Re: [PATCH 1/2] media: i2c: max96714: add HAS_EVENTS subdev flag

From: Laurent Pinchart
Date: Thu Sep 12 2024 - 08:06:10 EST


On Thu, Sep 12, 2024 at 01:11:13PM +0200, Tommaso Merciai wrote:
> Hi Laurent,
>
> On Thu, Sep 12, 2024 at 01:44:09PM +0300, Laurent Pinchart wrote:
> > Hi Tommaso,
> >
> > On Tue, Sep 10, 2024 at 03:44:27PM +0200, Tommaso Merciai wrote:
> > > Controls can be exposed to userspace via a v4l-subdevX device, and
> > > userspace has to be able to subscribe to control events so that it is
> > > notified when the control changes value. Add missing HAS_EVENTS flag.
> >
> > How is this supposed to work, given that the driver doesn't implement
> > .subscribe_event() ?
>
> You are completely right, sorry.
> I think in both cases I'm missing:
>
> diff --git a/drivers/media/i2c/max96714.c b/drivers/media/i2c/max96714.c
> index 94b1bc000e48..2257b6b807ea 100644
> --- a/drivers/media/i2c/max96714.c
> +++ b/drivers/media/i2c/max96714.c
> @@ -17,6 +17,7 @@
>
> #include <media/v4l2-cci.h>
> #include <media/v4l2-ctrls.h>
> +#include <media/v4l2-event.h>
> #include <media/v4l2-fwnode.h>
> #include <media/v4l2-subdev.h>
>
> @@ -488,6 +489,8 @@ static int max96714_log_status(struct v4l2_subdev *sd)
>
> static const struct v4l2_subdev_core_ops max96714_subdev_core_ops = {
> .log_status = max96714_log_status,
> + .subscribe_event = v4l2_ctrl_subdev_subscribe_event,
> + .unsubscribe_event = v4l2_event_subdev_unsubscribe,
> };
>
> static const struct v4l2_subdev_video_ops max96714_video_ops = {
>
> Like you suggest. Or I'm wrong?

That looks better :-)

Out of curiosity, what's your use case for control events ?

> > > Signed-off-by: Tommaso Merciai <tomm.merciai@xxxxxxxxx>
> > > ---
> > > drivers/media/i2c/max96714.c | 3 ++-
> > > 1 file changed, 2 insertions(+), 1 deletion(-)
> > >
> > > diff --git a/drivers/media/i2c/max96714.c b/drivers/media/i2c/max96714.c
> > > index 159753b13777..94b1bc000e48 100644
> > > --- a/drivers/media/i2c/max96714.c
> > > +++ b/drivers/media/i2c/max96714.c
> > > @@ -602,7 +602,8 @@ static int max96714_create_subdev(struct max96714_priv *priv)
> > > goto err_free_ctrl;
> > > }
> > >
> > > - priv->sd.flags |= V4L2_SUBDEV_FL_HAS_DEVNODE | V4L2_SUBDEV_FL_STREAMS;
> > > + priv->sd.flags |= V4L2_SUBDEV_FL_HAS_DEVNODE |
> > > + V4L2_SUBDEV_FL_HAS_EVENTS | V4L2_SUBDEV_FL_STREAMS;
> > > priv->sd.entity.function = MEDIA_ENT_F_VID_IF_BRIDGE;
> > > priv->sd.entity.ops = &max96714_entity_ops;
> > >

--
Regards,

Laurent Pinchart