regulator: mt6397: Implement of_map_mode

Implementing of_map_mode is necessary to be able to specify operating
modes in the devicetree using 'regulator-allowed-modes', and to change
regulator modes.

Signed-off-by: Anand K Mistry <amistry@google.com>
Link: https://lore.kernel.org/r/20200702162231.v2.3.I7acfb591bfacf3b1b04a3d388385098bfcc9fecd@changeid
Signed-off-by: Mark Brown <broonie@kernel.org>

drivers/regulator/mt6397-regulator.c

@@ -53,6 +53,7 @@ struct mt6397_regulator_info {
 		.vsel_mask = vosel_mask,				\
 		.enable_reg = enreg,					\
 		.enable_mask = BIT(0),					\
+		.of_map_mode = mt6397_map_mode,				\
 	},								\
 	.qi = BIT(13),							\
 	.vselon_reg = voselon,						\
@@ -144,6 +145,18 @@ static const unsigned int ldo_volt_table7[] = {
 	1300000, 1500000, 1800000, 2000000, 2500000, 2800000, 3000000, 3300000,
 };
 
+static unsigned int mt6397_map_mode(unsigned int mode)
+{
+	switch (mode) {
+	case MT6397_BUCK_MODE_AUTO:
+		return REGULATOR_MODE_NORMAL;
+	case MT6397_BUCK_MODE_FORCE_PWM:
+		return REGULATOR_MODE_FAST;
+	default:
+		return REGULATOR_MODE_INVALID;
+	}
+}
+
 static int mt6397_regulator_set_mode(struct regulator_dev *rdev,
 				     unsigned int mode)
 {