Document how rotation and orientation should be taken into account in
writing camera sensor drivers.
Signed-off-by: Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxx>
---
since v1:
- Simplify language (Laurent's suggestion) and add note on flipping
controls (Jacopo).
- Improve the last paragraph, say this is about rotation and orientation.
Documentation/driver-api/media/camera-sensor.rst | 16 ++++++++++++++++
.../userspace-api/media/v4l/ext-ctrls-camera.rst | 1 +
2 files changed, 17 insertions(+)
diff --git a/Documentation/driver-api/media/camera-sensor.rst b/Documentation/driver-api/media/camera-sensor.rst
index c7d4891bd24e..61caa7901c51 100644
--- a/Documentation/driver-api/media/camera-sensor.rst
+++ b/Documentation/driver-api/media/camera-sensor.rst
@@ -151,3 +151,19 @@ 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 and orientation
+------------------------
+
+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 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.
+
+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.
diff --git a/Documentation/userspace-api/media/v4l/ext-ctrls-camera.rst b/Documentation/userspace-api/media/v4l/ext-ctrls-camera.rst
index daa4f40869f8..29fe22da52a2 100644
--- a/Documentation/userspace-api/media/v4l/ext-ctrls-camera.rst
+++ b/Documentation/userspace-api/media/v4l/ext-ctrls-camera.rst
@@ -536,6 +536,7 @@ 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
