This patch add APIs to control the extcon device on extcon provider driver.
The extcon_dev_allocate() allocates the memory of extcon device and initializes
supported cables. And then extcon_dev_free() decrement the reference of the
device of extcon device and free the memory of the extcon device. This APIs
must need to implement devm_extcon_dev_allocate()/free() APIs.

Signed-off-by: Chanwoo Choi <cw00.c...@samsung.com>
---
 drivers/extcon/extcon-class.c | 295 +++++++++++++++++++++++-------------------
 include/linux/extcon.h        |  15 +++
 2 files changed, 177 insertions(+), 133 deletions(-)

diff --git a/drivers/extcon/extcon-class.c b/drivers/extcon/extcon-class.c
index 7ab21aa..600043c 100644
--- a/drivers/extcon/extcon-class.c
+++ b/drivers/extcon/extcon-class.c
@@ -558,6 +558,9 @@ static int create_extcon_class(void)
 
 static void extcon_dev_release(struct device *dev)
 {
+       struct extcon_dev *edev = dev_to_extcon_dev(dev);
+
+       kfree(edev);
 }
 
 static const char *muex_name = "mutually_exclusive";
@@ -576,7 +579,7 @@ static void dummy_sysfs_dev_release(struct device *dev)
  */
 int extcon_dev_register(struct extcon_dev *edev)
 {
-       int ret, index = 0;
+       int ret;
 
        if (!extcon_class) {
                ret = create_extcon_class();
@@ -584,80 +587,150 @@ int extcon_dev_register(struct extcon_dev *edev)
                        return ret;
        }
 
-       if (edev->supported_cable) {
-               /* Get size of array */
-               for (index = 0; edev->supported_cable[index]; index++)
-                       ;
-               edev->max_supported = index;
-       } else {
-               edev->max_supported = 0;
+       edev->name = edev->name ? edev->name : dev_name(edev->dev.parent);
+       if (IS_ERR_OR_NULL(edev->name)) {
+               dev_err(&edev->dev, "extcon device name is null\n");
+               return -EINVAL;
        }
+       dev_set_name(&edev->dev, "%s", edev->name);
 
-       if (index > SUPPORTED_CABLE_MAX) {
-               dev_err(&edev->dev, "extcon: maximum number of supported cables 
exceeded.\n");
-               return -EINVAL;
+       ret = device_add(&edev->dev);
+       if (ret) {
+               put_device(&edev->dev);
+               return ret;
        }
+#if defined(CONFIG_ANDROID)
+       if (switch_class)
+               ret = class_compat_create_link(switch_class, &edev->dev, NULL);
+#endif /* CONFIG_ANDROID */
 
-       edev->dev.class = extcon_class;
-       edev->dev.release = extcon_dev_release;
+       RAW_INIT_NOTIFIER_HEAD(&edev->nh);
 
-       edev->name = edev->name ? edev->name : dev_name(edev->dev.parent);
-       if (IS_ERR_OR_NULL(edev->name)) {
-               dev_err(&edev->dev,
-                       "extcon device name is null\n");
-               return -EINVAL;
+       dev_set_drvdata(&edev->dev, edev);
+       edev->state = 0;
+
+       mutex_lock(&extcon_dev_list_lock);
+       list_add(&edev->entry, &extcon_dev_list);
+       mutex_unlock(&extcon_dev_list_lock);
+
+       return 0;
+}
+EXPORT_SYMBOL_GPL(extcon_dev_register);
+
+/**
+ * extcon_dev_unregister() - Unregister the extcon device.
+ * @edev:      the extcon device instance to be unregistered.
+ */
+void extcon_dev_unregister(struct extcon_dev *edev)
+{
+       mutex_lock(&extcon_dev_list_lock);
+       list_del(&edev->entry);
+       mutex_unlock(&extcon_dev_list_lock);
+
+       if (IS_ERR_OR_NULL(get_device(&edev->dev))) {
+               dev_err(&edev->dev, "Failed to unregister extcon_dev (%s)\n",
+                               dev_name(&edev->dev));
+               return;
        }
-       dev_set_name(&edev->dev, "%s", edev->name);
 
