1 files changed, 25 insertions, 0 deletions

diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
index e611f6797e6a..e7e4460dcb92 100644
--- a/drivers/regulator/core.c
+++ b/drivers/regulator/core.c
@@ -1629,6 +1629,7 @@ static int _regulator_do_set_voltage(struct regulator_dev *rdev,
                                      int min_uV, int max_uV)
 {
         int ret;
+        int delay = 0;
         unsigned int selector;
 
         trace_regulator_set_voltage(rdev_get_name(rdev), min_uV, max_uV);
@@ -1662,6 +1663,22 @@ static int _regulator_do_set_voltage(struct regulator_dev *rdev,
                         }
                 }
 
+                /*
+                 * If we can't obtain the old selector there is not enough
+                 * info to call set_voltage_time_sel().
+                 */
+                if (rdev->desc->ops->set_voltage_time_sel &&
+                    rdev->desc->ops->get_voltage_sel) {
+                        unsigned int old_selector = 0;
+
+                        ret = rdev->desc->ops->get_voltage_sel(rdev);
+                        if (ret < 0)
+                                return ret;
+                        old_selector = ret;
+                        delay = rdev->desc->ops->set_voltage_time_sel(rdev,
+                                                old_selector, selector);
+                }
+
                 if (best_val != INT_MAX) {
                         ret = rdev->desc->ops->set_voltage_sel(rdev, selector);
                         selector = best_val;
@@ -1672,6 +1689,14 @@ static int _regulator_do_set_voltage(struct regulator_dev *rdev,
                 ret = -EINVAL;
         }
 
+        /* Insert any necessary delays */
+        if (delay >= 1000) {
+                mdelay(delay / 1000);
+                udelay(delay % 1000);
+        } else if (delay) {
+                udelay(delay);
+        }
+
         if (ret == 0)
                 _notifier_call_chain(rdev, REGULATOR_EVENT_VOLTAGE_CHANGE,
                                      NULL);