Re: [PATCH 16/16] media: i2c: ov9282: Support event handlers

[Dave Stevenson <dave.stevenson@raspberrypi.com>]

Hi Jacopo

+ Hans for comment on compliance / controls framework

On Thu, 6 Oct 2022 at 10:59, Jacopo Mondi <jacopo@jmondi.org> wrote:
>
> Hi Dave
>
> On Wed, Oct 05, 2022 at 04:28:09PM +0100, Dave Stevenson wrote:
> > As noted in the headers for V4L2_SUBDEV_FL_HAS_EVENTS,
> > "controls can send events, thus drivers exposing controls
> > should set this flag".
> >
>
> I was expecting this to only apply to drivers that actually generate
> events...
>
> Not sure I can give a tag here as my understanding of this part is
> limited, let's wait for other opinions :)

I had to rack my memory on this one.

It fixes a v4l2-compliance failure:
fail: v4l2-test-controls.cpp(835): subscribe event for control 'User
Controls' failed
test VIDIOC_(UN)SUBSCRIBE_EVENT/DQEVENT: FAIL
(v4l-utils built at ToT from today, so fd544473800 "support INTEGER
and INTEGER64 control arrays")

So either it is required by all drivers that expose controls, or it's
an issue in v4l2-compliance.
I believe it's the former as all controls can create a V4L2_EVENT_CTRL
event should the value or range change (very common for things like
HBLANK and VBLANK in image sensor drivers).

Thanks
  Dave

> > This driver exposes controls, but didn't reflect that it
> > could generate events. Correct this, and add the default
> > event handler functions.
> >
> > Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
> > ---
> >  drivers/media/i2c/ov9282.c | 10 +++++++++-
> >  1 file changed, 9 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/media/i2c/ov9282.c b/drivers/media/i2c/ov9282.c
> > index bc429455421e..416c9656e3ac 100644
> > --- a/drivers/media/i2c/ov9282.c
> > +++ b/drivers/media/i2c/ov9282.c
> > @@ -14,6 +14,7 @@
> >  #include <linux/regulator/consumer.h>
> >
> >  #include <media/v4l2-ctrls.h>
> > +#include <media/v4l2-event.h>
> >  #include <media/v4l2-fwnode.h>
> >  #include <media/v4l2-subdev.h>
> >
> > @@ -1189,6 +1190,11 @@ static int ov9282_parse_hw_config(struct ov9282 *ov9282)
> >  }
> >
> >  /* V4l2 subdevice ops */
> > +static const struct v4l2_subdev_core_ops ov9282_core_ops = {
> > +     .subscribe_event = v4l2_ctrl_subdev_subscribe_event,
> > +     .unsubscribe_event = v4l2_event_subdev_unsubscribe,
> > +};
> > +
> >  static const struct v4l2_subdev_video_ops ov9282_video_ops = {
> >       .s_stream = ov9282_set_stream,
> >  };
> > @@ -1203,6 +1209,7 @@ static const struct v4l2_subdev_pad_ops ov9282_pad_ops = {
> >  };
> >
> >  static const struct v4l2_subdev_ops ov9282_subdev_ops = {
> > +     .core = &ov9282_core_ops,
> >       .video = &ov9282_video_ops,
> >       .pad = &ov9282_pad_ops,
> >  };
> > @@ -1419,7 +1426,8 @@ static int ov9282_probe(struct i2c_client *client)
> >       }
> >
> >       /* Initialize subdev */
> > -     ov9282->sd.flags |= V4L2_SUBDEV_FL_HAS_DEVNODE;
> > +     ov9282->sd.flags |= V4L2_SUBDEV_FL_HAS_DEVNODE |
> > +                         V4L2_SUBDEV_FL_HAS_EVENTS;
> >       ov9282->sd.entity.function = MEDIA_ENT_F_CAM_SENSOR;
> >
> >       /* Initialize source pad */
> > --
> > 2.34.1
> >