From patchwork Mon Jan 21 23:06:37 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: =?utf-8?q?Niklas_S=C3=B6derlund?= X-Patchwork-Id: 317 Return-Path: Received: from bin-mail-out-06.binero.net (bin-mail-out-06.binero.net [195.74.38.229]) by lancelot.ideasonboard.com (Postfix) with ESMTPS id 5D08360B2D for ; Tue, 22 Jan 2019 00:07:15 +0100 (CET) X-Halon-ID: 4916dae7-1dd1-11e9-874f-005056917f90 Authorized-sender: niklas@soderlund.pp.se Received: from bismarck.berto.se (unknown [89.233.230.99]) by bin-vsp-out-02.atm.binero.net (Halon) with ESMTPA id 4916dae7-1dd1-11e9-874f-005056917f90; Tue, 22 Jan 2019 00:07:12 +0100 (CET) From: =?utf-8?q?Niklas_S=C3=B6derlund?= To: libcamera-devel@lists.libcamera.org Date: Tue, 22 Jan 2019 00:06:37 +0100 Message-Id: <20190121230640.8783-2-niklas.soderlund@ragnatech.se> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190121230640.8783-1-niklas.soderlund@ragnatech.se> References: <20190121230640.8783-1-niklas.soderlund@ragnatech.se> MIME-Version: 1.0 Subject: [libcamera-devel] [RFC 1/4] libcamera: camera: Add acquire() and release() X-BeenThere: libcamera-devel@lists.libcamera.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 21 Jan 2019 23:07:15 -0000 From: Laurent Pinchart --- 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 */