[PATCH v8 3/8] nvmem: core: take a reference on dev.of_node in nvmem_register()

[Michael Walle]

On Wed Oct 14, 2026 at 8:40 AM CEST, Manikandan Muralidharan wrote:
> nvmem_register() stores config->of_node (or config->dev->of_node)
> into nvmem->dev.of_node without taking its own reference. Callers
> that get the node via of_get_compatible_child() etc. and drop their
> reference right after registering leave nvmem->dev.of_node backed by
> no reference at all.
>
> Take an of_node_get() when assigning nvmem->dev.of_node and release
> it in nvmem_release(). Existing callers that hold their own get/put
> pair around the registration call need no changes, since get/put on
> a device_node is per-holder and independent of core now also holding
> one.
>
> Suggested-by: Michael Walle <mwalle at kernel.org>
> Signed-off-by: Manikandan Muralidharan <manikandan.m at microchip.com>

Nice!

Did you check if any callers are also taking a reference, which
might not be needed anymore now.

Reviewed-by: Michael Walle <mwalle at kernel.org>

-michael

> ---
>  drivers/nvmem/core.c | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/nvmem/core.c b/drivers/nvmem/core.c
> index 0556d140170a..98192597b935 100644
> --- a/drivers/nvmem/core.c
> +++ b/drivers/nvmem/core.c
> @@ -541,6 +541,7 @@ static void nvmem_release(struct device *dev)
>  
>  	ida_free(&nvmem_ida, nvmem->id);
>  	gpiod_put(nvmem->wp_gpio);
> +	of_node_put(nvmem->dev.of_node);
>  	kfree(nvmem->ops);
>  	kfree(nvmem);
>  }
> @@ -950,9 +951,9 @@ struct nvmem_device *nvmem_register(const struct nvmem_config *config)
>  	nvmem->keepout = config->keepout;
>  	nvmem->nkeepout = config->nkeepout;
>  	if (config->of_node)
> -		nvmem->dev.of_node = config->of_node;
> +		nvmem->dev.of_node = of_node_get(config->of_node);
>  	else
> -		nvmem->dev.of_node = config->dev->of_node;
> +		nvmem->dev.of_node = of_node_get(config->dev->of_node);
>  
>  	switch (config->id) {
>  	case NVMEM_DEVID_NONE:

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