On Mon, Aug 05, 2019 at 01:21:55PM +0800, Hsin-Hsiung Wang wrote:

+static const u32 vmch_voltages[] = {
+	2900000, 3000000, 3300000,
+};

+static const u32 vemc_voltages[] = {
+	2900000, 3000000, 3300000,
+};

Several of these tables appear to be identical.

+static inline unsigned int mt6358_map_mode(unsigned int mode)
+{
+	return mode == MT6358_BUCK_MODE_AUTO ?
+		REGULATOR_MODE_NORMAL : REGULATOR_MODE_FAST;
+}

There is no need for this to be an inline and please write normal
conditional statements to improve legibility.  There's other examples in
the driver.

+static int mt6358_get_buck_voltage_sel(struct regulator_dev *rdev)
+{
+	int ret, regval;
+	struct mt6358_regulator_info *info = rdev_get_drvdata(rdev);
+
+	ret = regmap_read(rdev->regmap, info->da_vsel_reg, &regval);
+	if (ret != 0) {
+		dev_info(&rdev->dev,
+			 "Failed to get mt6358 Buck %s vsel reg: %d\n",
+			 info->desc.name, ret);

dev_err() for errors here and throughout the driver.

+		return ret;
+	}
+
+	ret = (regval >> info->da_vsel_shift) & info->da_vsel_mask;
+
+	return ret;
+}

This looks like a standard get_voltage_sel_regmap()?

+err_mode:
+	if (ret != 0)
+		return ret;
+
+	return 0;

Or just return ret unconditionally?