{"id":3487,"url":"https://patchwork.libcamera.org/api/1.1/patches/3487/?format=json","web_url":"https://patchwork.libcamera.org/patch/3487/","project":{"id":1,"url":"https://patchwork.libcamera.org/api/1.1/projects/1/?format=json","name":"libcamera","link_name":"libcamera","list_id":"libcamera_core","list_email":"libcamera-devel@lists.libcamera.org","web_url":"","scm_url":"","webscm_url":""},"msgid":"<20200418103216.140572-2-jacopo@jmondi.org>","date":"2020-04-18T10:32:12","name":"[libcamera-devel,v4,1/5] Documentation: media: Update sub-device API intro","commit_ref":null,"pull_url":null,"state":"superseded","archived":false,"hash":"0e277b2ce2c35819104fbcd59d6a222d5fdf68cb","submitter":{"id":3,"url":"https://patchwork.libcamera.org/api/1.1/people/3/?format=json","name":"Jacopo Mondi","email":"jacopo@jmondi.org"},"delegate":null,"mbox":"https://patchwork.libcamera.org/patch/3487/mbox/","series":[{"id":816,"url":"https://patchwork.libcamera.org/api/1.1/series/816/?format=json","web_url":"https://patchwork.libcamera.org/project/libcamera/list/?series=816","date":"2020-04-18T10:32:11","name":"media: Register read-only sub-dev devnode","version":4,"mbox":"https://patchwork.libcamera.org/series/816/mbox/"}],"comments":"https://patchwork.libcamera.org/api/patches/3487/comments/","check":"pending","checks":"https://patchwork.libcamera.org/api/patches/3487/checks/","tags":{},"headers":{"Return-Path":"","Received":["from relay3-d.mail.gandi.net (relay3-d.mail.gandi.net\n\t[217.70.183.195])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTPS id 148C060401\n\tfor ;\n\tSat, 18 Apr 2020 12:29:29 +0200 (CEST)","from uno.homenet.telecomitalia.it (unknown [87.13.136.104])\n\t(Authenticated sender: jacopo@jmondi.org)\n\tby relay3-d.mail.gandi.net (Postfix) with ESMTPSA id E66E160002;\n\tSat, 18 Apr 2020 10:29:23 +0000 (UTC)"],"X-Originating-IP":"87.13.136.104","From":"Jacopo Mondi ","To":"linux-media@vger.kernel.org,\n\tlibcamera-devel@lists.libcamera.org","Cc":"Jacopo Mondi , mchehab@kernel.org,\n\thverkuil-cisco@xs4all.nl, sakari.ailus@linux.intel.com,\n\tandrey.konovalov@linaro.org, laurent.pinchart@ideasonboard.com","Date":"Sat, 18 Apr 2020 12:32:12 +0200","Message-Id":"<20200418103216.140572-2-jacopo@jmondi.org>","X-Mailer":"git-send-email 2.26.1","In-Reply-To":"<20200418103216.140572-1-jacopo@jmondi.org>","References":"<20200418103216.140572-1-jacopo@jmondi.org>","MIME-Version":"1.0","Content-Transfer-Encoding":"8bit","Subject":"[libcamera-devel] [PATCH v4 1/5] Documentation: media: Update\n\tsub-device API intro","X-BeenThere":"libcamera-devel@lists.libcamera.org","X-Mailman-Version":"2.1.29","Precedence":"list","List-Id":"","List-Unsubscribe":",\n\t","List-Archive":"","List-Post":"","List-Help":"","List-Subscribe":",\n\t","X-List-Received-Date":"Sat, 18 Apr 2020 10:29:29 -0000"},"content":"Update the V4L2 sub-device userspace API introduction to provide more\ndetails on why complex devices might want to register devnodes for the\nconnected subdevices.\n\nAcked-by: Sakari Ailus \nSuggested-by: Laurent Pinchart \nSigned-off-by: Jacopo Mondi \n---\n Documentation/driver-api/media/v4l2-subdev.rst | 9 +++++++--\n 1 file changed, 7 insertions(+), 2 deletions(-)","diff":"diff --git a/Documentation/driver-api/media/v4l2-subdev.rst b/Documentation/driver-api/media/v4l2-subdev.rst\nindex 29e07e23f888..41ccb3e5c707 100644\n--- a/Documentation/driver-api/media/v4l2-subdev.rst\n+++ b/Documentation/driver-api/media/v4l2-subdev.rst\n@@ -275,8 +275,13 @@ system the .unbind() method is called. All three callbacks are optional.\n V4L2 sub-device userspace API\n -----------------------------\n \n-Beside exposing a kernel API through the :c:type:`v4l2_subdev_ops` structure,\n-V4L2 sub-devices can also be controlled directly by userspace applications.\n+Bridge drivers traditionally expose one or multiple video nodes to userspace,\n+and control subdevices through the :c:type:`v4l2_subdev_ops` operations in\n+response to video node operations. This hides the complexity of the underlying\n+hardware from applications. For complex devices, finer-grained control of the\n+device than what the video nodes offer may be required. In those cases, bridge\n+drivers that implement :ref:`the media controller API ` may\n+opt for making the subdevice operations directly accessible from userpace.\n \n Device nodes named ``v4l-subdev``\\ *X* can be created in ``/dev`` to access\n sub-devices directly. If a sub-device supports direct userspace configuration\n","prefixes":["libcamera-devel","v4","1/5"]}