Re: [PATCH v4 01/11] dt-bindings: video-interfaces: Document 'location' property

[Pavel Machek <pavel@ucw.cz>]

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On Tue 2019-10-08 09:58:28, Jacopo Mondi wrote:
> Pavel,
> 
> On Tue, Oct 08, 2019 at 09:40:52AM +0200, Pavel Machek wrote:
> > On Mon 2019-10-07 18:29:03, Jacopo Mondi wrote:
> > > Add the 'location' device property, used to specify a device mounting
> > > position. The property is particularly meaningful for mobile devices
> > > with a well defined usage orientation.
> > >
> > > Signed-off-by: Jacopo Mondi <jacopo@jmondi.org>
> > > ---
> > >  .../devicetree/bindings/media/video-interfaces.txt    | 11 +++++++++++
> > >  1 file changed, 11 insertions(+)
> > >
> > > diff --git a/Documentation/devicetree/bindings/media/video-interfaces.txt b/Documentation/devicetree/bindings/media/video-interfaces.txt
> > > index f884ada0bffc..1211bdf80722 100644
> > > --- a/Documentation/devicetree/bindings/media/video-interfaces.txt
> > > +++ b/Documentation/devicetree/bindings/media/video-interfaces.txt
> > > @@ -89,6 +89,17 @@ Optional properties
> > >    but a number of degrees counter clockwise. Typical values are 0 and 180
> > >    (upside down).
> > >
> > > +- location: The mount location of a device (typically an image sensor or a flash
> > > +  LED) expressed as a position relative to the usage orientation of the system
> > > +  where the device is installed on.
> > > +  Possible values are:
> > > +  0 - Front. The device is mounted on the front facing side of the system.
> > > +  For mobile devices such as smartphones, tablets and laptops the front side is
> > > +  the user facing side.
> > > +  1 - Back. The device is mounted on the back side of the system, which is
> > > +  defined as the opposite side of the front facing one.
> > > +  2 - External. The device is not attached directly to the system but is
> > > +  attached in a way that allows it to move freely.
> >
> > I explained why this is not enough, and it did not change.
> 
> I replied to your email and you did not answered back.
> 
> I appreciate constructive inputs but just NAK, or throwing a proposal
> without following up as you did, doesn't help much in improving the end
> result.
> 
> I'll paste here my previous reply, so you get a chance to continue the
> discussion. Please follow up if you're interested in contributing.

Yes, you are basically saying someone can solve those problems in
future :-(.

I'd add note that for camera-style devices, main sensor would be the
"back" one, and that for phones, selfie sensor should be marked as a
"front" one.

Plus, I believe you need to add a value for moving sensors, as there
are already devices that use same sensor for "front" and "back".

								Pavel


> ------------------------------------------------------------------------
> > I don't think this is nearly enough of description. We have phones
> > with displays and cameras at both sides, where both sides can be used
> > to operate the system.
> >
> > We have phone with display spanning both sides -- Mi Max.
> >
> > https://www.idnes.cz/mobil/telefony/xiaomi-mi-mix-alpha-predstaveni.A190924_105858_telefony_oma
> >
> > We have Galaxy Fold.
> >
> > https://www.samsung.com/global/galaxy/galaxy-fold/
> >
> > What is front side when device can be used in different
> > configurations?
> >
> > Could we instead say that it is "main" vs "selfie" camera?
> 
> I'm not sure the intended usage is something that belongs to DT. And
> 'selfie' implies you have a device side facing you, most like the
> 'front' one I have defined here.
> 
> Not to mention again this devices are all but supported by mainline,
> which is just a partial justification as they might be an indication
> of a trend.
> 
> There is no usable reference place, reference side, reference usage
> mode that applies to -all- devices in the world, not one I can think
> of.
> 
> I still think defining a location property is not blocking any new
> extension that accommodate more advanced use cases. It's not like we're
> adding a "front-camera" property, it's a "location" and you can expand
> its accepted values with "front-when-device-folded" or whatever you
> need for future devices.
> 
> In the description I mentioned the "usage orientation" to leave room
> for possible device-specific details in the definition of the values
> accepted by the property.
> 
> > > +  location expressed as a position relative to the usage orientation of the
> > > +  system where the device is installed on.
> 
> 99% of devices in the world have a front and a back, as well as they
> have a top and a bottom. I still don't see why if a device does not
> simply has a front it cannot use something different. The property
> definition allows you to do so.
> 
> ------------------------------------------------------------------------
> 
> >
> > NAK.
> > 									Pavel
> >
> > --
> > (english) http://www.livejournal.com/~pavelmachek
> > (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
> 
> 



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