regulator: core: introduce regulator disable time

It is observed that some regulators do not get re-enabled without
waiting for the duration of disable time to completely turn off
Introduce the regulator disable time to make sure regulators are
disabled before enabling it.

Bug 1346985

Change-Id: I0bfff8f32dab7986ffab901b735fad6b4ec79c6f
Signed-off-by: Laxman Dewangan <ldewangan@nvidia.com>
Signed-off-by: Vineel Kumar Reddy Kovvuri <vineelkumarr@nvidia.com>
Reviewed-on: http://git-master/r/288742

1 files changed, 46 insertions, 2 deletions

diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
index 869b19722692..442eb6a76c94 100644
--- a/drivers/regulator/core.c
+++ b/drivers/regulator/core.c
@@ -108,6 +108,7 @@ static int _regulator_is_enabled(struct regulator_dev *rdev);
 static int _regulator_disable(struct regulator_dev *rdev);
 static int _regulator_enable(struct regulator_dev *rdev);
 static int _regulator_get_enable_time(struct regulator_dev *rdev);
+static int _regulator_get_disable_time(struct regulator_dev *rdev);
 static int _regulator_get_voltage(struct regulator_dev *rdev);
 static int _regulator_get_current_limit(struct regulator_dev *rdev);
 static unsigned int _regulator_get_mode(struct regulator_dev *rdev);
@@ -481,15 +482,25 @@ static ssize_t regulator_state_set(struct device *dev,
 			udelay(delay);
 		}
 	} else {
+		int delay = 0;
 		if (!rdev->desc->ops->disable) {
 			ret = -EINVAL;
 			goto end;
 		}
+		ret = _regulator_get_disable_time(rdev);
+		if (ret >= 0)
+			delay = ret;
 		ret = rdev->desc->ops->disable(rdev);
 		if (ret < 0) {
 			rdev_warn(rdev, "disable() failed: %d\n", ret);
 			goto end;
 		}
+		if (delay >= 1000) {
+			mdelay(delay / 1000);
+			udelay(delay % 1000);
+		} else if (delay) {
+			udelay(delay);
+		}
 	}
 
 end:
@@ -1171,8 +1182,9 @@ static int set_machine_constraints(struct regulator_dev *rdev,
 			if (ret >= 1000) {
 				mdelay(ret / 1000);
 				udelay(ret % 1000);
-			} else
+			} else {
 				udelay(ret);
+			}
 		}
 	}
 
@@ -1182,6 +1194,16 @@ static int set_machine_constraints(struct regulator_dev *rdev,
 			rdev_err(rdev, "failed to disable\n");
 			goto out;
 		}
+
+		ret = _regulator_get_disable_time(rdev);
+		if (ret > 0) {
+			if (ret >= 1000) {
+				mdelay(ret / 1000);
+				udelay(ret % 1000);
+			} else {
+				udelay(ret);
+			}
+		}
 	}
 
 	if (rdev->constraints->ramp_delay && ops->set_ramp_delay) {
@@ -1388,6 +1410,13 @@ static int _regulator_get_enable_time(struct regulator_dev *rdev)
 	return rdev->desc->ops->enable_time(rdev);
 }
 
+static int _regulator_get_disable_time(struct regulator_dev *rdev)
+{
+	if (rdev->constraints && rdev->constraints->disable_time)
+		return rdev->constraints->disable_time;
+	return rdev->desc->disable_time;
+}
+
 static struct regulator_dev *regulator_dev_lookup(struct device *dev,
 						  const char *supply,
 						  int *ret)
@@ -1897,7 +1926,15 @@ EXPORT_SYMBOL_GPL(regulator_enable);
 
 static int _regulator_do_disable(struct regulator_dev *rdev)
 {
-	int ret;
+	int ret, delay;
+
+	ret = _regulator_get_disable_time(rdev);
+	if (ret >= 0) {
+		delay = ret;
+	} else {
+		rdev_warn(rdev, "disable_time() failed: %d\n", ret);
+		delay = 0;
+	}
 
 	trace_regulator_disable(rdev_get_name(rdev));
 
@@ -1915,6 +1952,13 @@ static int _regulator_do_disable(struct regulator_dev *rdev)
 
 	trace_regulator_disable_complete(rdev_get_name(rdev));
 
+	if (delay >= 1000) {
+		mdelay(delay / 1000);
+		udelay(delay % 1000);
+	} else if (delay) {
+		udelay(delay);
+	}
+
 	_notifier_call_chain(rdev, REGULATOR_EVENT_DISABLE,
 			     NULL);
 	return 0;