From 21854f052025f53b8ca31e9a5bf28738ae5f9810 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Mateusz=20Ma=C4=87kowski?= <mmac@google.com>
Date: Tue, 7 Jul 2026 10:08:08 +0000
Subject: [PATCH 1/2] feat(model): add `DeviceTree::find_node` read-only lookup

---
 src/model.rs | 35 +++++++++++++++++++++++++++++++++++
 1 file changed, 35 insertions(+)

diff --git a/src/model.rs b/src/model.rs
index 0a38d44..00e842b 100644
--- a/src/model.rs
+++ b/src/model.rs
@@ -23,6 +23,7 @@ use core::fmt::Display;
 pub use node::{DeviceTreeNode, DeviceTreeNodeBuilder};
 pub use property::DeviceTreeProperty;
 
+use crate::Node;
 use crate::fdt::Fdt;
 use crate::memreserve::MemoryReservation;
 
@@ -89,6 +90,40 @@ impl DeviceTree {
         }
     }
 
+    /// Finds a node by its path and returns a reference to it.
+    ///
+    /// # Performance
+    ///
+    /// This method traverses the device tree, but since child lookup is a
+    /// constant-time operation, performance is linear in the number of path
+    /// segments.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use dtoolkit::Node;
+    /// use dtoolkit::model::{DeviceTree, DeviceTreeNode};
+    ///
+    /// let mut tree = DeviceTree::new();
+    /// tree.root.add_child(DeviceTreeNode::new("child").unwrap());
+    /// let child = tree.find_node("/child").unwrap();
+    /// assert_eq!(child.name(), "child");
+    /// ```
+    #[must_use]
+    pub fn find_node(&self, path: &str) -> Option<&DeviceTreeNode> {
+        if !path.starts_with('/') {
+            return None;
+        }
+        let mut current_node = &self.root;
+        if path == "/" {
+            return Some(current_node);
+        }
+        for component in path.split('/').filter(|s| !s.is_empty()) {
+            current_node = current_node.child(component)?;
+        }
+        Some(current_node)
+    }
+
     /// Finds a node by its path and returns a mutable reference to it.
     ///
     /// # Performance

From fd77afa778f0100506503bab1295f0cff8042fe0 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Mateusz=20Ma=C4=87kowski?= <mmac@google.com>
Date: Wed, 15 Jul 2026 13:32:43 +0000
Subject: [PATCH 2/2] feat(model): add DeviceTreeNode::add_child_mut

---
 src/model/node.rs | 30 ++++++++++++++++++++++++++++++
 1 file changed, 30 insertions(+)

diff --git a/src/model/node.rs b/src/model/node.rs
index 06b571f..3b5b5c8 100644
--- a/src/model/node.rs
+++ b/src/model/node.rs
@@ -392,6 +392,36 @@ impl DeviceTreeNode {
         self.children.insert(child.name.clone(), child);
     }
 
+    /// Adds a child to this node, returning a reference to it.
+    ///
+    /// # Performance
+    ///
+    /// This is a constant-time operation.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use dtoolkit::model::{DeviceTreeNode, DeviceTreeProperty};
+    /// use dtoolkit::{Node, Property};
+    ///
+    /// let mut node = DeviceTreeNode::new("my-node").unwrap();
+    /// let mut child = node.add_child_mut(DeviceTreeNode::new("child").unwrap());
+    /// child.add_property(DeviceTreeProperty::new("test", "value").unwrap());
+    /// assert_eq!(
+    ///     (&node)
+    ///         .child("child")
+    ///         .unwrap()
+    ///         .property("test")
+    ///         .unwrap()
+    ///         .value(),
+    ///     b"value"
+    /// );
+    /// ```
+    #[must_use]
+    pub fn add_child_mut(&mut self, child: DeviceTreeNode) -> &mut DeviceTreeNode {
+        self.children.entry(child.name.clone()).or_insert(child)
+    }
+
     /// Removes a child from this node by its name.
     ///
     /// # Performance