky , Miguel Ojeda , Alex Gaynor , Boqun Feng , Gary Guo , =?utf-8?q?Bj=C3=B6rn_Roy_Baron?= , Benno Lossin , Andreas Hindborg , Alice Ryhl , Trevor Gross , Danilo Krummrich , "Rafael J. Wysocki" , Bjorn Helgaas , =?utf-8?q?Krzysztof_Wilczy=C5=84ski?= Cc: rust-for-linux@vger.kernel.org, linux-leds@vger.kernel.org, linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, Markus Probst X-Developer-Signature: v=1; a=openpgp-sha256; l=9583; i=markus.probst@posteo.de; h=from:subject:message-id; bh=DY3Bm4NtAYa457ryVSDZmJmWwlLWDBAI1VLaFfmXsF8=; b=owEBbQKS/ZANAwAIATR2H/jnrUPSAcsmYgBpHdAEEYjQaao77eh/AETH+S0LG0GOjWF9QgXQe 83ayJq+TMiJAjMEAAEIAB0WIQSCdBjE9KxY53IwxHM0dh/4561D0gUCaR3QBAAKCRA0dh/4561D 0uT3D/90bs7tPvN5PTqcymMqxechfcFSJQiuBcupF00h7mtW+e3zc8rqqeG+Po8Ud/gfj2k1kKN FOjexFRC0EWSXn08YPxqaE0j2InwrXyMl7y6OyfdSivRU9EUtv/b4E8x9/wPwc0chTf/PkteLqr +T0JPWkvLnG/Uv/Bd2fSbhEPP62fpqLg2Wn4UXDpmAxPSJ2axyh4qOP0ic4sX04DAgJL+vfxDp2 9GG2JKhNFRvvok13cYFUW9tJ+pQldKgBUOHOQbewvZ7ywNYdQP9hgQQlSqXtBOqJTxMlke/dhu8 PPemVGlSkN/cMQolkjEWkgmVKSasJeZ/0Dlc4Gy+QyOL4B2UZmwocVAjnBLNnM7P8WMFR6FK21I jH2BaMBrPIeQ+cTHnrkqICrhTvwrVYJOrcZ67WdFyd6ScIDzLTKnjAGiZtoGG9cE4S2kyqWI8En Q2a4+Q4wQgx0BSg/8mxTPrZGCYkhHeFfat6IG8SMyn8Sc7RPP5WAHojWXQiloel2aufHhSW7IP0 dJEcwVrhZmQOjmW6vSyl+n8CX1vU3G+c/6VnN9CoadUA3+3qab8qsxGDIOQaZlppQ54VTV83jw1 rJcQRn8ougqfcLwiYk4zEvq4+0pbHE69CrMhFndr5OJUE/eRkum9R0K52SI2IR9X0Vg8lWWbGzT jUrF305DM+u9TTA== X-Developer-Key: i=markus.probst@posteo.de; 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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::Device::new_multicolor()` - the function to register a multicolor led class device * `led::Device::subleds()` - the function to access the brightness and intensity of the individual sub leds Signed-off-by: Markus Probst --- rust/bindings/bindings_helper.h | 1 + rust/kernel/led.rs | 13 ++- rust/kernel/led/multicolor.rs | 195 ++++++++++++++++++++++++++++++++++++= ++++ 3 files changed, 208 insertions(+), 1 deletion(-) diff --git a/rust/bindings/bindings_helper.h b/rust/bindings/bindings_helpe= r.h index f92abb578b56..8825b6df9c9e 100644 --- a/rust/bindings/bindings_helper.h +++ b/rust/bindings/bindings_helper.h @@ -62,6 +62,7 @@ #include #include #include +#include #include #include #include diff --git a/rust/kernel/led.rs b/rust/kernel/led.rs index d51735322093..7c1f6252605f 100644 --- a/rust/kernel/led.rs +++ b/rust/kernel/led.rs @@ -44,8 +44,12 @@ }, // }; =20 +#[cfg(CONFIG_LEDS_CLASS_MULTICOLOR)] +mod multicolor; mod normal; =20 +#[cfg(CONFIG_LEDS_CLASS_MULTICOLOR)] +pub use multicolor::{MultiColor, MultiColorSubLed}; pub use normal::Normal; =20 /// The led class device representation. @@ -285,7 +289,14 @@ 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::Mode {} =20 impl Mode for T {} diff --git a/rust/kernel/led/multicolor.rs b/rust/kernel/led/multicolor.rs new file mode 100644 index 000000000000..db5935448bd7 --- /dev/null +++ b/rust/kernel/led/multicolor.rs @@ -0,0 +1,195 @@ +// 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 crate::{ + alloc::KVec, + error::code::EINVAL, + prelude::*, // +}; + +use super::*; + +/// The led mode for the `struct led_classdev_mc`. Leds with this mode can= have multiple colors. +pub enum MultiColor {} + +/// The multicolor sub led info representation. +/// +/// This structure represents the Rust abstraction for a C `struct mc_subl= ed`. +#[repr(C)] +#[derive(Copy, Clone, Debug)] +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, + _p: PhantomData<()>, // Only allow creation with `MultiColorSubLed::ne= w`. +} + +// 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: 0, + intensity: 0, + channel: 0, + _p: PhantomData, + }; + let c_zeroed =3D bindings::mc_subled { + color_index: 0, + brightness: 0, + intensity: 0, + channel: 0, + }; + + assert!(offset_of!