Re: [PATCH] media: Accept non-subdev sinks in v4l2_create_fwnode_links_to_pad()

[Vaishnav Achath <vaishnav.a@ti.com>]

Hi Laurent,

On 20/04/23 22:15, Laurent Pinchart wrote:
> Hi Vaishnav,
> 
> On Thu, Apr 13, 2023 at 06:51:23PM +0530, Vaishnav Achath wrote:
>> Hi Laurent,
>>
>> Thank you for the patch, sorry for the delay in response,
>>
>> On 24/03/23 16:05, Laurent Pinchart wrote:
>>> The v4l2_create_fwnode_links_to_pad() helper requires the sink pad
>>> passed to it to belong to a subdev. This requirement can be lifted
>>> easily. Make the function usable for non-subdev sinks, which allows
>>> using it with video_device sinks.
>>>
>>> Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
>>> ---
>>>  drivers/media/v4l2-core/v4l2-mc.c | 15 ++++++---------
>>>  include/media/v4l2-mc.h           |  8 ++++----
>>>  2 files changed, 10 insertions(+), 13 deletions(-)
>>>
>>> diff --git a/drivers/media/v4l2-core/v4l2-mc.c b/drivers/media/v4l2-core/v4l2-mc.c
>>> index b01474717dca..bf0c18100664 100644
>>> --- a/drivers/media/v4l2-core/v4l2-mc.c
>>> +++ b/drivers/media/v4l2-core/v4l2-mc.c
>>> @@ -313,14 +313,11 @@ int v4l2_create_fwnode_links_to_pad(struct v4l2_subdev *src_sd,
>>>  				    struct media_pad *sink, u32 flags)
>>>  {
>>>  	struct fwnode_handle *endpoint;
>>> -	struct v4l2_subdev *sink_sd;
>>>  
>>>  	if (!(sink->flags & MEDIA_PAD_FL_SINK) ||
>>>  	    !is_media_entity_v4l2_subdev(sink->entity))
>>
>> should we drop the second check here also, i.e
>>
>> !is_media_entity_v4l2_subdev(sink->entity)
>>
>> to accept non-subdev sinks? is my understanding correct?
> 
> You're absolutely right. The patch has been merged already I'm afraid.
> Would you like to submit a fix, or should I do so ? In the latter case,
> can I include a Reported-by tag with your name ?
> 

Thank you for confirming, I have send a fix for this as I had tested with the
fix while reworking the j721e-csi2rx series,

https://lore.kernel.org/all/20230421100430.28962-1-vaishnav.a@ti.com/

Thanks and Regards,
Vaishnav

>>>  		return -EINVAL;
>>>  
>>> -	sink_sd = media_entity_to_v4l2_subdev(sink->entity);
>>> -
>>>  	fwnode_graph_for_each_endpoint(dev_fwnode(src_sd->dev), endpoint) {
>>>  		struct fwnode_handle *remote_ep;
>>>  		int src_idx, sink_idx, ret;
>>> @@ -340,7 +337,7 @@ int v4l2_create_fwnode_links_to_pad(struct v4l2_subdev *src_sd,
>>>  		 * ask the sink to verify it owns the remote endpoint,
>>>  		 * and translate to a sink pad.
>>>  		 */
>>> -		sink_idx = media_entity_get_fwnode_pad(&sink_sd->entity,
>>> +		sink_idx = media_entity_get_fwnode_pad(sink->entity,
>>>  						       remote_ep,
>>>  						       MEDIA_PAD_FL_SINK);
>>>  		fwnode_handle_put(remote_ep);
>>> @@ -362,17 +359,17 @@ int v4l2_create_fwnode_links_to_pad(struct v4l2_subdev *src_sd,
>>>  		if (media_entity_find_link(src, sink))
>>>  			continue;
>>>  
>>> -		dev_dbg(sink_sd->dev, "creating link %s:%d -> %s:%d\n",
>>> +		dev_dbg(src_sd->dev, "creating link %s:%d -> %s:%d\n",
>>>  			src_sd->entity.name, src_idx,
>>> -			sink_sd->entity.name, sink_idx);
>>> +			sink->entity->name, sink_idx);
>>>  
>>>  		ret = media_create_pad_link(&src_sd->entity, src_idx,
>>> -					    &sink_sd->entity, sink_idx, flags);
>>> +					    sink->entity, sink_idx, flags);
>>>  		if (ret) {
>>> -			dev_err(sink_sd->dev,
>>> +			dev_err(src_sd->dev,
>>>  				"link %s:%d -> %s:%d failed with %d\n",
>>>  				src_sd->entity.name, src_idx,
>>> -				sink_sd->entity.name, sink_idx, ret);
>>> +				sink->entity->name, sink_idx, ret);
>>>  
>>>  			fwnode_handle_put(endpoint);
>>>  			return ret;
>>> diff --git a/include/media/v4l2-mc.h b/include/media/v4l2-mc.h
>>> index c181685923d5..b39586dfba35 100644
>>> --- a/include/media/v4l2-mc.h
>>> +++ b/include/media/v4l2-mc.h
>>> @@ -87,17 +87,17 @@ int v4l_vb2q_enable_media_source(struct vb2_queue *q);
>>>  
>>>  /**
>>>   * v4l2_create_fwnode_links_to_pad - Create fwnode-based links from a
>>> - *                                   source subdev to a sink subdev pad.
>>> + *                                   source subdev to a sink pad.
>>>   *
>>>   * @src_sd: pointer to a source subdev
>>> - * @sink:  pointer to a subdev sink pad
>>> + * @sink:  pointer to a sink pad
>>>   * @flags: the link flags
>>>   *
>>>   * This function searches for fwnode endpoint connections from a source
>>>   * subdevice to a single sink pad, and if suitable connections are found,
>>>   * translates them into media links to that pad. The function can be
>>> - * called by the sink subdevice, in its v4l2-async notifier subdev bound
>>> - * callback, to create links from a bound source subdevice.
>>> + * called by the sink, in its v4l2-async notifier bound callback, to create
>>> + * links from a bound source subdevice.
>>>   *
>>>   * The @flags argument specifies the link flags. The caller shall ensure that
>>>   * the flags are valid regardless of the number of links that may be created.
> 

-- 
Regards,
Vaishnav