[libcamera-devel] [PATCH v2] libcamera: v4l2device: Obtain device capabilities

[Kieran Bingham]

The capabilities structure from the kernel can return capabilities of the
driver, or potentially more specific device capabilities.

Handle this with an inline function 'device_caps()' to return the device
specific capabilities when available, or fall back to the driver capabilities
otherwise.

Signed-off-by: Kieran Bingham <kieran.bingham at ideasonboard.com>
---
 src/libcamera/include/v4l2_device.h | 12 +++++++++---
 src/libcamera/v4l2_device.cpp       |  7 +++++++
 2 files changed, 16 insertions(+), 3 deletions(-)

diff --git a/src/libcamera/include/v4l2_device.h b/src/libcamera/include/v4l2_device.h
index b92e1f1c96c3..cb3601ca070c 100644
--- a/src/libcamera/include/v4l2_device.h
+++ b/src/libcamera/include/v4l2_device.h
@@ -26,10 +26,16 @@ struct V4L2Capability final : v4l2_capability {
 	{
 		return reinterpret_cast<const char *>(v4l2_capability::bus_info);
 	}
+	unsigned int device_caps() const
+	{
+		return capabilities & V4L2_CAP_DEVICE_CAPS
+				    ? v4l2_capability::device_caps
+				    : v4l2_capability::capabilities;
+	}
 
-	bool isCapture() const { return capabilities & V4L2_CAP_VIDEO_CAPTURE; }
-	bool isOutput() const { return capabilities & V4L2_CAP_VIDEO_OUTPUT; }
-	bool hasStreaming() const { return capabilities & V4L2_CAP_STREAMING; }
+	bool isCapture() const { return device_caps() & V4L2_CAP_VIDEO_CAPTURE; }
+	bool isOutput() const { return device_caps() & V4L2_CAP_VIDEO_OUTPUT; }
+	bool hasStreaming() const { return device_caps() & V4L2_CAP_STREAMING; }
 };
 
 class MediaEntity;
diff --git a/src/libcamera/v4l2_device.cpp b/src/libcamera/v4l2_device.cpp
index 2b17fa1eb0e8..0ce2b187f2f0 100644
--- a/src/libcamera/v4l2_device.cpp
+++ b/src/libcamera/v4l2_device.cpp
@@ -49,6 +49,13 @@ LOG_DEFINE_CATEGORY(V4L2)
  * \return The string containing the device location
  */
 
+/**
+ * \fn unsigned int V4L2Capability::device_caps()
+ * \brief Retrieve the capabilities of the device
+ * \return The device specific capabilities if V4L2_CAP_DEVICE_CAPS is set or
+ * 	   driver capabilities otherwise
+ */
+
 /**
  * \fn bool V4L2Capability::isCapture()
  * \brief Identify if the device is capable of capturing video
-- 
2.19.1