Re: [PATCH/RFC v3 06/19] video: display: OF support

[Philipp Zabel <p.zabel@pengutronix.de>]

Hi Laurent,

Am Samstag, den 10.08.2013, 01:03 +0200 schrieb Laurent Pinchart:
> Extend the notifier with DT node matching support, and add helper functions to
> build the notifier and link entities based on a graph representation in
> DT.
> 
> Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
> ---
>  drivers/video/display/display-core.c     | 334 +++++++++++++++++++++++++++++++
>  drivers/video/display/display-notifier.c | 187 +++++++++++++++++
>  include/video/display.h                  |  45 +++++
>  3 files changed, 566 insertions(+)
> 
> diff --git a/drivers/video/display/display-core.c b/drivers/video/display/display-core.c
> index c3b47d3..328ead7 100644
> --- a/drivers/video/display/display-core.c
> +++ b/drivers/video/display/display-core.c
[...]
> @@ -420,6 +599,161 @@ int display_entity_link_graph(struct device *dev, struct list_head *entities)
>  }
>  EXPORT_SYMBOL_GPL(display_entity_link_graph);
>  
> +#ifdef CONFIG_OF
> +
> +static int display_of_entity_link_entity(struct device *dev,
> +					 struct display_entity *entity,
> +					 struct list_head *entities,
> +					 struct display_entity *root)
> +{
> +	u32 link_flags = MEDIA_LNK_FL_IMMUTABLE | MEDIA_LNK_FL_ENABLED;
> +	const struct device_node *node = entity->dev->of_node;

the current device tree matching implementation only allows one display
entity per linux device. How about adding an of_node pointer to struct
display_entity directly and allow multiple display entity nodes below in
a single device node in the device tree?

lvds-encoder {
	channel@0 {
		port@0 {
			lvds0_input: endpoint {
			};
		};
		port@1 {
			lvds0_output: endpoint {
			};
		};
	};
	channel@1 {
		port@0 {
			lvds1_input: endpoint {
			};
		};
		lvds1: port@1 {
			lvds1_output: endpoint {
			};
		};
	};
};

> +	struct media_entity *local = &entity->entity;
> +	struct device_node *ep = NULL;
> +	int ret = 0;
> +
> +	dev_dbg(dev, "creating links for entity %s\n", local->name);
> +
> +	while (1) {
> +		struct media_entity *remote = NULL;
> +		struct media_pad *remote_pad;
> +		struct media_pad *local_pad;
> +		struct display_of_link link;
> +		struct display_entity *ent;
> +		struct device_node *next;
> +
> +		/* Get the next endpoint and parse its link. */
> +		next = display_of_get_next_endpoint(node, ep);
> +		if (next == NULL)
> +			break;
> +
> +		of_node_put(ep);
> +		ep = next;
> +
> +		dev_dbg(dev, "processing endpoint %s\n", ep->full_name);
> +
> +		ret = display_of_parse_link(ep, &link);
> +		if (ret < 0) {
> +			dev_err(dev, "failed to parse link for %s\n",
> +				ep->full_name);
> +			continue;
> +		}
> +
> +		/* Skip source pads, they will be processed from the other end of
> +		 * the link.
> +		 */
> +		if (link.local_port >= local->num_pads) {
> +			dev_err(dev, "invalid port number %u on %s\n",
> +				link.local_port, link.local_node->full_name);
> +			display_of_put_link(&link);
> +			ret = -EINVAL;
> +			break;
> +		}
> +
> +		local_pad = &local->pads[link.local_port];
> +
> +		if (local_pad->flags & MEDIA_PAD_FL_SOURCE) {
> +			dev_dbg(dev, "skipping source port %s:%u\n",
> +				link.local_node->full_name, link.local_port);
> +			display_of_put_link(&link);
> +			continue;
> +		}
> +
> +		/* Find the remote entity. If not found, just skip the link as
> +		 * it goes out of scope of the entities handled by the notifier.
> +		 */
> +		list_for_each_entry(ent, entities, list) {
> +			if (ent->dev->of_node == link.remote_node) {
> +				remote = &ent->entity;
> +				break;
> +			}
> +		}
> +
> +		if (root->dev->of_node == link.remote_node)
> +			remote = &root->entity;
> +
> +		if (remote == NULL) {
> +			dev_dbg(dev, "no entity found for %s\n",
> +				link.remote_node->full_name);
> +			display_of_put_link(&link);
> +			continue;
> +		}
> +
> +		if (link.remote_port >= remote->num_pads) {
> +			dev_err(dev, "invalid port number %u on %s\n",
> +				link.remote_port, link.remote_node->full_name);
> +			display_of_put_link(&link);
> +			ret = -EINVAL;
> +			break;
> +		}
> +
> +		remote_pad = &remote->pads[link.remote_port];
> +
> +		display_of_put_link(&link);
> +
> +		/* Create the media link. */
> +		dev_dbg(dev, "creating %s:%u -> %s:%u link\n",
> +			remote->name, remote_pad->index,
> +			local->name, local_pad->index);
> +
> +		ret = media_entity_create_link(remote, remote_pad->index,
> +					       local, local_pad->index,
> +					       link_flags);
> +		if (ret < 0) {
> +			dev_err(dev,
> +				"failed to create %s:%u -> %s:%u link\n",
> +				remote->name, remote_pad->index,
> +				local->name, local_pad->index);
> +			break;
> +		}
> +	}
> +
> +	of_node_put(ep);
> +	return ret;
> +}
[...]

