linux-kernel - [PATCH] staging: media: rkisp1: make links immutable by default

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Message-Id: <20200117201218.3745311-1-helen.koike@collabora.com>
Date:   Fri, 17 Jan 2020 17:12:18 -0300
From:   Helen Koike <helen.koike@...labora.com>
To:     linux-media@...r.kernel.org
Cc:     hverkuil-cisco@...all.nl, niklas.soderlund@...natech.se,
        kernel@...labora.com, laurent.pinchart@...asonboard.com,
        tfiga@...omium.org, Helen Koike <helen.koike@...labora.com>,
        Mauro Carvalho Chehab <mchehab@...nel.org>,
        devel@...verdev.osuosl.org, linux-kernel@...r.kernel.org,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Subject: [PATCH] staging: media: rkisp1: make links immutable by default

The only places which make sese to allow users to enable or disable
links are:

* between sensors and isp:
So users can select which sensor should be used while streaming

* between isp and the resizers:
              |
              v here
rkisp1_isp:2 -> rkisp1_resizer_mainpath -> rkisp1_mainpath (capture)
            \-> rkisp1_resizer_selfpath -> rkisp1_selfpath (capture)
              ^ here
              |

So users can disable one of the capture paths when unused, to avoid
worring about matching formats.

Make the following links immutable to simplify userspace:

rkisp1_resizer_mainpath -> rkisp1_mainpath
rkisp1_resizer_selfpath -> rkisp1_selfpath
rkisp1_params           -> rkisp1_isp
rkisp1_isp              -> rkisp1_stats

Signed-off-by: Helen Koike <helen.koike@...labora.com>

---
This is the topology graph after disabling all the links with
media -r
http://col.la/rkisp1immutable

Dashed links are the only one can can be enabled/disabled, the others
are immutable.

 drivers/staging/media/rkisp1/rkisp1-dev.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/staging/media/rkisp1/rkisp1-dev.c b/drivers/staging/media/rkisp1/rkisp1-dev.c
index 558126e66465..4030d5e71af1 100644
--- a/drivers/staging/media/rkisp1/rkisp1-dev.c
+++ b/drivers/staging/media/rkisp1/rkisp1-dev.c
@@ -145,14 +145,15 @@ static int rkisp1_create_links(struct rkisp1_device *rkisp1)
 		flags = 0;
 	}
 
-	flags = MEDIA_LNK_FL_ENABLED;
+	flags = MEDIA_LNK_FL_ENABLED | MEDIA_LNK_FL_IMMUTABLE;
 
 	/* create ISP->RSZ->CAP links */
 	for (i = 0; i < 2; i++) {
 		source = &rkisp1->isp.sd.entity;
 		sink = &rkisp1->resizer_devs[i].sd.entity;
 		ret = media_create_pad_link(source, RKISP1_ISP_PAD_SOURCE_VIDEO,
-					    sink, RKISP1_RSZ_PAD_SINK, flags);
+					    sink, RKISP1_RSZ_PAD_SINK,
+					    MEDIA_LNK_FL_ENABLED);
 		if (ret)
 			return ret;
 
-- 
2.24.0