Re: [PATCH v10 04/13] media: v4l2-ctrl: Document V4L2_CID_CAMERA_ORIENTATION

From: Hans Verkuil <hverkuil-cisco@xs4all.nl>
To: Jacopo Mondi <jacopo@jmondi.org>,
	"open list:MEDIA INPUT INFRASTRUCTURE (V4L/DVB)" 
	<linux-media@vger.kernel.org>,
	libcamera-devel@lists.libcamera.org,
	Mauro Carvalho Chehab <mchehab@kernel.org>,
	Sakari Ailus <sakari.ailus@linux.intel.com>,
	Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: tfiga@google.com, pavel@ucw.cz
Subject: Re: [PATCH v10 04/13] media: v4l2-ctrl: Document V4L2_CID_CAMERA_ORIENTATION
Date: Fri, 8 May 2020 13:02:27 +0200	[thread overview]
Message-ID: <eea16d6b-bc58-a78a-c4c8-6f857251a047@xs4all.nl> (raw)
In-Reply-To: <20200508100158.3437161-5-jacopo@jmondi.org>

On 08/05/2020 12:01, Jacopo Mondi wrote:
> Add documentation for the V4L2_CID_CAMERA_ORIENTATION camera
> control. The newly added read-only control reports the camera device
> orientation relative to the usage orientation of the system the camera
> is installed on.
> 
> Signed-off-by: Jacopo Mondi <jacopo@jmondi.org>
> ---
>  .../media/v4l/ext-ctrls-camera.rst            | 30 +++++++++++++++++++
>  1 file changed, 30 insertions(+)
> 
> diff --git a/Documentation/userspace-api/media/v4l/ext-ctrls-camera.rst b/Documentation/userspace-api/media/v4l/ext-ctrls-camera.rst
> index e39f84d2447f8..01e104bab6b3d 100644
> --- a/Documentation/userspace-api/media/v4l/ext-ctrls-camera.rst
> +++ b/Documentation/userspace-api/media/v4l/ext-ctrls-camera.rst
> @@ -510,6 +510,36 @@ 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_CAMERA_ORIENTATION (integer)``

integer -> menu

> +    This read-only control describes the camera orientation by reporting
> +    its mounting position on the device where the camera is installed. The
> +    control value is constant and not modifiable by software. This control is
> +    particularly meaningful for devices which have a well defined orientation,
> +    such as phones, laptops and portable devices since the control is expressed
> +    as a position relative to the device's intended usage orientation.
> +    For example, a camera installed on the user-facing side of a phone,
> +    a tablet or a laptop device is said to be have ``V4L2_ORIENTATION_FRONT``
> +    orientation, while a camera installed on the opposite side of the front one
> +    is said to be have ``V4L2_ORIENTATION_BACK`` orientation. Camera sensors not
> +    directly attached to the device, or attached in a way that allows them to
> +    move freely, such as webcams and digital cameras, are said to have the
> +    ``V4L2_ORIENTATION_EXTERNAL`` orientation.
> +
> +
> +
> +.. flat-table::
> +    :header-rows:  0
> +    :stub-columns: 0
> +
> +    * - ``V4L2_ORIENTATION_FRONT``

This really should be V4L2_CAMERA_ORIENTATION_FRONT. Yes, it is long, but just
'ORIENTATION' doesn't tell you which orientation is meant, that's too generic.

Regards,

	Hans

> +      - The camera is oriented towards the user facing side of the device.
> +    * - ``V4L2_ORIENTATION_BACK``
> +      - The camera is oriented towards the back facing side of the device.
> +    * - ``V4L2_ORIENTATION_EXTERNAL``
> +      - The camera is not directly attached to the device and is freely movable.
> +
> +
> +
>  .. [#f1]
>     This control may be changed to a menu control in the future, if more
>     options are required.
> 