Re: [PATCH] dt-bindings: usb: usb-device: Add panel-location

[Sakari Ailus <sakari.ailus@linux.intel.com>]

Hi Ricardo,

On Tue, Jan 07, 2025 at 11:37:18AM +0100, Ricardo Ribalda wrote:
> On Fri, 20 Dec 2024 at 23:00, Rob Herring <robh@kernel.org> wrote:
> >
> > On Thu, Dec 19, 2024 at 6:42 AM Ricardo Ribalda <ribalda@chromium.org> wrote:
> > >
> > > On Thu, 19 Dec 2024 at 13:24, Rob Herring <robh@kernel.org> wrote:
> > > >
> > > > On Tue, Dec 17, 2024 at 04:24:27PM +0100, Ricardo Ribalda wrote:
> > > > > Hi Rob
> > > > >
> > > > > On Tue, 17 Dec 2024 at 16:02, Rob Herring <robh@kernel.org> wrote:
> > > > > >
> > > > > > On Thu, Dec 12, 2024 at 09:44:37PM +0000, Ricardo Ribalda wrote:
> > > > > > > For some devices like cameras the system needs to know where they are
> > > > > > > mounted.
> > > > > >
> > > > > > Why do you need this and why only this property and not the dozens
> > > > > > others ACPI has?
> > > > >
> > > > > Userspace needs that information to correctly show it in the UI. Eg;
> > > > >
> > > > > - User facing camera needs to be mirrored during preview.
> > > > > - The user facing camera is selected by default during videoconferences
> > > > > - The world facing camera is selected by default when taking a photo
> > > > > - User facing camera have different parameter defaults than world facing.
> > > >
> > > > We already have "orientation" defined for this purpose.
> > >
> > > Do you mean orientation from
> > > bindings/media/video-interface-devices.yaml ?
> > >
> > > I see a couple of issues:
> > > - Orientation has a very specific meaning for USB typeC. I'd prefer if
> > > we could avoid using that word.
> >
> > Yes, but this is tied to the class of the device, not the bus. I find
> > defining the position for USB devices confusing.
> >
> > > - For other applications different than cameras it might be useful to
> > > know the positions top, bottom, left, right, which are not available
> > > in video-interface-devices
> >
> > Other devices may need some of the 20 other properties in the ACPI
> > table as well.
> >
> > > - The value "external" does not makes too much sense for listed usb devices
> >
> > Then don't use it.
> >
> > > - It makes our lives easier if dt and acpi have the same meaning (less
> > > conversion)
> >
> > We have little to no input into what ACPI does. If we're just going to
> > copy ACPI, then just use ACPI instead.
> >
> > > All that said, for my specific usecase, reusing orientation from
> > > bindings/media/video-interface-devices.yaml works... So if that is
> > > what you all prefer I can send a v2 with that.
> > > Let me know what you think
> >
> > We already have something for cameras. Use it.
> 
> So you are proposing a change like this?
> 
> diff --git a/Documentation/devicetree/bindings/usb/usb-device.yaml
> b/Documentation/devicetree/bindings/usb/usb-device.yaml
> index da890ee60ce6..5322772a4470 100644
> --- a/Documentation/devicetree/bindings/usb/usb-device.yaml
> +++ b/Documentation/devicetree/bindings/usb/usb-device.yaml
> @@ -37,6 +37,10 @@ properties:
>        but a device adhering to this binding may leave out all except
>        for "usbVID,PID".
> 
> +  orientation:
> +    description: If present, specifies the orientation of the usb device.
> +    $ref: /schemas/media/video-interface-devices.yaml#/properties/orientation

Do you need this for a camera or for other kinds of USB devices, too?

What about e.g. the rotation property?

> +
> 
> 
>    reg:
>      description: the number of the USB hub port or the USB host-controller
>        port to which this device is attached. The range is 1-255.

-- 
Regards,

Sakari Ailus