Hi Laurent,
On Wed, Mar 18, 2020 at 02:17:26AM +0200, Laurent Pinchart wrote:
> Hi Sakari,
>
> On Wed, Mar 18, 2020 at 01:04:32AM +0200, Laurent Pinchart wrote:
> > On Tue, Mar 17, 2020 at 02:44:56PM +0200, Sakari Ailus wrote:
> > > On Sun, Mar 15, 2020 at 02:55:11PM +0200, Laurent Pinchart wrote:
> > > > fwnode matching was designed to match on nodes corresponding to a
> > > > device. Some drivers, however, needed to match on endpoints, and have
> > > > passed endpoint fwnodes to v4l2-async. This works when both the subdev
> > > > and the notifier use the same fwnode types (endpoint or device), but
> > > > makes drivers that use different types incompatible.
> > > >
> > > > Fix this by extending the fwnode match to handle fwnodes of different
> > > > types. When the types (deduced from the node name) are different,
> > > > retrieve the device fwnode for the side that provides an endpoint
> > > > fwnode, and compare it with the device fwnode provided by the other
> > > > side. This allows interoperability between all drivers, regardless of
> > > > which type of fwnode they use for matching.
> > > >
> > > > Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@xxxxxxxxxxxxxxxx>
> > > > ---
> > > > This has been compile-tested only. Prabhakar, could you check if it
> > > > fixes your issue ?
> > > >
> > > > drivers/media/v4l2-core/v4l2-async.c | 42 +++++++++++++++++++++++++++-
> > > > 1 file changed, 41 insertions(+), 1 deletion(-)
> > > >
> > > > diff --git a/drivers/media/v4l2-core/v4l2-async.c b/drivers/media/v4l2-core/v4l2-async.c
> > > > index 8bde33c21ce4..995e5464cba7 100644
> > > > --- a/drivers/media/v4l2-core/v4l2-async.c
> > > > +++ b/drivers/media/v4l2-core/v4l2-async.c
> > > > @@ -71,7 +71,47 @@ static bool match_devname(struct v4l2_subdev *sd,
> > > >
> > > > static bool match_fwnode(struct v4l2_subdev *sd, struct v4l2_async_subdev *asd)
> > > > {
> > > > - return sd->fwnode == asd->match.fwnode;
> > > > + struct fwnode_handle *other_fwnode;
> > > > + struct fwnode_handle *dev_fwnode;
> > > > + bool asd_fwnode_is_ep;
> > > > + bool sd_fwnode_is_ep;
> > > > + const char *name;
> > > > +
> > > > + /*
> > > > + * Both the subdev and the async subdev can provide either an endpoint
> > > > + * fwnode or a device fwnode. Start with the simple case of direct
> > > > + * fwnode matching.
> > > > + */
> > > > + if (sd->fwnode == asd->match.fwnode)
> > > > + return true;
> > > > +
> > > > + /*
> > > > + * 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");
> > >
> > > Apart from the fact that you're parsing graph node names here, this looks
> > > good.
>
> And why is that an issue btw ? the ACPI fwnode ops seem to provide a
> .get_name() operation, would it return the ACPI bus ID here ?
I'd really prefer not to do graph parsing outside the main parser(s), OF,
ACPI and property frameworks.
Just for an example, the v4l2_fwnode_link_parse() was broken for ACPI for a
long time just because it did not use the graph parsing functions, but
implemented graph parsing on its own.
>
> > > How about checking instead that calling
> > > fwnode_graph_get_remote_endpoint(fwnode_graph_get_remote_endpoint()) yields
> > > the same node? That would ensure you're dealing with endpoint nodes without
> > > explicitly parsing the graph in any way.
> >
> > Would it be simpler to check for the presence of an endpoint property ?
There's no endpoint property, apart from an old ACPI definition.
There are differences in the implementations and this is not the best place
to try to take them all into account.
--
Kind regards,
Sakari Ailus
