An of_node can be duplicated from an existing device using device_set_of_node_from_dev() or initialized using device_set_node() In both cases, these functions have to be called before the device_add() call in order to have the of_node link created in the device sysfs directory. Further more, these 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 - Create the of_node sysfs link if needed
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 | 74 ++++++++++++++++++++++++++++++++++++++++++ include/linux/device.h | 2 ++ 2 files changed, 76 insertions(+)
diff --git a/drivers/base/core.c b/drivers/base/core.c index 521757408fc0..7e3af0ad770a 100644 --- a/drivers/base/core.c +++ b/drivers/base/core.c @@ -5127,6 +5127,80 @@ 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; + + sysfs_remove_link(&dev->kobj, "of_node"); + + 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) +{ + int ret; + + if (!of_node) + return; + + dev = get_device(dev); + if (!dev) + return; + + if (dev->of_node) { + dev_warn(dev, "Replace node %pOF with %pOF\n", dev->of_node, of_node); + device_remove_of_node(dev); + } + + dev->of_node = of_node_get(of_node); + + if (!dev->fwnode) + dev->fwnode = of_fwnode_handle(of_node); + + if (!dev->p) { + /* + * device_add() was not previously called. + * The of_node link will be created when device_add() is called. + */ + goto end; + } + + /* + * device_add() was previously called and so the of_node link was not + * created by device_add_class_symlinks(). + * Create this link now. + */ + ret = sysfs_create_link(&dev->kobj, of_node_kobj(of_node), "of_node"); + if (ret) + dev_warn(dev, "Error %d creating of_node link\n", ret); + +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 97c4b046c09d..1795121dee9a 100644 --- a/include/linux/device.h +++ b/include/linux/device.h @@ -1127,6 +1127,8 @@ int device_offline(struct device *dev); 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_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); void device_set_node(struct device *dev, struct fwnode_handle *fwnode);