On 01/31/2017 03:00 AM, Russell King - ARM Linux wrote:
On Mon, Jan 30, 2017 at 05:22:01PM -0800, Steve Longerbeam wrote:
I'm also having trouble finding a datasheet for it, but from what
I've read, it has a MIPI CSI-2 interface. It should work fine as long
as it presents a single source pad, registers asynchronously, and
sets its entity function to MEDIA_ENT_F_CAM_SENSOR.
Yes, it is MIPI CSI-2, and yes it has a single source pad, registers
asynchronously, but that's about as far as it goes.
The structure is a camera sensor followed by some processing. So just
like the smiapp code, I've ended up with multiple subdevs describing
each stage of the sensors pipeline.
Just like smiapp, the camera sensor block (which is the very far end
of the pipeline) is marked with MEDIA_ENT_F_CAM_SENSOR. However, in
front of that is the binner, which just like smiapp gets a separate
entity. It's this entity which is connected to the mipi-csi2 subdev.
wow, ok got it.
So the sensor pipeline and binner, and the OF graph connecting
them, are described in the device tree I presume.
The OF graph AFAIK, has no information about which ports are sinks
and which are sources, so of_parse_subdev() tries to determine that
based on the compatible string of the device node. So ATM
of_parse_subdev() assumes there is nothing but the imx6-mipi-csi2,
video-multiplexer, and camera sensors upstream from the CSI ports
in the OF graph.
I realize that's not a robust solution, and is the reason for the
"no sensor attached" below.
Is there any way to determine from the OF graph the data-direction
of a port (whether it is a sink or a source)? If so it will make
of_parse_subdev() much more robust.
Steve
Unlike smiapp, which does not set an entity function, I set my binner
entity as MEDIA_ENT_F_PROC_VIDEO_SCALER on the basis that that is
what V4L2 documentation recommend:
- .. row 27
.. _MEDIA-ENT-F-PROC-VIDEO-SCALER:
- ``MEDIA_ENT_F_PROC_VIDEO_SCALER``
- Video scaler. An entity capable of video scaling must have
at least one sink pad and one source pad, and scale the
video frame(s) received on its sink pad(s) to a different
resolution output on its source pad(s). The range of
supported scaling ratios is entity-specific and can differ
between the horizontal and vertical directions (in particular
scaling can be supported in one direction only). Binning and
skipping are considered as scaling.
This causes attempts to configure the ipu1_csi0 interface to fail:
media-ctl -v -d /dev/media1 --set-v4l2 '"ipu1_csi0":1[fmt:SGBRG8/512x512@1/30]'
Opening media device /dev/media1
Enumerating entities
Found 29 entities
Enumerating pads and links
Setting up format SGBRG8 512x512 on pad ipu1_csi0/1
Unable to set format: No such device (-19)
Unable to setup formats: No such device (19)
and in the kernel log:
ipu1_csi0: no sensor attached
And yes, I already know that my next problem is going to be that the bayer
formats are not supported in your driver (just like Philipp's driver) but
adding them should not be difficult... but only once this issue is resolved.
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