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Date:   Thu, 15 Aug 2019 10:00:25 +0300
From:   Sakari Ailus <sakari.ailus@linux.intel.com>
To:     Jacopo Mondi <jacopo@jmondi.org>
Cc:     Mauro Carvalho Chehab <mchehab@kernel.org>,
        Hans Verkuil <hverkuil-cisco@xs4all.nl>,
        Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
        "open list:MEDIA INPUT INFRASTRUCTURE (V4L/DVB)" 
        <linux-media@vger.kernel.org>,
        open list <linux-kernel@vger.kernel.org>
Subject: Re: [RFC 2/5] media: v4l2-ctrl: Document V4L2_CID_LOCATION
Message-ID: <20190815070025.GK6133@paasikivi.fi.intel.com>
References: <20190814202815.32491-1-jacopo@jmondi.org>
 <20190814202815.32491-3-jacopo@jmondi.org>
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Hi Jacopo,

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 <jacopo@jmondi.org>
> ---
>  .../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.

-- 
Sakari Ailus
sakari.ailus@linux.intel.com