2 files changed, 29 insertions, 0 deletions

diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
index 5c6aedaa934d..ff76abde3ab3 100644
--- a/drivers/regulator/core.c
+++ b/drivers/regulator/core.c
@@ -2280,6 +2280,30 @@ int regulator_set_voltage_time(struct regulator *regulator,
 EXPORT_SYMBOL_GPL(regulator_set_voltage_time);
 
 /**
+ *regulator_set_voltage_time_sel - get raise/fall time
+ * @regulator: regulator source
+ * @old_selector: selector for starting voltage
+ * @new_selector: selector for target voltage
+ *
+ * Provided with the starting and target voltage selectors, this function
+ * returns time in microseconds required to rise or fall to this new voltage
+ *
+ * Drivers providing uV_step in their regulator_desc and ramp_delay in
+ * regulation_constraints can use this as their set_voltage_time_sel()
+ * operation.
+ */
+int regulator_set_voltage_time_sel(struct regulator_dev *rdev,
+                                   unsigned int old_selector,
+                                   unsigned int new_selector)
+{
+        if (rdev->desc->ramp_delay && rdev->desc->uV_step)
+                return DIV_ROUND_UP(rdev->desc->uV_step *
+                        abs(new_selector - old_selector),
+                        rdev->desc->ramp_delay) * 1000;
+        return 0;
+}
+
+/**
  * regulator_sync_voltage - re-apply last regulator output voltage
  * @regulator: regulator source
  *
diff --git a/include/linux/regulator/driver.h b/include/linux/regulator/driver.h
index 80226383e561..ae5c25379237 100644
--- a/include/linux/regulator/driver.h
+++ b/include/linux/regulator/driver.h
@@ -170,6 +170,7 @@ enum regulator_type {
  *
  * @min_uV: Voltage given by the lowest selector (if linear mapping)
  * @uV_step: Voltage increase with each selector (if linear mapping)
+ * @ramp_delay: Time to settle down after voltage change (unit: mV/us)
  * @volt_table: Voltage mapping table (if table based mapping)
  *
  * @vsel_reg: Register for selector when using regulator_regmap_X_voltage_
@@ -189,6 +190,7 @@ struct regulator_desc {
 
         unsigned int min_uV;
         unsigned int uV_step;
+        unsigned int ramp_delay;
 
         const unsigned int *volt_table;
 
@@ -285,6 +287,9 @@ int regulator_set_voltage_sel_regmap(struct regulator_dev *rdev, unsigned sel);
 int regulator_is_enabled_regmap(struct regulator_dev *rdev);
 int regulator_enable_regmap(struct regulator_dev *rdev);
 int regulator_disable_regmap(struct regulator_dev *rdev);
+int regulator_set_voltage_time_sel(struct regulator_dev *rdev,
+                                   unsigned int old_selector,
+                                   unsigned int new_selector);
 
 void *regulator_get_init_drvdata(struct regulator_init_data *reg_init_data);