[libcamera-devel] [PATCH v5 4/6] libcamera: camera_sensor: Add V4L2 control operations

[Jacopo Mondi]

Add operations to get and set control and to retrieve the informations
on a V4L2 control. For simple camera sensors, the operations are
directly called on the underlying V4L2 subdevice.

Signed-off-by: Jacopo Mondi <jacopo at jmondi.org>
---
 src/libcamera/camera_sensor.cpp       | 65 +++++++++++++++++++++++++++
 src/libcamera/include/camera_sensor.h |  6 +++
 2 files changed, 71 insertions(+)

diff --git a/src/libcamera/camera_sensor.cpp b/src/libcamera/camera_sensor.cpp
index a804a68c9d91..637f86b05701 100644
--- a/src/libcamera/camera_sensor.cpp
+++ b/src/libcamera/camera_sensor.cpp
@@ -247,6 +247,71 @@ int CameraSensor::setFormat(V4L2SubdeviceFormat *format)
 	return subdev_->setFormat(0, format);
 }
 
+/**
+ * \brief Retrieve information about a control
+ * \param[in] id The control ID
+ * \return A pointer to the V4L2ControlInfo for control \a id, or nullptr
+ * if the sensor doesn't have such a control
+ */
+const V4L2ControlInfo *CameraSensor::getControlInfo(unsigned int id) const
+{
+	return subdev_->getControlInfo(id);
+}
+
+/**
+ * \brief Read controls from the sensor
+ * \param[inout] ctrls The list of controls to read
+ *
+ * Read the value of each control contained in \a ctrls, and store the
+ * value in the corresponding \a ctrls entry.
+ *
+ * If an integer number less than the requested number of controls is returned,
+ * only controls up to that index have been successfully read.
+ *
+ * Each V4L2Control instance in \a ctrls should be supported by the sensor and
+ * accessible (ie the V4L2_CTRL_FLAG_DISABLED flag should not be set), otherwise
+ * a negative error code (-EINVAL) is returned
+ *
+ * \sa V4L2Device::getControls()
+ *
+ * \return 0 on success or an error code otherwise
+ * \retval -EINVAL One of the control is not supported or not accessible
+ * \retval i The index of the control that failed
+ */
+int CameraSensor::getControls(V4L2Controls *ctrls)
+{
+	return subdev_->getControls(ctrls);
+}
+
+/**
+ * \brief Write controls to the sensor
+ * \param[in] ctrls The list of controls to write
+ *
+ * Write the value of each V4L2Control contained in \a ctrls. Each
+ * control should be initialized by the caller with a value, otherwise
+ * the result of the operation is undefined.
+ *
+ * The value of each control is updated to reflect what has been
+ * actually applied on the sensor.
+ *
+ * If an integer number less than the requested number of controls is returned,
+ * only controls up to that index have been successfully applied.
+ *
+ * Each V4L2Control instance in \a ctrls should be supported by the sensor and
+ * accessible (ie the V4L2_CTRL_FLAG_DISABLED flag should not be set), otherwise
+ * a negative error code (-EINVAL) is returned
+ *
+ * \sa V4L2Device::setControls()
+ *
+ * \return 0 on success or an error code otherwise
+ * \retval -EINVAL One of the control is not supported or not accessible
+ * \retval i The index of the control that failed
+ */
+int CameraSensor::setControls(V4L2Controls *ctrls)
+{
+	return subdev_->setControls(ctrls);
+}
+
 std::string CameraSensor::logPrefix() const
 {
 	return "'" + subdev_->entity()->name() + "'";
diff --git a/src/libcamera/include/camera_sensor.h b/src/libcamera/include/camera_sensor.h
index b823480241a7..b4f4b66e96c4 100644
--- a/src/libcamera/include/camera_sensor.h
+++ b/src/libcamera/include/camera_sensor.h
@@ -17,6 +17,8 @@
 namespace libcamera {
 
 class MediaEntity;
+class V4L2ControlInfo;
+class V4L2Controls;
 class V4L2Subdevice;
 
 struct V4L2SubdeviceFormat;
@@ -41,6 +43,10 @@ public:
 				      const Size &size) const;
 	int setFormat(V4L2SubdeviceFormat *format);
 
+	const V4L2ControlInfo *getControlInfo(unsigned int id) const;
+	int getControls(V4L2Controls *ctrls);
+	int setControls(V4L2Controls *ctrls);
+
 protected:
 	std::string logPrefix() const;
 
-- 
2.21.0