regulator: core: Add support for active-discharge configuration

Add support to enable/disable active discharge of regulator via
machine constraints. This configuration is done when setting
machine constraint during regulator register and if regulator
driver implemented the callback ops.

Signed-off-by: Laxman Dewangan <ldewangan@nvidia.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
index 744c988..7ebb7c8 100644
--- a/drivers/regulator/core.c
+++ b/drivers/regulator/core.c
@@ -1140,6 +1140,17 @@
 		}
 	}
 
+	if (rdev->constraints->active_discharge && ops->set_active_discharge) {
+		bool ad_state = (rdev->constraints->active_discharge ==
+			      REGULATOR_ACTIVE_DISCHARGE_ENABLE) ? true : false;
+
+		ret = ops->set_active_discharge(rdev, ad_state);
+		if (ret < 0) {
+			rdev_err(rdev, "failed to set active discharge\n");
+			return ret;
+		}
+	}
+
 	print_constraints(rdev);
 	return 0;
 out:
diff --git a/drivers/regulator/of_regulator.c b/drivers/regulator/of_regulator.c
index 499e437..fe2e3344 100644
--- a/drivers/regulator/of_regulator.c
+++ b/drivers/regulator/of_regulator.c
@@ -93,6 +93,12 @@
 
 	constraints->soft_start = of_property_read_bool(np,
 					"regulator-soft-start");
+	ret = of_property_read_u32(np, "regulator-active-discharge", &pval);
+	if (!ret) {
+		constraints->active_discharge =
+				(pval) ? REGULATOR_ACTIVE_DISCHARGE_ENABLE :
+					REGULATOR_ACTIVE_DISCHARGE_DISABLE;
+	}
 
 	if (!of_property_read_u32(np, "regulator-initial-mode", &pval)) {
 		if (desc && desc->of_map_mode) {