[PATCH 1/6] driver core: Introduce device_{add,remove}_of_node()

Herve Codina
2024-11-04T17:20:10Z

An of_node can be set to a device using device_set_node().
This function cannot prevent any of_node and/or fwnode overwrites.

When adding an of_node on an already present device, the following
operations need to be done:
- Attach the of_node if no of_node were already attached
- Attach the of_node as a fwnode if no fwnode were already attached

This is the purpose of device_add_of_node().
device_remove_of_node() reverts the operations done by
device_add_of_node().

Cc: stable@vger.kernel.org
Signed-off-by: Herve Codina <herve.codina@bootlin.com>
---
drivers/base/core.c | 52 ++++++++++++++++++++++++++++++++++++++++++
include/linux/device.h | 2 ++
2 files changed, 54 insertions(+)

diff --git a/drivers/base/core.c b/drivers/base/core.c
index 24c572031403..0aa63371f55d 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -5118,6 +5118,58 @@ void set_secondary_fwnode(struct device *dev, struct fwnode_handle *fwnode)
}
EXPORT_SYMBOL_GPL(set_secondary_fwnode);

+/**
+ * device_remove_of_node - Remove an of_node from a device
+ * @dev: device whose device-tree node is being removed
+ */
+void device_remove_of_node(struct device *dev)
+{
+ dev = get_device(dev);
+ if (!dev)
+ return;
+
+ if (!dev->of_node)
+ goto end;
+
+ if (dev->fwnode == of_fwnode_handle(dev->of_node))
+ dev->fwnode = NULL;
+
+ of_node_put(dev->of_node);
+ dev->of_node = NULL;
+
+end:
+ put_device(dev);
+}
+EXPORT_SYMBOL_GPL(device_remove_of_node);
+
+/**
+ * device_add_of_node - Add an of_node to an existing device
+ * @dev: device whose device-tree node is being added
+ * @of_node: of_node to add
+ */
+void device_add_of_node(struct device *dev, struct device_node *of_node)
+{
+ if (!of_node)
+ return;
+
+ dev = get_device(dev);
+ if (!dev)
+ return;
+
+ if (WARN(dev->of_node, "%s: Cannot replace node %pOF with %pOF\n",
+ dev_name(dev), dev->of_node, of_node))
+ goto end;
+
+ dev->of_node = of_node_get(of_node);
+
+ if (!dev->fwnode)
+ dev->fwnode = of_fwnode_handle(of_node);
+
+end:
+ put_device(dev);
+}
+EXPORT_SYMBOL_GPL(device_add_of_node);
+
/**
* device_set_of_node_from_dev - reuse device-tree node of another device
* @dev: device whose device-tree node is being set
diff --git a/include/linux/device.h b/include/linux/device.h
index b4bde8d22697..e3aa25ce1f90 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -1146,6 +1146,8 @@ int device_online(struct device *dev);
void set_primary_fwnode(struct device *dev, struct fwnode_handle *fwnode);
void set_secondary_fwnode(struct device *dev, struct fwnode_handle *fwnode);
void device_set_node(struct device *dev, struct fwnode_handle *fwnode);
+void device_add_of_node(struct device *dev, struct device_node *of_node);
+void device_remove_of_node(struct device *dev);
void device_set_of_node_from_dev(struct device *dev, const struct device *dev2);

static inline struct device_node *dev_of_node(struct device *dev)
--
2.46.2