libcamera: camera_sensor: Prepare for multi-subdev camera sensors

While most camera sensors are exposed to userspace as a single subdev,
this is not always the case. A notable exception is the smiapp driver,
which exposes two or three subdevs. The subdev at the output of the
camera sensor will thus have more than one pad. Prepare for this by
removing the single-pad restriction, and locating the source pad
dynamically.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>

2 files changed, 16 insertions, 9 deletions

diff --git a/src/libcamera/camera_sensor.cpp b/src/libcamera/camera_sensor.cpp
index d6a823f4..4154700a 100644
--- a/src/libcamera/camera_sensor.cpp
+++ b/src/libcamera/camera_sensor.cpp
@@ -131,7 +131,7 @@ LOG_DEFINE_CATEGORY(CameraSensor);
  * Once constructed the instance must be initialized with init().
  */
 CameraSensor::CameraSensor(const MediaEntity *entity)
-	: entity_(entity), properties_(properties::properties)
+	: entity_(entity), pad_(UINT_MAX), properties_(properties::properties)
 {
 }
 
@@ -152,9 +152,14 @@ CameraSensor::~CameraSensor()
  */
 int CameraSensor::init()
 {
-	int ret;
+	for (const MediaPad *pad : entity_->pads()) {
+		if (pad->flags() & MEDIA_PAD_FL_SOURCE) {
+			pad_ = pad->index();
+			break;
+		}
+	}
 
-	if (entity_->pads().size() != 1) {
+	if (pad_ == UINT_MAX) {
 		LOG(CameraSensor, Error)
 			<< "Sensors with more than one pad are not supported";
 		return -EINVAL;
@@ -197,7 +202,7 @@ int CameraSensor::init()
 
 	/* Create and open the subdev. */
 	subdev_ = std::make_unique<V4L2Subdevice>(entity_);
-	ret = subdev_->open();
+	int ret = subdev_->open();
 	if (ret < 0)
 		return ret;
 
@@ -241,7 +246,7 @@ int CameraSensor::init()
 	properties_.set(properties::Rotation, propertyValue);
 
 	/* Enumerate and cache media bus codes and sizes. */
-	const ImageFormats formats = subdev_->formats(0);
+	const ImageFormats formats = subdev_->formats(pad_);
 	if (formats.isEmpty()) {
 		LOG(CameraSensor, Error) << "No image format found";
 		return -EINVAL;
@@ -405,7 +410,7 @@ V4L2SubdeviceFormat CameraSensor::getFormat(const std::vector<unsigned int> &mbu
  */
 int CameraSensor::setFormat(V4L2SubdeviceFormat *format)
 {
-	return subdev_->setFormat(0, format);
+	return subdev_->setFormat(pad_, format);
 }
 
 /**
@@ -489,7 +494,7 @@ int CameraSensor::sensorInfo(CameraSensorInfo *info) const
 
 	/* Get the active area size. */
 	Rectangle rect = {};
-	int ret = subdev_->getSelection(0, V4L2_SEL_TGT_CROP_DEFAULT, &rect);
+	int ret = subdev_->getSelection(pad_, V4L2_SEL_TGT_CROP_DEFAULT, &rect);
 	if (ret) {
 		LOG(CameraSensor, Error)
 			<< "Failed to construct camera sensor info: "
@@ -500,7 +505,7 @@ int CameraSensor::sensorInfo(CameraSensorInfo *info) const
 	info->activeAreaSize = { rect.width, rect.height };
 
 	/* It's mandatory for the subdevice to report its crop rectangle. */
-	ret = subdev_->getSelection(0, V4L2_SEL_TGT_CROP, &info->analogCrop);
+	ret = subdev_->getSelection(pad_, V4L2_SEL_TGT_CROP, &info->analogCrop);
 	if (ret) {
 		LOG(CameraSensor, Error)
 			<< "Failed to construct camera sensor info: "
@@ -510,7 +515,7 @@ int CameraSensor::sensorInfo(CameraSensorInfo *info) const
 
 	/* The bit depth and image size depend on the currently applied format. */
 	V4L2SubdeviceFormat format{};
-	ret = subdev_->getFormat(0, &format);
+	ret = subdev_->getFormat(pad_, &format);
 	if (ret)
 		return ret;
 	info->bitsPerPixel = format.bitsPerPixel();
diff --git a/src/libcamera/include/camera_sensor.h b/src/libcamera/include/camera_sensor.h
index 92cd9035..24993b74 100644
--- a/src/libcamera/include/camera_sensor.h
+++ b/src/libcamera/include/camera_sensor.h
@@ -70,6 +70,8 @@ protected:
 private:
 	const MediaEntity *entity_;
 	std::unique_ptr<V4L2Subdevice> subdev_;
+	unsigned int pad_;
+
 	std::string model_;
 
 	std::vector<unsigned int> mbusCodes_;