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Subject: Re: [RFC 2/5] media: v4l2-ctrl: Document V4L2_CID_LOCATION
To:     Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
        Jacopo Mondi <jacopo@jmondi.org>
Cc:     Mauro Carvalho Chehab <mchehab@kernel.org>,
        Sakari Ailus <sakari.ailus@linux.intel.com>,
        "open list:MEDIA INPUT INFRASTRUCTURE (V4L/DVB)" 
        <linux-media@vger.kernel.org>,
        open list <linux-kernel@vger.kernel.org>
References: <20190814202815.32491-1-jacopo@jmondi.org>
 <20190814202815.32491-3-jacopo@jmondi.org>
 <20190814224340.GD5015@pendragon.ideasonboard.com>
From:   Hans Verkuil <hverkuil-cisco@xs4all.nl>
Message-ID: <664fe7b3-9051-30da-736e-710a4e9cecde@xs4all.nl>
Date:   Thu, 15 Aug 2019 16:10:40 +0200
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On 8/15/19 12:43 AM, Laurent Pinchart wrote:
> Hi Jacopo,
> 
> Thank you for the patch.
> 
> 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)``
> 
> Maybe V4L2_CID_CAMERA_SENSOR_LOCATION ? Same for the values below.

Probably a better name, if a bit long. But we might need other location
controls in the future (e.g. flash location), so CID_LOCATION is just too
generic.

Regards,

	Hans

> 
>> +    This read-only control describes the camera location by reporting its
> 
> Here too I would mention camera sensor instead of just camera (or
> possibly imaging sensor).
> 
>> +    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
>> +    of a phone device is said to be installed in the ``V4L2_LOCATION_FRONT``
>> +    position.
> 
> The DT bindings could use such an example :-) I would extend this to
> tablets and laptops.
> 
>> +
>> +
>> +
> 
> Do we need three blank lines ?
> 
>> +.. 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.
>