Hi Alexander,

On Tue, Nov 23, 2021 at 08:38:47AM +0100, Alexander Stein wrote:

Am Dienstag, dem 23.11.2021 um 02:15 +0200 schrieb Laurent Pinchart:

quoted

On Sun, Nov 21, 2021 at 09:07:26PM -0600, Adam Ford wrote:

quoted

On Sun, Nov 21, 2021 at 5:18 PM Laurent Pinchart wrote:

quoted

On Sat, Nov 06, 2021 at 10:54:26AM -0500, Adam Ford wrote:

quoted

The baseboard has support for a TDNext 5640 Camera which
uses an OV5640 connected to a 2-lane CSI2 interface.

With the CSI and mipi_csi2 drivers pointing to an OV5640 camera, the media
pipeline can be configured with the following:

    media-ctl --links "'ov5640 1-003c':0->'imx7-mipi-csis.0':0[1]"

The camera and various nodes in the pipeline can be configured for UYVY:
    media-ctl -v -V "'ov5640 1-003c':0 [fmt:UYVY8_1X16/640x480 field:none]"
    media-ctl -v -V "'csi':0 [fmt:UYVY8_1X16/640x480 field:none]"

Signed-off-by: Adam Ford <redacted>

As the ov5640 is on an add-on module, would a DT overlay be better ?

At least for the Beacon / LogicPD boards, I would prefer to avoid the
overlays.  We have an i.M6Q and an OMAP3 board with cameras enabled in
our development kit device trees.  If the cameras are not connected,
they just display a message that the cameras are not communicating and
move on.  I'm OK with that.

You know the board better than I do, so I won't push against this, but I
still think it may not lead to the best user experience, especially if a
user wanted to connect a different sensor to the development board.

I see the advantages of overlays compared to "stacked" .dts files. But
is there any general supported interface how to actually apply an overlay?
Documentation/devicetree/overlay-notes.rst
states of_overlay_fdt_apply() but there is only exactly one user in-
kernel (rcar-du). Is it expected that the bootloader like u-boot shall
apply the .dtbo files?

I believe the boot loader is expected to apply overlays nowadays, yes.
That's my personal workflow.

-- 
Regards,

Laurent Pinchart