[libcamera-devel] [PATCH 3/8] libcamera: v4l2_subdevice: Extend [gs]etFormat() to specify format type

[Laurent Pinchart]

The V4L2 subdevice API exposes ACTIVE and TRY formats, but the
V4L2Subdevice getFormat() and setFormat() operations only apply on
ACTIVE formats. Extend them to support TRY formats as well.

Signed-off-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
---
 src/libcamera/include/v4l2_subdevice.h | 11 +++++++++--
 src/libcamera/v4l2_subdevice.cpp       | 23 +++++++++++++++++++----
 2 files changed, 28 insertions(+), 6 deletions(-)

diff --git a/src/libcamera/include/v4l2_subdevice.h b/src/libcamera/include/v4l2_subdevice.h
index 9c077674f997..4a04eadfb1f9 100644
--- a/src/libcamera/include/v4l2_subdevice.h
+++ b/src/libcamera/include/v4l2_subdevice.h
@@ -32,6 +32,11 @@ struct V4L2SubdeviceFormat {
 class V4L2Subdevice : public V4L2Device
 {
 public:
+	enum Whence {
+		ActiveFormat,
+		TryFormat,
+	};
+
 	explicit V4L2Subdevice(const MediaEntity *entity);
 	V4L2Subdevice(const V4L2Subdevice &) = delete;
 	V4L2Subdevice &operator=(const V4L2Subdevice &) = delete;
@@ -46,8 +51,10 @@ public:
 
 	ImageFormats formats(unsigned int pad);
 
-	int getFormat(unsigned int pad, V4L2SubdeviceFormat *format);
-	int setFormat(unsigned int pad, V4L2SubdeviceFormat *format);
+	int getFormat(unsigned int pad, V4L2SubdeviceFormat *format,
+		      Whence whence = ActiveFormat);
+	int setFormat(unsigned int pad, V4L2SubdeviceFormat *format,
+		      Whence whence = ActiveFormat);
 
 	static V4L2Subdevice *fromEntityName(const MediaDevice *media,
 					     const std::string &entity);
diff --git a/src/libcamera/v4l2_subdevice.cpp b/src/libcamera/v4l2_subdevice.cpp
index f2bcd7f73c5c..d9c90a34c0d8 100644
--- a/src/libcamera/v4l2_subdevice.cpp
+++ b/src/libcamera/v4l2_subdevice.cpp
@@ -95,6 +95,15 @@ const std::string V4L2SubdeviceFormat::toString() const
  * any device left open will be closed, and any resources released.
  */
 
+/**
+ * \enum V4L2Subdevice::Whence
+ * \brief Specify the type of format for getFormat() and setFormat() operations
+ * \var V4L2Subdevice::ActiveFormat
+ * \brief The format operation applies to ACTIVE formats
+ * \var V4L2Subdevice::TryFormat
+ * \brief The format operation applies to TRY formats
+ */
+
 /**
  * \brief Create a V4L2 subdevice from a MediaEntity using its device node
  * path
@@ -184,12 +193,15 @@ ImageFormats V4L2Subdevice::formats(unsigned int pad)
  * \brief Retrieve the image format set on one of the V4L2 subdevice pads
  * \param[in] pad The 0-indexed pad number the format is to be retrieved from
  * \param[out] format The image bus format
+ * \param[in] whence The format to retrieve, ACTIVE or TRY
  * \return 0 on success or a negative error code otherwise
  */
-int V4L2Subdevice::getFormat(unsigned int pad, V4L2SubdeviceFormat *format)
+int V4L2Subdevice::getFormat(unsigned int pad, V4L2SubdeviceFormat *format,
+			     Whence whence)
 {
 	struct v4l2_subdev_format subdevFmt = {};
-	subdevFmt.which = V4L2_SUBDEV_FORMAT_ACTIVE;
+	subdevFmt.which = whence == ActiveFormat ? V4L2_SUBDEV_FORMAT_ACTIVE
+			: V4L2_SUBDEV_FORMAT_TRY;
 	subdevFmt.pad = pad;
 
 	int ret = ioctl(VIDIOC_SUBDEV_G_FMT, &subdevFmt);
@@ -211,6 +223,7 @@ int V4L2Subdevice::getFormat(unsigned int pad, V4L2SubdeviceFormat *format)
  * \brief Set an image format on one of the V4L2 subdevice pads
  * \param[in] pad The 0-indexed pad number the format is to be applied to
  * \param[inout] format The image bus format to apply to the subdevice's pad
+ * \param[in] whence The format to set, ACTIVE or TRY
  *
  * Apply the requested image format to the desired media pad and return the
  * actually applied format parameters, as \ref V4L2Subdevice::getFormat would
@@ -218,10 +231,12 @@ int V4L2Subdevice::getFormat(unsigned int pad, V4L2SubdeviceFormat *format)
  *
  * \return 0 on success or a negative error code otherwise
  */
-int V4L2Subdevice::setFormat(unsigned int pad, V4L2SubdeviceFormat *format)
+int V4L2Subdevice::setFormat(unsigned int pad, V4L2SubdeviceFormat *format,
+			     Whence whence)
 {
 	struct v4l2_subdev_format subdevFmt = {};
-	subdevFmt.which = V4L2_SUBDEV_FORMAT_ACTIVE;
+	subdevFmt.which = whence == ActiveFormat ? V4L2_SUBDEV_FORMAT_ACTIVE
+			: V4L2_SUBDEV_FORMAT_TRY;
 	subdevFmt.pad = pad;
 	subdevFmt.format.width = format->size.width;
 	subdevFmt.format.height = format->size.height;
-- 
Regards,

Laurent Pinchart