From nobody Sat Oct 4 06:35:18 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 0E0892FBDE4 for ; Tue, 30 Sep 2025 12:27:40 +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=1759235263; cv=none; b=cepiDw2NmFO7F5ZyXUscr7IQTLR9nEV5Jm6ypo+/OGuXu2KQtY6vrIHfDedsAdZrNjG5wo5cVMTZGg8par6XrW4C8+ow7jNNIaMGoAsBspca5B4d6c9d4rLI1aSI4rSjfdHEIhP9tSbvYTALEvqSMf6//DC60CCID5hlnjtPxs0= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1759235263; c=relaxed/simple; bh=GhamRMgiRuEY8EYeFYRn0QQWl17r0gKB8us6iMNro3w=; h=From:Date:Subject:MIME-Version:Message-Id:In-Reply-To:To:Cc: Content-Type:References; b=WzGudqlnGhLbdgz4akc062w85K/cntIlkhUpigqYTDVxIPmhrjdwggUi2JeAya3ZDbrP7eggDmi3vYgnLTCEy8CiJoJJwcWVrXpwgodbzmKfXLkfwGaWwiw+HVdzCr4tAL1IHZSn5/lIfaqmPSb+QpSPkOR5s09KNMS6rprtk6M= 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=Eu5z51NA; 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="Eu5z51NA" Received: from eucas1p1.samsung.com (unknown [182.198.249.206]) by mailout1.w1.samsung.com (KnoxPortal) with ESMTP id 20250930122732euoutp01e01dec61d3f9d29d6138a47182f0781d~qDyQ_DzI-0459504595euoutp01S for ; Tue, 30 Sep 2025 12:27:32 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 mailout1.w1.samsung.com 20250930122732euoutp01e01dec61d3f9d29d6138a47182f0781d~qDyQ_DzI-0459504595euoutp01S DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=samsung.com; s=mail20170921; t=1759235252; bh=1YXxUdy2h6s4QZQQ5Cl3vowj7ed1PIKtu4444nNQC8g=; h=From:Date:Subject:In-Reply-To:To:Cc:References:From; b=Eu5z51NA7Yk+M1VBGwFFYmkydDctsBCFpi6uE0v/2tVcIkow7s7NMGOHxOxLfY8hT K3EfR/tRy5V9ejM6xuZ/mml9sO1tvt2dU2m8kbQLV1I6WEmrkMPbdz9RYoSeon2VAX QmaI2P8tMznOT+x86A00BMA19cGFLQHg9a14P9nw= Received: from eusmtip2.samsung.com (unknown [203.254.199.222]) by eucas1p2.samsung.com (KnoxPortal) with ESMTPA id 20250930122732eucas1p2fbf9c050934b356165377776a8aef247~qDyQdc00B2309923099eucas1p2w; Tue, 30 Sep 2025 12:27:32 +0000 (GMT) Received: from AMDC4942.eu.corp.samsungelectronics.net (unknown [106.210.136.40]) by eusmtip2.samsung.com (KnoxPortal) with ESMTPA id 20250930122730eusmtip2fa430534fbeba49aa7a2a625f228c890~qDyPSuez52410724107eusmtip2r; Tue, 30 Sep 2025 12:27:30 +0000 (GMT) From: Michal Wilczynski Date: Tue, 30 Sep 2025 14:20:33 +0200 Subject: [PATCH v15 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: <20250930-rust-next-pwm-working-fan-for-sending-v15-2-5661c3090877@samsung.com> In-Reply-To: <20250930-rust-next-pwm-working-fan-for-sending-v15-0-5661c3090877@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: 20250930122732eucas1p2fbf9c050934b356165377776a8aef247 X-Msg-Generator: CA Content-Type: text/plain; charset="utf-8" X-RootMTR: 20250930122732eucas1p2fbf9c050934b356165377776a8aef247 X-EPHeader: CA X-CMS-RootMailID: 20250930122732eucas1p2fbf9c050934b356165377776a8aef247 References: <20250930-rust-next-pwm-working-fan-for-sending-v15-0-5661c3090877@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 | 13 +++++ 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, 147 insertions(+) diff --git a/MAINTAINERS b/MAINTAINERS index fe168477caa45799dfe07de2f54de6d6a1ce0615..5d7c0676c1d00a02b3d7db2de88= b039c08c99c6e 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -20387,6 +20387,14 @@ 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 f00ce973dddf651287168b44228574f4d5c28dc0..2b608f4378138775ee3ba4d53f6= 82952e1914118 100644 --- a/drivers/pwm/Kconfig +++ b/drivers/pwm/Kconfig @@ -800,4 +800,17 @@ 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 "Rust PWM abstractions support" + depends on RUST + depends on PWM=3Dy + 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 84d60635e8a9baef1f1a1b2752dc0fa044f8542f..7a06ee5781eadc9f21ccd456b57= 4a9cb152cd58c 100644 --- a/rust/bindings/bindings_helper.h +++ b/rust/bindings/bindings_helper.h @@ -66,6 +66,7 @@ #include #include #include +#include #include #include #include diff --git a/rust/helpers/helpers.c b/rust/helpers/helpers.c index 7cf7fe95e41dd51717050648d6160bebebdf4b26..861052ffffaff60e9c2e8109e55= f3b6158ff2281 100644 --- a/rust/helpers/helpers.c +++ b/rust/helpers/helpers.c @@ -35,6 +35,7 @@ #include "platform.c" #include "poll.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 ed53169e795c0badf548025a57f946fa18bc73e3..e339b552f9650803b1efa1eb8ec= c6fe9d2c56563 100644 --- a/rust/kernel/lib.rs +++ b/rust/kernel/lib.rs @@ -117,6 +117,8 @@ 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