regulators: helpers: Fix handling of bypass_val_on in get_bypass_regmap

The handling of bypass_val_on that was added in
regulator_get_bypass_regmap is done unconditionally however
several drivers don't define a value for bypass_val_on. This
results in those drivers reporting bypass being enabled when
it is not. In regulator_set_bypass_regmap we use bypass_mask
if bypass_val_on is zero. This patch adds similar handling in
regulator_get_bypass_regmap.

Fixes: commit dd1a571d ("regulator: helpers: Ensure bypass register field matches ON value")
Signed-off-by: Charles Keepax <ckeepax@opensource.wolfsonmicro.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

drivers/regulator/helpers.c

@@ -454,13 +454,17 @@ EXPORT_SYMBOL_GPL(regulator_set_bypass_regmap);
 int regulator_get_bypass_regmap(struct regulator_dev *rdev, bool *enable)
 {
 	unsigned int val;
+	unsigned int val_on = rdev->desc->bypass_val_on;
 	int ret;
 
 	ret = regmap_read(rdev->regmap, rdev->desc->bypass_reg, &val);
 	if (ret != 0)
 		return ret;
 
-	*enable = (val & rdev->desc->bypass_mask) == rdev->desc->bypass_val_on;
+	if (!val_on)
+		val_on = rdev->desc->bypass_mask;
+
+	*enable = (val & rdev->desc->bypass_mask) == val_on;
 
 	return 0;
 }