[libcamera-devel] [PATCH 02/12] libcamera: camera_sensor: Make V4L2_CID_EXPOSURE mandatory

[Jacopo Mondi]

Add the V4L2_CID_EXPOSURE control to the list of mandatory controls the
sensor driver has to report and document this new requirement.

Signed-off-by: Jacopo Mondi <jacopo at jmondi.org>
---
 Documentation/sensor_driver_requirements.rst | 11 ++++++++++-
 src/libcamera/camera_sensor.cpp              |  1 +
 2 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/Documentation/sensor_driver_requirements.rst b/Documentation/sensor_driver_requirements.rst
index 0e658aaa03b5..97e98b9e12ef 100644
--- a/Documentation/sensor_driver_requirements.rst
+++ b/Documentation/sensor_driver_requirements.rst
@@ -26,11 +26,20 @@ The sensor driver shall support the following V4L2 controls:
 
 * `V4L2_CID_HBLANK`_
 * `V4L2_CID_PIXEL_RATE`_
+* `V4L2_CID_EXPOSURE`_
 
 .. _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_EXPOSURE: https://www.kernel.org/doc/html/latest/userspace-api/media/v4l/control.html
+
+The `HBLANK` and `PIXEL_RATE` controls are used to compute the sensor
+output timings.
+
+The `EXPOSURE` control shall report the image integration time in number of
+lines. The V4L2 documentation does not specify a unit for this control, drivers
+compliant with the V4L2 specification might need to be changed to be used by
+libcamera.
 
-Both controls are used to compute the sensor output timings.
 
 Optional Requirements
 ---------------------
diff --git a/src/libcamera/camera_sensor.cpp b/src/libcamera/camera_sensor.cpp
index 05a1d7c22e97..f7939b94d2f8 100644
--- a/src/libcamera/camera_sensor.cpp
+++ b/src/libcamera/camera_sensor.cpp
@@ -245,6 +245,7 @@ int CameraSensor::validateSensorDriver()
 	const std::vector<uint32_t> mandatoryControls{
 		V4L2_CID_PIXEL_RATE,
 		V4L2_CID_HBLANK,
+		V4L2_CID_EXPOSURE,
 	};
 
 	ControlList ctrls = subdev_->getControls(mandatoryControls);
-- 
2.29.2