[libcamera-devel] [RFC 1/4] libcamera: camera: Add acquire() and release()
Niklas Söderlund
niklas.soderlund at ragnatech.se
Tue Jan 22 00:06:37 CET 2019
From: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
---
include/libcamera/camera.h | 5 +++++
src/libcamera/camera.cpp | 33 +++++++++++++++++++++++++++++++++
2 files changed, 38 insertions(+)
diff --git a/include/libcamera/camera.h b/include/libcamera/camera.h
index 2ea1a6883311cf9f..03b285c840c246e1 100644
--- a/include/libcamera/camera.h
+++ b/include/libcamera/camera.h
@@ -22,11 +22,16 @@ public:
const std::string &name() const;
+ int acquire();
+ void release();
+
private:
explicit Camera(const std::string &name);
~Camera();
std::string name_;
+
+ bool acquired_;
};
} /* namespace libcamera */
diff --git a/src/libcamera/camera.cpp b/src/libcamera/camera.cpp
index acf912bee95cbec4..b80bc36e410a6e0a 100644
--- a/src/libcamera/camera.cpp
+++ b/src/libcamera/camera.cpp
@@ -92,4 +92,37 @@ Camera::~Camera()
{
}
+/**
+ * \brief Acquire the camera device for exclusive access
+ *
+ * After opening the device with open(), exclusive access must be obtained
+ * before performing operations that change the device state. This function is
+ * not blocking, if the device has already been acquired (by the same or another
+ * process) the -EBUSY error code is returned.
+ *
+ * Once exclusive access isn't needed anymore, the device should be released
+ * with a call to the release() function.
+ *
+ * \return 0 on success or a negative error code on error.
+ */
+int Camera::acquire()
+{
+ if (acquired_)
+ return -EBUSY;
+
+ acquired_ = true;
+ return 0;
+}
+
+/**
+ * \brief Release exclusive access to the camera device
+ *
+ * Releasing the camera device allows other users to acquire exclusive access
+ * with the acquire() function.
+ */
+void Camera::release()
+{
+ acquired_ = false;
+}
+
} /* namespace libcamera */
--
2.20.1
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