Hi Sakari,
On Thu, Aug 15, 2019 at 04:08:49PM +0300, Sakari Ailus wrote:
> On Thu, Aug 15, 2019 at 03:59:38PM +0300, Laurent Pinchart wrote:
> > On Thu, Aug 15, 2019 at 10:00:25AM +0300, Sakari Ailus wrote:
> > > On Wed, Aug 14, 2019 at 10:28:12PM +0200, Jacopo Mondi wrote:
> > > > Add documentation for the V4L2_CID_LOCATION camera control. The newly
> > > > added read-only control reports the camera device mounting position.
> > > >
> > > > Signed-off-by: Jacopo Mondi
> > > > ---
> > > > .../media/uapi/v4l/ext-ctrls-camera.rst | 23 +++
> > > > 1 file changed, 23 insertions(+)
> > > >
> > > > diff --git a/Documentation/media/uapi/v4l/ext-ctrls-camera.rst
> > > > b/Documentation/media/uapi/v4l/ext-ctrls-camera.rst
> > > > index 51c1d5c9eb00..fc0a02eee6d4 100644
> > > > --- a/Documentation/media/uapi/v4l/ext-ctrls-camera.rst
> > > > +++ b/Documentation/media/uapi/v4l/ext-ctrls-camera.rst
> > > > @@ -510,6 +510,29 @@ enum v4l2_scene_mode -
> > > > value down. A value of zero stops the motion if one is in progress
> > > > and has no effect otherwise.
> > > >
> > > > +``V4L2_CID_LOCATION (integer)``
> > > > +This read-only control describes the camera location by reporting
> > > > its
> > > > +mounting position on the device where the camera is installed. This
> > > > +control is particularly meaningful for devices which have a well
> > > > defined
> > > > +orientation, such as phones, laptops and portable devices as the
> > > > camera
> > > > +location is expressed as a position relative to the device intended
> > > > +usage position. In example, a camera installed on the user-facing
> > > > side
> > >
> > > s/In/For/
> > >
> > > > +of a phone device is said to be installed in the
> > > > ``V4L2_LOCATION_FRONT``
> > > > +position.
> > > > +
> > > > +
> > > > +
> > > > +.. flat-table::
> > > > +:header-rows: 0
> > > > +:stub-columns: 0
> > > > +
> > > > +* - ``V4L2_LOCATION_FRONT``
> > > > + - The camera device is located on the front side of the device.
> > > > +* - ``V4L2_LOCATION_BACK``
> > > > + - The camera device is located on the back side of the device.
> > > > +
> > > > +
> > > > +
> > > > .. [#f1]
> > > > This control may be changed to a menu control in the future, if more
> > > > options are required.
> > >
> > > There's an effective limit of 64 for menus. ACPI has less than ten
> > > different locations for a device, I think 64 will be enough here.
> > >
> > > So I'd be actually in favour of switching to a menu.
> >
> > Why ? As you explained yourself, it's a static read-only control, all it
> > needs to report is a single value.
>
> Yes. That's true. It wasn't meant for this but it's nevertheless a
> convenient API to get that information, both as integer and string.
But why is that needed ? The integer seems enough to me.
--
Regards,
Laurent Pinchart
