From nobody Thu Dec 18 12:51:55 2025 Received: from mout-p-101.mailbox.org (mout-p-101.mailbox.org [80.241.56.151]) (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 D3F6C27BF86; Fri, 30 May 2025 19:29:36 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=80.241.56.151 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1748633378; cv=none; b=Ejc+U8ph88T9w9lZupq0ahb4CublbaL3hMoxCNI6jl+EB3QAGMdnb9bXamWxtA/rM/08iTXU1AUNtmDX7WrnoQO3xHzJSn2JqeL45m3ZpWZotMS5KiCbCwUc/jGnYTBZvlAcO1rNjlzOxh2cS65qk4k2o9Djeyqj4WL3fE9yvxw= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1748633378; c=relaxed/simple; bh=kznznVOiTt0rMPoIbwckts/UG2t7rn7iMzsEsUG214w=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=JMyT+3A40BNd6Cx5bzI5P2v90pT2G2QB4fg84E9F2DykrWviuDuuBDQpEi/8romBMrQH9nbKeAUInWP1Yt1CpEPyTxsvMNX80I495JRL/erwHcBD+ny06ChlK1YAwPV0yhkzb1v7pHpMXaEPvw+FaDuJq15gy0egUNWRxcct8cs= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=buenzli.dev; spf=pass smtp.mailfrom=buenzli.dev; arc=none smtp.client-ip=80.241.56.151 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=buenzli.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=buenzli.dev Received: from smtp1.mailbox.org (smtp1.mailbox.org [10.196.197.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by mout-p-101.mailbox.org (Postfix) with ESMTPS id 4b8Cws1XJzz9spY; Fri, 30 May 2025 21:29:33 +0200 (CEST) From: Remo Senekowitsch To: Rob Herring , Saravana Kannan , Miguel Ojeda , Alex Gaynor , Boqun Feng , Gary Guo , =?UTF-8?q?Bj=C3=B6rn=20Roy=20Baron?= , Benno Lossin , Andreas Hindborg , Alice Ryhl , Trevor Gross , Danilo Krummrich , Greg Kroah-Hartman , "Rafael J. Wysocki" , Dirk Behme , Remo Senekowitsch Cc: linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, rust-for-linux@vger.kernel.org Subject: [PATCH v7 4/9] rust: device: Enable printing fwnode name and path Date: Fri, 30 May 2025 21:28:51 +0200 Message-ID: <20250530192856.1177011-5-remo@buenzli.dev> In-Reply-To: <20250530192856.1177011-1-remo@buenzli.dev> References: <20250530192856.1177011-1-remo@buenzli.dev> 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 Content-Type: text/plain; charset="utf-8" Add two new public methods `display_name` and `display_path` to `FwNode`. They can be used by driver authors for logging purposes. In addition, they will be used by core property abstractions for automatic logging, for example when a driver attempts to read a required but missing property. Signed-off-by: Remo Senekowitsch --- rust/kernel/device/property.rs | 79 +++++++++++++++++++++++++++++++++- 1 file changed, 78 insertions(+), 1 deletion(-) diff --git a/rust/kernel/device/property.rs b/rust/kernel/device/property.rs index 50c61aa056e6b..8e0414b0517e4 100644 --- a/rust/kernel/device/property.rs +++ b/rust/kernel/device/property.rs @@ -9,7 +9,7 @@ use crate::{ bindings, str::CStr, - types::{ARef, Opaque}, + types::{ARef, Either, Opaque}, }; =20 /// A reference-counted fwnode_handle. @@ -57,6 +57,83 @@ pub(crate) fn as_raw(&self) -> *mut bindings::fwnode_han= dle { self.0.get() } =20 + /// Returns an object that implements [`Display`](core::fmt::Display) = for + /// printing the name of a node. + pub fn display_name(&self) -> impl core::fmt::Display + '_ { + struct FwNodeDisplayName<'a>(&'a FwNode); + + impl core::fmt::Display for FwNodeDisplayName<'_> { + fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::= Result { + // SAFETY: `self` is valid by its type invariant. + let name =3D unsafe { bindings::fwnode_get_name(self.0.as_= raw()) }; + if name.is_null() { + return Ok(()); + } + // SAFETY: + // - `fwnode_get_name` returns null or a valid C string. + // - `name` was checked to be non-null. + let name =3D unsafe { CStr::from_char_ptr(name) }; + write!(f, "{name}") + } + } + + FwNodeDisplayName(self) + } + + /// Returns an object that implements [`Display`](core::fmt::Display) = for + /// printing the full path of a node. + pub fn display_path(&self) -> impl core::fmt::Display + '_ { + struct FwNodeDisplayPath<'a>(&'a FwNode); + + impl core::fmt::Display for FwNodeDisplayPath<'_> { + fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::= Result { + // The logic here is the same as the one in lib/vsprintf.c + // (fwnode_full_name_string). + + // SAFETY: `self.0.as_raw()` is valid by its type invarian= t. + let num_parents =3D unsafe { bindings::fwnode_count_parent= s(self.0.as_raw()) }; + + for depth in (0..=3Dnum_parents).rev() { + let fwnode =3D if depth =3D=3D 0 { + Either::Left(self.0) + } else { + // SAFETY: `self.0.as_raw()` is valid. + let ptr =3D + unsafe { bindings::fwnode_get_nth_parent(self.= 0.as_raw(), depth) }; + // SAFETY: + // - The depth passed to `fwnode_get_nth_parent` is + // within the valid range, so the returned point= er is + // not null. + // - The reference count was incremented by + // `fwnode_get_nth_parent`. + // - That increment is relinquished to + // `FwNode::from_raw`. + Either::Right(unsafe { FwNode::from_raw(ptr) }) + }; + // Take a reference to the owned or borrowed `FwNode`. + let fwnode: &FwNode =3D match &fwnode { + Either::Left(f) =3D> f, + Either::Right(f) =3D> f, + }; + + // SAFETY: `fwnode` is valid by its type invariant. + let prefix =3D unsafe { bindings::fwnode_get_name_pref= ix(fwnode.as_raw()) }; + if !prefix.is_null() { + // SAFETY: `fwnode_get_name_prefix` returns null o= r a + // valid C string. + let prefix =3D unsafe { CStr::from_char_ptr(prefix= ) }; + write!(f, "{prefix}")?; + } + write!(f, "{}", fwnode.display_name())?; + } + + Ok(()) + } + } + + FwNodeDisplayPath(self) + } + /// Checks if property is present or not. pub fn property_present(&self, name: &CStr) -> bool { // SAFETY: By the invariant of `CStr`, `name` is null-terminated. --=20 2.49.0