extcon: Add resource-managed extcon register function

Add resource-managed extcon device register function for convenience.
For example, if a extcon device is attached with new
devm_extcon_dev_register(), that extcon device is automatically
unregistered on driver detach.

Signed-off-by: Sangjung Woo <sangjung.woo@samsung.com>
[Fix bug about devm_extcon_dev_match/release() and code clean by Chanwoo Choi]
Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>

2 files changed, 82 insertions, 0 deletions

diff --git a/drivers/extcon/extcon-class.c b/drivers/extcon/extcon-class.c
index 7ab21aa6eaa1..f6df68989651 100644
--- a/drivers/extcon/extcon-class.c
+++ b/drivers/extcon/extcon-class.c
@@ -819,6 +819,75 @@ void extcon_dev_unregister(struct extcon_dev *edev)
 }
 EXPORT_SYMBOL_GPL(extcon_dev_unregister);
 
+static void devm_extcon_dev_unreg(struct device *dev, void *res)
+{
+        extcon_dev_unregister(*(struct extcon_dev **)res);
+}
+
+static int devm_extcon_dev_match(struct device *dev, void *res, void *data)
+{
+        struct extcon_dev **r = res;
+
+        if (!r || !*r) {
+                WARN_ON(!r || !*r);
+                return 0;
+        }
+
+        return *r == data;
+}
+
+/**
+ * devm_extcon_dev_register() - Resource-managed extcon_dev_register()
+ * @dev:        device to allocate extcon device
+ * @edev:       the new extcon device to register
+ *
+ * Managed extcon_dev_register() function. If extcon device is attached with
+ * this function, that extcon device is automatically unregistered on driver
+ * detach. Internally this function calls extcon_dev_register() function.
+ * To get more information, refer that function.
+ *
+ * If extcon device is registered with this function and the device needs to be
+ * unregistered separately, devm_extcon_dev_unregister() should be used.
+ *
+ * Returns 0 if success or negaive error number if failure.
+ */
+int devm_extcon_dev_register(struct device *dev, struct extcon_dev *edev)
+{
+        struct extcon_dev **ptr;
+        int ret;
+
+        ptr = devres_alloc(devm_extcon_dev_unreg, sizeof(*ptr), GFP_KERNEL);
+        if (!ptr)
+                return -ENOMEM;
+
+        ret = extcon_dev_register(edev);
+        if (ret) {
+                devres_free(ptr);
+                return ret;
+        }
+
+        *ptr = edev;
+        devres_add(dev, ptr);
+
+        return 0;
+}
+EXPORT_SYMBOL_GPL(devm_extcon_dev_register);
+
+/**
+ * devm_extcon_dev_unregister() - Resource-managed extcon_dev_unregister()
+ * @dev:        device the extcon belongs to
+ * @edev:       the extcon device to unregister
+ *
+ * Unregister extcon device that is registered with devm_extcon_dev_register()
+ * function.
+ */
+void devm_extcon_dev_unregister(struct device *dev, struct extcon_dev *edev)
+{
+        WARN_ON(devres_release(dev, devm_extcon_dev_unreg,
+                               devm_extcon_dev_match, edev));
+}
+EXPORT_SYMBOL_GPL(devm_extcon_dev_unregister);
+
 #ifdef CONFIG_OF
 /*
  * extcon_get_edev_by_phandle - Get the extcon device from devicetree
diff --git a/include/linux/extcon.h b/include/linux/extcon.h
index f488145bb2d4..548447be2d8f 100644
--- a/include/linux/extcon.h
+++ b/include/linux/extcon.h
@@ -185,6 +185,10 @@ struct extcon_specific_cable_nb {
  */
 extern int extcon_dev_register(struct extcon_dev *edev);
 extern void extcon_dev_unregister(struct extcon_dev *edev);
+extern int devm_extcon_dev_register(struct device *dev,
+                                    struct extcon_dev *edev);
+extern void devm_extcon_dev_unregister(struct device *dev,
+                                       struct extcon_dev *edev);
 extern struct extcon_dev *extcon_get_extcon_dev(const char *extcon_name);
 
 /*
@@ -254,6 +258,15 @@ static inline int extcon_dev_register(struct extcon_dev *edev)
 
 static inline void extcon_dev_unregister(struct extcon_dev *edev) { }
 
+static inline int devm_extcon_dev_register(struct device *dev,
+                                           struct extcon_dev *edev)
+{
+        return -EINVAL;
+}
+
+static inline void devm_extcon_dev_unregister(struct device *dev,
+                                              struct extcon_dev *edev) { }
+
 static inline u32 extcon_get_state(struct extcon_dev *edev)
 {
         return 0;