extcon: Add new extcon_register_notifier_all() to monitor all external connectors

The extcon core already provides the extcon_register_notifier() function
in order to register the notifier block which is used to monitor
the state change for the specific external connector such as EXTCON_USB,
EXTCON_USB_HOST and so on. The extcon consumer uses the this function.

The extcon consumer might need to monitor the all supported external
connectors from the extcon device. In this case, The extcon consumer
should have each notifier_block structure for each external connector.

This patch adds the new extcon_register_notifier_all() function
that extcon consumer is able to monitor the state change of all
supported external connectors by using only one notifier_block structure.

- List of new added functions:
int extcon_register_notifier_all(struct extcon_dev *edev,
			struct notifier_block *nb);
int extcon_unregister_notifier_all(struct extcon_dev *edev,
			struct notifier_block *nb);
int devm_extcon_register_notifier_all(struct device *dev,
			struct extcon_dev *edev, struct notifier_block *nb);
void devm_extcon_unregister_notifier_all(struct device *dev,
			struct extcon_dev *edev, struct notifier_block *nb);

Suggested-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
Tested-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Hans de Goede <hdegoede@redhat.com>

1 files changed, 66 insertions, 0 deletions

diff --git a/drivers/extcon/extcon.c b/drivers/extcon/extcon.c
index 09ac5e70c2f3..e7750545469f 100644
--- a/drivers/extcon/extcon.c
+++ b/drivers/extcon/extcon.c
@@ -448,8 +448,19 @@ int extcon_sync(struct extcon_dev *edev, unsigned int id)
 	spin_lock_irqsave(&edev->lock, flags);
 
 	state = !!(edev->state & BIT(index));
+
+	/*
+	 * Call functions in a raw notifier chain for the specific one
+	 * external connector.
+	 */
 	raw_notifier_call_chain(&edev->nh[index], state, edev);
 
+	/*
+	 * Call functions in a raw notifier chain for the all supported
+	 * external connectors.
+	 */
+	raw_notifier_call_chain(&edev->nh_all, state, edev);
+
 	/* This could be in interrupt handler */
 	prop_buf = (char *)get_zeroed_page(GFP_ATOMIC);
 	if (!prop_buf) {
@@ -954,6 +965,59 @@ int extcon_unregister_notifier(struct extcon_dev *edev, unsigned int id,
 }
 EXPORT_SYMBOL_GPL(extcon_unregister_notifier);
 
+/**
+ * extcon_register_notifier_all() - Register a notifier block for all connectors
+ * @edev:	the extcon device that has the external connecotr.
+ * @nb:		a notifier block to be registered.
+ *
+ * This fucntion registers a notifier block in order to receive the state
+ * change of all supported external connectors from extcon device.
+ * And The second parameter given to the callback of nb (val) is
+ * the current state and third parameter is the edev pointer.
+ *
+ * Returns 0 if success or error number if fail
+ */
+int extcon_register_notifier_all(struct extcon_dev *edev,
+				struct notifier_block *nb)
+{
+	unsigned long flags;
+	int ret;
+
+	if (!edev || !nb)
+		return -EINVAL;
+
+	spin_lock_irqsave(&edev->lock, flags);
+	ret = raw_notifier_chain_register(&edev->nh_all, nb);
+	spin_unlock_irqrestore(&edev->lock, flags);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(extcon_register_notifier_all);
+
+/**
+ * extcon_unregister_notifier_all() - Unregister a notifier block from extcon.
+ * @edev:	the extcon device that has the external connecotr.
+ * @nb:		a notifier block to be registered.
+ *
+ * Returns 0 if success or error number if fail
+ */
+int extcon_unregister_notifier_all(struct extcon_dev *edev,
+				struct notifier_block *nb)
+{
+	unsigned long flags;
+	int ret;
+
+	if (!edev || !nb)
+		return -EINVAL;
+
+	spin_lock_irqsave(&edev->lock, flags);
+	ret = raw_notifier_chain_unregister(&edev->nh_all, nb);
+	spin_unlock_irqrestore(&edev->lock, flags);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(extcon_unregister_notifier_all);
+
 static struct attribute *extcon_attrs[] = {
 	&dev_attr_state.attr,
 	&dev_attr_name.attr,
@@ -1212,6 +1276,8 @@ int extcon_dev_register(struct extcon_dev *edev)
 	for (index = 0; index < edev->max_supported; index++)
 		RAW_INIT_NOTIFIER_HEAD(&edev->nh[index]);
 
+	RAW_INIT_NOTIFIER_HEAD(&edev->nh_all);
+
 	dev_set_drvdata(&edev->dev, edev);
 	edev->state = 0;