regulator: core: Add PRE_DISABLE notification

Add a PRE_DISABLE notification so that consumers can use a
notifier to run any steps required to prepare for the
regulator being switched off. Since the regulator disable
can fail an abort notification is also added.

Signed-off-by: Richard Fitzgerald <rf@opensource.wolfsonmicro.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

2 files changed, 20 insertions, 0 deletions

diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
index cd87c0c37034..53de911a0954 100644
--- a/drivers/regulator/core.c
+++ b/drivers/regulator/core.c
@@ -1976,9 +1976,18 @@ static int _regulator_disable(struct regulator_dev *rdev)
 
                 /* we are last user */
                 if (_regulator_can_change_status(rdev)) {
+                        ret = _notifier_call_chain(rdev,
+                                                   REGULATOR_EVENT_PRE_DISABLE,
+                                                   NULL);
+                        if (ret & NOTIFY_STOP_MASK)
+                                return -EINVAL;
+
                         ret = _regulator_do_disable(rdev);
                         if (ret < 0) {
                                 rdev_err(rdev, "failed to disable\n");
+                                _notifier_call_chain(rdev,
+                                                REGULATOR_EVENT_ABORT_DISABLE,
+                                                NULL);
                                 return ret;
                         }
                         _notifier_call_chain(rdev, REGULATOR_EVENT_DISABLE,
@@ -2035,9 +2044,16 @@ static int _regulator_force_disable(struct regulator_dev *rdev)
 {
         int ret = 0;
 
+        ret = _notifier_call_chain(rdev, REGULATOR_EVENT_FORCE_DISABLE |
+                        REGULATOR_EVENT_PRE_DISABLE, NULL);
+        if (ret & NOTIFY_STOP_MASK)
+                return -EINVAL;
+
         ret = _regulator_do_disable(rdev);
         if (ret < 0) {
                 rdev_err(rdev, "failed to force disable\n");
+                _notifier_call_chain(rdev, REGULATOR_EVENT_FORCE_DISABLE |
+                                REGULATOR_EVENT_ABORT_DISABLE, NULL);
                 return ret;
         }
 
diff --git a/include/linux/regulator/consumer.h b/include/linux/regulator/consumer.h
index d347c805f923..9efddd2a63ee 100644
--- a/include/linux/regulator/consumer.h
+++ b/include/linux/regulator/consumer.h
@@ -99,6 +99,8 @@ struct regmap;
  *                      Data passed is "struct pre_voltage_change_data"
  * ABORT_VOLTAGE_CHANGE Regulator voltage change failed for some reason.
  *                      Data passed is old voltage cast to (void *).
+ * PRE_DISABLE    Regulator is about to be disabled
+ * ABORT_DISABLE  Regulator disable failed for some reason
  *
  * NOTE: These events can be OR'ed together when passed into handler.
  */
@@ -113,6 +115,8 @@ struct regmap;
 #define REGULATOR_EVENT_DISABLE                 0x80
 #define REGULATOR_EVENT_PRE_VOLTAGE_CHANGE      0x100
 #define REGULATOR_EVENT_ABORT_VOLTAGE_CHANGE    0x200
+#define REGULATOR_EVENT_PRE_DISABLE             0x400
+#define REGULATOR_EVENT_ABORT_DISABLE           0x800
 
 /**
  * struct pre_voltage_change_data - Data sent with PRE_VOLTAGE_CHANGE event