-       if (edev->max_supported) {
-               char buf[10];
-               char *str;
-               struct extcon_cable *cable;
+       device_unregister(&edev->dev);
 
-               edev->cables = kzalloc(sizeof(struct extcon_cable) *
-                                      edev->max_supported, GFP_KERNEL);
-               if (!edev->cables) {
+#if defined(CONFIG_ANDROID)
+       if (switch_class)
+               class_compat_remove_link(switch_class, &edev->dev, NULL);
+#endif
+}
+EXPORT_SYMBOL_GPL(extcon_dev_unregister);
+
+/*
+ * extcon_dev_allocate() - Allocate the memory of extcon device.
+ * @supported_cable:   Array of supported cable names ending with NULL.
+ *                     If supported_cable is NULL, cable name related APIs
+ *                     are disabled.
+ *
+ * This function allocates the memory for extcon device without allocating
+ * memory in each extcon provider driver and initialize default setting for
+ * extcon device.
+ *
+ * Return the pointer of extcon device if success or ERR_PTR(err) if fail
+ */
+struct extcon_dev *extcon_dev_allocate(const char **supported_cable)
+{
+       struct extcon_dev *edev;
+       int index, ret, count = 0;
+
+       edev = kzalloc(sizeof(*edev), GFP_KERNEL);
+       if (!edev) {
+               pr_err("Failed to allocate the memory for extcon device\n");
+               return ERR_PTR(-ENOMEM);
+       }
+
+       edev->max_supported = 0;
+       edev->supported_cable = supported_cable;
+       if (edev->supported_cable) {
+               for (count = 0; edev->supported_cable[count]; count++)
+                       ;
+               edev->max_supported = count;
+               if (count > SUPPORTED_CABLE_MAX) {
+                       pr_err("Exceed max number of supported cables\n");
                        ret = -ENOMEM;
-                       goto err_sysfs_alloc;
+                       goto err;
                }
-               for (index = 0; index < edev->max_supported; index++) {
-                       cable = &edev->cables[index];
+       }
 
-                       snprintf(buf, 10, "cable.%d", index);
-                       str = kzalloc(sizeof(char) * (strlen(buf) + 1),
-                                     GFP_KERNEL);
-                       if (!str) {
-                               for (index--; index >= 0; index--) {
-                                       cable = &edev->cables[index];
-                                       kfree(cable->attr_g.name);
-                               }
-                               ret = -ENOMEM;
+       edev->dev.class = extcon_class;
+       edev->dev.release = extcon_dev_release;
+       device_initialize(&edev->dev);
+       spin_lock_init(&edev->lock);
+
+       if (!edev->max_supported)
+               return 0;
+
+       edev->cables = kzalloc(sizeof(struct extcon_cable) *
+                              edev->max_supported, GFP_KERNEL);
+       if (!edev->cables) {
+               ret = -ENOMEM;
+               goto err;
+       }
 
-                               goto err_alloc_cables;
+       for (index = 0; index < edev->max_supported; index++) {
+               struct extcon_cable *cable = &edev->cables[index];
+               char buf[10];
+               char *str;
+
+               snprintf(buf, 10, "cable.%d", index);
+               str = kzalloc(sizeof(char) * (strlen(buf) + 1),
+                             GFP_KERNEL);
+               if (!str) {
+                       for (index--; index >= 0; index--) {
+                               cable = &edev->cables[index];
+                               kfree(cable->attr_g.name);
                        }
-                       strcpy(str, buf);
-
-                       cable->edev = edev;
-                       cable->cable_index = index;
-                       cable->attrs[0] = &cable->attr_name.attr;
-                       cable->attrs[1] = &cable->attr_state.attr;
-                       cable->attrs[2] = NULL;
-                       cable->attr_g.name = str;
-                       cable->attr_g.attrs = cable->attrs;
-
-                       sysfs_attr_init(&cable->attr_name.attr);
-                       cable->attr_name.attr.name = "name";
-                       cable->attr_name.attr.mode = 0444;
-                       cable->attr_name.show = cable_name_show;
-
-                       sysfs_attr_init(&cable->attr_state.attr);
-                       cable->attr_state.attr.name = "state";
-                       cable->attr_state.attr.mode = 0444;
-                       cable->attr_state.show = cable_state_show;
+                       ret = -ENOMEM;
+                       goto err_alloc_cables;
                }
+               strcpy(str, buf);
+
+               cable->edev = edev;
+               cable->cable_index = index;
+               cable->attrs[0] = &cable->attr_name.attr;
+               cable->attrs[1] = &cable->attr_state.attr;
+               cable->attrs[2] = NULL;
+               cable->attr_g.name = str;
+               cable->attr_g.attrs = cable->attrs;
+
+               sysfs_attr_init(&cable->attr_name.attr);
+               cable->attr_name.attr.name = "name";
+               cable->attr_name.attr.mode = 0444;
+               cable->attr_name.show = cable_name_show;
+
+               sysfs_attr_init(&cable->attr_state.attr);
+               cable->attr_state.attr.name = "state";
+               cable->attr_state.attr.mode = 0444;
+               cable->attr_state.show = cable_state_show;
        }
 
