Re: [PATCH v3 06/13] media: platform: video-mux: Register a subdev notifier

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Hi Hans,


On 04/20/2018 05:28 AM, Hans Verkuil wrote:
On 03/21/18 01:37, Steve Longerbeam wrote:
Parse neighbor remote devices on the video muxes input ports, add them to a
subdev notifier, and register the subdev notifier for the video mux, by
calling v4l2_async_register_fwnode_subdev().

Signed-off-by: Steve Longerbeam <steve_longerbeam@xxxxxxxxxx>
---
Changes since v2:
- none
Changes since v1:
- add #include <linux/slab.h> for kcalloc() declaration.
---
  drivers/media/platform/video-mux.c | 36 +++++++++++++++++++++++++++++++++++-
  1 file changed, 35 insertions(+), 1 deletion(-)

diff --git a/drivers/media/platform/video-mux.c b/drivers/media/platform/video-mux.c
index ee89ad7..b93b0af 100644
--- a/drivers/media/platform/video-mux.c
+++ b/drivers/media/platform/video-mux.c
@@ -21,8 +21,10 @@
  #include <linux/of.h>
  #include <linux/of_graph.h>
  #include <linux/platform_device.h>
+#include <linux/slab.h>
  #include <media/v4l2-async.h>
  #include <media/v4l2-device.h>
+#include <media/v4l2-fwnode.h>
  #include <media/v4l2-subdev.h>
struct video_mux {
@@ -193,6 +195,38 @@ static const struct v4l2_subdev_ops video_mux_subdev_ops = {
  	.video = &video_mux_subdev_video_ops,
  };
+static int video_mux_parse_endpoint(struct device *dev,
+				    struct v4l2_fwnode_endpoint *vep,
+				    struct v4l2_async_subdev *asd)
+{
+	/*
+	 * it's not an error if remote is missing on a video-mux
+	 * input port, return -ENOTCONN to skip this endpoint with
+	 * no error.
+	 */
+	return fwnode_device_is_available(asd->match.fwnode) ? 0 : -ENOTCONN;
+}
+
+static int video_mux_async_register(struct video_mux *vmux,
+				    unsigned int num_pads)
+{
+	unsigned int i, *ports;
+	int ret;
+
+	ports = kcalloc(num_pads - 1, sizeof(*ports), GFP_KERNEL);
+	if (!ports)
+		return -ENOMEM;
+	for (i = 0; i < num_pads - 1; i++)
+		ports[i] = i;
+
+	ret = v4l2_async_register_fwnode_subdev(
+		&vmux->subdev, sizeof(struct v4l2_async_subdev),
+		ports, num_pads - 1, video_mux_parse_endpoint);
+
+	kfree(ports);
+	return ret;
+}
+
  static int video_mux_probe(struct platform_device *pdev)
  {
  	struct device_node *np = pdev->dev.of_node;
@@ -258,7 +292,7 @@ static int video_mux_probe(struct platform_device *pdev)
vmux->subdev.entity.ops = &video_mux_ops; - return v4l2_async_register_subdev(&vmux->subdev);
+	return video_mux_async_register(vmux, num_pads);
I would prefer to change the last argument to 'num_pads - 1' and drop the ' - 1'
part in the video_mux_async_register() function. Perhaps renaming the num_pads
argument there to num_input_pads.

Yes makes sense. I will do that.

Steve



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