1 files changed, 45 insertions, 0 deletions

diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
index e7e4460dcb92..3ffc6979d164 100644
--- a/drivers/regulator/core.c
+++ b/drivers/regulator/core.c
@@ -1765,6 +1765,51 @@ out:
 EXPORT_SYMBOL_GPL(regulator_set_voltage);
 
 /**
+ * regulator_set_voltage_time - get raise/fall time
+ * @regulator: regulator source
+ * @old_uV: starting voltage in microvolts
+ * @new_uV: target voltage in microvolts
+ *
+ * Provided with the starting and ending voltage, this function attempts to
+ * calculate the time in microseconds required to rise or fall to this new
+ * voltage.
+ */
+int regulator_set_voltage_time(struct regulator *regulator,
+                               int old_uV, int new_uV)
+{
+        struct regulator_dev    *rdev = regulator->rdev;
+        struct regulator_ops    *ops = rdev->desc->ops;
+        int old_sel = -1;
+        int new_sel = -1;
+        int voltage;
+        int i;
+
+        /* Currently requires operations to do this */
+        if (!ops->list_voltage || !ops->set_voltage_time_sel
+            || !rdev->desc->n_voltages)
+                return -EINVAL;
+
+        for (i = 0; i < rdev->desc->n_voltages; i++) {
+                /* We only look for exact voltage matches here */
+                voltage = regulator_list_voltage(regulator, i);
+                if (voltage < 0)
+                        return -EINVAL;
+                if (voltage == 0)
+                        continue;
+                if (voltage == old_uV)
+                        old_sel = i;
+                if (voltage == new_uV)
+                        new_sel = i;
+        }
+
+        if (old_sel < 0 || new_sel < 0)
+                return -EINVAL;
+
+        return ops->set_voltage_time_sel(rdev, old_sel, new_sel);
+}
+EXPORT_SYMBOL_GPL(regulator_set_voltage_time);
+
+/**
  * regulator_sync_voltage - re-apply last regulator output voltage
  * @regulator: regulator source
  *