From nobody Wed Dec 17 12:04:52 2025 Received: from mailout1.w1.samsung.com (mailout1.w1.samsung.com [210.118.77.11]) (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 57EAB33A02B for ; Thu, 16 Oct 2025 13:38:22 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=210.118.77.11 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760621905; cv=none; b=CshTOGq7sCoNSteO4jpBqGSFzEYk7hIeOjCs2d0lz+/xLTzZGgLqZRbfy9aYeFDQwAk6W6ghZUR0+fjyrfR7rhFOapqCPtC0aUVyrWP4zR3+oWirEbli15bb+GlvAyT3gnT5Gk3bRBXWvXaMCj2Krai83QbHYYz77lm5YU9vwCE= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760621905; c=relaxed/simple; bh=48ITCLqk03LSrwEBRdBghQvTvSWYoyMFBncQRajOO7o=; h=From:Date:Subject:MIME-Version:Message-Id:In-Reply-To:To:Cc: Content-Type:References; b=K53Zwy0ITiZz4ANqD8TidYEQ3v/Zk1hJc+6H6JJk5mbB7DR08KU0saLrVcSOpwJCs2YVZWqHbdv93Q36VjcxrwiiN7d5qrkxOzI7eMzHamcFUCTDZGzTBrDJuhyD6vdXA/o1yWKOkgtEptebOI6YY1LruBfH2XSE/47K2fuO6iw= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=samsung.com; spf=pass smtp.mailfrom=samsung.com; dkim=pass (1024-bit key) header.d=samsung.com header.i=@samsung.com header.b=jAVo1uoZ; arc=none smtp.client-ip=210.118.77.11 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=samsung.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=samsung.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=samsung.com header.i=@samsung.com header.b="jAVo1uoZ" Received: from eucas1p1.samsung.com (unknown [182.198.249.206]) by mailout1.w1.samsung.com (KnoxPortal) with ESMTP id 20251016133818euoutp017a85292cdbb13968e246a3852c1a586b~u-EnXzMZ-0221002210euoutp01Q for ; Thu, 16 Oct 2025 13:38:18 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 mailout1.w1.samsung.com 20251016133818euoutp017a85292cdbb13968e246a3852c1a586b~u-EnXzMZ-0221002210euoutp01Q DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=samsung.com; s=mail20170921; t=1760621898; bh=5NdA4UIjY+CPEqi/4nTsJb9LgGjoLEpFa1PTeLAFS3w=; h=From:Date:Subject:In-Reply-To:To:Cc:References:From; b=jAVo1uoZQXepXIQlsuSC1errQk20wf+uB29Vd60uxT/62FP5SSl9lh98UyI5/1cMu j+P1RkNLnjr71ZoJGC2peGb4dzbt2ITh40vskAvRIUgBFulLxxoZDVo5L70RpYErw4 jiUUcj841eS8UukyULAG5dB9hPVUq7mR5/jlga/A= Received: from eusmtip2.samsung.com (unknown [203.254.199.222]) by eucas1p1.samsung.com (KnoxPortal) with ESMTPA id 20251016133817eucas1p1cbf94e071419dbaaa52a13afa1dc155b~u-Emzrr7o2689226892eucas1p1F; Thu, 16 Oct 2025 13:38:17 +0000 (GMT) Received: from AMDC4942.eu.corp.samsungelectronics.net (unknown [106.210.136.40]) by eusmtip2.samsung.com (KnoxPortal) with ESMTPA id 20251016133816eusmtip252598a608252463c9a648d5a914d08d7~u-ElsXOiS1688716887eusmtip2O; Thu, 16 Oct 2025 13:38:16 +0000 (GMT) From: Michal Wilczynski Date: Thu, 16 Oct 2025 15:38:02 +0200 Subject: [PATCH v16 2/7] rust: pwm: Add Kconfig and basic data structures Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Message-Id: <20251016-rust-next-pwm-working-fan-for-sending-v16-2-a5df2405d2bd@samsung.com> In-Reply-To: <20251016-rust-next-pwm-working-fan-for-sending-v16-0-a5df2405d2bd@samsung.com> To: =?utf-8?q?Uwe_Kleine-K=C3=B6nig?= , Miguel Ojeda , Alex Gaynor , Boqun Feng , Gary Guo , =?utf-8?q?Bj=C3=B6rn_Roy_Baron?= , Andreas Hindborg , Alice Ryhl , Trevor Gross , Danilo Krummrich , Michal Wilczynski , Guo Ren , Fu Wei , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Paul Walmsley , Palmer Dabbelt , Albert Ou , Alexandre Ghiti , Marek Szyprowski , Benno Lossin , Michael Turquette , Drew Fustini , Daniel Almeida , Benno Lossin , Drew Fustini Cc: linux-kernel@vger.kernel.org, linux-pwm@vger.kernel.org, rust-for-linux@vger.kernel.org, linux-riscv@lists.infradead.org, devicetree@vger.kernel.org, Elle Rhumsaa X-Mailer: b4 0.15-dev X-CMS-MailID: 20251016133817eucas1p1cbf94e071419dbaaa52a13afa1dc155b X-Msg-Generator: CA