(MultiColorSubLed, color) =3D=3D offset_of!(bindings= ::mc_subled, color_index)); + assert_same_type(&0u32, &c_zeroed.color_index); + + assert!( + offset_of!(MultiColorSubLed, brightness) =3D=3D offset_of!(binding= s::mc_subled, brightness) + ); + assert_same_type(&rust_zeroed.brightness, &c_zeroed.brightness); + + assert!(offset_of!(MultiColorSubLed, intensity) =3D=3D offset_of!(bind= ings::mc_subled, intensity)); + assert_same_type(&rust_zeroed.intensity, &c_zeroed.intensity); + + assert!(offset_of!(MultiColorSubLed, channel) =3D=3D offset_of!(bindin= gs::mc_subled, channel)); + 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. + pub const fn new(color: Color) -> Self { + Self { + color, + brightness: 0, + intensity: 0, + channel: 0, + _p: PhantomData, + } + } + + /// Set arbitrary data for the driver. + pub const fn channel(mut self, channel: u32) -> Self { + self.channel =3D channel; + self + } + + /// Set the initial intensity of the subled. + pub const fn initial_intensity(mut self, intensity: u32) -> Self { + self.intensity =3D intensity; + self + } +} + +impl private::Mode for MultiColor { + type Type =3D bindings::led_classdev_mc; + const REGISTER: RegisterFunc =3D bindings::led_classdev_mu= lticolor_register_ext; + const UNREGISTER: UnregisterFunc =3D bindings::led_classde= v_multicolor_unregister; + + unsafe fn device<'a>(raw: *mut Self::Type) -> &'a device::Device { + // SAFETY: + // - The function's contract guarantees that `raw` is a valid poin= ter to `led_classdev`. + unsafe { device::Device::from_raw((*raw).led_cdev.dev) } + } + + unsafe fn from_classdev(led_cdev: *mut bindings::led_classdev) -> *mut= Self::Type { + // SAFETY: The function's contract guarantees that `led_cdev` is a= valid pointer to + // `led_classdev` embedded within a `Self::Type`. + unsafe { container_of!(led_cdev, bindings::led_classdev_mc, led_cd= ev) } + } + + unsafe fn pre_brightness_set(raw: *mut Self::Type, brightness: u32) { + // SAFETY: The function's contract guarantees that `raw` is a vali= d pointer to + // `led_classdev_mc`. + unsafe { bindings::led_mc_calc_color_components(raw, brightness) }; + } + + fn release(led_cdev: &mut Self::Type) { + // 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::Device:= :new_multicolor`. + let _subleds_vec =3D unsafe { + KVec::from_raw_parts( + led_cdev.subled_info, + led_cdev.num_colors as usize, + led_cdev.num_colors as usize, + ) + }; + } +} + +impl> Device { + /// Registers a new multicolor led classdev. + /// + /// The [`Device`] will be unregistered on drop. + pub fn new_multicolor<'a>( + parent: &'a T::Bus, + init_data: InitData<'a>, + ops: T, + subleds: &'a [MultiColorSubLed], + ) -> impl PinInit, Error> + 'a { + assert!(subleds.len() <=3D u32::MAX as usize); + Self::__new(parent, init_data, ops, |led_cdev| { + let mut subleds_vec =3D KVec::new(); + subleds_vec.extend_from_slice(subleds, GFP_KERNEL)?; + let (subled_info, num_colors, capacity) =3D subleds_vec.into_r= aw_parts(); + debug_assert_eq!(num_colors, capacity); + + let mut used =3D 0; + if subleds.iter().any(|subled| { + let bit =3D 1 << (subled.color as u32); + if (used & bit) !=3D 0 { + true + } else { + used |=3D bit; + false + } + }) { + dev_err!(parent.as_ref(), "duplicate color in multicolor l= ed\n"); + return Err(EINVAL); + } + + Ok(bindings::led_classdev_mc { + led_cdev, + // CAST: We checked above that the length of subleds fits = into a u32. + num_colors: num_colors as u32, + // CAST: The safeguards in the const block ensure that `Mu= ltiColorSubLed` has an + // identical layout to `mc_subled`. + subled_info: subled_info.cast::(), + }) + }) + } + + /// 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 =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::(), + raw.num_colors as usize, + ) + } + } +} --=20 2.51.0