On Mon, Sep 14, 2020 at 11:04:42AM +0800, Henry Chen wrote:

> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (c) 2019 MediaTek Inc.
> + */

Please make the entire comment a C++ one so things look more
intentional, and are you sure about that copyright date?

> +static int dvfsrc_set_voltage_sel(struct regulator_dev *rdev,
> +				  unsigned int selector)
> +{
> +	struct device *dvfsrc_dev = to_dvfsrc_dev(rdev);
> +	int id = rdev_get_id(rdev);
> +
> +	switch (id) {
> +	case DVFSRC_ID_VCORE:
> +		mtk_dvfsrc_send_request(dvfsrc_dev,
> +					MTK_DVFSRC_CMD_VCORE_REQUEST,
> +					selector);
> +	break;
> +	case DVFSRC_ID_VSCP:
> +		mtk_dvfsrc_send_request(dvfsrc_dev,
> +					MTK_DVFSRC_CMD_VSCP_REQUEST,
> +					selector);
> +	break;

Just have two separate operations rather than the switch statement, and
where you do have switch statements please follow the kernel coding
style.