Re: [PATCH 1/4] driver: core: introduce dev_add_sync_state()

[Konrad Dybcio]

On 6/26/26 6:32 PM, Brian Masney wrote:
> We have cases where a device node represents a provider for multiple
> types of resources, like clocks, power-domains, resets, etc. We
> currently have dev_set_drv_sync_state() where a framework or driver
> can set the sync_state callback for a device node, however it currently
> only supports a single sync_state callback.
> 
> The pmdomain subsystem currently sets up a sync_state callback in the
> core framework, and the clk subsystem will setup it's own separate
> sync_state callback in the core framework. These can collide with each
> other on some types of devices that have multiple types of resources.
> Additionally, some clk drivers already have their own separate
> sync_state callback already defined.
> 
> Let's introduce support for allowing drivers and frameworks to add their
> own sync_state callback via a new function dev_add_sync_state() so that
> multiple sync_state callbacks can coexist.
> 
> Link: https://lore.kernel.org/linux-clk/CAPx+jO9JiV16ePLk59hTQzEMnA96Va6Ns4jqJbwyZ6oTT0AjXA@xxxxxxxxxxxxxx/
> Signed-off-by: Brian Masney <bmasney@xxxxxxxxxx>
> Assisted-by: Claude:claude-opus-4-6
> ---

[...]

> +int dev_add_sync_state(struct device *dev,
> +			   void (*fn)(struct device *dev))
> +{
> +	struct sync_state_entry *entry;
> +
> +	if (!dev || !dev->driver)
> +		return 0;
> +
> +	list_for_each_entry(entry, &dev->sync_state_list, node)
> +		if (entry->fn == fn)
> +			return 0;

Do we expect this to be a valid call, i.e. should we WARN_ON here?

Konrad