From nobody Fri Dec 19 17:52:12 2025 Received: from mout-p-102.mailbox.org (mout-p-102.mailbox.org [80.241.56.152]) (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 A2B602DCBF7; Sat, 24 May 2025 19:22:59 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=80.241.56.152 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1748114581; cv=none; b=jSIe93b2HIXkQHE5ugrM2lD5wL0fMAg7gwu8V4eqwylqHL2J7hyZXhVGvQHqsOr4PFfdlq1ZpIq5KnrcvumDPOhELENhsRoM5aK0/xtf9yE6ReNM5HWYSCLtxcmYn9S128EcjcGwin/B90YiYJPtXTeG6Mnu+OuQRLwL0sHrq6Q= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1748114581; c=relaxed/simple; bh=fOzZvbDXSMEXRk0rGZRdRjBIfJRFcL7ZXeXZpEFVu9M=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=dbdKQCkjItkp5LGX0uvjlje2yv3+cRcoQk4PsRpZYq3ajNvYgmsxEVHDLiQKOA9X1gJt8QueAUft98u439XjuN49KqMAKIhLbhKGwYKY84bdxWaDOyAdbDWQLxsyFCq920FC+V9q2w8JfCGBdtZpXidfCqtHFSeO59GwRlYcqM4= 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=80.241.56.152 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 smtp102.mailbox.org (smtp102.mailbox.org [10.196.197.102]) (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-102.mailbox.org (Postfix) with ESMTPS id 4b4X402L0dz9tWL; Sat, 24 May 2025 21:22:56 +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 v6 4/9] rust: device: Enable printing fwnode name and path Date: Sat, 24 May 2025 21:22:27 +0200 Message-ID: <20250524192232.705860-5-remo@buenzli.dev> In-Reply-To: <20250524192232.705860-1-remo@buenzli.dev> References: <20250524192232.705860-1-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 | 75 ++++++++++++++++++++++++++++++++++ 1 file changed, 75 insertions(+) diff --git a/rust/kernel/device/property.rs b/rust/kernel/device/property.rs index 71a0605b8ecad..09c38775b2354 100644 --- a/rust/kernel/device/property.rs +++ b/rust/kernel/device/property.rs @@ -32,6 +32,81 @@ 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 { + self.0.as_raw() + } else { + // SAFETY: `self.0.as_raw()` is valid. + unsafe { bindings::fwnode_get_nth_parent(self.0.as= _raw(), depth) } + }; + + // SAFETY: `fwnode` is valid, it is either `self.0.as_= raw()` + // or the return value of `bindings::fwnode_get_nth_pa= rent` + // which returns a valid pointer to a `fwnode_handle` = if the + // provided depth is within the valid range, which we = know + // to be true. + let prefix =3D unsafe { bindings::fwnode_get_name_pref= ix(fwnode) }; + 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, "{}", self.0.display_name())?; + + if depth !=3D 0 { + // SAFETY: + // - `fwnode` is valid, because `depth` is + // a valid depth of a parent of `self.0.as_raw()= `. + // - `fwnode_get_nth_parent` increments the refcou= nt and + // we are responsible to decrement it. + unsafe { bindings::fwnode_handle_put(fwnode) } + } + } + + 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