On Mon, Aug 28, 2017 at 02:58:52PM +0200, Fabrice Gasnier wrote:

> +	ret = clk_prepare_enable(priv->clk);
> +	if (ret) {
> +		dev_err(&pdev->dev, "clk prepare failed\n");

If you're printing an error include the error code, it'll help users
figure out what went wrong.

> +	dev_info(&pdev->dev, "STM32 VREFBUF initialized\n");

This is just noise, remove it.

> +static int __init stm32_vrefbuf_init(void)
> +{
> +	return platform_driver_register(&stm32_vrefbuf_driver);
> +}
> +subsys_initcall(stm32_vrefbuf_init);

Why is this at subsys_initcall()?