On Tue, 4 Feb 2025 08:34:56 +0100
Herve Codina <herve.codina@xxxxxxxxxxx> wrote:
> 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().
>
> Signed-off-by: Herve Codina <herve.codina@xxxxxxxxxxx>
A few passing comments. Not suggestions to actually change anything
at this stage though. Maybe a potential follow up if you think it's
a good idea.
> ---
> drivers/base/core.c | 61 ++++++++++++++++++++++++++++++++++++++++++
> include/linux/device.h | 2 ++
> 2 files changed, 63 insertions(+)
>
> diff --git a/drivers/base/core.c b/drivers/base/core.c
> index 5a1f05198114..d1b044af64de 100644
> --- a/drivers/base/core.c
> +++ b/drivers/base/core.c
> @@ -5170,6 +5170,67 @@ 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;
Maybe use
struct device *d __free(put_device) = get_device(dev);
if (!d->of_node);
return;
Not a reason to respin though!
> +
> + 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
> + *
> + * Return: 0 on success or error code on failure.
> + */
> +int device_add_of_node(struct device *dev, struct device_node *of_node)
> +{
> + int ret;
> +
> + if (!of_node)
> + return -EINVAL;
> +
> + dev = get_device(dev);
Likewise could use __free() magic here as well for slight simpliciations.
> + if (!dev)
> + return -EINVAL;
> +
> + if (dev->of_node) {
> + dev_err(dev, "Cannot replace node %pOF with %pOF\n",
> + dev->of_node, of_node);
> + ret = -EBUSY;
> + goto end;
> + }
> +
> + dev->of_node = of_node_get(of_node);
> +
> + if (!dev->fwnode)
> + dev->fwnode = of_fwnode_handle(of_node);
> +
> + ret = 0;
> +end:
> + put_device(dev);
> + return ret;
> +}
> +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 80a5b3268986..1244e5892292 100644
> --- a/include/linux/device.h
> +++ b/include/linux/device.h
> @@ -1191,6 +1191,8 @@ 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);
> +int 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)
