Re: [PATCH v1 3/3] v4l: async: Match parent devices

From: Laurent Pinchart
Date: Thu May 18 2017 - 10:01:43 EST


Hi Kieran,

Thank you for the patch.

On Wednesday 17 May 2017 16:03:39 Kieran Bingham wrote:
> From: Kieran Bingham <kieran.bingham+renesas@xxxxxxxxxxxxxxxx>
>
> Devices supporting multiple endpoints on a single device node must set
> their subdevice fwnode to the endpoint to allow distinct comparisons.
>
> Adapt the match_fwnode call to compare against the provided fwnodes
> first, but also to search for a comparison against the parent fwnode.
>
> This allows notifiers to pass the endpoint for comparison and still
> support existing subdevices which store their default parent device
> node.
>
> Signed-off-by: Kieran Bingham <kieran.bingham+renesas@xxxxxxxxxxxxxxxx>
> ---
> drivers/media/v4l2-core/v4l2-async.c | 20 ++++++++++++++++----
> 1 file changed, 16 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/media/v4l2-core/v4l2-async.c
> b/drivers/media/v4l2-core/v4l2-async.c index e1e181db90f7..65735a5c4350
> 100644
> --- a/drivers/media/v4l2-core/v4l2-async.c
> +++ b/drivers/media/v4l2-core/v4l2-async.c
> @@ -41,14 +41,26 @@ static bool match_devname(struct v4l2_subdev *sd,
> return !strcmp(asd->match.device_name.name, dev_name(sd->dev));
> }
>
/*
* Check whether the two device_node pointers refer to the same OF node. We
* can't compare pointers directly as they can differ if overlays have been
* applied.
*/

> +static bool match_of(struct device_node *a, struct device_node *b)
> +{
> + return !of_node_cmp(of_node_full_name(a), of_node_full_name(b));
> +}
> +
> static bool match_fwnode(struct v4l2_subdev *sd, struct v4l2_async_subdev
> *asd)
> {
> + struct device_node *sdnode;
> + struct fwnode_handle *async_device;

I would name this asd_fwnode, and to be consistent rename sdnode to sd_ofnode.

> +
> + async_device = fwnode_graph_get_port_parent(asd->match.fwnode.fwnode);
> +
> if (!is_of_node(sd->fwnode) || !is_of_node(asd->match.fwnode.fwnode))
> - return sd->fwnode == asd->match.fwnode.fwnode;
> + return sd->fwnode == asd->match.fwnode.fwnode ||
> + sd->fwnode == async_device;

I wonder whether we could simplify this by changing the
fwnode_graph_get_port_parent() API. At the moment the function walks two or
three levels up depending on whether there's a ports name or not. If we turned
in into a function that accepts an endpoint, port or device node, and returns
the device node unconditionally (basically, returning the argument if its name
is not "port(@[0-9]+)?" or "endpoint(@[0-9]+)?", and walking up until it
reaches the device node otherwise), you could write the above

asd_fwnode = fwnode_graph_get_port_parent(asd->match.fwnode.fwnode);

if (!is_of_node(sd->fwnode) || !is_of_node(asd_fwnode))
sd->fwnode == asd_fwnode;

sdnode = to_of_node(sd->fwnode);

return match_of(sdnode, to_of_node(asd_node));

> +
> + sdnode = to_of_node(sd->fwnode);
>
> - return !of_node_cmp(of_node_full_name(to_of_node(sd->fwnode)),
> - of_node_full_name(
> - to_of_node(asd->match.fwnode.fwnode)));
> + return match_of(sdnode, to_of_node(asd->match.fwnode.fwnode)) ||
> + match_of(sdnode, to_of_node(async_device));

This is getting a bit complex, could you document the function ?

> }
>
> static bool match_custom(struct v4l2_subdev *sd, struct v4l2_async_subdev
> *asd)

--
Regards,

Laurent Pinchart