regulator: core: Allow fixed enable_time to be set in the regulator_desc

Many regulators have a fixed specification for their enable time. Allow
this to be set in the regulator_desc as a number to save them having to
implement an explicit operation.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

drivers/regulator/core.c

@@ -1189,7 +1189,7 @@ static struct regulator *create_regulator(struct regulator_dev *rdev,
 static int _regulator_get_enable_time(struct regulator_dev *rdev)
 {
 	if (!rdev->desc->ops->enable_time)
-		return 0;
+		return rdev->desc->enable_time;
 	return rdev->desc->ops->enable_time(rdev);
 }
 

include/linux/regulator/driver.h

@@ -180,6 +180,8 @@ enum regulator_type {
  * @vsel_mask: Mask for register bitfield used for selector
  * @enable_reg: Register for control when using regmap enable/disable ops
  * @enable_mask: Mask for control when using regmap enable/disable ops
+ *
+ * @enable_time: Time taken for initial enable of regulator (in uS).
  */
 struct regulator_desc {
 	const char *name;
@@ -201,6 +203,8 @@ struct regulator_desc {
 	unsigned int vsel_mask;
 	unsigned int enable_reg;
 	unsigned int enable_mask;
+
+	unsigned int enable_time;
 };
 
 /**