On Mon, May 26, 2025 at 04:20:37PM +0800, Ai Chao wrote:

Hi Johannes:

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Hi Johannes:

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"simplifies the code" is no need to callof_node_put() .

Fair. Except that's not what you _actually_ changed here. Like I said,
either it's buggy before or after.

In the function i2sbus_probe, it not return a struct device_node, so , I
think function for_each_child_of_node_scoped is better than
for_each_child_of_node.

You still haven't explained why it's even correct.

johannes

The for_each_child_of_node() function is used to iterate over all child
nodes of a device tree node.
During each iteration, it retrieves a pointer to the child node via
of_get_next_child() and automatically increments the node's reference count
(of_node_get()).

This is not complete story, you missed the second part of it.

Each call to of_get_next_child() increases the reference count (refcount) of
the returned child node, ensuring that the node is not freed while in use.
for_each_child_of_node() increments the child node's reference count in each
iteration but does not decrement it automatically.
If of_node_put() is not called manually, the reference count will never
reach zero, resulting in a memory leak of the node.

Best regards,
Ai Chao

-- 
With best wishes
Dmitry