2 files changed, 76 insertions, 1 deletions

diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
index 288c75abc190..a27a5b6267dd 100644
--- a/drivers/regulator/core.c
+++ b/drivers/regulator/core.c
@@ -1409,6 +1409,65 @@ struct regulator *regulator_get_exclusive(struct device *dev, const char *id)
 }
 EXPORT_SYMBOL_GPL(regulator_get_exclusive);
 
+/**
+ * regulator_get_optional - obtain optional access to a regulator.
+ * @dev: device for regulator "consumer"
+ * @id: Supply name or regulator ID.
+ *
+ * Returns a struct regulator corresponding to the regulator producer,
+ * or IS_ERR() condition containing errno.  Other consumers will be
+ * unable to obtain this reference is held and the use count for the
+ * regulator will be initialised to reflect the current state of the
+ * regulator.
+ *
+ * This is intended for use by consumers for devices which can have
+ * some supplies unconnected in normal use, such as some MMC devices.
+ * It can allow the regulator core to provide stub supplies for other
+ * supplies requested using normal regulator_get() calls without
+ * disrupting the operation of drivers that can handle absent
+ * supplies.
+ *
+ * Use of supply names configured via regulator_set_device_supply() is
+ * strongly encouraged.  It is recommended that the supply name used
+ * should match the name used for the supply and/or the relevant
+ * device pins in the datasheet.
+ */
+struct regulator *regulator_get_optional(struct device *dev, const char *id)
+{
+        return _regulator_get(dev, id, 0);
+}
+EXPORT_SYMBOL_GPL(regulator_get_optional);
+
+/**
+ * devm_regulator_get_optional - Resource managed regulator_get_optional()
+ * @dev: device for regulator "consumer"
+ * @id: Supply name or regulator ID.
+ *
+ * Managed regulator_get_optional(). Regulators returned from this
+ * function are automatically regulator_put() on driver detach. See
+ * regulator_get_optional() for more information.
+ */
+struct regulator *devm_regulator_get_optional(struct device *dev,
+                                              const char *id)
+{
+        struct regulator **ptr, *regulator;
+
+        ptr = devres_alloc(devm_regulator_release, sizeof(*ptr), GFP_KERNEL);
+        if (!ptr)
+                return ERR_PTR(-ENOMEM);
+
+        regulator = regulator_get_optional(dev, id);
+        if (!IS_ERR(regulator)) {
+                *ptr = regulator;
+                devres_add(dev, ptr);
+        } else {
+                devres_free(ptr);
+        }
+
+        return regulator;
+}
+EXPORT_SYMBOL_GPL(devm_regulator_get_optional);
+
 /* Locks held by regulator_put() */
 static void _regulator_put(struct regulator *regulator)
 {
diff --git a/include/linux/regulator/consumer.h b/include/linux/regulator/consumer.h
index 60da4a62c402..e2bac6db4abc 100644
--- a/include/linux/regulator/consumer.h
+++ b/include/linux/regulator/consumer.h
@@ -137,6 +137,10 @@ struct regulator *__must_check devm_regulator_get(struct device *dev,
                                              const char *id);
 struct regulator *__must_check regulator_get_exclusive(struct device *dev,
                                                        const char *id);
+struct regulator *__must_check regulator_get_optional(struct device *dev,
+                                                      const char *id);
+struct regulator *__must_check devm_regulator_get_optional(struct device *dev,
+                                                           const char *id);
 void regulator_put(struct regulator *regulator);
 void devm_regulator_put(struct regulator *regulator);
 
@@ -212,14 +216,26 @@ static inline struct regulator *__must_check regulator_get(struct device *dev,
 }
 
 static inline struct regulator *__must_check
+devm_regulator_get(struct device *dev, const char *id)
+{
+        return NULL;
+}
+
+static inline struct regulator *__must_check
 regulator_get_exclusive(struct device *dev, const char *id)
 {
         return NULL;
 }
 
+static inline struct regulator *__must_check
+regulator_get_optional(struct device *dev, const char *id)
+{
+        return NULL;
+}
+
 
 static inline struct regulator *__must_check
-devm_regulator_get(struct device *dev, const char *id)
+devm_regulator_get_optional(struct device *dev, const char *id)
 {
         return NULL;
 }