media: cec-notifier: Get notifier by device and connector name

In non device-tree world, we can need to get the notifier by the driver
name directly and eventually defer probe if not yet created.

This patch adds a variant of the get function by using the device name
instead and will not create a notifier if not yet created.

But the i915 driver exposes at least 2 HDMI connectors, this patch also
adds the possibility to add a connector name tied to the notifier device
to form a tuple and associate different CEC controllers for each HDMI
connectors.
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Reviewed-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

drivers/media/cec/cec-notifier.c

@@ -21,6 +21,7 @@ struct cec_notifier {
 	struct list_head head;
 	struct kref kref;
 	struct device *dev;
+	const char *conn;
 	struct cec_adapter *cec_adap;
 	void (*callback)(struct cec_adapter *adap, u16 pa);
 
@@ -30,13 +31,14 @@ struct cec_notifier {
 static LIST_HEAD(cec_notifiers);
 static DEFINE_MUTEX(cec_notifiers_lock);
 
-struct cec_notifier *cec_notifier_get(struct device *dev)
+struct cec_notifier *cec_notifier_get_conn(struct device *dev, const char *conn)
 {
 	struct cec_notifier *n;
 
 	mutex_lock(&cec_notifiers_lock);
 	list_for_each_entry(n, &cec_notifiers, head) {
-		if (n->dev == dev) {
+		if (n->dev == dev &&
+		    (!conn || !strcmp(n->conn, conn))) {
 			kref_get(&n->kref);
 			mutex_unlock(&cec_notifiers_lock);
 			return n;
@@ -46,6 +48,8 @@ struct cec_notifier *cec_notifier_get(struct device *dev)
 	if (!n)
 		goto unlock;
 	n->dev = dev;
+	if (conn)
+		n->conn = kstrdup(conn, GFP_KERNEL);
 	n->phys_addr = CEC_PHYS_ADDR_INVALID;
 	mutex_init(&n->lock);
 	kref_init(&n->kref);
@@ -54,7 +58,7 @@ struct cec_notifier *cec_notifier_get(struct device *dev)
 	mutex_unlock(&cec_notifiers_lock);
 	return n;
 }
-EXPORT_SYMBOL_GPL(cec_notifier_get);
+EXPORT_SYMBOL_GPL(cec_notifier_get_conn);
 
 static void cec_notifier_release(struct kref *kref)
 {
@@ -62,6 +66,7 @@ static void cec_notifier_release(struct kref *kref)
 		container_of(kref, struct cec_notifier, kref);
 
 	list_del(&n->head);
+	kfree(n->conn);
 	kfree(n);
 }
 

include/media/cec-notifier.h

@@ -20,8 +20,10 @@ struct cec_notifier;
 #if IS_REACHABLE(CONFIG_CEC_CORE) && IS_ENABLED(CONFIG_CEC_NOTIFIER)
 
 /**
- * cec_notifier_get - find or create a new cec_notifier for the given device.
+ * cec_notifier_get_conn - find or create a new cec_notifier for the given
+ * device and connector tuple.
  * @dev: device that sends the events.
+ * @conn: the connector name from which the event occurs
  *
  * If a notifier for device @dev already exists, then increase the refcount
  * and return that notifier.
@@ -31,7 +33,8 @@ struct cec_notifier;
  *
  * Return NULL if the memory could not be allocated.
  */
-struct cec_notifier *cec_notifier_get(struct device *dev);
+struct cec_notifier *cec_notifier_get_conn(struct device *dev,
+					   const char *conn);
 
 /**
  * cec_notifier_put - decrease refcount and delete when the refcount reaches 0.
@@ -85,7 +88,8 @@ void cec_register_cec_notifier(struct cec_adapter *adap,
 			       struct cec_notifier *notifier);
 
 #else
-static inline struct cec_notifier *cec_notifier_get(struct device *dev)
+static inline struct cec_notifier *cec_notifier_get_conn(struct device *dev,
+							 const char *conn)
 {
 	/* A non-NULL pointer is expected on success */
 	return (struct cec_notifier *)0xdeadfeed;
@@ -120,6 +124,23 @@ static inline void cec_register_cec_notifier(struct cec_adapter *adap,
 }
 #endif
 
+/**
+ * cec_notifier_get - find or create a new cec_notifier for the given device.
+ * @dev: device that sends the events.
+ *
+ * If a notifier for device @dev already exists, then increase the refcount
+ * and return that notifier.
+ *
+ * If it doesn't exist, then allocate a new notifier struct and return a
+ * pointer to that new struct.
+ *
+ * Return NULL if the memory could not be allocated.
+ */
+static inline struct cec_notifier *cec_notifier_get(struct device *dev)
+{
+	return cec_notifier_get_conn(dev, NULL);
+}
+
 /**
  * cec_notifier_phys_addr_invalidate() - set the physical address to INVALID
  *