-       if (edev->max_supported && edev->mutually_exclusive) {
+       if (edev->mutually_exclusive) {
                char buf[80];
                char *name;
 
@@ -703,59 +776,32 @@ int extcon_dev_register(struct extcon_dev *edev)
                }
                edev->attr_g_muex.name = muex_name;
                edev->attr_g_muex.attrs = edev->attrs_muex;
-
        }
 
-       if (edev->max_supported) {
-               edev->extcon_dev_type.groups =
-                       kzalloc(sizeof(struct attribute_group *) *
-                               (edev->max_supported + 2), GFP_KERNEL);
-               if (!edev->extcon_dev_type.groups) {
-                       ret = -ENOMEM;
-                       goto err_alloc_groups;
-               }
-
-               edev->extcon_dev_type.name = dev_name(&edev->dev);
-               edev->extcon_dev_type.release = dummy_sysfs_dev_release;
-
-               for (index = 0; index < edev->max_supported; index++)
-                       edev->extcon_dev_type.groups[index] =
-                               &edev->cables[index].attr_g;
-               if (edev->mutually_exclusive)
-                       edev->extcon_dev_type.groups[index] =
-                               &edev->attr_g_muex;
-
-               edev->dev.type = &edev->extcon_dev_type;
+       edev->extcon_dev_type.groups =
+               kzalloc(sizeof(struct attribute_group *) *
+                       (edev->max_supported + 2), GFP_KERNEL);
+       if (!edev->extcon_dev_type.groups) {
+               ret = -ENOMEM;
+               goto err_alloc_groups;
        }
 
-       ret = device_register(&edev->dev);
-       if (ret) {
-               put_device(&edev->dev);
-               goto err_dev;
-       }
-#if defined(CONFIG_ANDROID)
-       if (switch_class)
-               ret = class_compat_create_link(switch_class, &edev->dev, NULL);
-#endif /* CONFIG_ANDROID */
-
-       spin_lock_init(&edev->lock);
-
-       RAW_INIT_NOTIFIER_HEAD(&edev->nh);
+       edev->extcon_dev_type.name = dev_name(&edev->dev);
+       edev->extcon_dev_type.release = dummy_sysfs_dev_release;
 
-       dev_set_drvdata(&edev->dev, edev);
-       edev->state = 0;
+       for (index = 0; index < edev->max_supported; index++)
+               edev->extcon_dev_type.groups[index] =
+                       &edev->cables[index].attr_g;
+       if (edev->mutually_exclusive)
+               edev->extcon_dev_type.groups[index] =
+                       &edev->attr_g_muex;
 
-       mutex_lock(&extcon_dev_list_lock);
-       list_add(&edev->entry, &extcon_dev_list);
-       mutex_unlock(&extcon_dev_list_lock);
+       edev->dev.type = &edev->extcon_dev_type;
 
-       return 0;
+       return edev;
 