Content-Type: text/plain; charset="utf-8" X-RootMTR: 20251016133817eucas1p1cbf94e071419dbaaa52a13afa1dc155b X-EPHeader: CA X-CMS-RootMailID: 20251016133817eucas1p1cbf94e071419dbaaa52a13afa1dc155b References: <20251016-rust-next-pwm-working-fan-for-sending-v16-0-a5df2405d2bd@samsung.com> Introduce the foundational support for PWM abstractions in Rust. This commit adds the `RUST_PWM_ABSTRACTIONS` Kconfig option to enable the feature, along with the necessary build-system support and C helpers. It also introduces the first set of safe wrappers for the PWM subsystem, covering the basic data carrying C structs and enums: - `Polarity`: A safe wrapper for `enum pwm_polarity`. - `Waveform`: A wrapper for `struct pwm_waveform`. - `State`: A wrapper for `struct pwm_state`. These types provide memory safe, idiomatic Rust representations of the core PWM data structures and form the building blocks for the abstractions that will follow. Tested-by: Drew Fustini Reviewed-by: Daniel Almeida Reviewed-by: Elle Rhumsaa Signed-off-by: Michal Wilczynski --- MAINTAINERS | 8 ++++ drivers/pwm/Kconfig | 12 +++++ rust/bindings/bindings_helper.h | 1 + rust/helpers/helpers.c | 1 + rust/helpers/pwm.c | 20 ++++++++ rust/kernel/lib.rs | 2 + rust/kernel/pwm.rs | 102 ++++++++++++++++++++++++++++++++++++= ++++ 7 files changed, 146 insertions(+) diff --git a/MAINTAINERS b/MAINTAINERS index 46126ce2f968e4f9260263f1574ee29f5ff0de1c..b01a016373c85fb1879e8948ced= fc4e2ebc3915f 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -20763,6 +20763,14 @@ F: include/linux/pwm.h F: include/linux/pwm_backlight.h K: pwm_(config|apply_might_sleep|apply_atomic|ops) =20 +PWM SUBSYSTEM BINDINGS [RUST] +M: Michal Wilczynski +L: linux-pwm@vger.kernel.org +L: rust-for-linux@vger.kernel.org +S: Maintained +F: rust/helpers/pwm.c +F: rust/kernel/pwm.rs + PXA GPIO DRIVER M: Robert Jarzmik L: linux-gpio@vger.kernel.org diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig index c2fd3f4b62d9ea422a51a73fa87dc7a73703ebaf..d87c4521268c18e1d11ced8c8c7= 2ec79abc67b22 100644 --- a/drivers/pwm/Kconfig +++ b/drivers/pwm/Kconfig @@ -819,4 +819,16 @@ config PWM_XILINX To compile this driver as a module, choose M here: the module will be called pwm-xilinx. =20 + config RUST_PWM_ABSTRACTIONS + bool + depends on RUST + help + This option enables the safe Rust abstraction layer for the PWM + subsystem. It provides idiomatic wrappers and traits necessary for + writing PWM controller drivers in Rust. + + The abstractions handle resource management (like memory and reference + counting) and provide safe interfaces to the underlying C core, + allowing driver logic to be written in safe Rust. + endif diff --git a/rust/bindings/bindings_helper.h b/rust/bindings/bindings_helpe= r.h index 2e43c66635a2c9f31bd99b9817bd2d6ab89fbcf2..70b11fc6338c4f38b854419ab5b= c44afe4905678 100644 --- a/rust/bindings/bindings_helper.h +++ b/rust/bindings/bindings_helper.h @@ -72,6 +72,7 @@ #include #include #include +#include #include #include #include diff --git a/rust/helpers/helpers.c b/rust/helpers/helpers.c index 551da6c9b5064c324d6f62bafcec672c6c6f5bee..014f20df9148220809ea2b8dcfe= 9776b0fe214d3 100644 --- a/rust/helpers/helpers.c +++ b/rust/helpers/helpers.c @@ -43,6 +43,7 @@ #include "poll.c" #include "processor.c" #include "property.c" +#include "pwm.c" #include "rbtree.c" #include "rcu.c" #include "refcount.c" diff --git a/rust/helpers/pwm.c b/rust/helpers/pwm.c new file mode 100644 index 0000000000000000000000000000000000000000..d75c588863685d3990b525bb1b8= 4aa4bc35ac397 --- /dev/null +++ b/rust/helpers/pwm.c @@ -0,0 +1,20 @@ +// SPDX-License-Identifier: GPL-2.0 +// Copyright (c) 2025 Samsung Electronics Co., Ltd. +// Author: Michal Wilczynski + +#include + +struct device *rust_helper_pwmchip_parent(const struct pwm_chip *chip) +{ + return pwmchip_parent(chip); +} + +void *rust_helper_pwmchip_get_drvdata(struct pwm_chip *chip) +{ + return pwmchip_get_drvdata(chip); +} + +void rust_helper_pwmchip_set_drvdata(struct pwm_chip *chip, void *data) +{ + pwmchip_set_drvdata(chip, data); +} diff --git a/rust/kernel/lib.rs b/rust/kernel/lib.rs index 3dd7bebe78882a932f54f305864d5f372a7cd695..68c71d888fdb84183569120f067= 3c0f983d0ec9b 100644 --- a/rust/kernel/lib.rs +++ b/rust/kernel/lib.rs @@ -129,6 +129,8 @@ pub mod seq_file; pub mod sizes; mod static_assert; +#[cfg(CONFIG_RUST_PWM_ABSTRACTIONS)] +pub mod pwm; #[doc(hidden)] pub mod std_vendor; pub mod str; diff --git a/rust/kernel/pwm.rs b/rust/kernel/pwm.rs new file mode 100644 index 0000000000000000000000000000000000000000..beabf0086a2f1beea01e0b0a9f6= 540c601f77a49 --- /dev/null +++ b/rust/kernel/pwm.rs @@ -0,0 +1,102 @@ +// SPDX-License-Identifier: GPL-2.0 +// Copyright (c) 2025 Samsung Electronics Co., Ltd. +// Author: Michal Wilczynski + +//! PWM subsystem abstractions. +//! +//! C header: [`include/linux/pwm.h`](srctree/include/linux/pwm.h). + +use crate::{ + bindings, + prelude::*, + types::Opaque, +}; +use core::convert::TryFrom; + +/// PWM polarity. Mirrors [`enum pwm_polarity`](srctree/include/linux/pwm.= h). +#[derive(Copy, Clone, Debug, PartialEq, Eq)] +pub enum Polarity { + /// Normal polarity (duty cycle defines the high period of the signal). + Normal, + + /// Inversed polarity (duty cycle defines the low period of the signal= ). + Inversed, +} + +impl TryFrom for Polarity { + type Error =3D Error; + + fn try_from(polarity: bindings::pwm_polarity) -> Result { + match polarity { + bindings::pwm_polarity_PWM_POLARITY_NORMAL =3D> Ok(Polarity::N= ormal), + bindings::pwm_polarity_PWM_POLARITY_INVERSED =3D> Ok(Polarity:= :Inversed), + _ =3D> Err(EINVAL), + } + } +} + +impl From for bindings::pwm_polarity { + fn from(polarity: Polarity) -> Self { + match polarity { + Polarity::Normal =3D> bindings::pwm_polarity_PWM_POLARITY_NORM= AL, + Polarity::Inversed =3D> bindings::pwm_polarity_PWM_POLARITY_IN= VERSED, + } + } +} + +/// Represents a PWM waveform configuration. +/// Mirrors struct [`struct pwm_waveform`](srctree/include/linux/pwm.h). +#[derive(Copy, Clone, Debug, Default, PartialEq, Eq)] +pub struct Waveform { + /// Total duration of one complete PWM cycle, in nanoseconds. + pub period_length_ns: u64, + + /// Duty-cycle active time, in nanoseconds. + /// + /// For a typical normal polarity configuration (active-high) this is = the + /// high time of the signal. + pub duty_length_ns: u64, + + /// Duty-cycle start offset, in nanoseconds. + /// + /// Delay from the beginning of the period to the first active edge. + /// In most simple PWM setups this is `0`, so the duty cycle starts + /// immediately at each period=E2=80=99s start. + pub duty_offset_ns: u64, +} + +impl From for Waveform { + fn from(wf: bindings::pwm_waveform) -> Self { + Waveform { + period_length_ns: wf.period_length_ns, + duty_length_ns: wf.duty_length_ns, + duty_offset_ns: wf.duty_offset_ns, + } + } +} + +impl From for bindings::pwm_waveform { + fn from(wf: Waveform) -> Self { + bindings::pwm_waveform { + period_length_ns: wf.period_length_ns, + duty_length_ns: wf.duty_length_ns, + duty_offset_ns: wf.duty_offset_ns, + } + } +} + +/// Wrapper for PWM state [`struct pwm_state`](srctree/include/linux/pwm.h= ). +#[repr(transparent)] +pub struct State(bindings::pwm_state); + +impl State { + /// Creates a `State` wrapper by taking ownership of a C `pwm_state` v= alue. + pub(crate) fn from_c(c_state: bindings::pwm_state) -> Self { + State(c_state) + } + + /// Returns `true` if the PWM signal is enabled. + pub fn enabled(&self) -> bool { + self.0.enabled + } +} --=20 2.34.1