Hi Kieran,
On Wed, Mar 18, 2020 at 09:16:01AM +0000, Kieran Bingham wrote:
> On 18/03/2020 00:25, Laurent Pinchart wrote:
> > When a notifier supplies a device fwnode and a subdev supplies an
> > endpoint fwnode, incorrect matches may occur if multiple subdevs
> > correspond to the same device fwnode. This can't be handled
> > transparently in the framework, and requires the notifier to switch to
> > endpoint fwnodes. Log a message to notify of this problem. A second
> > message is added to help accelerating the transition to endpoint
> > matching.
>
> Only minor comments and discussion below:
>
> Reviewed-by: Kieran Bingham <kieran.bingham+renesas@xxxxxxxxxxxxxxxx>
>
> > Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@xxxxxxxxxxxxxxxx>
> > ---
> > drivers/media/v4l2-core/v4l2-async.c | 24 +++++++++++++++++++++++-
> > 1 file changed, 23 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/media/v4l2-core/v4l2-async.c b/drivers/media/v4l2-core/v4l2-async.c
> > index 224b39a7aeb1..9f393a7be455 100644
> > --- a/drivers/media/v4l2-core/v4l2-async.c
> > +++ b/drivers/media/v4l2-core/v4l2-async.c
> > @@ -77,6 +77,7 @@ static bool match_fwnode(struct v4l2_async_notifier *notifier,
> > struct fwnode_handle *dev_fwnode;
> > bool asd_fwnode_is_ep;
> > bool sd_fwnode_is_ep;
> > + struct device *dev;
> > const char *name;
> >
> > /*
> > @@ -113,7 +114,28 @@ static bool match_fwnode(struct v4l2_async_notifier *notifier,
> >
> > fwnode_handle_put(dev_fwnode);
> >
> > - return dev_fwnode == other_fwnode;
> > + if (dev_fwnode != other_fwnode)
> > + return false;
> > +
> > + /*
> > + * We have an heterogenous match. Retrieve the struct device of the
>
> s/an/a/
>
> s/heterogenous/heterogeneous/ (and that's not an en-gb/en-us thing)
> Also in $SUBJECT
>
> > + * side that matched on a device fwnode to print its driver name.
> > + */
> > + if (sd_fwnode_is_ep)
> > + dev = notifier->v4l2_dev ? notifier->v4l2_dev->dev
> > + : notifier->sd->dev;
>
> Eugh ... I guess if this gets needed elsewhere, notifiers need a helper
> to get the appropriate dev out... but if this is the only place, then so
> be it.
I'll let the next person who needs this create a helper :-)
> > + else
> > + dev = sd->dev;
> > +
> > + if (dev && dev->driver) {
> > + if (sd_fwnode_is_ep)
> > + dev_info(dev, "Driver %s uses device fwnode, incorrect match may occur\n",
> > + dev->driver->name);
> > + dev_info(dev, "Consider updating driver %s to match on endpoints\n",
> > + dev->driver->name);
>
> I think I interpret that in the case that existing drivers match on
> dev->dev (i.e. no endpoints involved) then this will not print, as we
> would already have matched and returned earlier in the function.
>
> I don't think that's a problem, but it means people will not be
> 'encouraged' to move to endpoint matching until they encounter a device
> which uses endpoints.
>
> Perhaps that's ok ... but I was almost thinking of being more 'pushy'
> and guiding device matches to move to endpoints too ;-)
I don't think we can do that, as not all devices have endpoints. For
instance, a lens controller or a flash controller will be referred to by
phandle properties, without using OF graph. We still need to support
matching them.
> > + }
> > +
> > + return true;
> > }
> >
> > static bool match_custom(struct v4l2_async_notifier *notifier,
--
Regards,
Laurent Pinchart
