[libcamera-devel] [PATCH v3 4/6] libcamera: camera_sensor: Add tryFormat()

[Jacopo Mondi]

Add a function to the CameraSensor class that allows to test a format
without applying it to the subdevice and without modifying any control
value associated with the camera sensor.

Signed-off-by: Jacopo Mondi <jacopo.mondi at ideasonboard.com>
Reviewed-by: Paul Elder <paul.elder at ideasonboard.com>
---
 include/libcamera/internal/camera_sensor.h |  1 +
 src/libcamera/camera_sensor.cpp            | 17 +++++++++++++++++
 2 files changed, 18 insertions(+)

diff --git a/include/libcamera/internal/camera_sensor.h b/include/libcamera/internal/camera_sensor.h
index 928c61af7f4e..02c77ab037da 100644
--- a/include/libcamera/internal/camera_sensor.h
+++ b/include/libcamera/internal/camera_sensor.h
@@ -56,6 +56,7 @@ public:
 				      const Size &size) const;
 	int setFormat(V4L2SubdeviceFormat *format,
 		      Transform transform = Transform::Identity);
+	int tryFormat(V4L2SubdeviceFormat *format) const;
 
 	const ControlInfoMap &controls() const;
 	ControlList getControls(const std::vector<uint32_t> &ids);
diff --git a/src/libcamera/camera_sensor.cpp b/src/libcamera/camera_sensor.cpp
index e442b89dacd0..06f315210240 100644
--- a/src/libcamera/camera_sensor.cpp
+++ b/src/libcamera/camera_sensor.cpp
@@ -795,6 +795,23 @@ int CameraSensor::setFormat(V4L2SubdeviceFormat *format, Transform transform)
 	return 0;
 }
 
+/**
+ * \brief Try the sensor output format
+ * \param[in] format The desired sensor output format
+ *
+ * The ranges of any controls associated with the sensor are not updated.
+ *
+ * \todo Add support for Transform by changing the format's Bayer ordering
+ * before calling subdev_->setFormat().
+ *
+ * \return 0 on success or a negative error code otherwise
+ */
+int CameraSensor::tryFormat(V4L2SubdeviceFormat *format) const
+{
+	return subdev_->setFormat(pad_, format,
+				  V4L2Subdevice::Whence::TryFormat);
+}
+
 /**
  * \brief Retrieve the supported V4L2 controls and their information
  *
-- 
2.40.0