[libcamera-devel] [PATCH v3 1/5] libcamera: camera_sensor: Make VBLANK mandatory

[Naushir Patuck]

From: Jacopo Mondi <jacopo at jmondi.org>

Add the V4L2_CID_VBLANK control to the list of mandatory controls
the sensor driver has to report and document the new requirement.

The vertical blanking control is used to calculate the frame duration.

Signed-off-by: Jacopo Mondi <jacopo at jmondi.org>
Signed-off-by: Naushir Patuck <naush at raspberrypi.com>
Reviewed-by: Naushir Patuck <naush at raspberrypi.com>
---
 Documentation/sensor_driver_requirements.rst | 6 ++++--
 src/libcamera/camera_sensor.cpp              | 1 +
 2 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/Documentation/sensor_driver_requirements.rst b/Documentation/sensor_driver_requirements.rst
index 6dcd4e68d64d..590797f054ce 100644
--- a/Documentation/sensor_driver_requirements.rst
+++ b/Documentation/sensor_driver_requirements.rst
@@ -27,18 +27,20 @@ The sensor driver shall support the following V4L2 controls:
 * `V4L2_CID_EXPOSURE`_
 * `V4L2_CID_HBLANK`_
 * `V4L2_CID_PIXEL_RATE`_
+* `V4L2_CID_VBLANK`_
 
 .. _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
 
 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 incorrect
 results.
 
-The `HBLANK` and `PIXEL_RATE` controls are used to compute the sensor output
-timings.
+The `HBLANK`, `PIXEL_RATE` and `VBLANK` 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 ca33c0094088..ab315bdc468c 100644
--- a/src/libcamera/camera_sensor.cpp
+++ b/src/libcamera/camera_sensor.cpp
@@ -244,6 +244,7 @@ int CameraSensor::validateSensorDriver()
 		V4L2_CID_EXPOSURE,
 		V4L2_CID_HBLANK,
 		V4L2_CID_PIXEL_RATE,
+		V4L2_CID_VBLANK,
 	};
 
 	ControlList ctrls = subdev_->getControls(mandatoryControls);
-- 
2.25.1