Re: [PATCH v2 4/4] media: v4l2-async: Don't check fwnode name to detect endpoint

[Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>]

Hi Laurent,

On 18/03/2020 00:25, Laurent Pinchart wrote:
> Use the presence of a "remote-endpoint" property to detect if a fwnode
> is an endpoint node, as checking the node name won't work on ACPI-based
> implementations.

Technically, won't this property only detect that the endpoint is
connected to another endpoint, and 'un-connected' endpoints wont' match?

Of course in this instance - an unconnected endpoint is likely not much
use and probably even shouldn't match ;-) ~(but it may still 'be' an
endpoint).

Also - would this patch be squashed into 1/4?

I'll leave it to Sakari to comment on the actual validity of this
approach all the same :-)

--
Kieran


> 
> Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
> ---
>  drivers/media/v4l2-core/v4l2-async.c | 9 ++++-----
>  1 file changed, 4 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/media/v4l2-core/v4l2-async.c b/drivers/media/v4l2-core/v4l2-async.c
> index 9f393a7be455..a5f83ba502df 100644
> --- a/drivers/media/v4l2-core/v4l2-async.c
> +++ b/drivers/media/v4l2-core/v4l2-async.c
> @@ -78,7 +78,6 @@ static bool match_fwnode(struct v4l2_async_notifier *notifier,
>  	bool asd_fwnode_is_ep;
>  	bool sd_fwnode_is_ep;
>  	struct device *dev;
> -	const char *name;
>  
>  	/*
>  	 * Both the subdev and the async subdev can provide either an endpoint
> @@ -92,10 +91,10 @@ static bool match_fwnode(struct v4l2_async_notifier *notifier,
>  	 * Otherwise, check if the sd fwnode and the asd fwnode refer to an
>  	 * endpoint or a device. If they're of the same type, there's no match.
>  	 */
> -	name = fwnode_get_name(sd->fwnode);
> -	sd_fwnode_is_ep = name && strstarts(name, "endpoint");
> -	name = fwnode_get_name(asd->match.fwnode);
> -	asd_fwnode_is_ep = name && strstarts(name, "endpoint");
> +	sd_fwnode_is_ep = fwnode_property_present(sd->fwnode,
> +						  "remote-endpoint");
> +	asd_fwnode_is_ep = fwnode_property_present(asd->match.fwnode,
> +						   "remote-endpoint");
>  
>  	if (sd_fwnode_is_ep == asd_fwnode_is_ep)
>  		return false;
>