Re: [PATCH RFC v3] media: OF: add video sync endpoint property

[Sylwester Nawrocki]

Hi Prabhakar,

On 07/12/2013 06:29 AM, Prabhakar Lad wrote:
> On Fri, Jul 12, 2013 at 2:45 AM, Sylwester Nawrocki
> <sylvester.nawrocki@xxxxxxxxx>  wrote:
> > On 07/11/2013 01:41 PM, Prabhakar Lad wrote:
> > [...]
> >
> > > > > diff --git a/drivers/media/v4l2-core/v4l2-of.c
> > > > > b/drivers/media/v4l2-core/v4l2-of.c
> > > > > index aa59639..1a54530 100644
> > > > > --- a/drivers/media/v4l2-core/v4l2-of.c
> > > > > +++ b/drivers/media/v4l2-core/v4l2-of.c
> > > > > @@ -100,6 +100,26 @@ static void v4l2_of_parse_parallel_bus(const struct
> > > > > device_node *node,
> > > > >           if (!of_property_read_u32(node, "data-shift",&v))
> > > > >                   bus->data_shift = v;
> > > > >
> > > > > +       if (!of_property_read_u32(node, "video-sync",&v)) {
> > > > > +               switch (v) {
> > > > > +               case V4L2_MBUS_VIDEO_SEPARATE_SYNC:
> > > > > +                       flags |= V4L2_MBUS_VIDEO_SEPARATE_SYNC;
> > > >
> > > >
> > > >
> > > > I'm not convinced all those video sync types is something that really
> > > > belongs
> > > > to the flags field. In my understanding this field is supposed to hold
> > > > only
> > > > the _signal polarity_ information.
> > > Ok, so there should be a function say v4l2_of_parse_signal_polarity()
> > > to get the polarity alone then.
> >
> >
> > I don't think this is required, I would just extend
> > v4l2_of_parse_parallel_bus()
> > function to also handle sync-on-green-active property.
> If that is the case than I have to add a member say 'signal_polarity'
> in struct v4l2_of_bus_parallel and assign the polarity to it.
> Let me know if you are OK with it.

It probably would have been sensible to do something like this, however 
I can't
see any advantage at the moment. struct v4l2_of_bus_parallel::flags 
currently
holds all the polarity flags. Let's just add relevant macros for 
sync-on-green
and store them in the flags field, as is done with the others.
Those V4L2_MUS_* flags are used by soc-camera to negotiate the 
capabilities,
so I would rather not split them further without good reason, even though
struct v4l2_mbus_config::flags is used in those negotiation routines, 
rather
than struct v4l2_of_bus_parallel::flags.

--
Thanks,
Sylwester


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