media: cec-notifier: small improvements

Allow calling cec_notifier_set_phys_addr and
cec_notifier_set_phys_addr_from_edid with a NULL notifier, in which
case these functions do nothing.

Add a cec_notifier_phys_addr_invalidate helper function (the notifier
equivalent of cec_phys_addr_invalidate).

These changes simplify drm CEC driver support.
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

drivers/media/cec/cec-notifier.c

@@ -87,6 +87,9 @@ EXPORT_SYMBOL_GPL(cec_notifier_put);
 
 void cec_notifier_set_phys_addr(struct cec_notifier *n, u16 pa)
 {
+	if (n == NULL)
+		return;
+
 	mutex_lock(&n->lock);
 	n->phys_addr = pa;
 	if (n->callback)
@@ -100,6 +103,9 @@ void cec_notifier_set_phys_addr_from_edid(struct cec_notifier *n,
 {
 	u16 pa = CEC_PHYS_ADDR_INVALID;
 
+	if (n == NULL)
+		return;
+
 	if (edid && edid->extensions)
 		pa = cec_get_edid_phys_addr((const u8 *)edid,
 				EDID_LENGTH * (edid->extensions + 1), NULL);

include/media/cec-notifier.h

@@ -57,6 +57,7 @@ void cec_notifier_put(struct cec_notifier *n);
  * @pa: the CEC physical address
  *
  * Set a new CEC physical address.
+ * Does nothing if @n == NULL.
  */
 void cec_notifier_set_phys_addr(struct cec_notifier *n, u16 pa);
 
@@ -66,6 +67,7 @@ void cec_notifier_set_phys_addr(struct cec_notifier *n, u16 pa);
  * @edid: the struct edid pointer
  *
  * Parses the EDID to obtain the new CEC physical address and set it.
+ * Does nothing if @n == NULL.
  */
 void cec_notifier_set_phys_addr_from_edid(struct cec_notifier *n,
 					  const struct edid *edid);
@@ -118,4 +120,17 @@ static inline void cec_notifier_unregister(struct cec_notifier *n)
 
 #endif
 
+/**
+ * cec_notifier_phys_addr_invalidate() - set the physical address to INVALID
+ *
+ * @n: the CEC notifier
+ *
+ * This is a simple helper function to invalidate the physical
+ * address. Does nothing if @n == NULL.
+ */
+static inline void cec_notifier_phys_addr_invalidate(struct cec_notifier *n)
+{
+	cec_notifier_set_phys_addr(n, CEC_PHYS_ADDR_INVALID);
+}
+
 #endif