On Thu, Oct 29, 2020 at 04:15:38PM +0100, Vincent Whitchurch wrote:

> +	config.init_data = of_get_regulator_init_data(dev, dev->of_node, &da9121_reg);
> +	if (!config.init_data)
> +		return -ENOMEM;

Don't do this, the core can do the DT bit for you and there is no reason
not to register the device if there are no constraints.  -ENOMEM would
also be the wrong error code here.