regulator: core: Add REGULATOR_EVENT_PRE_VOLTAGE_CHANGE (and ABORT)

In some cases we need to know when a regulator is about to be changed.
Add a way for clients to be notified.  Note that for set_voltage() we
don't necessarily know what voltage we'll end up with, so we tell the
client what the range will be so they can prepare.

Signed-off-by: Heiko Stübner <heiko@sntech.de>
Signed-off-by: Doug Anderson <dianders@chromium.org>
Signed-off-by: Mark Brown <broonie+linaro@kernel.org>
(cherry picked from commit 7179569aeb52197fd2a9909ba226c4c9cc0e2e2a)

diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
index 131e9933f2a3add23b6938a950499e7bcbca58f1..d7b9b4dc8a3db12ef7094e54e80b959289fc142c 100644 (file)
--- a/drivers/regulator/core.c
+++ b/drivers/regulator/core.c
@@ -88,7 +88,7 @@ static int _regulator_disable(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);
-static void _notifier_call_chain(struct regulator_dev *rdev,
+static int _notifier_call_chain(struct regulator_dev *rdev,
                                  unsigned long event, void *data);
 static int _regulator_do_set_voltage(struct regulator_dev *rdev,
                                     int min_uV, int max_uV);
@@ -2304,6 +2304,55 @@ int regulator_map_voltage_linear(struct regulator_dev *rdev,
 }
 EXPORT_SYMBOL_GPL(regulator_map_voltage_linear);
 
+static int _regulator_call_set_voltage(struct regulator_dev *rdev,
+                                      int min_uV, int max_uV,
+                                      unsigned *selector)
+{
+       struct pre_voltage_change_data data;
+       int ret;
+
+       data.old_uV = _regulator_get_voltage(rdev);
+       data.min_uV = min_uV;
+       data.max_uV = max_uV;
+       ret = _notifier_call_chain(rdev, REGULATOR_EVENT_PRE_VOLTAGE_CHANGE,
+                                  &data);
+       if (ret & NOTIFY_STOP_MASK)
+               return -EINVAL;
+
+       ret = rdev->desc->ops->set_voltage(rdev, min_uV, max_uV, selector);
+       if (ret >= 0)
+               return ret;
+
+       _notifier_call_chain(rdev, REGULATOR_EVENT_ABORT_VOLTAGE_CHANGE,
+                            (void *)data.old_uV);
+
+       return ret;
+}
+
+static int _regulator_call_set_voltage_sel(struct regulator_dev *rdev,
+                                          int uV, unsigned selector)
+{
+       struct pre_voltage_change_data data;
+       int ret;
+
+       data.old_uV = _regulator_get_voltage(rdev);
+       data.min_uV = uV;
+       data.max_uV = uV;
+       ret = _notifier_call_chain(rdev, REGULATOR_EVENT_PRE_VOLTAGE_CHANGE,
+                                  &data);
+       if (ret & NOTIFY_STOP_MASK)
+               return -EINVAL;
+
+       ret = rdev->desc->ops->set_voltage_sel(rdev, selector);
+       if (ret >= 0)
+               return ret;
+
+       _notifier_call_chain(rdev, REGULATOR_EVENT_ABORT_VOLTAGE_CHANGE,
+                            (void *)data.old_uV);
+
+       return ret;
+}
+
 static int _regulator_do_set_voltage(struct regulator_dev *rdev,
                                     int min_uV, int max_uV)
 {
@@ -2331,8 +2380,8 @@ static int _regulator_do_set_voltage(struct regulator_dev *rdev,
        }
 
        if (rdev->desc->ops->set_voltage) {
-               ret = rdev->desc->ops->set_voltage(rdev, min_uV, max_uV,
-                                                  &selector);
+               ret = _regulator_call_set_voltage(rdev, min_uV, max_uV,
+                                                 &selector);
 
                if (ret >= 0) {
                        if (rdev->desc->ops->list_voltage)
@@ -2363,8 +2412,8 @@ static int _regulator_do_set_voltage(struct regulator_dev *rdev,
                                if (old_selector == selector)
                                        ret = 0;
                                else
-                                       ret = rdev->desc->ops->set_voltage_sel(
-                                                               rdev, ret);
+                                       ret = _regulator_call_set_voltage_sel(
+                                               rdev, best_val, selector);
                        } else {
                                ret = -EINVAL;
                        }
@@ -3047,11 +3096,11 @@ EXPORT_SYMBOL_GPL(regulator_unregister_notifier);
 /* notify regulator consumers and downstream regulator consumers.
  * Note mutex must be held by caller.
  */
-static void _notifier_call_chain(struct regulator_dev *rdev,
+static int _notifier_call_chain(struct regulator_dev *rdev,
                                  unsigned long event, void *data)
 {
        /* call rdev chain first */
-       blocking_notifier_call_chain(&rdev->notifier, event, data);
+       return blocking_notifier_call_chain(&rdev->notifier, event, data);
 }
 
 /**

diff --git a/include/linux/regulator/consumer.h b/include/linux/regulator/consumer.h
index 3a8d78abd2056700602cb0785f1057acde1fd624..c726653fec4ea59384949dcc62f4591265c6091e 100644 (file)
--- a/include/linux/regulator/consumer.h
+++ b/include/linux/regulator/consumer.h
@@ -92,7 +92,12 @@ struct notifier_block;
  * OVER_TEMP      Regulator over temp.
  * FORCE_DISABLE  Regulator forcibly shut down by software.
  * VOLTAGE_CHANGE Regulator voltage changed.
+ *                Data passed is old voltage cast to (void *).
  * DISABLE        Regulator was disabled.
+ * PRE_VOLTAGE_CHANGE   Regulator is about to have voltage changed.
+ *                      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 *).
  *
  * NOTE: These events can be OR'ed together when passed into handler.
  */
@@ -105,6 +110,21 @@ struct notifier_block;
 #define REGULATOR_EVENT_FORCE_DISABLE          0x20
 #define REGULATOR_EVENT_VOLTAGE_CHANGE         0x40
 #define REGULATOR_EVENT_DISABLE                0x80
+#define REGULATOR_EVENT_PRE_VOLTAGE_CHANGE     0x100
+#define REGULATOR_EVENT_ABORT_VOLTAGE_CHANGE   0x200
+
+/**
+ * struct pre_voltage_change_data - Data sent with PRE_VOLTAGE_CHANGE event
+ *
+ * @old_uV: Current voltage before change.
+ * @min_uV: Min voltage we'll change to.
+ * @max_uV: Max voltage we'll change to.
+ */
+struct pre_voltage_change_data {
+       unsigned long old_uV;
+       unsigned long min_uV;
+       unsigned long max_uV;
+};
 
 struct regulator;