From: Steve Longerbeam <slongerbeam@gmail.com>
To: linux-media@vger.kernel.org
Cc: Steve Longerbeam <steve_longerbeam@mentor.com>,
Steve Longerbeam <slongerbeam@gmail.com>,
Philipp Zabel <p.zabel@pengutronix.de>,
Mauro Carvalho Chehab <mchehab@kernel.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
devel@driverdev.osuosl.org (open list:STAGING SUBSYSTEM),
linux-kernel@vger.kernel.org (open list)
Subject: [PATCH v6 14/17] media: staging/imx: TODO: Remove one assumption about OF graph parsing
Date: Mon, 9 Jul 2018 15:39:14 -0700 [thread overview]
Message-ID: <1531175957-1973-15-git-send-email-steve_longerbeam@mentor.com> (raw)
In-Reply-To: <1531175957-1973-1-git-send-email-steve_longerbeam@mentor.com>
The move to subdev notifiers fixes one assumption of OF graph parsing.
If a subdevice has non-video related ports, the subdev driver knows not
to follow those ports when adding remote devices to its subdev notifier.
Signed-off-by: Steve Longerbeam <steve_longerbeam@mentor.com>
---
drivers/staging/media/imx/TODO | 29 +++++++----------------------
1 file changed, 7 insertions(+), 22 deletions(-)
diff --git a/drivers/staging/media/imx/TODO b/drivers/staging/media/imx/TODO
index 9eb7326..aeeb154 100644
--- a/drivers/staging/media/imx/TODO
+++ b/drivers/staging/media/imx/TODO
@@ -17,29 +17,15 @@
decided whether this feature is useful enough to make it generally
available by exporting to v4l2-core.
-- The OF graph is walked at probe time to form the list of fwnodes to
- be passed to v4l2_async_notifier_register(), starting from the IPU
- CSI ports. And after all async subdevices have been bound,
- v4l2_fwnode_parse_link() is used to form the media links between
- the entities discovered by walking the OF graph.
+- After all async subdevices have been bound, v4l2_fwnode_parse_link()
+ is used to form the media links between the devices discovered in
+ the OF graph.
While this approach allows support for arbitrary OF graphs, there
are some assumptions for this to work:
- 1. All port parent nodes reachable in the graph from the IPU CSI
- ports bind to V4L2 async subdevice drivers.
-
- If a device has mixed-use ports such as video plus audio, the
- endpoints from the audio ports are followed to devices that must
- bind to V4L2 subdevice drivers, and not for example, to an ALSA
- driver or a non-V4L2 media driver. If the device were bound to
- such a driver, imx-media would never get an async completion
- notification because the device fwnode was added to the async
- list, but the driver does not interface with the V4L2 async
- framework.
-
- 2. Every port reachable in the graph is treated as a media pad,
- owned by the V4L2 subdevice that is bound to the port's parent.
+ 1. If a port owned by a device in the graph has endpoint nodes, the
+ port is treated as a media pad.
This presents problems for devices that don't make this port = pad
assumption. Examples are SMIAPP compatible cameras which define only
@@ -54,9 +40,8 @@
possible long-term solution is to implement a subdev API that
maps a port id to a media pad index.
- 3. Every endpoint of a port reachable in the graph is treated as
- a media link, between V4L2 subdevices that are bound to the
- port parents of the local and remote endpoints.
+ 2. Every endpoint of a port owned by a device in the graph is treated
+ as a media link.
Which means a port must not contain mixed-use endpoints, they
must all refer to media links between V4L2 subdevices.
--
2.7.4
next prev parent reply other threads:[~2018-07-09 22:40 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1531175957-1973-1-git-send-email-steve_longerbeam@mentor.com>
2018-07-09 22:39 ` [PATCH v6 01/17] media: v4l2-fwnode: ignore endpoints that have no remote port parent Steve Longerbeam
2018-07-09 22:39 ` [PATCH v6 02/17] media: v4l2: async: Allow searching for asd of any type Steve Longerbeam
2018-09-24 17:06 ` Mauro Carvalho Chehab
2018-09-25 21:04 ` Steve Longerbeam
2018-09-25 22:20 ` Mauro Carvalho Chehab
2018-09-26 1:05 ` Steve Longerbeam
2018-09-26 9:33 ` Mauro Carvalho Chehab
2018-09-26 10:40 ` Sakari Ailus
2018-09-26 17:49 ` Steve Longerbeam
2018-09-28 12:16 ` Sakari Ailus
2018-09-29 17:40 ` Steve Longerbeam
2018-07-09 22:39 ` [PATCH v6 03/17] media: v4l2: async: Add v4l2_async_notifier_add_subdev Steve Longerbeam
2018-08-03 15:13 ` jacopo mondi
2018-08-04 16:39 ` Steve Longerbeam
2018-07-09 22:39 ` [PATCH v6 04/17] media: v4l2: async: Add convenience functions to allocate and add asd's Steve Longerbeam
2018-07-09 22:39 ` [PATCH v6 05/17] media: v4l2-fwnode: Switch to v4l2_async_notifier_add_subdev Steve Longerbeam
2018-07-09 22:39 ` [PATCH v6 06/17] media: v4l2-fwnode: Add a convenience function for registering subdevs with notifiers Steve Longerbeam
2018-09-13 10:37 ` jacopo mondi
2018-09-13 12:44 ` Sakari Ailus
2018-09-13 12:58 ` jacopo mondi
2018-09-14 0:57 ` Steve Longerbeam
2018-07-09 22:39 ` [PATCH v6 07/17] media: platform: video-mux: Register a subdev notifier Steve Longerbeam
2018-07-09 22:39 ` [PATCH v6 08/17] media: imx: csi: " Steve Longerbeam
2018-07-09 22:39 ` [PATCH v6 09/17] media: imx: mipi csi-2: " Steve Longerbeam
2018-07-09 22:39 ` [PATCH v6 10/17] media: staging/imx: of: Remove recursive graph walk Steve Longerbeam
2018-07-09 22:39 ` [PATCH v6 11/17] media: staging/imx: Loop through all registered subdevs for media links Steve Longerbeam
2018-07-09 22:39 ` [PATCH v6 12/17] media: staging/imx: Rename root notifier Steve Longerbeam
2018-07-09 22:39 ` [PATCH v6 13/17] media: staging/imx: Switch to v4l2_async_notifier_add_*_subdev Steve Longerbeam
2018-07-09 22:39 ` Steve Longerbeam [this message]
2018-07-09 22:39 ` [PATCH v6 16/17] media: v4l2: async: Remove notifier subdevs array Steve Longerbeam
2018-07-23 12:35 ` Sakari Ailus
2018-07-23 16:44 ` Steve Longerbeam
2018-07-23 17:24 ` Sakari Ailus
2018-08-04 10:33 ` jacopo mondi
2018-08-04 17:20 ` Steve Longerbeam
2018-07-09 22:39 ` [PATCH v6 17/17] [media] v4l2-subdev.rst: Update doc regarding subdev descriptors Steve Longerbeam
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