For example like this:

diff --git a/drivers/video/display/display-core.c b/drivers/video/display/display-core.c
index 7910c23..a04feed 100644
--- a/drivers/video/display/display-core.c
+++ b/drivers/video/display/display-core.c
@@ -302,6 +302,9 @@ int display_entity_init(struct display_entity *entity, unsigned int num_sinks,
 	kref_init(&entity->ref);
 	entity->state = DISPLAY_ENTITY_STATE_OFF;
 
+	if (!entity->of_node && entity->dev)
+		entity->of_node = entity->dev->of_node;
+
 	num_pads = num_sinks + num_sources;
 	pads = kzalloc(sizeof(*pads) * num_pads, GFP_KERNEL);
 	if (pads == NULL)
@@ -665,7 +668,7 @@ static int display_of_entity_link_entity(struct device *dev,
 					 struct display_entity *root)
 {
 	u32 link_flags = MEDIA_LNK_FL_IMMUTABLE | MEDIA_LNK_FL_ENABLED;
-	const struct device_node *node = entity->dev->of_node;
+	const struct device_node *node = entity->of_node;
 	struct media_entity *local = &entity->entity;
 	struct device_node *ep = NULL;
 	int num_sink, ret = 0;
@@ -727,13 +730,13 @@ static int display_of_entity_link_entity(struct device *dev,
 		 * it goes out of scope of the entities handled by the notifier.
 		 */
 		list_for_each_entry(ent, entities, list) {
-			if (ent->dev->of_node == link.remote_node) {
+			if (ent->of_node == link.remote_node) {
 				remote = &ent->entity;
 				break;
 			}
 		}
 
-		if (root && root->dev->of_node == link.remote_node)
+		if (root && root->of_node == link.remote_node)
 			remote = &root->entity;
 
 		if (remote == NULL) {
diff --git a/drivers/video/display/display-notifier.c b/drivers/video/display/display-notifier.c
index a3998c7..d0da6e5 100644
--- a/drivers/video/display/display-notifier.c
+++ b/drivers/video/display/display-notifier.c
@@ -28,28 +28,30 @@ static DEFINE_MUTEX(display_entity_mutex);
  * Notifiers
  */
 
-static bool match_platform(struct device *dev,
+static bool match_platform(struct display_entity *entity,
 			   struct display_entity_match *match)
 {
 	pr_debug("%s: matching device '%s' with name '%s'\n", __func__,
-		 dev_name(dev), match->match.platform.name);
+		 dev_name(entity->dev), match->match.platform.name);
 
-	return !strcmp(match->match.platform.name, dev_name(dev));
+	return !strcmp(match->match.platform.name, dev_name(entity->dev));
 }
 
-static bool match_dt(struct device *dev, struct display_entity_match *match)
+static bool match_dt(struct display_entity *entity,
+		     struct display_entity_match *match)
 {
 	pr_debug("%s: matching device node '%s' with node '%s'\n", __func__,
-		 dev->of_node->full_name, match->match.dt.node->full_name);
+		 entity->of_node->full_name, match->match.dt.node->full_name);
 
-	return match->match.dt.node == dev->of_node;
+	return match->match.dt.node == entity->of_node;
 }
 
 static struct display_entity_match *
 display_entity_notifier_match(struct display_entity_notifier *notifier,
 			      struct display_entity *entity)
 {
-	bool (*match_func)(struct device *, struct display_entity_match *);
+	bool (*match_func)(struct display_entity *,
+			   struct display_entity_match *);
 	struct display_entity_match *match;
 
 	pr_debug("%s: matching entity '%s' (ptr 0x%p dev '%s')\n", __func__,
@@ -66,7 +68,7 @@ display_entity_notifier_match(struct display_entity_notifier *notifier,
 			break;
 		}
 
-		if (match_func(entity->dev, match))
+		if (match_func(entity, match))
 			return match;
 	}
 
diff --git a/include/video/display.h b/include/video/display.h
index 4c402bee..d1f8833 100644
--- a/include/video/display.h
+++ b/include/video/display.h
@@ -228,6 +228,7 @@ struct display_entity {
 	struct list_head list;
 	struct device *dev;
 	struct module *owner;
+	struct device_node *of_node;
 	struct kref ref;
 
 	char name[32];
-- 
1.8.4.rc3

regards
Philipp