media: cec: core: add note about *_from_edid() function usage in drm

In the drm subsystem, the source physical address is, in most cases,
available without having to parse the EDID again. Add notes about
preferring to use the pre-parsed address instead.

Cc: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Cc: linux-media@vger.kernel.org
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Acked-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Link: https://patchwork.freedesktop.org/patch/msgid/20230831105144.25923-1-jani.nikula@intel.com

drivers/media/cec/core/cec-adap.c

@@ -1688,6 +1688,11 @@ void cec_s_phys_addr(struct cec_adapter *adap, u16 phys_addr, bool block)
 }
 EXPORT_SYMBOL_GPL(cec_s_phys_addr);
 
+/*
+ * Note: In the drm subsystem, prefer calling (if possible):
+ *
+ * cec_s_phys_addr(adap, connector->display_info.source_physical_address, false);
+ */
 void cec_s_phys_addr_from_edid(struct cec_adapter *adap,
 			       const struct edid *edid)
 {

drivers/media/cec/core/cec-notifier.c

@@ -195,6 +195,11 @@ void cec_notifier_set_phys_addr(struct cec_notifier *n, u16 pa)
 }
 EXPORT_SYMBOL_GPL(cec_notifier_set_phys_addr);
 
+/*
+ * Note: In the drm subsystem, prefer calling (if possible):
+ *
+ * cec_notifier_set_phys_addr(n, connector->display_info.source_physical_address);
+ */
 void cec_notifier_set_phys_addr_from_edid(struct cec_notifier *n,
 					  const struct edid *edid)
 {