libcamera: v4l2_device: Add method to retrieve all supported controls

Add a new controls() method to the V4L2Device class to retrieve the map
of all supported controls. This is needed in order to dynamically query
the supported controls, for instance for drivers that support different
sets of controls depending on the device model.

To make the API easier to use, create a type alias for the control ID to
ControlInfo and use it.

Remove the getControlInfo() method that is not used externally, as it
can now be replaced by accessing the full list of controls.

Update the CameraSensor API accordingly.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Reviewed-by: Jacopo Mondi <jacopo@jmondi.org>
Reviewed-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>

1 files changed, 9 insertions, 16 deletions

diff --git a/src/libcamera/v4l2_device.cpp b/src/libcamera/v4l2_device.cpp
index 06939dea..e3ec44a7 100644
--- a/src/libcamera/v4l2_device.cpp
+++ b/src/libcamera/v4l2_device.cpp
@@ -111,19 +111,10 @@ void V4L2Device::close()
  */
 
 /**
- * \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 device doesn't have such a control
+ * \fn V4L2Device::controls()
+ * \brief Retrieve the supported V4L2 controls and their information
+ * \return A map of the V4L2 controls supported by the device
  */
-const V4L2ControlInfo *V4L2Device::getControlInfo(unsigned int id) const
-{
-	auto it = controls_.find(id);
-	if (it == controls_.end())
-		return nullptr;
-
-	return &it->second;
-}
 
 /**
  * \brief Read controls from the device
@@ -158,13 +149,14 @@ int V4L2Device::getControls(V4L2ControlList *ctrls)
 
 	for (unsigned int i = 0; i < count; ++i) {
 		const V4L2Control *ctrl = ctrls->getByIndex(i);
-		const V4L2ControlInfo *info = getControlInfo(ctrl->id());
-		if (!info) {
+		const auto iter = controls_.find(ctrl->id());
+		if (iter == controls_.end()) {
 			LOG(V4L2, Error)
 				<< "Control '" << ctrl->id() << "' not found";
 			return -EINVAL;
 		}
 
+		const V4L2ControlInfo *info = &iter->second;
 		controlInfo[i] = info;
 		v4l2Ctrls[i].id = info->id();
 	}
@@ -232,13 +224,14 @@ int V4L2Device::setControls(V4L2ControlList *ctrls)
 
 	for (unsigned int i = 0; i < count; ++i) {
 		const V4L2Control *ctrl = ctrls->getByIndex(i);
-		const V4L2ControlInfo *info = getControlInfo(ctrl->id());
-		if (!info) {
+		const auto iter = controls_.find(ctrl->id());
+		if (iter == controls_.end()) {
 			LOG(V4L2, Error)
 				<< "Control '" << ctrl->id() << "' not found";
 			return -EINVAL;
 		}
 
+		const V4L2ControlInfo *info = &iter->second;
 		controlInfo[i] = info;
 		v4l2Ctrls[i].id = info->id();