On 09/11/2013 01:33 PM, Laurent Pinchart wrote:
> Hi Philipp,
>
> On Wednesday 04 September 2013 16:21:38 Philipp Zabel wrote:
>> 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+rene...@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?
>
> That's a very good point. We had a similar issues in V4L2, with sensors that
> would create several entities. However, in those cases, the sensors would be
> connected to the rest of the pipeline through a single entity :
>
> Sensor Entity 1 -> ... -> Sensor Entity N -> V4L2 pipeline ...
>
> The core code thus had to care about a single sensor entity when building the
> pipeline. We could solve the problem in a similar way for panels, but
> encoders
> need a more elaborate solution.
Why? Sorry, I don't see why an encoder is different in this respect than a
panel.
I'm sure I'm missing something here.
>
> I see (at least) two possibilities here, either explicitly describing all
> entities that make the device in DT (as you have proposed below), or creating
> a hierarchy of entities, with parent entities that can contain several child
> entities. I've CC'ed Guennadi, Hans, Sylwester and Sakari to get their
> opinion
> on the matter.
I think the way this is done today in complex devices is that the driver just
exposes itself as a single sub-device, but internally it has its own pipeline of
sub-devices. The only one that I know of (platform/s5p-tv/hdmi_drv) doesn't
expose
them to a media controller, they are completely hidden inside the hdmi driver.
The ability to support hierarchies of entities would be very nice. However, I
don't know how much work that would be to implement and if it is worth the
effort.
Regards,
Hans
>
>> lvds-encoder {
>> channel@0 {
>
> If I understand this correctly, your LVDS encoder has two independent
> channels. In the general case a device made of multiple entities might have
> those entities chained, so "channel" might not be the best term. "entity"
> might be a better choice.
>
>> 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];
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