[libcamera-devel,1/2] libcamera: v4l2_device: Add tryFormat support
diff mbox series

Message ID 20190503153403.8728-2-kieran.bingham@ideasonboard.com
State Superseded
Headers show
Series
  • V4L2Device Try format support
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Commit Message

Kieran Bingham May 3, 2019, 3:34 p.m. UTC 
Extend the internal functionality of setFormat{Single,Multi}plane to
allow 'trying' a format. This provides the facility of checking a format
with the driver before committing to it.

Signed-off-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
---
 src/libcamera/include/v4l2_device.h |  7 +++++--
 src/libcamera/v4l2_device.cpp       | 29 +++++++++++++++++++++++------
 2 files changed, 28 insertions(+), 8 deletions(-)

Patch
diff mbox series 

diff --git a/src/libcamera/include/v4l2_device.h b/src/libcamera/include/v4l2_device.h
index 2e7bd1e7f4cc..a08615c3bd9a 100644
--- a/src/libcamera/include/v4l2_device.h
+++ b/src/libcamera/include/v4l2_device.h
@@ -126,6 +126,7 @@  public:
 
 	int getFormat(V4L2DeviceFormat *format);
 	int setFormat(V4L2DeviceFormat *format);
+	int tryFormat(V4L2DeviceFormat *format);
 
 	int exportBuffers(BufferPool *pool);
 	int importBuffers(BufferPool *pool);
@@ -145,10 +146,12 @@  protected:
 
 private:
 	int getFormatSingleplane(V4L2DeviceFormat *format);
-	int setFormatSingleplane(V4L2DeviceFormat *format);
+	int trySetFormatSingleplane(V4L2DeviceFormat *format,
+				    unsigned long request);
 
 	int getFormatMultiplane(V4L2DeviceFormat *format);
-	int setFormatMultiplane(V4L2DeviceFormat *format);
+	int trySetFormatMultiplane(V4L2DeviceFormat *format,
+				   unsigned long request);
 
 	int requestBuffers(unsigned int count);
 	int createPlane(Buffer *buffer, unsigned int plane,
diff --git a/src/libcamera/v4l2_device.cpp b/src/libcamera/v4l2_device.cpp
index 1bbf79673c16..d965c7226b04 100644
--- a/src/libcamera/v4l2_device.cpp
+++ b/src/libcamera/v4l2_device.cpp
@@ -434,8 +434,23 @@  int V4L2Device::getFormat(V4L2DeviceFormat *format)
  */
 int V4L2Device::setFormat(V4L2DeviceFormat *format)
 {
-	return caps_.isMultiplanar() ? setFormatMultiplane(format) :
-				       setFormatSingleplane(format);
+	return caps_.isMultiplanar() ? trySetFormatMultiplane(format, VIDIOC_S_FMT) :
+				       trySetFormatSingleplane(format, VIDIOC_S_FMT);
+}
+
+/**
+ * \brief Validate an image format on the V4L2 device
+ * \param[inout] format The image format to apply to the device
+ *
+ * Try the supplied \a format on the device, and return the format parameters
+ * that would have been applied, as \ref V4L2Device::setFormat would do.
+ *
+ * \return 0 on success or a negative error code otherwise
+ */
+int V4L2Device::tryFormat(V4L2DeviceFormat *format)
+{
+	return caps_.isMultiplanar() ? trySetFormatMultiplane(format, VIDIOC_TRY_FMT) :
+				       trySetFormatSingleplane(format, VIDIOC_TRY_FMT);
 }
 
 int V4L2Device::getFormatSingleplane(V4L2DeviceFormat *format)
@@ -462,7 +477,8 @@  int V4L2Device::getFormatSingleplane(V4L2DeviceFormat *format)
 	return 0;
 }
 
-int V4L2Device::setFormatSingleplane(V4L2DeviceFormat *format)
+int V4L2Device::trySetFormatSingleplane(V4L2DeviceFormat *format,
+					unsigned long request)
 {
 	struct v4l2_format v4l2Format = {};
 	struct v4l2_pix_format *pix = &v4l2Format.fmt.pix;
@@ -475,7 +491,7 @@  int V4L2Device::setFormatSingleplane(V4L2DeviceFormat *format)
 	pix->bytesperline = format->planes[0].bpl;
 	pix->field = V4L2_FIELD_NONE;
 
-	ret = ioctl(fd_, VIDIOC_S_FMT, &v4l2Format);
+	ret = ioctl(fd_, request, &v4l2Format);
 	if (ret) {
 		ret = -errno;
 		LOG(V4L2, Error) << "Unable to set format: " << strerror(-ret);
@@ -523,7 +539,8 @@  int V4L2Device::getFormatMultiplane(V4L2DeviceFormat *format)
 	return 0;
 }
 
-int V4L2Device::setFormatMultiplane(V4L2DeviceFormat *format)
+int V4L2Device::trySetFormatMultiplane(V4L2DeviceFormat *format,
+				       unsigned long request)
 {
 	struct v4l2_format v4l2Format = {};
 	struct v4l2_pix_format_mplane *pix = &v4l2Format.fmt.pix_mp;
@@ -541,7 +558,7 @@  int V4L2Device::setFormatMultiplane(V4L2DeviceFormat *format)
 		pix->plane_fmt[i].sizeimage = format->planes[i].size;
 	}
 
-	ret = ioctl(fd_, VIDIOC_S_FMT, &v4l2Format);
+	ret = ioctl(fd_, request, &v4l2Format);
 	if (ret) {
 		ret = -errno;
 		LOG(V4L2, Error) << "Unable to set format: " << strerror(-ret);