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Diffstat (limited to 'Documentation/sensor_driver_requirements.rst')
| -rw-r--r-- | Documentation/sensor_driver_requirements.rst | 19 |
1 files changed, 19 insertions, 0 deletions
diff --git a/Documentation/sensor_driver_requirements.rst b/Documentation/sensor_driver_requirements.rst index b0854be3..0e516b34 100644 --- a/Documentation/sensor_driver_requirements.rst +++ b/Documentation/sensor_driver_requirements.rst @@ -24,16 +24,23 @@ The sensor driver is assumed to be fully compliant with the V4L2 specification. For RAW sensors, the sensor driver shall support the following V4L2 controls: +* `V4L2_CID_ANALOGUE_GAIN`_ * `V4L2_CID_EXPOSURE`_ * `V4L2_CID_HBLANK`_ * `V4L2_CID_PIXEL_RATE`_ * `V4L2_CID_VBLANK`_ +.. _V4L2_CID_ANALOGUE_GAIN: https://www.kernel.org/doc/html/latest/userspace-api/media/v4l/ext-ctrls-image-source.html .. _V4L2_CID_EXPOSURE: https://www.kernel.org/doc/html/latest/userspace-api/media/v4l/control.html .. _V4L2_CID_HBLANK: https://www.kernel.org/doc/html/latest/userspace-api/media/v4l/ext-ctrls-image-source.html .. _V4L2_CID_PIXEL_RATE: https://www.kernel.org/doc/html/latest/userspace-api/media/v4l/ext-ctrls-image-process.html .. _V4L2_CID_VBLANK: https://www.kernel.org/doc/html/latest/userspace-api/media/v4l/ext-ctrls-image-source.html +The ``ANALOGUE_GAIN`` control units are sensor-specific. libcamera requires +a sensor-specific CameraSensorHelper implementation to translate between the +sensor specific ``gain code`` and the analogue ``gain value`` expressed as an +absolute number as defined by ``controls::AnalogueGain``. + While V4L2 doesn't specify a unit for the ``EXPOSURE`` control, libcamera requires it to be expressed as a number of image lines. Camera sensor drivers that do not comply with this requirement will need to be adapted or will produce @@ -55,6 +62,18 @@ The sensor driver should support the following V4L2 controls: The controls are used to register the camera location and rotation. +In order to support rotating the image the sensor driver should support + +* `V4L2_CID_HFLIP`_ +* `V4L2_CID_VFLIP`_ + +.. _V4L2_CID_HFLIP: https://www.kernel.org/doc/html/latest/userspace-api/media/v4l/control.html +.. _V4L2_CID_VFLIP: https://www.kernel.org/doc/html/latest/userspace-api/media/v4l/control.html + +The controls must be writable from userspace. In case of a RAW Bayer sensors, +drivers should correctly report if vertical/horizontal flips modify the Bayer +pattern ordering by reporting the `V4L2_CTRL_FLAG_MODIFY_LAYOUT` control flag. + The sensor driver should implement support for the V4L2 Selection API, specifically it should implement support for the `VIDIOC_SUBDEV_G_SELECTION`_ ioctl with support for the following selection |