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 <remo@buenzli.dev>
---
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},
};
/// A reference-counted fwnode_handle.
@@ -57,6 +57,83 @@ pub(crate) fn as_raw(&self) -> *mut bindings::fwnode_handle {
self.0.get()
}
+ /// 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 = 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 = 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 invariant.
+ let num_parents = unsafe { bindings::fwnode_count_parents(self.0.as_raw()) };
+
+ for depth in (0..=num_parents).rev() {
+ let fwnode = if depth == 0 {
+ Either::Left(self.0)
+ } else {
+ // SAFETY: `self.0.as_raw()` is valid.
+ let ptr =
+ 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 pointer 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 = match &fwnode {
+ Either::Left(f) => f,
+ Either::Right(f) => f,
+ };
+
+ // SAFETY: `fwnode` is valid by its type invariant.
+ let prefix = unsafe { bindings::fwnode_get_name_prefix(fwnode.as_raw()) };
+ if !prefix.is_null() {
+ // SAFETY: `fwnode_get_name_prefix` returns null or a
+ // valid C string.
+ let prefix = 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.
--
2.49.0