Document how rotation and orientation should be taken into account in
writing camera sensor drivers.
Signed-off-by: Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxx>
Reviewed-by: Jacopo Mondi <jacopo.mondi@xxxxxxxxxxxxxxxx>
---
since v4:
- Add "flipping" to the section name.
- Add a note on flipping controls not being inverted.
- Move the flipping related paragraph to the end of the section.
.../driver-api/media/camera-sensor.rst | 22 +++++++++++++++++++
.../media/v4l/ext-ctrls-camera.rst | 3 +++
2 files changed, 25 insertions(+)
diff --git a/Documentation/driver-api/media/camera-sensor.rst b/Documentation/driver-api/media/camera-sensor.rst
index c7d4891bd24e7..93f4f2536c250 100644
--- a/Documentation/driver-api/media/camera-sensor.rst
+++ b/Documentation/driver-api/media/camera-sensor.rst
@@ -151,3 +151,25 @@ used to obtain device's power state after the power state transition:
The function returns a non-zero value if it succeeded getting the power count or
runtime PM was disabled, in either of which cases the driver may proceed to
access the device.
+
+Rotation, orientation and flipping
+----------------------------------
+
+Some systems have the camera sensor mounted upside down compared to its natural
+mounting rotation. In such cases, drivers shall expose the information to
+userspace with the :ref:`V4L2_CID_CAMERA_SENSOR_ROTATION
+<v4l2-camera-sensor-rotation>` control.
+
+Sensor drivers shall also report the sensor's mounting orientation with the
+:ref:`V4L2_CID_CAMERA_SENSOR_ORIENTATION <v4l2-camera-sensor-orientation>`.
+
+Use ``v4l2_fwnode_device_parse()`` to obtain rotation and orientation
+information from system firmware and ``v4l2_ctrl_new_fwnode_properties()`` to
+register the appropriate controls.
+
+Sensor drivers that have any vertical or horizontal flips embedded in the
+register programming sequences shall initialize the V4L2_CID_HFLIP and
+V4L2_CID_VFLIP controls with the values programmed by the register sequences.
+The default values of these controls shall be 0 (disabled). Especially these
+controls shall not be inverted, independently of the sensor's mounting
+rotation.
diff --git a/Documentation/userspace-api/media/v4l/ext-ctrls-camera.rst b/Documentation/userspace-api/media/v4l/ext-ctrls-camera.rst
index daa4f40869f8f..cdc515c604683 100644
--- a/Documentation/userspace-api/media/v4l/ext-ctrls-camera.rst
+++ b/Documentation/userspace-api/media/v4l/ext-ctrls-camera.rst
@@ -506,6 +506,8 @@ enum v4l2_scene_mode -
value down. A value of zero stops the motion if one is in progress
and has no effect otherwise.
+.. _v4l2-camera-sensor-orientation:
+
``V4L2_CID_CAMERA_ORIENTATION (menu)``
This read-only control describes the camera orientation by reporting its
mounting position on the device where the camera is installed. The control
@@ -536,6 +538,7 @@ enum v4l2_scene_mode -
- The camera is not directly attached to the device and is freely movable.
+.. _v4l2-camera-sensor-rotation:
``V4L2_CID_CAMERA_SENSOR_ROTATION (integer)``
This read-only control describes the rotation correction in degrees in the
--
2.30.2
