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>

4 files changed, 32 insertions, 0 deletions

diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
index 744c9889f88d..7ebb7c899158 100644
--- a/drivers/regulator/core.c
+++ b/drivers/regulator/core.c
@@ -1140,6 +1140,17 @@ static int set_machine_constraints(struct regulator_dev *rdev,
                 }
         }
 
+        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 499e437c7e91..fe2e33441dae 100644
--- a/drivers/regulator/of_regulator.c
+++ b/drivers/regulator/of_regulator.c
@@ -93,6 +93,12 @@ static void of_get_regulation_constraints(struct device_node *np,
 
         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) {
diff --git a/include/linux/regulator/driver.h b/include/linux/regulator/driver.h
index 16ac9e108806..59dbaf78a25c 100644
--- a/include/linux/regulator/driver.h
+++ b/include/linux/regulator/driver.h
@@ -93,6 +93,8 @@ struct regulator_linear_range {
  * @get_current_limit: Get the configured limit for a current-limited regulator.
  * @set_input_current_limit: Configure an input limit.
  *
+ * @set_active_discharge: Set active discharge enable/disable of regulators.
+ *
  * @set_mode: Set the configured operating mode for the regulator.
  * @get_mode: Get the configured operating mode for the regulator.
  * @get_status: Return actual (not as-configured) status of regulator, as a
@@ -149,6 +151,7 @@ struct regulator_ops {
 
         int (*set_input_current_limit) (struct regulator_dev *, int lim_uA);
         int (*set_over_current_protection) (struct regulator_dev *);
+        int (*set_active_discharge) (struct regulator_dev *, bool enable);
 
         /* enable/disable regulator */
         int (*enable) (struct regulator_dev *);
diff --git a/include/linux/regulator/machine.h b/include/linux/regulator/machine.h
index a1067d0b3991..5d627c83a630 100644
--- a/include/linux/regulator/machine.h
+++ b/include/linux/regulator/machine.h
@@ -42,6 +42,13 @@ struct regulator;
 #define REGULATOR_CHANGE_DRMS           0x10
 #define REGULATOR_CHANGE_BYPASS         0x20
 
+/* Regulator active discharge flags */
+enum regulator_active_discharge {
+        REGULATOR_ACTIVE_DISCHARGE_DEFAULT,
+        REGULATOR_ACTIVE_DISCHARGE_DISABLE,
+        REGULATOR_ACTIVE_DISCHARGE_ENABLE,
+};
+
 /**
  * struct regulator_state - regulator state during low power system states
  *
@@ -100,6 +107,9 @@ struct regulator_state {
  * @initial_state: Suspend state to set by default.
  * @initial_mode: Mode to set at startup.
  * @ramp_delay: Time to settle down after voltage change (unit: uV/us)
+ * @active_discharge: Enable/disable active discharge. The enum
+ *                    regulator_active_discharge values are used for
+ *                    initialisation.
  * @enable_time: Turn-on time of the rails (unit: microseconds)
  */
 struct regulation_constraints {
@@ -140,6 +150,8 @@ struct regulation_constraints {
         unsigned int ramp_delay;
         unsigned int enable_time;
 
+        unsigned int active_discharge;
+
         /* constraint flags */
         unsigned always_on:1;   /* regulator never off when system is on */
         unsigned boot_on:1;     /* bootloader/firmware enabled regulator */