regulator: hi6421v600: Fix setting idle mode

commit db27f829 changed eco_mode << (ffs(sreg->eco_mode_mask) - 1)
to sreg->eco_mode_mask << (ffs(sreg->eco_mode_mask) - 1) which is wrong.
Fix it by simply set val = sreg->eco_mode_mask.

In additional, sreg->eco_mode_mask can be 0 (LDO3, LDO33, LDO34).
Return -EINVAL if idle mode is not supported when sreg->eco_mode_mask is 0.

While at it, also use unsigned int for reg_val/val which is the expected
type for regmap_read and regmap_update_bits.

Fixes: db27f829 ("staging: regulator: hi6421v600-regulator: use shorter names for OF properties")
Signed-off-by: Axel Lin <axel.lin@ingics.com>
Link: https://lore.kernel.org/r/20210619123423.4091429-1-axel.lin@ingics.comSigned-off-by: Mark Brown <broonie@kernel.org>

drivers/regulator/hi6421v600-regulator.c

@@ -117,7 +117,7 @@ static int hi6421_spmi_regulator_enable(struct regulator_dev *rdev)
 static unsigned int hi6421_spmi_regulator_get_mode(struct regulator_dev *rdev)
 {
 	struct hi6421_spmi_reg_info *sreg = rdev_get_drvdata(rdev);
-	u32 reg_val;
+	unsigned int reg_val;
 
 	regmap_read(rdev->regmap, rdev->desc->enable_reg, &reg_val);
 
@@ -131,14 +131,17 @@ static int hi6421_spmi_regulator_set_mode(struct regulator_dev *rdev,
 					  unsigned int mode)
 {
 	struct hi6421_spmi_reg_info *sreg = rdev_get_drvdata(rdev);
-	u32 val;
+	unsigned int val;
 
 	switch (mode) {
 	case REGULATOR_MODE_NORMAL:
 		val = 0;
 		break;
 	case REGULATOR_MODE_IDLE:
-		val = sreg->eco_mode_mask << (ffs(sreg->eco_mode_mask) - 1);
+		if (!sreg->eco_mode_mask)
+			return -EINVAL;
+
+		val = sreg->eco_mode_mask;
 		break;
 	default:
 		return -EINVAL;