On Fri April 19 2013 09:48:27 Guennadi Liakhovetski wrote:
> Hi Hans
>
> Thanks for reviewing.
>
> On Fri, 19 Apr 2013, Hans Verkuil wrote:
>
> > On Thu April 18 2013 23:35:27 Guennadi Liakhovetski wrote:
> > > This struct shall be used by subdevice drivers to pass per-subdevice data,
> > > e.g. power supplies, to generic V4L2 methods, at the same time allowing
> > > optional host-specific extensions via the host_priv pointer. To avoid
> > > having to pass two pointers to those methods, add a pointer to this new
> > > struct to struct v4l2_subdev.
> > >
> > > Signed-off-by: Guennadi Liakhovetski <g.liakhovet...@gmx.de>
> > > ---
> > > include/media/v4l2-subdev.h | 13 +++++++++++++
> > > 1 files changed, 13 insertions(+), 0 deletions(-)
> > >
> > > diff --git a/include/media/v4l2-subdev.h b/include/media/v4l2-subdev.h
> > > index eb91366..b15c6e0 100644
> > > --- a/include/media/v4l2-subdev.h
> > > +++ b/include/media/v4l2-subdev.h
> > > @@ -561,6 +561,17 @@ struct v4l2_subdev_internal_ops {
> > > /* Set this flag if this subdev generates events. */
> > > #define V4L2_SUBDEV_FL_HAS_EVENTS (1U << 3)
> > >
> > > +struct regulator_bulk_data;
> > > +
> > > +struct v4l2_subdev_platform_data {
> > > + /* Optional regulators uset to power on/off the subdevice */
> > > + struct regulator_bulk_data *regulators;
> > > + int num_regulators;
> > > +
> > > + /* Per-subdevice data, specific for a certain video host device */
> > > + void *host_priv;
> > > +};
> > > +
> > > /* Each instance of a subdev driver should create this struct, either
> > > stand-alone or embedded in a larger struct.
> > > */
> > > @@ -589,6 +600,8 @@ struct v4l2_subdev {
> > > /* pointer to the physical device */
> > > struct device *dev;
> > > struct v4l2_async_subdev_list asdl;
> > > + /* common part of subdevice platform data */
> > > + struct v4l2_subdev_platform_data *pdata;
> > > };
> > >
> > > static inline struct v4l2_subdev *v4l2_async_to_subdev(
> > >
> >
> > Sorry, this is the wrong approach.
> >
> > This is data that is of no use to the subdev driver itself. It really is
> > v4l2_subdev_host_platform_data, and as such must be maintained by the bridge
> > driver.
>
> I don't think so. It has been discussed and agreed upon, that only
> subdevice drivers know when to switch power on and off, because only they
> know when they need to access the hardware. So, they have to manage
> regulators. In fact, those regulators supply power to respective
> subdevices, e.g. a camera sensor. Why should the bridge driver manage
> them? The V4L2 core can (and probably should) provide helper functions for
> that, like soc-camera currently does, but in any case it's the subdevice
> driver, that has to call them.
Ah, OK. I just realized I missed some context there. I didn't pay much
attention to the regulator discussions since that's not my area of expertise.
In that case my only comment is to drop the host_priv pointer since that just
duplicates v4l2_get/set_subdev_hostdata().
Regards,
Hans
>
> Thanks
> Guennadi
>
> > It can use v4l2_get/set_subdev_hostdata() to associate this struct with a
> > subdev, though.
> >
> > Regards,
> >
> > Hans
>
> ---
> Guennadi Liakhovetski, Ph.D.
> Freelance Open-Source Software Developer
> http://www.open-technology.de/
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