-err_dev:
-       if (edev->max_supported)
-               kfree(edev->extcon_dev_type.groups);
 err_alloc_groups:
-       if (edev->max_supported && edev->mutually_exclusive) {
+       if (edev->mutually_exclusive) {
                for (index = 0; edev->mutually_exclusive[index]; index++)
                        kfree(edev->d_attrs_muex[index].attr.name);
                kfree(edev->d_attrs_muex);
@@ -765,36 +811,22 @@ err_muex:
        for (index = 0; index < edev->max_supported; index++)
                kfree(edev->cables[index].attr_g.name);
 err_alloc_cables:
-       if (edev->max_supported)
-               kfree(edev->cables);
-err_sysfs_alloc:
-       return ret;
+       kfree(edev->cables);
+err:
+       kfree(edev);
+
+       return ERR_PTR(ret);
 }
-EXPORT_SYMBOL_GPL(extcon_dev_register);
+EXPORT_SYMBOL_GPL(extcon_dev_allocate);
 
-/**
- * extcon_dev_unregister() - Unregister the extcon device.
- * @edev:      the extcon device instance to be unregistered.
- *
- * Note that this does not call kfree(edev) because edev was not allocated
- * by this class.
+/*
+ * extcon_dev_free() - Free the memory of extcon device.
+ * @edev:      the extcon device to free
  */
-void extcon_dev_unregister(struct extcon_dev *edev)
+void extcon_dev_free(struct extcon_dev *edev)
 {
        int index;
 
-       mutex_lock(&extcon_dev_list_lock);
-       list_del(&edev->entry);
-       mutex_unlock(&extcon_dev_list_lock);
-
-       if (IS_ERR_OR_NULL(get_device(&edev->dev))) {
-               dev_err(&edev->dev, "Failed to unregister extcon_dev (%s)\n",
-                               dev_name(&edev->dev));
-               return;
-       }
-
-       device_unregister(&edev->dev);
-
        if (edev->mutually_exclusive && edev->max_supported) {
                for (index = 0; edev->mutually_exclusive[index];
                                index++)
@@ -811,13 +843,10 @@ void extcon_dev_unregister(struct extcon_dev *edev)
                kfree(edev->cables);
        }
 
-#if defined(CONFIG_ANDROID)
-       if (switch_class)
-               class_compat_remove_link(switch_class, &edev->dev, NULL);
-#endif
-       put_device(&edev->dev);
+       if (edev)
+               put_device(&edev->dev);
 }
-EXPORT_SYMBOL_GPL(extcon_dev_unregister);
+EXPORT_SYMBOL_GPL(extcon_dev_free);
 
 #ifdef CONFIG_OF
 /*
diff --git a/include/linux/extcon.h b/include/linux/extcon.h
index f488145..ffb3a03 100644
--- a/include/linux/extcon.h
+++ b/include/linux/extcon.h
@@ -179,6 +179,8 @@ struct extcon_specific_cable_nb {
 
 #if IS_ENABLED(CONFIG_EXTCON)
 
+#define dev_to_extcon_dev(d) container_of(d, struct extcon_dev, dev)
+
 /*
  * Following APIs are for notifiers or configurations.
  * Notifiers are the external port and connection devices.
@@ -242,6 +244,12 @@ extern int extcon_unregister_notifier(struct extcon_dev 
*edev,
                                      struct notifier_block *nb);
 
 /*
+ * Following APIs control the memory of extcon device.
+ */
+extern struct extcon_dev *extcon_dev_allocate(const char **cables);
+extern void extcon_dev_free(struct extcon_dev *edev);
+
+/*
  * Following API get the extcon device from devicetree.
  * This function use phandle of devicetree to get extcon device directly.
  */
@@ -336,5 +344,12 @@ static inline struct extcon_dev 
*extcon_get_edev_by_phandle(struct device *dev,
 {
        return ERR_PTR(-ENODEV);
 }
+
+static inline struct extcon_dev *extcon_dev_allocate(const char **cables)
+{
+       return ERR_PTR(-ENOMEM);
+}
+
+static inline void extcon_dev_free(struct extcon_dev *edev) { }
 #endif /* CONFIG_EXTCON */
 #endif /* __LINUX_EXTCON_H__ */
-- 
1.8.0

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